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BEGIN:VEVENT
SUMMARY:OTHER | Dr. Simon Trebst
DTSTART;VALUE=DATE-TIME:20101123T140000
DTEND;VALUE=DATE-TIME:20101123T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000001@events.thp.uni-koeln.de
DESCRIPTION:Dr. Simon Trebst\, Microsoft Research\, University of Californ
ia\, Santa Barbara\n\nDisentangling complex many-body systems: From frustr
ated magnets to quantum Hall liquids\n\n
LOCATION:Hörsaal 2
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Prof. Dr. Markus Müller
DTSTART;VALUE=DATE-TIME:20101117T143000
DTEND;VALUE=DATE-TIME:20101117T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000002@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Markus Müller\, The Abdus Salam International Centr
e for Theoretical Physics\n\nQuantum Glasses\n\n
LOCATION:Seminarraum 201
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Prof. Dr. Reinhard Lipowsky
DTSTART;VALUE=DATE-TIME:20101130T164500
DTEND;VALUE=DATE-TIME:20101130T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000006@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Reinhard Lipowsky\, Department of Theory & Bio-Syste
ms\, MPI of Colloids and Interfaces\, Potsdam\n\nWhat keeps us going: Forc
e generation and transport by molecular motors\n\nAll eukaryotic cells inc
luding those of our body contain a large variety of molecular machines tha
t convert the chemical energy released from nucleotide hydrolysis into mec
hanical work. This talk focusses on molecular stepping motors such as kine
sin\, which use their two motor domains or "heads" to walk along very thin
filaments.\nOur theory for these motors starts from their enzymatic activ
ity during ATP hydrolysis and from the corresponding nucleotide states. Th
is approach provides a general classification scheme for the different mot
or cycles\, each of which can be characterized in terms of its free energy
transduction and entropy production arbitrarily far from chemical and/or
mechanical equilibrium. The properties of single motors are then used to d
escribe the cooperative behavior of many motors. The latter behavior inclu
des cargo transport by one or two (antagonistic) team of motors. Systems c
onsisting of many motors and cargo particles can undergo traffic phase tra
nsitions.
LOCATION:Hörsaal 3
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Prof. Dr. Berenike Maier
DTSTART;VALUE=DATE-TIME:20101117T084000
DTEND;VALUE=DATE-TIME:20101117T093000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000008@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Berenike Maier\, University of Münster\n\nControlli
ng bacterial motors\n\n
LOCATION:Institute of Genetics\, 4th floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Prof. Dr. Markus Kollmann
DTSTART;VALUE=DATE-TIME:20101117T110000
DTEND;VALUE=DATE-TIME:20101117T115000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000009@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Markus Kollmann\, University of Düsseldorf\n\nEvolv
ed optimality - to what extent are microbes optimized for fast growth\n\n
LOCATION:Institute of Genetics\, 4th floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Prof. Dr. Joachim Krug
DTSTART;VALUE=DATE-TIME:20101117T093000
DTEND;VALUE=DATE-TIME:20101117T100000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000010@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Joachim Krug\, University of Cologne\n\nThe role of
population size in the adaptation of microbial populations\n\n
LOCATION:Institute of Genetics\, 4th floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Dr. Bernd Rosenow
DTSTART;VALUE=DATE-TIME:20101119T164500
DTEND;VALUE=DATE-TIME:20101119T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000011@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Bernd Rosenow\, University of Leipzig\n\nSpectroscop
y of Majorana fermions in non-linear transport\n\nMuch effort has been dev
oted recently to the search for experimental demonstrations of Majorana fe
rmions and the exotic quantum statistics that can be encoded by them. In t
his talk I will mainly focus on Majorana fermions in the non-abelian quant
um Hall state at filling fraction nu=5/2. To detect them\, there have been
several proposals for transport experiments in the linear regime\, which
however are not robust with respect to disorder in realistic samples. I
will discuss signatures of Majorana states in non-linear transport through
a Coulomb blockaded antidot of nu=5/2 quantum Hall fluid surrounded by an
integer quantum Hall state. In contrast with linear Coulomb blockade (C
B)\, current-voltage characteristics in the non-linear regime of the CB ho
ld information of the many-particle excitation spectrum of the system. A p
eak in the differential conductance dI/dV will appear whenever a proper re
sonance condition between the source-drain voltage and the excitations of
the dot is met. The "diamond structure" that characterizes the CB out of t
he linear response regime could serve to identify the nature of the nu=5/2
state.\n
LOCATION:Seminar Room ITP
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Prof. Dr. Jereon van den Brink
DTSTART;VALUE=DATE-TIME:20101119T120000
DTEND;VALUE=DATE-TIME:20101119T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000012@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Jereon van den Brink\, IFW Dresden\n\nThe light that
resonant inelastic X-ray scattering sheds on high Tc cuprates\n\n
LOCATION:Seminar Room ITP
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Prof. Dr. Igor Herbut
DTSTART;VALUE=DATE-TIME:20101126T120000
DTEND;VALUE=DATE-TIME:20101126T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000016@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Igor Herbut\, Simon Fraser University\, Canada\n\nZe
ro-modes and the structure of Dirac's vortex core in graphene\n\nThe vorte
x in any O(2) order parameter on graphene's honeycomb lattice is known to
produce zero-energy states. I will discus how these rather special states
in the middle of the spectrum induce local order in the core of the vortex
. The local order parameters in general close the algebra Cl(3)x U(1)\, wh
ere Cl(3) is the three dimensional Clifford algebra\, with the members of
this algebra depending on the type of order supporting the vortex. The sup
erconducting order will be discussed in some detail\, and the curious dual
ity between the topological insulation and the superconductivity in graphe
ne will be pointed out.
LOCATION:Seminar Room ITP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Dr. D. Vollhardt
DTSTART;VALUE=DATE-TIME:20110520T163000
DTEND;VALUE=DATE-TIME:20110520T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000017@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. D. Vollhardt\, University of Augsburg\n\nConstructio
n of exact ground states for correlated electron models\n\nA general schem
e for the construction of exact ground states of correlated electron model
s will\nbe discussed. It consists of three steps: The transformation of th
e Hamiltonian into positive semidefinite\nform\, the construction of many-
particle ground states of this Hamiltonian\, and the proof of the\nuniquen
ess of these ground states. This approach works in any dimension\, assumes
no integrability of\nthe model and only requires sufficiently many micros
copic parameters in the Hamiltonian. Thereby\nground states of diamond Hub
bard chains are constructed which exhibit a multitude of properties such\n
as flat-band ferromagnetism and correlation induced metallic\, half-metall
ic or insulating behavior.\nFurthermore\, the exact ground state of a 1D p
eriodic Anderson model is shown to explain the unusual\nferromagnetism in
the f electron material CeRh3B2. Finally\, it is proved that pentagon chai
n polymers\nmay be designed to become ferromagnetic or half metallic.
LOCATION:Seminar Room ITP
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Speakers from Cologne and Saarbrücken
DTSTART;VALUE=DATE-TIME:20101202T150000
DTEND;VALUE=DATE-TIME:20101202T191500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000018@events.thp.uni-koeln.de
DESCRIPTION:Speakers from Cologne and Saarbrücken\, \n\nWorkshop on Vira
l Evolution\n\nA two-day workshop bringing together theoretical and bioinf
ormatic approaches to problems of viral evolution. \nSpeakers include Thom
as Lengauer\, Alejandro Pironti\, Bastian Beggel\, Stephan Schiffels\, Kas
ia Bozek\, Glenn Lawyer\, Michael Lässig\, Alexander Thielen\, Ville Must
onen\, Sven-Eric Schelhorn and Jasmina Bogojeska
LOCATION:Institut für Genetik\, Lecture Hall 4th floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Priv.-Doz. Dr. Roland Diehl
DTSTART;VALUE=DATE-TIME:20101214T164500
DTEND;VALUE=DATE-TIME:20101214T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000019@events.thp.uni-koeln.de
DESCRIPTION:Priv.-Doz. Dr. Roland Diehl\, Max Planck Institut für extrate
rrestrische Physik\, Garching\n\nKosmische Radioaktivität und Astronomie
mit Gammastrahlen-Teleskopen\n\nKernfusions-Reaktionen in Sternen und in S
upernova-Explosionen bringen die Vielfalt der chemischen Elemente hervor\,
die wir im Universum vorfinden. In diesen Prozessen entstehen auch Beimis
chungen instabiler Atomkerne. Deren radioaktiver Zerfall im interstellaren
Raum geht meist einher mit Aussendung charakteristischer Linienstrahlung
bei Gammastrahlen-Energien. Astronomische Teleskope im Weltraum können so
einen Blick auf kosmische Nukleosynthese erhalten. Die ESA-Mission INTEGR
AL liefert seit 2002 Beobachtungsdaten von verschiedenen Regionen in unser
er Milchstrasse. Insbesondere langlebige Isotope wie 44Ti\, 26Al und 60Fe
wurden gemessen\, aber auch Annihilations- strahlung von interstellaren Po
sitronen. Die Technik der Gammastrahlenteleskope wird im Vortrag vorgestel
lt\, bevor die astrophysikalischen Prozesse\, die bisherigen Erkenntnisse
und offene Fragen diskutiert werden. Hierbei werden insbesondere Kernfusio
nsprozesse in kosmischer Umgebung\, Supernova-Explosionen und das interste
llare Medium behandelt.
LOCATION:Hörsaal 3
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Dr. B. Trauzettel
DTSTART;VALUE=DATE-TIME:20101126T163000
DTEND;VALUE=DATE-TIME:20101126T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000015@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. B. Trauzettel\, Universität Würzburg\n\nDirac Ferm
ions in Graphene and Topological Insulators\n\nThe carbon atoms in graphen
e (Nobel Prize in Physics 2010) form a honeycomb lattice which gives rise
to many of the peculiar physical properties of this fascinating material.
Dictated by the interaction with the ions of the lattice\, the low energy
electrons in graphene have the same dispersion relation as mass-less Dirac
fermions. We will discuss interesting physical phenomena of Dirac fermion
s in graphene such as Klein tunneling\, transport through evanescent modes
\, and consequences of the spectrum on quantum computing devices based on
graphene quantum dots.\nFurthermore\, we will address another in some sens
e even richer condensed matter system that shows Dirac fermion physics: To
pological insulators (TIs) behave like usual insulators in the bulk but li
ke metals at the boundaries. This gives rise to Dirac fermions at the edge
of a TI. In nature\, TIs have been first realized in HgTe/CdTe quantum we
lls (in 2D) and later on also in 3D in BiSb\, BiSe\, as well as BiTe cryst
als. We will discuss interesting physical properties of 2D TIs where spin
and charge properties of the system are ultimately locked to each other.
LOCATION:Seminar Room ITP
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Prof. Dr. Alexander Balatsky
DTSTART;VALUE=DATE-TIME:20101201T143000
DTEND;VALUE=DATE-TIME:20101201T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000020@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Alexander Balatsky\, Los Alamos National Laboratory\
n\nHidden order and other surprises in f-electron lattices\n\nHeavy fermio
ns exhibit strong correlations and variety of ordered states stemming from
strong hybridization and Kondo screening. Nature of some of these ordered
states like Hidden Order in URu2Si2 is not settled. Recent advances in lo
cal scanning spectroscopies shed a new light on these correlated states an
d reveal significant suprises in the electronics of Kondo lattices. I focu
s on the hybridization wave as the order parameter in URu2Si2 and possibly
other materials with similar band structures. I will introduce a simple p
henomenological model for the 'hidden order' transition in the heavy Fermi
on material URu2Si2. The 'hidden order' is identified as an incommensurate
\, momentum-carrying hybridization between the light hole band and the hea
vy electron band. The model is qualitatively consistent with numerous expe
rimental results obtained from e.g. neutron scattering and scanning tunnel
ing microscopy. I also will present predictions which are amenable to curr
ent experiments.
LOCATION:Seminar Room ITP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Dr. Karyn Le Hur
DTSTART;VALUE=DATE-TIME:20101210T164500
DTEND;VALUE=DATE-TIME:20101210T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000021@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Karyn Le Hur\, Yale University\n\nLow-Dimensional Qu
antum Systems\n\nSystems of low dimensions have provided special opportuni
ties\, challenges\, and fascination for condensed matter physicists. Issue
s of long-range order\, dimensional crossover\, and instabilities are all
significant in such systems. In this Talk\, I provide a pedagogical overvi
ew of my theoretical research in relation to low-dimensional electron syst
ems ranging from nano “zero-dimensional” systems to (quasi) twodimensi
onal systems such as high-Tc superconductors\, graphene\, topological insu
lators and novel oxide heterostructures. We shall also spend some time on
onedimensional systems which are described by the Tomonaga-Luttinger parad
igm. Finally\, I show that condensed matter concepts can also be applied t
o cold atoms in optical lattices and photon systems.
LOCATION:Seminar Room ITP
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Vera Spillner
DTSTART;VALUE=DATE-TIME:20101207T120000
DTEND;VALUE=DATE-TIME:20101207T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000024@events.thp.uni-koeln.de
DESCRIPTION:Vera Spillner\, Uni Bonn/ Uni Heidelberg\n\nDo we understand q
uantum mechanics?\n\n
LOCATION:Seminarraum Theorie
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Michael Köhn
DTSTART;VALUE=DATE-TIME:20101214T120000
DTEND;VALUE=DATE-TIME:20101214T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000025@events.thp.uni-koeln.de
DESCRIPTION:Michael Köhn\, Albert-Einstein-Institut\, Potsdam\n\nArithmet
ic Quantum Gravity\n\n
LOCATION:Seminarraum Theorie
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Laleh Haghverdi
DTSTART;VALUE=DATE-TIME:20101203T133000
DTEND;VALUE=DATE-TIME:20101203T143000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000023@events.thp.uni-koeln.de
DESCRIPTION:Laleh Haghverdi\, University of Cologne\n\nAdaptation in Asexu
al Populations\n\n
LOCATION:Institute of Genetics\, 4th floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Dr. Larissa Lorenz
DTSTART;VALUE=DATE-TIME:20110111T120000
DTEND;VALUE=DATE-TIME:20110111T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000026@events.thp.uni-koeln.de
DESCRIPTION:Dr. Larissa Lorenz\, Université de Louvain-la-Neuve\n\nCosmic
string loop distribution with a gravitational wave cutoff\n\n
LOCATION:Seminarraum Theorie
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Tobias Sikosek
DTSTART;VALUE=DATE-TIME:20110112T160000
DTEND;VALUE=DATE-TIME:20110112T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000027@events.thp.uni-koeln.de
DESCRIPTION:Tobias Sikosek\, University of Münster\n\nThe resolution of a
daptive conflicts by functional promiscuity and gene duplication\n\nOngoin
g theoretical and experimental developments in the area of protein evoluti
on emphasise the importance of functionally promiscuous\, or multi-functio
nal\, ancestors and the possibility of proteins that can assume more than
one stable structural state. A recently popularised model of protein evolu
tion is the `Escape from an Adaptive Conflict' (EAC)\, a type of subfuncti
onalisation. This conflict of a single gene to adapt to more than one sele
ction pressure can lead to a certain degree of multi-functionality prior t
o a gene duplication event. After duplication\, the resulting paralogs are
thought to specialise on different sub-functions of their ancestor. Here\
, using a simple biophysical protein model and taking structural stability
as an indicator for biological activity\, we demonstrate under which cond
itions adaptive conflicts on a dual fitness landscape can be resolved by m
ultifunctionality\, gene duplication and subfunctionalisation.
LOCATION:Institute of Genetics\, 4th floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Moritz Ernst
DTSTART;VALUE=DATE-TIME:20101214T150000
DTEND;VALUE=DATE-TIME:20101214T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000028@events.thp.uni-koeln.de
DESCRIPTION:Moritz Ernst\, University of Cologne\n\nOptimization of Quantu
m Information Theoretical Quantities over Tensor Product Spaces\n\n
LOCATION:Hörsaal 2
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Sahand Razzaghi
DTSTART;VALUE=DATE-TIME:20110107T140000
DTEND;VALUE=DATE-TIME:20110107T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000029@events.thp.uni-koeln.de
DESCRIPTION:Sahand Razzaghi\, Institut für Materialphysik im Weltraum\, D
LR\n\nLogarithmic Decays at Glass-Glass Transitions\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Prof. Dr. Roderich Moessner
DTSTART;VALUE=DATE-TIME:20110111T164500
DTEND;VALUE=DATE-TIME:20110111T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000030@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Roderich Moessner\, Max-Planck-Institut für komplex
er Systeme\, Dresden\n\nMagnetic Monopoles in Spin Ice\n\nFractionalisatio
n is a counterintuitive phenomenon\, in which an 'elementary' particle app
ears to break into two independent entities. A celebrated example of this
is spin-charge separation\, in which an electron's magnetic (spin) and ele
ctric (charge) degrees of freedom appear to become independent. Spin ice m
aterials such as Dy2Ti2O7 and Ho2Ti2O7 provide a rare instance of fraction
alisation in three dimensions: their elementary excitations carry a fracti
on of the magnetic moment of the microscopic spin degrees of freedom\, and
they can be thought of as magnetic monopoles. The peculiar nature of thes
e excitations leads to unique signatures in the equilibrium and response p
roperties of spin ice materials. These include unusual neutron scattering
structure factors\, dynamical arrest and long lived non-equilibrium metast
able states\, as well as a response to external magnetic fields that promo
tes spin ice as a magnetic analogue of an electrolyte. This talk reviews s
everal of these striking phenomena\, and discusses open questions and futu
re perspectives.
LOCATION:Hörsaal 3
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Dr. Alexander Kamenshchik
DTSTART;VALUE=DATE-TIME:20110113T120000
DTEND;VALUE=DATE-TIME:20110113T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000031@events.thp.uni-koeln.de
DESCRIPTION:Dr. Alexander Kamenshchik\, Uni Bologna / Landau Institute\, M
oscow\n\nTolman-Oppenheimer-Volkoff equations in presence of the Chaplygin
gas: stars and wormhole-like solutions\n\n
LOCATION:Konferenzraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Salvatore Manmana
DTSTART;VALUE=DATE-TIME:20110107T120000
DTEND;VALUE=DATE-TIME:20110107T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000032@events.thp.uni-koeln.de
DESCRIPTION:Salvatore Manmana\, University of Colorado at Boulder\n\nPhase
diagram and continuous pair-unbinding transition of the bilinear-biquadra
tic S=1 Heisenberg chain in a magnetic field\n\nWe investigate the propert
ies of the Heisenberg S=1 chain with bilinear and biquadratic interactions
in a magnetic field using the Density Matrix Renormalization Group\, Beth
e ansatz and field theoretical considerations. In a large region of the pa
rameter space\, we identify a magnetized ferroquadrupolar Luttinger liquid
consisting of a quasi-condensate of bound magnon pairs. This liquid under
goes a continuous pair unbinding transition to a more conventional Lutting
er liquid region obtained by polarizing the system above the Haldane gap r
egion. This pair unbinding transition is shown to be in the Ising universa
lity class on top of a Luttinger liquid\, leading to an effective central
charge 3/2. We also revisit the nature of the partially polarized Luttinge
r liquid around and above the Uimin-Lai-Sutherland point. Our results conf
irm that this is a two-component liquid and rule out the formation of a si
ngle-component vector chiral phase.
LOCATION:Seminarraum Theorie
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | François Crépin
DTSTART;VALUE=DATE-TIME:20110121T120000
DTEND;VALUE=DATE-TIME:20110121T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000033@events.thp.uni-koeln.de
DESCRIPTION:François Crépin\, Laboratoire de Physique des Solides\, Univ
ersité Paris Sud\n\nBose-Fermi mixtures in a 1D disordered potential\n\nO
ne-dimensional systems allow for a detailed study of the competing eects
of disor-\nder and interactions on the localization of a Fermi or Bose gas
.[1] While non-interacting\nfermions are always localized in a random pote
ntial\, a transition to a superconducting\nphase occurs for strong enough
attractive interactions. Similarly\, strong repulsive in-\nteractions will
trigger the localization of a Bose gas.[1\,2] During this talk\, I will p
resent\nthe study of an interacting mixture of bosons and spinless fermion
s in a random po-\ntential. Super\nuid correlations are enhanced by inters
pecies interactions\, while the\ndisordered potential tries to pin each co
mponent of the gas. Using renormalization\ngroup methods\, supplemented by
a variational calculation\, we have found several lo-\ncalized or super\n
uid phases\, including a new insulating phase\, similar to the Bose glass\
,\nin which both species are coupled and localized.[3] We also computed th
e dynamical\nstructure factor for typical parameters of various ultra-cold
atoms experiments. Each\nphase exhibits its own signature\, that could be
probed in Bragg scattering experiments.\n\n[1] T. Giamarchi and H. J. Sch
ulz\, Phys. Rev. B 37\, 325 (1988)\n[2] M. P. A. Fisher et al.\, Phys. Rev
. B 40\, 546 (1989)\n[3] F. Crépin\, G. Zaránd\, P. Simon\, Phys. Rev. L
ett. 105\, 115301 (2010)
LOCATION:Seminar room of the Institute of Theoretical Physics
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Matthias Sperl
DTSTART;VALUE=DATE-TIME:20110204T163000
DTEND;VALUE=DATE-TIME:20110204T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000034@events.thp.uni-koeln.de
DESCRIPTION:Dr. Matthias Sperl\, Institut für Materialphysik im Weltraum\
, DLR Köln\n\nGlass-Transition Singularities\n\nAt the glass transition\,
no thermodynamic anomalies or diverging length scales in static propertie
s have been\nseen so far experimentally. On the other hand\, dynamical cor
relation functions diverge at the transition and\nshow rich features over
many orders of magnitude in time. One approach to explain glassy dynamics
is the\nframework of mode-coupling theory: The equations of motion for den
sity correlation functions in a fluid are\napproximated self-consistently
and in the long-time limit yield glass- transition singularities. Such\nsi
ngularities are known from caustics in optics (e.g. seen in rainbows and c
offee mugs)\, and in fluids they\nexplain many features in glassy dynamics
.\n\nIn addition to liquid-glass transitions\, the theory predicts glass-g
lass transitions. These glass-glass\ntransitions are a consequence of the
mathematical structure of the theory\, and their experimental confirmation
\ntherefore lends credibility to the theory. The mathematical features and
dynamical predictions of the theory\nshall be demonstrated with data from
colloidal suspensions\, liquid water\, and static granular matter.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Claudia Stephan
DTSTART;VALUE=DATE-TIME:20110118T120000
DTEND;VALUE=DATE-TIME:20110118T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000035@events.thp.uni-koeln.de
DESCRIPTION:Claudia Stephan\, Universität Bonn\n\nPhenomenological Aspect
s of F-Theory GUTs\n\nF-theory can be thought of the correct way to descri
be Type IIB theory with 7-branes in generic situations where the string co
upling cannot be assumed to be small. It geometrizes the variation of the
string coupling and the backreaction of the 7-branes on the ambient space
by introducing two additional auxiliary dimensions. Thus\, it is formulate
d using twelve dimensions. For string phenomenology it is very interesting
because one the one hand exceptional gauge groups are available\, which a
re highly relevant in the context of unification and are heavily exploited
in heterotic string theory\, and on the other hand the particle physics d
egrees of freedom localize on submanifolds of the compactification\, as is
the case in Type II theories with intersecting D-branes. Given this local
ization\, a considerable number of phenomenological questions can be answe
red in a so-called local model where large parts of the compactification s
pace are decoupled and particle physics essentially takes place in eight s
pace-time dimensions. I will briefly introduce the mathematical descriptio
n of the theory and then focus on local model building with explicit examp
les in the framework of SU(5) GUTs.
LOCATION:Konferenzraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Various
DTSTART;VALUE=DATE-TIME:20110126T150000
DTEND;VALUE=DATE-TIME:20110126T190000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000036@events.thp.uni-koeln.de
DESCRIPTION:Various\, Various\n\nSFB 680 Seminar day: Evolution and epigen
etics\n\nA two day workshop exploring both theoretical and experimental as
pects of the interface between evolution and epigenetics. \n\nSpeakers inc
lude Juliette de Meaux (Münster)\, Thomas Wiehe (Cologne)\, Filippos Klir
onomos (Cologne)\, Matteo Pellegrini (UCLA)\, Oliver Bossdorf (Bern)\, Fra
nziska Turk (Cologne)\, Christoph Grunau (Perpignan)\, Jan-Willem Veening
(Groningen) and Ales Pecinka (Cologne).
LOCATION:Institute of Genetics\, 4th floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Manuel Krämer
DTSTART;VALUE=DATE-TIME:20110125T120000
DTEND;VALUE=DATE-TIME:20110125T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000037@events.thp.uni-koeln.de
DESCRIPTION:Manuel Krämer\, Universität zu Köln\n\nQuantum gravitationa
l contributions to the CMB anisotropy spectrum\n\nIn this talk we present
a method to derive the primordial power spectrum of density fluctuations i
n the framework of quantum cosmology. For this purpose\, we perform a Born
-Oppenheimer approximation to the Wheeler-DeWitt equation for an inflation
ary universe with a scalar field. In this way we first recover the scale-i
nvariant power spectrum that is found as an approximation in the simplest
inflationary models. We then obtain quantum gravitational corrections to t
his spectrum and discuss whether they lead to measurable signatures in the
CMB anisotropy spectrum.
LOCATION:Seminarraum Theorie
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Andrej Fischer
DTSTART;VALUE=DATE-TIME:20110202T160000
DTEND;VALUE=DATE-TIME:20110202T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000038@events.thp.uni-koeln.de
DESCRIPTION:Andrej Fischer\, Institut für Theoretische Physik\, Universit
ät Köln\n\nGermline fitness based scoring of cancer mutations \n\nThe ef
fects of mutations in cancer can be analyzed with respect to the evolution
ary conservation of the genomic target. I will briefly discuss\, how to us
e Kimura's one locus model to infer fitness effects of mutations in a cont
rolled manner and how to asses the significance of such scoring schemes wh
en it comes to understand cancer evolution.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Markus Garst
DTSTART;VALUE=DATE-TIME:20110201T164500
DTEND;VALUE=DATE-TIME:20110201T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000039@events.thp.uni-koeln.de
DESCRIPTION:Markus Garst\, Institut für Theoretische Physik\, Universitä
t Köln\n\nSpin currents pushing magnetic whirls\n\nHelical magnets suppor
t topologically stable excitations characterized by a full twist of the ma
gnetization on a length scale determined by spin-orbit coupling. Such magn
etic whirls are known as Skyrmions\, originally conceived by Tony Skyrme i
n a different context to model baryons. In the presence of a magnetic fiel
d\, magnetic Skyrmions can even condense in the magnetic ground state form
ing a magnetic lattice similar as the vortex lattice in type II supercondu
ctors.\nSuch a Skyrmion lattice has been recently identified by neutron sc
attering in MnSi. I give an overview of the helical magnet MnSi and report
on recent spin-transfer torque experiments. The magnetization within the
Skyrmion lattice phase can be manipulated upon applying an ultralow electr
ic current\, five orders of magnitudes smaller than those typically applie
d in experimental studies on current-driven magnetization dynamics on nano
structures. I explain the efficient spin-transfer torques arising from the
coupling of spin currents to the magnetic whirls and discuss future persp
ectives.
LOCATION:Hörsaal 3
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Philipp Altrock
DTSTART;VALUE=DATE-TIME:20110222T110000
DTEND;VALUE=DATE-TIME:20110222T114000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000043@events.thp.uni-koeln.de
DESCRIPTION:Philipp Altrock \, MPI for Evolutionary Biology\, Plön\n\nFix
ation times in evolutionary game dynamics - the role of selection intensit
y\n\nIn populations with a finite number of individuals\, demographic fluc
tuations play an important role. The dynamics of such finite populations a
re analyzed in the framework of stochastic evolutionary game theory. In ev
olutionary biology\, the probability that a mutant strategy spreads in the
population and takes over is an important quantity that is well understoo
d. Here\, focus is on the mean exit time such a fixation event is expected
to take (fixation time). Starting from a master equation for the distribu
tion of fixation times of\, e.g.\, a birth-death process\, one derives and
generally solves recursions for the moments. A concept that allows a deep
er insight here is weak selection. This corresponds to a perturbation theo
ry with neutral evolution as a reference\, where all strategies perform eq
ually well. Weak selection considers only small deviations from neutral ev
olution and is a highly relevant case in biology - most (point) mutations
only provide a small change in the overall reproductive success. Various n
ew aspects of the mean exit times in evolutionary games under weak selecti
on can be addressed: How do the exit times depend on the parameters of the
evolutionary game? How universal is the folklore of weak selection result
s when comparing the two most important classes of birth-death processes?
How can the counter-intuitive effect be understood that a beneficial mutat
ion can take over slower than a neutral mutation?
LOCATION:Institute for Genetics\, Zülpicher Str. 47a\, Seminar Room\, 4th
floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Chaitanya Gokhale
DTSTART;VALUE=DATE-TIME:20110222T114500
DTEND;VALUE=DATE-TIME:20110222T123000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000044@events.thp.uni-koeln.de
DESCRIPTION:Chaitanya Gokhale\, MPI for Evolutionary Biology\, Plön\n\nSt
atic and Dynamic Fitness Landscapes: Studies from population and evolution
ary game dynamics\n\nEvolutionary dynamics can proceed on two types of fit
ness landscapes\, static or dynamic. Population movement on a static fitne
ss landscape has been studied in great detail but usually the dimensions o
f the landscape are kept to a minimum. I address the time required for pop
ulations to move in a d dimensional fitness landscape from one fitness pea
k to another. If there are multiple paths via a fitness valley or a single
ridge which is neutral then which is a faster route and when? As populati
ons move over the fitness landscape they may change the landscape itself.
To analyse such dynamic fitness landscapes I employ evolutionary game theo
ry. Traditionally evolutionary game dynamics of two players with two strat
egies is studied. These games have been used to model many biologically re
levant scenarios\, from social dilemmas in mammals to microbial diversity.
Some of these games take place between a number of individuals and not ju
st two. We generalise the important results from two player\, two strategy
games to multiplayer games. Our results hold for any game and can easily
be applied for specific cases\, e.g. public goods games or multiplayer sta
g hunts.
LOCATION: Institute for Genetics\, Zülpicher Str. 47a\, Seminar Room\, 4t
h floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Aurelin Decelle
DTSTART;VALUE=DATE-TIME:20110209T160000
DTEND;VALUE=DATE-TIME:20110209T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000042@events.thp.uni-koeln.de
DESCRIPTION:Aurelin Decelle\, LPTMS\, Universite Paris-Sud\n\nInference an
d learning in Community Structure\n\nDetecting community structure from ne
twork topology is a well known problem with many possible applications. A
large number of studies was conducted over the last decade\, but a princip
al approach that would for instance output that a random graph does not ha
ve any community structure is still missing. Based on a random graph model
for a community structure I will first show the existence of a phase tran
sition between possible and impossible community inference. This phase tra
nsition is related to some known results from statistical physics of spin
glasses\, for optimal inference the partition function of a corresponding
spin glass model needs to be computed. Then I will turn to real-world netw
orks and inspired by the theoretical results I Introduce a new message pas
sing algorithm which is able to learn parameters of the community structur
e (number of communities\, ...)\, and to infer the most likely community a
ssignment. As an application I will present some results on real-world net
.
LOCATION:Institute of Theoretical Physics\, Zülpicher Str. 77\, Seminar R
oom
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Su-Chan Park
DTSTART;VALUE=DATE-TIME:20110222T140000
DTEND;VALUE=DATE-TIME:20110222T144500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000045@events.thp.uni-koeln.de
DESCRIPTION:Su-Chan Park \, Catholic University of Korea\n\nClonal interfe
rence\, multiple mutations\, and recombination: a two-locus infinite sites
model\n\nIn asexual populations\, both clonal interference\, competition
for fixation among concurrent beneficial mutations\, and genetic drift\, w
aste of beneficial mutations purely by random events\, limit the speed of
adaptation. In sexual population\, on the other hand\, loss of beneficial
mutations due to clonal interference can be alleviated by genetic recombin
ation. By considering the simplest two-locus model with an infinite number
of sites each\, we study quantitatively how much the speed of adaptation
can be enhanced by genetic recombination. We first consider the infinite p
opulation size limit which renders the population dynamics deterministic a
nd tractable analytically to a certain extent. Having a hint from the dete
rministic dynamics\, we investigate the finite population dynamics using n
umerical simulations.
LOCATION:Institute for Genetics\, Zülpicher Str. 47a\, Seminar Room\, 4th
floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | I. Paul
DTSTART;VALUE=DATE-TIME:20110204T121500
DTEND;VALUE=DATE-TIME:20110204T131500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000046@events.thp.uni-koeln.de
DESCRIPTION:I. Paul\, Institut Neel\, Grenoble\n\nSpin-lattice coupling ef
fects in the iron based superconductors\n\nThe newly discovered iron base
d superconductors with unusually high transition temperatures\nexhibit a r
ich phase diagram that includes structural\, magnetic and superconducting
transitions.\nAs such\, these materials are the latest playgrounds to stud
y how in complex materials different\nphases compete\, and how this uncon
ventional setting eventually gives rise to superconductivity.\nThe first
part of the talk will be a review of this topic. From a theoretical point
of view one\nof the goals at present is to identify the microscopic intera
ctions that give rise to the rich phase\ndiagram. This is the motivation t
o present in the second part of the talk a study of the effects of\nmagne
to-elastic couplings between the magnetic and the lattice degrees of freed
om. We will argue\nthat several unusual magneto-structural features of the
se materials can be understood from this\npoint of view.
LOCATION:seminar room ITP
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Alejandro Lobos
DTSTART;VALUE=DATE-TIME:20110211T121500
DTEND;VALUE=DATE-TIME:20110211T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000047@events.thp.uni-koeln.de
DESCRIPTION:Alejandro Lobos\, University of Geneva\n\nDissipative effects
in ultrathin superconducting wires coupled to a diffusive metals\n\nUltr
athin superconducting wires (UTSCW) fabricated recently by the means of no
vel experimental techniques have been the subject of intense experimental
and theoretical research. When the diameter is smaller than the coherence
length of the bulk superconductor\, these systems are effectively one-dim
ensional (1D)\, since the order parameter can only vary along the parallel
direction. Interestingly\, the theory predicts the vanishing of long-rang
e order (LRO) due to strong quantum critical \nfluctuations\, a fact that
allows the use of UTSCW to address fundamental questions in Quantum Critic
al Phenomena. In this work\, we focus on UTSCW under the effect of enviro
nment-induced dissipation. Presumably\, this is a realistic situation in m
any experimental setups. Remarkably\, we show that a weak coupling to a di
ffusive metallic film can reinforce superconductivity in the wire throug
h the quench of order-parameter fl\nuctuations. We obtain the critical poi
nts and phases of the system at T=0\, and in particular\, we predict a qua
ntum phase transition towards a superconducting phase with LRO as a functi
on of the wire's superconducting stiffness and coupling parameter to the
metal. We also discuss implications for experiments.
LOCATION:Seminar Room THP
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Karen Rodríguez
DTSTART;VALUE=DATE-TIME:20110221T140000
DTEND;VALUE=DATE-TIME:20110221T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000048@events.thp.uni-koeln.de
DESCRIPTION:Karen Rodríguez\, Institut für Theoretische Physik\, Leibniz
Universität Hannover\n\nQuantum magnetism in 1D optical lattices\n\n
LOCATION:Bibliothek Kernphysik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Arne Traulsen
DTSTART;VALUE=DATE-TIME:20110415T163000
DTEND;VALUE=DATE-TIME:20110415T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000049@events.thp.uni-koeln.de
DESCRIPTION:Dr. Arne Traulsen\, MPI for Evolutionary Biology\, Plön\n\nEv
olutionary game theory: How noise can affect the evolution of cooperation
and punishment\n\nTraditionally\, evolutionary game dynamics is described
in terms of\ndeterministic differential equations. In the past years\, evo
lutionary game\ndynamics has benefitted from considering finite population
s\, which adds a\nnatural source of noise. The intensity of selection\, wh
ich corresponds to an\ninverse temperature\, determines the interplay betw
een selection and noise.\nWeak selection allows numerous new results in st
ochastic evolutionary game\ndynamics\, but sometimes also strong selection
allows analytical results.\nTheoretical aspects of this development will
be discussed and examples from\nthe evolution of cooperation and punishmen
t will be given\, where noise can\nbecome crucial for the dynamics.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Prof. Victor Gurarie
DTSTART;VALUE=DATE-TIME:20110303T091500
DTEND;VALUE=DATE-TIME:20110303T101500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000050@events.thp.uni-koeln.de
DESCRIPTION:Prof. Victor Gurarie\, University of Colorado at Boulder\n\nSi
ngle-particle Green's functions and topological insulators\n\n
LOCATION:Seminar room of the Theory Institute
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Prof. Victor Gurarie
DTSTART;VALUE=DATE-TIME:20110303T091500
DTEND;VALUE=DATE-TIME:20110303T101500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000051@events.thp.uni-koeln.de
DESCRIPTION:Prof. Victor Gurarie\, University of Colorado at Boulder\n\nSi
ngle-particle Green's functions and topological insulators\n\n
LOCATION:Seminar room of the Theory Institute
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Prof. Dr. Naoto Nagaosa
DTSTART;VALUE=DATE-TIME:20110311T110000
DTEND;VALUE=DATE-TIME:20110311T120000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000052@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Naoto Nagaosa\, Department of Applied Physics\, Univ
ersity of Tokyo\n\nDynamics of Skyrmion Crystals in Metallic Thin Films\n\
nWe study the collective dynamics of the Skyrmion crystal (SkX) in thin fi
lms of ferromagnetic metals resulting from the nontrivial Skyrmion topolog
y. We show that the current-driven motion of the crystal reduces the topol
ogical Hall effect and the Skyrmion trajectories bend away from the direct
ion of the electric current (the Skyrmion Hall effect). We find a new diss
ipation mechanism in non-collinear spin textures that can lead to a much f
aster spin relaxation than Gilbert damping\, calculate the dispersion of p
honons in the SkX\, and discuss effects of impurity pinning of Skyrmions.\
n\nThis work has been done in collaboration with Jiadong Zang\, Maxim Most
ovoy\, and Jung Hoon Han.
LOCATION:Seminarraum II. Physikalisches Institut
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Nick Manton
DTSTART;VALUE=DATE-TIME:20110408T163000
DTEND;VALUE=DATE-TIME:20110408T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000053@events.thp.uni-koeln.de
DESCRIPTION:Prof. Nick Manton\, DAMTP\, University of Cambridge\n\nVortice
s and their geometry\n\nThe equations of the Ginzburg-Landau theory of sup
erconductivity retain\ntheir mathematical fascination. The talk will discu
ss various results\nconcerning the vortex solutions in two dimensions at t
he critical point\nbetween the Type I and Type II regime. Here vortices ne
ither attract\nnor repel\, so there are many static vortex and multi-vorte
x solutions.\nThese also exist in curved background geometries. In a model
where the\nvortices can move ballistically\, one can study the effective
mass of one\nvortex\, what happens in vortex collisions\, and the properti
es of an\ninteracting gas of many vortices. There are some precise but sur
prising\nmathematical results here. Whether they have physical relevance i
s (at\nleast for the speaker) an open issue.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Dr Tim Newman
DTSTART;VALUE=DATE-TIME:20110624T163000
DTEND;VALUE=DATE-TIME:20110624T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000054@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr Tim Newman\, University of Dundee\n\nEmbryogenesis an
d cancer progression: discrete theoretical methods applied to living syste
ms\n\nThe discreteness of biological components\, whether they be proteins
in a cell or individuals in an ecological population\, has important\ncon
sequences for the dynamics of biological systems. This concept is quite na
tural for statistical physicists\, but not widely recognised\nin the life
sciences. I will discuss some examples relevant to cell biology\, cancer p
rogression\, and embryo development\, in which\nstochastic process theory
along with agent-based computer simulations have helped provide new insigh
ts and understanding.\n
LOCATION:Seminar Room ITP
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Prof. Dr. Claus Kiefer
DTSTART;VALUE=DATE-TIME:20110527T121500
DTEND;VALUE=DATE-TIME:20110527T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000075@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Claus Kiefer\, Institut für Theoretische Physik\, U
niversität zu Köln\n\nQuantum Gravity\, Cosmology\, and Black Holes\n\nT
his talk is one of a series of presentations of research groups organized\
nby the Bonn-Cologne Graduate School of Physics and Astronomy. The\naim is
to provide insights into the research done at physics institutes in \nBon
n and Cologne.\nInterested students (Bachelor\, Master\, and PhD) are most
welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Andrew Mitchell
DTSTART;VALUE=DATE-TIME:20110506T163000
DTEND;VALUE=DATE-TIME:20110506T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000056@events.thp.uni-koeln.de
DESCRIPTION:Dr. Andrew Mitchell\, Institut für Theoretische Physik\, Univ
ersität zu Köln\n\nReal-Space Renormalization Group Flow in Kondo System
s\n\nThe Kondo effect is a classic paradigm in condensed matter theory\, w
hich describes the dynamic screening of a quantum impurity embedded in a m
etallic host. The underlying renormalization group (RG) description of suc
h problems is by now very well understood. But comparatively little is kno
wn in real-space: while a length-scale associated with the screening proce
ss has been proposed theoretically\, its physical interpretation remains c
ontroversial. We demonstrate that as one moves away from the impurity\, ph
ysical quantities evolve in a characteristic way\, reproducing fully the R
G flow between fixed points. Behaviour typical of each fixed point can thu
s be identified in distinct regions of space. The implications of these re
sults are discussed in relation to the popular 'Kondo screening cloud' pic
ture.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Prof. Dr. Peter Reiter
DTSTART;VALUE=DATE-TIME:20110415T130000
DTEND;VALUE=DATE-TIME:20110415T134500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000057@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Peter Reiter\, IKP Cologne\n\nAt the limits - experi
ments with exotic nuclei\n\nThis talk is one of a series of presentations
of research groups organized\nby the Bonn-Cologne Graduate School of Physi
cs and Astronomy. The\naim is to provide insights into the research done a
t physics institutes in \nBonn and Cologne.\nInterested students (Bachelor
\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Klaus Hornberger
DTSTART;VALUE=DATE-TIME:20110429T163000
DTEND;VALUE=DATE-TIME:20110429T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000058@events.thp.uni-koeln.de
DESCRIPTION:Prof. Klaus Hornberger\, University of Duisburg-Essen\n\nEnvir
onmental distinction of pointer states\n\nAn important aspect for understa
nding the emergence of classical dynamics in a quantum mechanical framewor
k\nis to explain the origin of super-selection rules observed at macroscop
ic scales. Two specific cases will be\ndiscussed\, based on microscopicall
y realistic master equations.\nIn the first part\, I will show how the dis
tinction and stability of chiral molecular configuration states can be\nex
plained by decoherence. In the second part\, the emergence and dynamics of
motional pointer states will be\nexplored\, by associating them with the
solitonic solutions of a nonlinear equation related to a particular\nstoch
astic unraveling of the appropriate master equation.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Prof. Dr. U. Thoma
DTSTART;VALUE=DATE-TIME:20110415T121500
DTEND;VALUE=DATE-TIME:20110415T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000059@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. U. Thoma\, HISKP Bonn\n\nHadron spectroscopy - Explo
ring the bound states of the strong interaction\n\nThis talk is one of a s
eries of presentations of research groups organized\nby the Bonn-Cologne G
raduate School of Physics and Astronomy. The\naim is to provide insights i
nto the research done at physics institutes in \nBonn and Cologne.\nIntere
sted students (Bachelor\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Prof. Dr. Dieter Meschede (Bonn)\, Prof. Dr. Stephan Schlem
mer (Cologne)
DTSTART;VALUE=DATE-TIME:20110406T160000
DTEND;VALUE=DATE-TIME:20110406T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000060@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Dieter Meschede (Bonn)\, Prof. Dr. Stephan Schlemmer
(Cologne)\, BCGS\n\nInformationsveranstaltung für Physik-Studierende üb
er die Graduiertenschule BCGS\n\nSie interessieren sich für die gemeinsam
e Graduiertenschule der Fachgruppe\nPhysik/Astronomie der Uni Bonn und der
Fachgruppe Physik der Uni Köln\, die im\nRahmen der Exzellenzinitiative
des Bundes und der Länder ausgezeichnet wurde?\nSie möchten mehr über d
as Programm und seine Vorteile wissen?\nDann laden wir Sie ganz herzlich z
u unserer Informationsveranstaltung mit\nanschließender Diskussion mit st
udentischen Mitgliedern der BCGS ein.
LOCATION:Hörsaal I
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Prof. Dr. Klaus Volkert
DTSTART;VALUE=DATE-TIME:20110405T120000
DTEND;VALUE=DATE-TIME:20110405T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000061@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Klaus Volkert\, Universität Wuppertal\n\nNeue Forme
n braucht der Raum\n\nEtwa ab Mitte des 19. Jhs. führten verschiedene Ent
wicklungen innerhalb der Mathematik schließlich dazu\, dass der klassisch
e Raum der Euklidischen Geometrie - wie man ihn z.B. in Newtons absolutem
Raum wieder findet - seine Monopolstellung verlor. In diesem Zusammenhang
sind u.a. die Entstehung der verschiedenen nichteuklidischen Geometrien (h
yperbolisch\, sphärisch\, elliptisch) und der Aufbruch in höhere Dimensi
onen (insbesondere natürlich in die vierte) zum nennen. Im Vortrag möcht
e ich hauptsächlich auf ein weniger bekanntes aber durchaus interessantes
Thema eingehen\, nämlich auf die sogenannten Clifford-Kleinschen Raumfor
men. Das sind Mannigfaltigkeiten\, welche lokal wie ein klassisch-geometri
scher Raum aussehen\, die sich aber global von diesen unterscheiden. Da un
sere Kentnis des Universums immer nur lokal sein kann\, stellte sich somit
- schon vor der Relativitätstheorie - die Frage\, in welchem Raum wir de
nn leben.
LOCATION:Seminarraum Theorie
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Royce K.P. Zia
DTSTART;VALUE=DATE-TIME:20110610T163000
DTEND;VALUE=DATE-TIME:20110610T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000062@events.thp.uni-koeln.de
DESCRIPTION:Prof. Royce K.P. Zia\, Virginia Tech\, Blacksburg\n\nTowards a
classification scheme for non-equilibrium steady states\n\nWe propose a g
eneral classification of nonequilibrium steady states in terms of their st
ationary probability distribution and the associated probability currents.
The stationary\nprobabilities can be represented graph-theoretically as d
irected Cayley trees\; closing a single loop in such a graph leads to a re
presentation of probability currents. This classification\nallows us to id
entify all choices of transition rates\, based on a master equation\, whic
h generate the same nonequilibrium steady state. We explore the implicatio
ns of this freedom\, e.g.\,\nfor entropy production\, and provide a number
of examples.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Fabio Staniscia
DTSTART;VALUE=DATE-TIME:20110407T091500
DTEND;VALUE=DATE-TIME:20110407T103000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000063@events.thp.uni-koeln.de
DESCRIPTION:Fabio Staniscia\, Sincrotrone Trieste and Dipartimento di Fisi
ca\, Università di Trieste\n\nNegative Specific Heat in the Canonical Sta
tistical Ensemble\n\nWe study the influence of the interaction range on th
e out-of-equilibrium\nbehavior of both isolated and thermostated systems.\
nIn the case of short-range (extensive) systems\, we investigate coarsenin
g\ndynamics. There we find the existence of a short-time regime where the\
nlaws relating the rate of growth of domains' size with the interaction\nr
ange are different in isolated and thermostated systems.\nIn the case of l
ong-range (non-extensive) systems\, we focus on the\n"Quasi-stationary sta
tes" in which these systems are trapped before\nreaching the thermodynamic
equilibrium.\nThere\, we demonstrate that one can in principle measure ne
gative specific\nheat both in the case of isolated and thermostated system
s.\nThis is a surprising result since for classical systems at equilibrium
\nnegative specific heat can be found just in isolated systems\, while it
is\ngenerally recognized that a positive specific heat should always be\nm
easured in systems in contact with a thermal bath.
LOCATION:Conference Room Theoretical Physics
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Ganna Rozhnova
DTSTART;VALUE=DATE-TIME:20110513T163000
DTEND;VALUE=DATE-TIME:20110513T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000064@events.thp.uni-koeln.de
DESCRIPTION:Dr. Ganna Rozhnova\, Universidade de Lisboa\n\nStochastic fluc
tuations in systems with intrinsic noise\n\nIn this talk\, we will describ
e a mechanism that generates oscillations in simple stochastic models of e
pidemic dynamics. We will show that\, first\, intrinsic (demographic) stoc
hasticity can generate large coherent fluctuations which behave as sustain
ed oscillations and that\, second\, the power spectrum of these fluctuatio
ns can be calculated analytically using the system size expansion. The app
lication of this analysis to the problem of the modeling of recurrent epid
emics shows that\, in systems whose sizes represent real populations\, the
role of stochastic effects becomes fundamental for the interpretation of
historical data.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Prof. Dr. U. Benjamin Kaupp
DTSTART;VALUE=DATE-TIME:20110412T164500
DTEND;VALUE=DATE-TIME:20110412T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000065@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. U. Benjamin Kaupp\, Center of Advanced European Stud
ies and Research Caesar\, Bonn\n\nEmpfindlichkeit am physikalischen Limit
– wie detektieren Zellen ein einzelnes Photon oder Molekül?\n\nSehzelle
n können ein einziges Photon detektieren und in ein elektrisches Signal u
mwandeln. Spermien navigieren in einem chemischen Gradienten von Lockstoff
en. Sie können ein einziges Lockstoffmolekül\, das von der Eizelle ausge
sendet wird\, registrieren und dadurch ihr Schwimmverhalten verändern. In
meiner Vortrag werde ich die zellulären Signalwege erläutern\, die dies
e Empfindlichkeit an der physikalischen Grenze ermöglichen. Während der
Evolution haben sich verschiedene Signalwege entwickelt\, die Variationen
eines zellulären Verarbeitungsmoduls darstellen. Wahrscheinlich können v
iele andere Zelltypen\, beispielsweise Riechzellen\, die auf Pheromone spe
zialisiert sind\, einzelne Moleküle detektieren und in ein elektrisches S
ignal umwandeln.
LOCATION:Hörsaal 3
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Prof. Dr. Nick Barton
DTSTART;VALUE=DATE-TIME:20110503T171500
DTEND;VALUE=DATE-TIME:20110503T181500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000066@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Nick Barton\, ISI Vienna\n\nStatistical mechanics a
nd the evolution of complex traits\n\nThe evolution of complex traits depe
nds on the underlying allele frequencies\, yet these cannot usually be mea
sured. An analogy with statistical mechanics leads to an approximation tha
t accurately predicts the dynamics of the trait\, without knowing the alle
le frequencies. The stationary distribution of the traits under mutation\
, selection and random drift maximises the entropy\, subject to constraint
s on the expectations of the traits\, and the distribution is accurately p
redicted even when conditions change abruptly. This approach suggests way
s to understand the overall evolution of a population\, without the need t
o specify the detailed genetics.
LOCATION:Institute for Genetics\, Zülpicher Str. 47a\, Lecture Hall\, 4th
floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Prof. Dr. Johannes Berg
DTSTART;VALUE=DATE-TIME:20110429T121500
DTEND;VALUE=DATE-TIME:20110429T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000067@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Johannes Berg\, Institut für Theoretische Physik\,
Universität zu Köln\n\nNoise versus information - statistical physics an
d biological systems\n\nThis talk is one of a series of presentations of r
esearch groups organized\nby the Bonn-Cologne Graduate School of Physics a
nd Astronomy. The\naim is to provide insights into the research done at ph
ysics institutes in \nBonn and Cologne.\nInterested students (Bachelor\, M
aster\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Prof. Dr. Norbert Wermes
DTSTART;VALUE=DATE-TIME:20110429T130000
DTEND;VALUE=DATE-TIME:20110429T134500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000068@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Norbert Wermes\, Physikalisches Institut\, Universit
ät Bonn\n\nParticle Physics at High Energies - Novel Detector Development
and Physics Experiments \n\nThis talk is one of a series of presentations
of research groups organized\nby the Bonn-Cologne Graduate School of Phys
ics and Astronomy. The\naim is to provide insights into the research done
at physics institutes in \nBonn and Cologne.\nInterested students (Bachelo
r\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Armin Bunde
DTSTART;VALUE=DATE-TIME:20110527T163000
DTEND;VALUE=DATE-TIME:20110527T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000069@events.thp.uni-koeln.de
DESCRIPTION:Prof. Armin Bunde\, Justus-Liebig Universität Giessen\n\nLong
-term correlations in nature: On the clustering of extreme events and the
estimation of external trends\n\nIn this talk\, I discuss long-term memo
ry in nature (particularly in climate) and its implications for the occu
rrence of extremes.\nI also show how external trends can be estimated in r
ecords with long-term memory and apply the results\nto the estimation of
anthropogenic global warming.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Prof. Dr. Markus Braden
DTSTART;VALUE=DATE-TIME:20110513T121500
DTEND;VALUE=DATE-TIME:20110513T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000070@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Markus Braden\, II. Physikalisches Institut\, Univer
sität zu Köln\n\nThe Neutron: the ideal sonde for phonons and magnetism\
n\nThis talk is one of a series of presentations of research groups organi
zed\nby the Bonn-Cologne Graduate School of Physics and Astronomy. The\nai
m is to provide insights into the research done at physics institutes in \
nBonn and Cologne.\nInterested students (Bachelor\, Master\, and PhD) are
most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Prof. Dr. Hans-Werner Hammer
DTSTART;VALUE=DATE-TIME:20110513T130000
DTEND;VALUE=DATE-TIME:20110513T134500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000071@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Hans-Werner Hammer\, HISKP Bonn\n\nTheoretical hadro
n physics and quantum field theory\n\nThis talk is one of a series of pres
entations of research groups organized\nby the Bonn-Cologne Graduate Schoo
l of Physics and Astronomy. The\naim is to provide insights into the resea
rch done at physics institutes in \nBonn and Cologne.\nInterested students
(Bachelor\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Joachim Rambeau
DTSTART;VALUE=DATE-TIME:20110512T100000
DTEND;VALUE=DATE-TIME:20110512T111000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000072@events.thp.uni-koeln.de
DESCRIPTION:Joachim Rambeau\, LPT Orsay\n\nExtremum statistics of one dime
nsional growing interfaces\n\nInterfaces have been widely studied in the p
ast few decades for their\nrelevance in various domains: growing of thin f
ilms\, vapor deposition\,\nwetting\, bacterial growth. In this talk I will
caracterize the properties\nof the extremum of various types of interface
s. This central quantity\nrefines our knowledge of the geometry of such ob
jects.\nFirst I will consider equilibrated interfaces and present analytic
al\nresults concerning the distribution of their Maximal Relative Height\n
(MRH). Then\, as an extension to disordered systems\, I will consider the\
nMRH of elastic interfaces in random media. The second part of the talk\nf
ocuses on the growing regime in the KPZ universality class. Our\nanalytica
l results on the non-intersecting Brownian motions model give new\ninsight
s about this out of equilibrium system.
LOCATION:Conference Room ITP
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Steffen Karalus
DTSTART;VALUE=DATE-TIME:20110517T120000
DTEND;VALUE=DATE-TIME:20110517T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000073@events.thp.uni-koeln.de
DESCRIPTION:Steffen Karalus\, Institute of Theoretical Physics\, Cologne\n
\nThermodynamics of polymer adsorption to a flexible membrane\n\n
LOCATION:Konferenzraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Jakub Otwinowski
DTSTART;VALUE=DATE-TIME:20110524T120000
DTEND;VALUE=DATE-TIME:20110524T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000074@events.thp.uni-koeln.de
DESCRIPTION:Jakub Otwinowski\, Emory University\n\nAccumulation of benefic
ial mutations in one dimension\n\n
LOCATION:Konferenzraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Prof. Dr. Marek Kowalski
DTSTART;VALUE=DATE-TIME:20110527T130000
DTEND;VALUE=DATE-TIME:20110527T134500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000076@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Marek Kowalski\, Physikalisches Institut\, Universit
ät Bonn\n\nFrom neutrinos to dark energy - astroparticle physics in Bonn\
n\nThis talk is one of a series of presentations of research groups organi
zed\nby the Bonn-Cologne Graduate School of Physics and Astronomy. The\nai
m is to provide insights into the research done at physics institutes in \
nBonn and Cologne.\nInterested students (Bachelor\, Master\, and PhD) are
most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Prof. Dr. Gudrun Wolfschmidt
DTSTART;VALUE=DATE-TIME:20110607T193000
DTEND;VALUE=DATE-TIME:20110607T210000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000077@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Gudrun Wolfschmidt\, Universität Hamburg\n\nCoperni
cus und die Folgen - Die Geschichte des astronomischen Weltbildes (Reihe "
Weltwissen: Das Universum")\n\nWir sind das Zentrum des Universums – das
glaubte man seit der Antike\, bis ein bahnbrechender Denker damit aufräu
mte: Im 16. Jahrhundert erklärte Nicolaus Copernicus\, dass sich die ande
ren Himmelskörper nicht um die Erde drehen. Vielmehr liege die Mitte des
Universums “nahe der Sonne\,” lautete der Gedanke\, der einen Umbruch
in der Geschichte des Weltbildes lostrat. Der Vortrag skizziert die Entwic
klung der astronomischen Weltanschauung seit Copernicus und erläutert auc
h die Bedeutung von Galileo Galilei. Als weitere Phasen in der Entwicklung
des heliozentrischen Weltbildes werden Johannes Keplers Gesetze der Plane
tenbewegung und Isaac Newtons Gravitationsgesetz einführend dargestellt.
Schließlich verfolgt der Vortrag die Entwicklung weiter bis zur Gegenwart
\, in der wir längst erkannt haben\, dass wir am Rand unserer Milchstraß
e leben – nur einer von unzähligen Galaxien.
LOCATION:Hörsaal I (Physikal. Institute! Diesmal nicht im Hauptgebäude.)
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Prof. Dr. Thomas Nattermann
DTSTART;VALUE=DATE-TIME:20110610T121500
DTEND;VALUE=DATE-TIME:20110610T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000078@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Thomas Nattermann\, Institut für Theoretische Physi
k\, Universität zu Köln\n\nFrom disordered superconductors to helimagnet
s\n\nThis talk is one of a series of presentations of research groups orga
nized\nby the Bonn-Cologne Graduate School of Physics and Astronomy. The\n
aim is to provide insights into the research done at physics institutes in
\nBonn and Cologne.\nInterested students (Bachelor\, Master\, and PhD) ar
e most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Dr. Reiner Vianden
DTSTART;VALUE=DATE-TIME:20110610T130000
DTEND;VALUE=DATE-TIME:20110610T134500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000079@events.thp.uni-koeln.de
DESCRIPTION:Dr. Reiner Vianden\, HISKP Bonn\n\nMaterial Science at the HIS
KP\n\nThis talk is one of a series of presentations of research groups org
anized\nby the Bonn-Cologne Graduate School of Physics and Astronomy. The\
naim is to provide insights into the research done at physics institutes i
n \nBonn and Cologne.\nInterested students (Bachelor\, Master\, and PhD) a
re most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Natalja Strelkowa
DTSTART;VALUE=DATE-TIME:20110621T170000
DTEND;VALUE=DATE-TIME:20110621T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000080@events.thp.uni-koeln.de
DESCRIPTION:Natalja Strelkowa\, Imperial College\, London\n\nThe generaliz
ed repressilator model and applications of feedback control for synthetic
gene regulatory networks\n\nWe study the temporal dynamics of the generali
zed repressilator\, a network of coupled repressing genes arranged in a di
rected ring topology\, and give analytical conditions for the emergence of
a finite sequence of unstable periodic orbits that lead to reachable long
-lived oscillating transients. Such transients dominate the finite time ho
rizon dynamics that is relevant in confined\, noisy environments such as b
acterial cells\, and are therefore of interest for bioengineering and synt
hetic biology. We show that the family of unstable orbits possesses spatia
l symmetries and can also be understood in terms of traveling wave solutio
ns of kink-like topological defects. The long-lived oscillatory transients
correspond to the propagation of quasistable two-kink configurations that
unravel over a long time.\nBased on the quasi-stable periodic orbits in t
his genetic network we propose a design for a switchable and controllable
genetic oscillator. The oscillator operates around a quasi-stable periodic
orbit using the classical engineering idea of read-out based control. The
insights from the read-out based control scheme for the genetic oscillato
r lead us to the idea to implement an algorithmic controller\, which would
direct any genetic circuit to a desired state. The algorithm operates mod
el-free\, i.e. in principle it is applicable to any genetic network and th
e input information is a data matrix of measured time series from the netw
ork dynamics. The application areas for readout-based control in genetic n
etworks open a new perspective for tissue engineering\, whenever quantitat
ively and temporarily targeted intervention is required.
LOCATION:Institute of Genetics\, 4th floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Prof. Dr. A. Klemm
DTSTART;VALUE=DATE-TIME:20110701T121500
DTEND;VALUE=DATE-TIME:20110701T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000081@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. A. Klemm\, Physikalisches Institut\, Universität Bo
nn\n\nString Theory\n\nThis talk is one of a series of presentations of re
search groups organized\nby the Bonn-Cologne Graduate School of Physics an
d Astronomy. The\naim is to provide insights into the research done at phy
sics institutes in \nBonn and Cologne.\nInterested students (Bachelor\, Ma
ster\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Prof. Dr. A. Eckart
DTSTART;VALUE=DATE-TIME:20110701T130000
DTEND;VALUE=DATE-TIME:20110701T134500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000082@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. A. Eckart\, I. Physikalisches Institut\, Universitä
t zu Köln\n\nNuclei of Nearby Galaxies\n\nThis talk is one of a series of
presentations of research groups organized\nby the Bonn-Cologne Graduate
School of Physics and Astronomy. The\naim is to provide insights into the
research done at physics institutes in \nBonn and Cologne.\nInterested stu
dents (Bachelor\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Dr. Mariam Bouhmadi-López
DTSTART;VALUE=DATE-TIME:20110621T120000
DTEND;VALUE=DATE-TIME:20110621T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000083@events.thp.uni-koeln.de
DESCRIPTION:Dr. Mariam Bouhmadi-López\, Instituto Superior Técnico\, Lis
sabon\n\nHolography\, modified gravity and extra-dimensions\n\n
LOCATION:Seminarraum Theorie
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Marvin Jens
DTSTART;VALUE=DATE-TIME:20110707T170000
DTEND;VALUE=DATE-TIME:20110707T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000084@events.thp.uni-koeln.de
DESCRIPTION:Marvin Jens\, Max-Dellbrück Centre for Molecular Medicine\n\n
Why all this RNA? The transcriptome from the perspective of RNA binding pr
oteins.\n\nIn eukaryotic cells mRNA levels do not directly translate\ninto
protein levels because processing\, transport\, translation and\ndegradat
ion of mRNA are controlled post-transcriptionally. The key\nplayers in thi
s mode of gene regulation are RNA binding proteins\n(RBPs). Their specific
substrate is the pool of cellular RNA\,\ncontaining large amounts of untr
anslated\, regulatory sequences that\nare oftentimes crucial to the develo
pment of complex multi-cellular\norganism and are linked to various human
diseases. In contrast to\ngene promoters\, the concentration of RNA regula
tory elements is not\nfixed but linked to the highly dynamic abundances of
mRNA molecules.\nTogether with the oftentimes weak specificities of RBPs
the deeper \nunderstanding of RBP:mRNA interactions requires to explicitel
y account for \ncompetition effects. In this talk I will present general f
eatures of transcriptomes at different \nleafs of the evolutionary tree of
the metazoa\, recent results on the human RBP \nHuR/ELAVL1\, and the outl
ine of a project to experimentally test predictions of \na competition the
ory of RBP binding.
LOCATION:Ground floor lecture theater Biocenter\, Zülpicher Str. 47b
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Dr. Andreas Rauscher
DTSTART;VALUE=DATE-TIME:20110621T193000
DTEND;VALUE=DATE-TIME:20110621T210000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000085@events.thp.uni-koeln.de
DESCRIPTION:Dr. Andreas Rauscher\, Institut für Filmwissenschaft und Medi
endramaturgie\, Johannes-Gutenberg-Universität Mainz\n\nMetaphorische Dim
ensionen der Kultserie "Star Trek"\, Vortragsreihe Weltwissen: Das Univers
um\n\n"Raumschiff Enterprise" begründete ein TV-Universum\, das mit Ableg
ern wie "Star Trek: The Next Generation" und "Deep Space Nine" bis heute w
eltweit Kultstatus genießt und seinen Fans als "Trekkies" einen Eintrag i
ns Oxford English Dictionary bescherte. Andreas Rauscher erörtert diese m
etaphorischen Weiten des Star-Trek-Universums aus medienwissenschaftlicher
Sicht. Die Abenteuer im All spiegeln immer wieder Ereignisse aus unserer
irdischen Realität. Standen die Anfänge noch im Zeichen der Kennedy-Ära
und des Kalten Krieges\, so sind die späteren Serien u.a. geprägt durch
die Ideen der UNO und die Infragestellung von Mythologien und Utopien.
LOCATION:Aula 1\, Hauptgebäude
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Kathrin Müller
DTSTART;VALUE=DATE-TIME:20110707T111500
DTEND;VALUE=DATE-TIME:20110707T121500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000086@events.thp.uni-koeln.de
DESCRIPTION:Kathrin Müller\, Heinrich-Heine Universität\, Düsseldorf\n\
nProjection of the structure of classical fluids to effective pair potenti
als\n\nThe presentation treats the successful projection of the structure
of classical fluids to effective pair potentials for a 2D system of super-
paramagnetic colloids under a rotating external magnetic field. Knowing th
e structure of a system in form of the radial distribution function from e
xperiments\, the aim is to find a simple pair potential that reproduces th
e pair structure. To this end\, a search algorithm was designed and implem
ented. It can seek for the right parameters of a given potential\, resulti
ng in the best fitting radial distribution function. It is shown that this
combination works well for finding the right parameters of a superpositio
n of a Lennard Jones Potential and a Yukawa Potential. This approach was e
xtended to an anisotropic (patchy) potential in an effort to reproduce ver
y unusual structures found in experiments\, such as network chains includi
ng a number of Y-junctions.\n
LOCATION:THP Raum 104k
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Dr. Somayyeh Belbasi
DTSTART;VALUE=DATE-TIME:20110705T120000
DTEND;VALUE=DATE-TIME:20110705T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000087@events.thp.uni-koeln.de
DESCRIPTION:Dr. Somayyeh Belbasi\, Zanjan University\, Iran\n\nVehicular t
raffic flow at an intersection\n\n
LOCATION:Konferenzraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Prof. Jeong-Man Park
DTSTART;VALUE=DATE-TIME:20110712T120000
DTEND;VALUE=DATE-TIME:20110712T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000088@events.thp.uni-koeln.de
DESCRIPTION:Prof. Jeong-Man Park\, Catholic University of Korea\n\nSpin-co
herent representation of Crow-Kimura and Eigen models\n\n
LOCATION:Konferenzraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Dr. Jochen Horn
DTSTART;VALUE=DATE-TIME:20110708T160000
DTEND;VALUE=DATE-TIME:20110708T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000089@events.thp.uni-koeln.de
DESCRIPTION:Dr. Jochen Horn\, Systems Engineering and Optics Design\, Carl
Zeiss Meditec Inc.\n\nChallenges of Medical Solutions: Development of Opt
ical Diagnostic Instruments\n\n
LOCATION:Hörsaal II
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Ehud Altman
DTSTART;VALUE=DATE-TIME:20110712T160000
DTEND;VALUE=DATE-TIME:20110712T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000090@events.thp.uni-koeln.de
DESCRIPTION:Ehud Altman\, Weizmann Institute\n\nQuantized pumping and topo
logical Bose insulators\n\nSpinless bosons in a one dimensional chain at i
nteger filling can form two\ngapped phases\, the Mott and Haldane insulato
rs\, which do not break any obvious\nsymmetry.\nI will argue that the dist
inction between the two phases is protected by\nlattice inversion symmetry
.\nBreaking this symmetry gaps out the transition and leaves the critical
point\nas an isolated gapless point in the two-parameter space of the orig
inal tuning\nparameter and the symmetry breaking perturbation.\nI will sho
w that encircling this point adiabatically entails pumping of\nexactly one
boson across the Bose insulator.\nWhen multiple chains are coupled\, the
two insulating phases are no longer\nsharply distinct\, but the pumping pr
operty survives and allows to associate a\ntopological flux with gapless r
egions in the phase diagram.\nThis leads to strict constraints on the topo
logy of the phase diagram of\nsystems of quasi-one dimensional interacting
bosons.\nFinally I will use the pumping property to elucidate the topolog
ical invariant\nunderlying the Haldane phase and to discuss possible exten
sions to interacting\ntopological phases in higher dimensions.
LOCATION:Hörsaal II
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Dr. A. Altland
DTSTART;VALUE=DATE-TIME:20110715T163000
DTEND;VALUE=DATE-TIME:20110715T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000091@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. A. Altland\, Institut für Theoretische Physik\, Uni
versität zu Köln\n\nQuantum phase transitions in the cold atom kicked ro
tor\n\nI will discuss the physics of transport phenomena in\ndriven chaoti
c environments (`kicked rotors')\, as\nrealized in recent atom optic exper
iments. The behavior\nof these systems depends sensitively on the value of
a \nscaled Planck constant \\tilde h: for irrational values of\n\\tilde h
/(4\\pi) they fall into the universality class of\ndisordered electronic s
ystems and I will discuss the corresponding\nlocalization phenomena. In co
ntrast\, for rational values the\nrotor-Anderson insulator acquires an inf
inite conductivity\nand turns into a `super-metal'. This implies the exis
tence of a novel \n'metal/super-metal' quantum phase transition in cold at
om systems.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Theo Costi
DTSTART;VALUE=DATE-TIME:20110722T140000
DTEND;VALUE=DATE-TIME:20110722T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000092@events.thp.uni-koeln.de
DESCRIPTION:Theo Costi\, Forschungszentrum Jülich\n\nCharge Kondo effect
in Lead Telluride doped with Thallium impurities\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:DIS | Tim Dressler
DTSTART;VALUE=DATE-TIME:20110801T140000
DTEND;VALUE=DATE-TIME:20110801T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000093@events.thp.uni-koeln.de
DESCRIPTION:Tim Dressler\, ITP Köln\n\nÜber die Korrelation von Subgraph
en aus Fitnesslandschaften\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Prof. Dr. N Wermes\, Dr. H. Krüger\, Dr. E. von Törne
DTSTART;VALUE=DATE-TIME:20110926T090000
DTEND;VALUE=DATE-TIME:20110926T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000095@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. N Wermes\, Dr. H. Krüger\, Dr. E. von Törne\, BCGS
\n\nBCGS Intensive Week "From Chips to Higgs"\n\nThis BCGS intensive week
aims at providing an in-depth insight of an LHC experiment\, including phy
sics and detectors. What does one need to know to address the physics ques
tions at the LHC\, to build an LHC detector and to analyze LHC data? While
following these lines\, particular emphasis is given to\nthe physics curr
ently done and expected at the LHC (Standard Model\, Higgs\, SUSY\, Extra
Dimensions)\, the scientific and technical requirements of LHC detectors\
, the physics of tracking and energy measuring detectors\, the necessity o
f and a hands-on tutorial into the "how-to" of designing integrated circui
ts (chips)\, the experimental methods to address the LHC physics questions
\n
LOCATION:Physics Department Bonn
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Dr. Igor Burmistrov
DTSTART;VALUE=DATE-TIME:20110817T150000
DTEND;VALUE=DATE-TIME:20110817T163000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000096@events.thp.uni-koeln.de
DESCRIPTION:Dr. Igor Burmistrov\, Landau Institute for Theoretical Physic
s\, Moscow\n\nSpin and Charge Correlations in Quantum Dots: An Exact Solut
ion\n\nThe inclusion of charging and spin-exchange interactions within the
\nUniversal Hamiltonian description of quantum dots is a highly non-trivia
l \nproblem owing to the fact that it leads to a formulation of the proble
m in terms \nof a non-Abelian action. We present an exact analytical solut
ion of the problem\, \nin particular\, in the vicinity of the Stoner insta
bility point. We calculate exactly \nseveral physical observables\, includ
ing the tunneling density of states (TDOS)\nand the spin susceptibility. W
e find that due to the presence of spin-exchange \ninteraction\, at the vi
cinity of the instability point the TDOS exhibits a non-monotonous\nbehavi
or as function of the tunneling energy. This effect survives even at\ntemp
eratures much higher than the exchange energy. Also\, we find that in\nthe
same temperature range the single-particle level fluctuations enhances\nt
he spin-susceptibility in the vicinity of the Stoner instability. Experime
ntally\, \nour results could be tested in nearly ferromagnetic materials.
Some of the \nresults are published in I.S. Burmistrov\, Yu. Gefen\, M.N.
Kiselev\, JETP Lett. 92\, 766 (2010).
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Prof. Dr. Berenike Maier
DTSTART;VALUE=DATE-TIME:20111025T164500
DTEND;VALUE=DATE-TIME:20111025T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000097@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Berenike Maier\, University of Cologne\n\nForce gene
ration in bacterial interactions: How\, when\, and why?\n\nBacteria are th
e smallest free-living organisms\, but they are not isolated. Bacteria com
municate by exchanging chemical signals and DNA in a process called gene t
ransfer. They can actively control the transition from a lifestyle as indi
vidual motile cells to a lifestyle in large and structured clusters. The t
ype IV pilus is an extracellular polymer which is essential for gene trans
fer\, cluster formation\, motility\, and adhesion in many bacterial specie
s. When it depolymerizes\, it generates force exceeding 100pN\, making it
the strongest molecular motor characterized so far. Using a combination be
tween nanotechnological and genetic tools we address the molecular mechani
sm of force generation\, its regulation\, and its biological function.\n
LOCATION:Hörsaal 3
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Günter Radons
DTSTART;VALUE=DATE-TIME:20111104T163000
DTEND;VALUE=DATE-TIME:20111104T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000098@events.thp.uni-koeln.de
DESCRIPTION:Prof. Günter Radons\, TU Chemnitz\n\nNonlinear Dynamics of Co
mplex Hysteretic Systems\n\nUnder the influence of external fields a large
variety of materials and systems shows complex hysteretic behavior. The
latter means that in addition to major hysteresis loops\, one finds\nmany
subloops or minor loops\, if the external field is reversed or oscillates
at some intermediate values. Well-known examples range from adsorption in
porous media to the magnetization\nof magnetic materials. Such a behavior
is traditionally described by so-called hysteresis operators\, for which t
he Preisach operator is one of the most prominent representatives.\nCorres
pondingly\, the interaction of such hysteretic systems with its environmen
t is naturally described by operator-differential equations. Despite its i
mportance the dynamics resulting\nfrom such equations is not well understo
od. In this talk I will review the working principles of the Preisach hyst
eresis operator and its applications. Subsequently recent results on dynam
ical systems with such hysteretic\nsubsystems will be presented. They rang
e from the appearance of 1/f-noise under simple input-output conditions to
the co-existence of infinitely many attractors for\noperator-difference o
r operator-differential equations describing e.g. the motion of an iron sa
mple in an inhomogeneous magnetic field.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Armin Bunde
DTSTART;VALUE=DATE-TIME:20111118T163000
DTEND;VALUE=DATE-TIME:20111118T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000099@events.thp.uni-koeln.de
DESCRIPTION:Prof. Armin Bunde\, Justus-Liebig Universität Giessen\n\nLong
-term correlations in nature: On the clustering of extreme events and the
estimation of external trends\n\nIn this talk\, I discuss long-term memor
y in nature (particularly in climate) and its implications for the occurr
ence of extremes.\nI also show how external trends can be estimated in rec
ords with long-term memory and apply the results to the estimation of ant
hropogenic global warming.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Johannes Neidhart
DTSTART;VALUE=DATE-TIME:20110915T110000
DTEND;VALUE=DATE-TIME:20110915T120000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000100@events.thp.uni-koeln.de
DESCRIPTION:Johannes Neidhart\, Arbeitsgruppe Krug\n\nAdaptive Walks in Ra
ndom and Correlated Fitness Landscapes\n\nIn a high dimensional genotype s
pace\, biological evolution in the limit of strong selection and rare muta
tions is studied. Adaptation processes can be treated as an uphill walk in
fitness\, which terminates at a fitness maximum.\nWhen fitness is assigne
d randomly\, it is shown\, that the mean walk length shows logarithmic beh
aviour in the number of initially available beneficial steps\, with a pref
actor\, determined by the tail of the fitness distribution.
LOCATION:Seminarraum THP
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Michael Baake
DTSTART;VALUE=DATE-TIME:20110919T150000
DTEND;VALUE=DATE-TIME:20110919T155000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000101@events.thp.uni-koeln.de
DESCRIPTION:Michael Baake\, Universität Bielefeld\n\nKinematic diffractio
n from a mathematical viewpoint\n\nMathematical diffraction theory is conc
erned with the analysis of the diffraction image of a given structure and
the corresponding inverse problem of structure determination. In recent ye
ars\, the understanding of systems with continuous and mixed spectra has i
mproved considerably\, while their relevance has grown in practice as well
. Here\, the phenomenon of homometry shows various unexpected new facets\,
particularly so in the presence of disorder. After an introduction to the
mathematical tools\, we review pure point spectra\, based on the Poisson
summation formula for lattice Dirac combs\, aiming at the diffraction form
ulas of perfect crystals and quasicrystals. We continue by considering cla
ssic deterministic examples with singular or absolutely continuous diffrac
tion spectra\, and we recall an isospectral family of structures with cont
inuously varying entropy. We close with a summary of more recent results o
n the diffraction of dynamical systems of algebraic or stochastic origin.\
n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Volker Bach
DTSTART;VALUE=DATE-TIME:20110919T140000
DTEND;VALUE=DATE-TIME:20110919T145000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000102@events.thp.uni-koeln.de
DESCRIPTION:Volker Bach\, Technische Universität Braunschweig\n\nExistenc
e and construction of resonances in minimally coupled nonrelativistic QED\
n\nAn excited eigenvalue of an atom is believed to be unstable and turn in
to a resonance under a perturbation. In this talk the precise definition o
f such resonances is given and their existence and construction is outline
d in case the atom is minimally coupled to the quantized radiation field.
This model is infrared singular and notoriously difficult to treat. We rev
iew Sigal’s recent construction of resonances based on the “Feshbach m
ap” and present a novel\, alternative construction based on “Pizzo’s
method”.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Benjamin Schlein
DTSTART;VALUE=DATE-TIME:20110919T163000
DTEND;VALUE=DATE-TIME:20110919T172000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000103@events.thp.uni-koeln.de
DESCRIPTION:Benjamin Schlein\, Hausdorff-Zentrum für Mathematik\, Bonn\n\
nThe average density of states of hermitian Wigner matrices\n\nIn this tal
k we will consider the density of states (DOS) of Wigner matrices on very
small intervals. In such intervals\, the fluctuations of the DOS are impor
tant and one cannot expect convergence to the semicircle law to hold in pr
obability. Assuming the entries of the matrices to have a sufficiently reg
ular law\, we prove\, nevertheless\, that the average DOS still converges
to the semicircle law\, on arbitrarily small intervals.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Wojciech de Roeck
DTSTART;VALUE=DATE-TIME:20110919T173000
DTEND;VALUE=DATE-TIME:20110919T182000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000104@events.thp.uni-koeln.de
DESCRIPTION:Wojciech de Roeck\, Universität Heidelberg\n\nDiffusion in Ha
miltonian models\n\nIrreversible phenomena like diffusion and thermalizati
on obviously occur in our world\, which is described by deterministic and
time-reversible equations (Newton’s equations of motion or the Schrödin
ger equation in quantum mechanics). However\, up to today we seem to lack
the tools to describe and derive these phenomena rigorously (apart from a
few special models). In physics\, one usually models them by stochastic ev
olution equations and the transition from deterministic equations to stoch
astic ones remains a leap of faith. Our work treats one of the simplest po
ssible models: a quantum particle interacting with a gas of bosons. With t
he help of a time-dependent renormalization group analysis\, we prove diff
usion.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Christoph Schweigert
DTSTART;VALUE=DATE-TIME:20110920T140000
DTEND;VALUE=DATE-TIME:20110920T145000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000105@events.thp.uni-koeln.de
DESCRIPTION:Christoph Schweigert\, Universität Hamburg\n\nHigher categori
es in field theory – an invitation\n\nWe explain the notation of a bicat
egory and its use in topological\, classical and quantum field theory. \n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Dorothea Bahns
DTSTART;VALUE=DATE-TIME:20110920T150000
DTEND;VALUE=DATE-TIME:20110920T155000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000106@events.thp.uni-koeln.de
DESCRIPTION:Dorothea Bahns\, Universität Göttingen\n\nString theory outs
ide the critical dimension\n\nI will review some recent developments in st
ring theory in a setting initiated by Klaus Pohlmeyer in the 1980s. Here\,
a Poisson algebra is assigned to surfaces of extremal area immersed in Mi
nkowski space\, e.g. to the world sheet of a string. Two deformations of t
his Poisson algebra (quantization schemes) have been proposed. One is base
d on the quantization of an auxiliary Lie algebra in terms of its universa
l enveloping algebra\, the other is based on the deformation theory of qua
si-Lie-bialgebras. Contrary to the ordinary setting of string theory\, whi
ch is based on conformal field theory\, these two quantization schemes do
not require a critical dimension for consistency.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Herbert Spohn
DTSTART;VALUE=DATE-TIME:20110921T140000
DTEND;VALUE=DATE-TIME:20110921T145000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000107@events.thp.uni-koeln.de
DESCRIPTION:Herbert Spohn\, Technische Universität München\n\nThe one-di
mensional KPZ equation and its universality class\n\nIn 1986 Kardar\, Pari
si\, and Zhang proposed a stochastic PDE for the motion of driven interfac
es. Bertini and Giacomin (1997) explained how to approximate the solution
to the 1D KPZ equation through the weakly asymmetric simple exclusion proc
ess. Based on work of Tracy and Widom on the PASEP\, we report a formula f
or the one-point generating function of the KPZ equation in the case of sh
arp wedge initial data. The long time limit is given by the Tracy-Widom di
stribution from GUE random matrices. Of particular interest are the finite
time corrections. This is joint work with Tomohiro Sasamoto. \n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Manfred Salmhofer
DTSTART;VALUE=DATE-TIME:20110921T163000
DTEND;VALUE=DATE-TIME:20110921T172000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000108@events.thp.uni-koeln.de
DESCRIPTION:Manfred Salmhofer\, Universität Heidelberg\n\nRenormalization
group analysis of Fermi systems with pointlike singularities\n\nWe consid
er the quantum field theoretical description of quantum many-body systems.
In fermionic gases at low densities\, and in specific materials of solid-
state physics\, the Fermi surface becomes small or even degenerates to a p
oint. A multiscale analysis can be used to determine the correlation funct
ions by convergent expansions. In the talk I will discuss models for doubl
e-layer graphene and the dilute Fermi gas\, and explain the main ideas in
the analysis.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Leonid Pastur
DTSTART;VALUE=DATE-TIME:20110921T150000
DTEND;VALUE=DATE-TIME:20110921T155000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000109@events.thp.uni-koeln.de
DESCRIPTION:Leonid Pastur\, Institute for Low Temperatures\, Kharkiv\, Ukr
aine\n\nFluctuation laws of spectral statistics for large random matrices\
n\nWe consider certain functions of eigenvalues and eigenvectors (spectral
statistics) of real symmetric and hermitian random matrices of large size
. We first show that for these functions an analog of the Law of Large Num
bers is valid as the size of matrices tends to infinity. We then discuss t
he scale and the form for limiting fluctuations laws of the statistics and
show that the laws can be standard Gaussian (i.e.\, analogous to usual Ce
ntral Limit Theorem for appropriately normalized sums of i.i.d. random var
iables) in non-standard asymptotic settings\, certain non-Gaussian in seem
ingly standard asymptotic settings\, and other non-Gaussian in non-standar
d asymptotic settings.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Rainer Verch
DTSTART;VALUE=DATE-TIME:20110922T140000
DTEND;VALUE=DATE-TIME:20110922T145000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000110@events.thp.uni-koeln.de
DESCRIPTION:Rainer Verch\, Universität Leipzig\n\nQuantum fields on non-c
ommutative space: non-commutative potential scattering and Wick rotation\n
\nIn this talk\, two different strands of quantum field theory on non-comm
utative space will be presented. First\, the scattering of the quantized D
irac field on Minkowski spacetime will be discussed\, and it will be expla
ined how this gives rise to observables of the quantized Dirac field on Mo
yal-deformed Minkowski spacetime. Furthermore\, it will be argued that thi
s construction is a model for obtaining a correspondence between more gene
ral Lorentzian non-commutative geometries in the sense of spectral geometr
y and observables of quantum field theories over such non-commutative Lore
ntzian geometries. In the second strand of the talk\, the problem of Wick
rotation\, i.e. the relation between a quantum field theory on Euclidean s
pace on one hand\, and Minkowski spacetime on the other\, will be generali
zed for the Moyal deformations of Euclidean space and Minkowski spacetime.
It will be shown that there is a relation if the Moyal deformation leaves
the time coordinate untouched. These latter results were obtained in join
t work with H. Grosse\, G. Lechner and T. Ludwig.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Stefan Weinzierl
DTSTART;VALUE=DATE-TIME:20110922T150000
DTEND;VALUE=DATE-TIME:20110922T155000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000111@events.thp.uni-koeln.de
DESCRIPTION:Stefan Weinzierl\, Universität Mainz\n\nHidden mathematical b
eauty in scattering amplitudes\n\nThis talk will be on a topic related to
mathematics and (particle) physics. Scattering amplitudes in particle phys
ics are related to the probability with which a certain scattering process
occurs. The scattering amplitudes are calculable in perturbation theory.
Higher orders in the perturbative expansion are needed for precision predi
ctions for the experiments at the LHC collider. Recent progress in the cal
culation of scattering amplitudes has shown that these scattering amplitud
es have a much simpler structure than previously believed. This simplicity
is directly related to mathematical structures hiding underneath. The com
plexity of scattering amplitudes increases with the number of external leg
s and with the number of internal loops. Simplicity with respect to the nu
mber of external legs is obtained by formulating the theory not in space-t
ime\, but in twistor space instead. Simplicity with respect to the number
of internal loops is obtained by making use of the algebra of transcendent
al functions\, like the algebra of multiple poly-logarithms. Here\, partic
le physics touches the domain of the theory of motives.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Hanno Gottschalk
DTSTART;VALUE=DATE-TIME:20110922T163000
DTEND;VALUE=DATE-TIME:20110922T172000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000112@events.thp.uni-koeln.de
DESCRIPTION:Hanno Gottschalk\, Universität Wuppertal\n\nOn the Anti-de-Si
tter / conformal field theory conjecture from a Euclidean quantum field st
andpoint\n\nThe symmetry group on the Anti-de-Sitter space acts as a confo
rmal group on its boundary. It is shown that quantum fields on Euclidean A
dS – when restricted via suitable scaling – indeed fulfill conformal i
nvariance on the boundary. Even in the case of non-interacting fields some
new renormalization factors are required. In the case of interacting fiel
ds in AdS2 or fields with cut offs in arbitrary dimensions a new kind of s
omewhat intriguing infra-red problem arises. While the approach taken here
does not reflect the richness of Maldacena’s AdS/CFT conjecture on supe
rgravity and Yang-Mills theory\, the AdS/CFT problem for Euclidean quantum
fields allows the statement and proof of some rigorous results on the bas
is of what has been established in Constructive QFT.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Klaus Fredenhagen
DTSTART;VALUE=DATE-TIME:20110922T173000
DTEND;VALUE=DATE-TIME:20110922T182000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000113@events.thp.uni-koeln.de
DESCRIPTION:Klaus Fredenhagen\, Universität Hamburg\n\nEpstein-Glaser ren
ormalization and Batalin-Vilkovisky formalism\n\nThe Batalin-Vilkovisky fo
rmalism for field theories with gauge symmetries is revisited. It is shown
that the step from the classical theory to the quantum theory\, which is
usually discussed via the path integral\, can be performed by the renormal
ized time ordering operator which is obtained by a generalization of Epste
in-Glaser renormalization.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Jonas Larson
DTSTART;VALUE=DATE-TIME:20111021T163000
DTEND;VALUE=DATE-TIME:20111021T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000114@events.thp.uni-koeln.de
DESCRIPTION:Dr. Jonas Larson\, University of Cologne and Stockholm Univers
ity\n\nSynthetic magnetic fields for neutral ultracold atoms\n\nI will bri
efly review some recent developments on how to achieve and manipulate
effective gauge fields for ultracold atoms. Starting with some historical
remarks on effective\ngauge theories in molecular and time-dependent syst
ems\, I move on to show how this translates to ultracold atoms exposed to
spatially varying laser fields. This research has gained great\nattention
lately\, and the experimental efforts are seriously beginning to pay off
. At the present\, the non-Abelian case has not been experimentally demons
trated but will in the near\nfuture... An important example of a non-Abeli
an gauge potential is the one of Rashba\, which for a particular choice
of atom-laser configuration can be constructed in these systems. This\nop
ens the door for sudies of effects such as\, spin Hall currents\, relativi
stic Zitterbewegung\, half quantized vortices. Combined with optical latti
ces\, there's even hope to explore\nquantized Hall physics and interesti
ng physics that comes with it.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Fabian Hassler
DTSTART;VALUE=DATE-TIME:20111111T140000
DTEND;VALUE=DATE-TIME:20111111T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000115@events.thp.uni-koeln.de
DESCRIPTION:Fabian Hassler\, RWTH Aachen\n\nClassification of topological
insulators/ superconductors via their transport properties\n\nThe topologi
cal invariant of a topological insulator (or superconductor) is given by t
he number of symmetry-protected edge states present at the Fermi level. De
spite this fact\, established expressions for the topological invariant re
quire knowledge of all states below the Fermi energy. Here\, we propose a
way to calculate the topological invariant employing solely its scattering
matrix at the Fermi level without knowledge of the full spectrum. Since t
he approach based on scattering matrices requires much less information th
an the Hamiltonian-based approaches (surface versus bulk)\, it is numerica
lly more efficient. In particular\, is better-suited for studying disorder
ed systems. Moreover\, it directly connects the topological invariant to t
ransport properties potentially providing a new way to probe topological p
hases.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Prof. Dr. Herbert Dreiner
DTSTART;VALUE=DATE-TIME:20111018T164500
DTEND;VALUE=DATE-TIME:20111018T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000116@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Herbert Dreiner\, Universitä\;t Bonn\n\nRadioakt
ivitä\;t\, Kernkraftwerke und Fukushima\n\nEs werden die physikalische
n Grundlagen\, die den Problemen in \nFukushima zu Grunde liegen besproch
en. Es gibt auch interessante\nGemeinsamkeiten mit den Unfä\;llen in H
arrisburg (Three Mile Island)\,\nsowie (erstaunlicherweise) auch mit Tsche
rnobyl. Dazu werden einige\nExperimente live vorgefuehrt.
LOCATION:Hörsaal 2
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Prof. Dr. David DiVincenzo
DTSTART;VALUE=DATE-TIME:20111213T164500
DTEND;VALUE=DATE-TIME:20111213T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000117@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. David DiVincenzo\, RWTH and Forschungszentrum Jü
\;lich \n\nProspects for Quantum Computers\n\nThe basic principles of quan
tum computation were enunciated twenty years ago\, and within ten years th
ere was good motivation to build one\, and a basic idea of the physical ch
allenges that would need to be overcome to achieving working quantum compu
tation in the lab. Since then there has been steady progress in achieving
this goal\, involving striking advances in the solid state control of sin
gle quanta. I will give my overview of the status of spin qubits and supe
rconducting qubits\, and indicate where they may be going in the future.
LOCATION:Hörsaal 3
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Erik Aurell
DTSTART;VALUE=DATE-TIME:20111014T143000
DTEND;VALUE=DATE-TIME:20111014T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000118@events.thp.uni-koeln.de
DESCRIPTION:Erik Aurell\, KTH Royal Institute of Technology\, Sweden\, and
Aalto University\, Finland\n\nComputing stationary states by message-pass
ing\n\nComputing marginals of probability distributions (magnetizations\,
spin-spin correlations\netc) is an important problem in statistical physic
s of disordered systems and many \nother fields. In decision problems one
typically wants to estimate the likelihood\nthat a single variable takes a
given value\, given the interactions with all the\nother variables\, then
fix that variable to its most likely value\, and so estimate the\nmost li
kely configuration of all the variables. An important technical applicatio
n\nis decoding in communication systems\, where the task is to estimate th
e code word\nmost likely to have been sent from the recieved signal and wh
at one knows about the\nchannel.\n\nIn principle one can compute the margi
nals of any Markov chain by Monte Carlo\, but\nsuch methods are inherently
slow for large systems. Over the last decade there has \ntherefore been i
ntense interest in approximate methods to compute marginals of probability
\ndistributions deterministically (the cavity method\, Belief Propagation
\, iterative decoding)\,\nwhich overall work by nodes (representing variab
les) sending messages between each other\nand so collectively yield someti
mes exact and often very good estimates of the marginals. In \nthe languag
e of physics all these methods compute a variational ansatz of the Boltzma
nn-Gibbs \nfree energy of an equilibrium statistical mechanical system whe
re the messages are related to \nLagrange multipliers.\n\nI will describe
recent work on extending message-passing from computing the stationary\nst
ates of Markov chains obeying detailed balance to Markov chains which do n
ot. This\n"dynamic cavity method" works to some extent\, and in particular
outperforms dynamic\nmean-field methods on standard kinetic (non-equilibr
ium) Ising systems. \n\nThis is joint work with Hamed Mahmoudi (2011a-c)\,
building on earlier work by Montanari\nand co-workers (2009) and Neri and
Bolle (2009).\n \n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Dmitri Diakonov
DTSTART;VALUE=DATE-TIME:20111209T163000
DTEND;VALUE=DATE-TIME:20111209T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000119@events.thp.uni-koeln.de
DESCRIPTION:Dr. Dmitri Diakonov\, Petersburg Nuclear Physics Institute\n\n
Towards microscopic quantum gravity\n\nThe Einstein – Hilbert action of
General Relativity is not fit to describe quantum fluctuations of the metr
ics as it does not restrict either large fluctuations or fast varying ones
. Therefore\, it defines at best an effective theory which\, of course\, i
s tremendously successful. A hint how to construct a true and well defined
`microscopic’ gravitation theory is provided by the fact that there are
fermions in Nature. Fermions require that the field variables to be used
are the vierbein and the Lorentz spin connection. This leads to Cartan’s
formulation of General Relativity\, but field fluctuations are not restri
cted there either because none of the possible general covariant action te
rms is sign-definite. A way out is to present the vierbein as a bilinear
"current" of more fundamental fermion (spinor) fields. Path integrals over
Grassmann variables are well defined for whatever sign of the fermion act
ion. We suggest that in the ultraviolet limit quantum gravity possesses on
ly spinor and gauge field degrees of freedom\, like in the Standard Model.
The theory can be easily regularized by putting it on a space lattice. It
is explicitly invariant under local Lorentz transformations and\, in the
continuum limit\, under diffeomorphisms. It is a theory that is well-behav
ed at small distances\, and quantum fluctuations are well defined. We disc
uss how to check if Newton’s law is reproduced in the infrared limit in
the world with fluctuating metrics. Our formulation of quantum gravity all
ows its unification with the Standard Model\, and that will be also briefl
y discussed.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Hendrik Bluhm
DTSTART;VALUE=DATE-TIME:20111104T140000
DTEND;VALUE=DATE-TIME:20111104T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000120@events.thp.uni-koeln.de
DESCRIPTION:Hendrik Bluhm\, RWTH Aachen\n\nCoherence and coupling of GaAs
two-electron spin qubits\n\nSemiconductor spin qubits are promising candid
ates for quantum computation because of their slow decoherence and potenti
al for scalability. All fundamental single qubit operations have been demo
nstrated for GaAs-based spin qubits\, but they suffer from decoherence due
to hyperfine coupling to nuclear spins. We have developed effective techn
iques to mitigate this decoherence channel for two-electron spin qubits in
double quantum dots.\n\nBy repeatedly inverting the qubit in a way that d
ecouples its evolution from the fluctuations of the nuclear spin bath\, it
s coherence time can be extended to more than 200 ms\, two orders of magni
tude longer than previously shown. Alternatively\, operating the qubit as
a feedback loop that controls the nuclear bath also enhances the coherence
time and enables universal single qubit control with greatly improved gat
e fidelities.\n\nHaving achieved good single qubit control\, a fundamental
milestones is to couple qubits in order to generate entanglement. We demo
nstrate a protocol to implement two-qubit gates using the Coulomb interact
ion between adjacent double dots while decoupling both qubits from slow el
ectrical fluctuations. These results indicate that Bell states can be crea
ted with sufficient fidelity to demonstrate entanglement.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Gregory Schehr
DTSTART;VALUE=DATE-TIME:20111202T163000
DTEND;VALUE=DATE-TIME:20111202T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000121@events.thp.uni-koeln.de
DESCRIPTION:Dr. Gregory Schehr\, University Paris-Sud\n\nExtreme value sta
tistics of non-intersecting Brownian motions : from random matrices to 2d
Yang-Mills theory on the sphere\n\nNon-intersecting random walkers (or ''v
icious walkers'') have been studied\nin various physical situations\, rang
ing from polymer physics to wetting\nand melting transitions and more rece
ntly in connection with random matrix\ntheory or stochastic growth process
es. In this talk\, I will present a\nmethod based on path integrals associ
ated to free Fermions models to study\nsuch statistical systems. I will us
e this method to calculate exactly the\ncumulative distribution function (
CDF) of the maximal height of p vicious\nwalkers with a wall (excursions)
and without a wall (bridges). In the case\nof excursions\, I will show tha
t the CDF is identical to the partition\nfunction of 2d Yang Mills theory
on a sphere with the gauge group Sp(2p).\nTaking advantage of a large p an
alysis achieved in that context\, I will\nshow that the CDF\, properly shi
fted and scaled\, converges to the\nTracy-Widom distribution for $\\beta =
1$\, which describes the fluctuations\nof the largest eigenvalue of Rando
m Matrices in the Gaussian Orthogonal\nEnsemble.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Dr. Hildegard Meyer-Ortmanns
DTSTART;VALUE=DATE-TIME:20120127T163000
DTEND;VALUE=DATE-TIME:20120127T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000122@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Hildegard Meyer-Ortmanns\, Jacobs University Bremen\
n\nOn the versatile role of fluctuations in biological systems\n\nNoise is
ubiquitous in dynamical systems. Its impact on the dynamics can be quite
versatile\, ranging from bad signal-to-noise ratios to qualitatively new p
henomena such as oscillations\nof populations\, which would be absent with
out noise. Here "noise" stands for stochastic fluctuations of various orig
in. Of particular interest are stochastic fluctuations in the context\nof
biology. What is their role in evolutionary processes or in the living cel
l as the basic unit of life? We shall focus on a dynamical unit which cons
ists of only two species\ninteracting in a non-linear way. This unit may b
e regarded as a coarse-grained description of a genetic circuit. For compa
rison we shall first discuss the unit in a deterministic\ndescription and
then turn to a fully stochastic one. There we shall unravel the effect of
demographic fluctuations and fluctuations in the reaction times. The power
spectrum will show\nwhich source of stochastic behavior is dominant. We s
hall compare analytic predictions with Gillespie simulations. The results
raise an interesting generic question about oscillatory\ngenetic systems
observed in nature.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Tilman Enss
DTSTART;VALUE=DATE-TIME:20111118T140000
DTEND;VALUE=DATE-TIME:20111118T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000123@events.thp.uni-koeln.de
DESCRIPTION:Tilman Enss\, TU München\n\nRelaxation and thermalization in
one-dimensional quantum models\n\nThe time evolution of a 1d quantum syste
m after a quench is a challenging many-body problem which can be studied n
umerically using time-dependent density matrix renormalization group (DMRG
) techniques. As shown by Lieb and Robinson\, information spreads at a fin
ite velocity resulting in an effective "light cone". In my talk I will pre
sent a very efficient DMRG algorithm based on this light cone structure. W
ith the help of the DMRG data and analytical results for non-interacting c
ases I will discuss the relaxation and thermalization of doublon states in
the fermionic Hubbard model.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Dr. Milena Grifoni
DTSTART;VALUE=DATE-TIME:20111216T163000
DTEND;VALUE=DATE-TIME:20111216T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000131@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Milena Grifoni\, University of Regensburg\n\nQuantum
interference effects in interacting quantum dots \n\nWe consider multiple
quantum dots or molecular junctions in the single-electron tunneling regi
me which\, due to a high degree of spatial\nsymmetry\, have a degenerate m
any-body spectrum. As a consequence\, interference phenomena which cause a
\ncurrent blocking can occur at specific values of the bias and gate volta
ge. We present here\n necessary and sufficient conditions for interference
blockade also in the presence of spin-polarized\nleads. As an example we
analyze a benzene single-electron transistor. For a setup with parallel\np
olarized leads\, we show how to exploit the current blocking to selectivel
y prepare the system in a defined spin state\n without application of any
external magnetic field.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Roberto Bondesan
DTSTART;VALUE=DATE-TIME:20111215T104500
DTEND;VALUE=DATE-TIME:20111215T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000132@events.thp.uni-koeln.de
DESCRIPTION:Roberto Bondesan\, ENS Paris\n\nEdge states in the spin quantu
m Hall effect\n\nI discuss edge states in network models for Anderson loca
lization. For the case of the spin quantum Hall effect\, some transport pr
operties maps to a classical localization problem formulated in terms of a
loop model. Using conformal field theory and lattice algebras\, critical
exponents governing the decay of the conductance at higher plateaus transi
tions can be predicted\, and are found to be in very good agreement with n
umerical simulations.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Dr. Gianluca Calcagni
DTSTART;VALUE=DATE-TIME:20111122T120000
DTEND;VALUE=DATE-TIME:20111122T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000125@events.thp.uni-koeln.de
DESCRIPTION:Dr. Gianluca Calcagni\, Albert-Einstein-Institut\, Potsdam\n\n
Inflationary observables and observational constraints in loop quantum cos
mology \n\nIn the inflationary scenario of loop quantum cosmology (LQC) in
the presence of inverse-volume corrections\, we study the power spectra o
f scalar and tensor perturbations convenient to confront with observations
. Using the recent data of cosmic microwave background (CMB) and other cos
mological experiments\, for the first time we place experimental bounds on
the LQC quantum corrections for several inflaton potentials.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Igor Rouzine
DTSTART;VALUE=DATE-TIME:20111124T160000
DTEND;VALUE=DATE-TIME:20111124T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000126@events.thp.uni-koeln.de
DESCRIPTION:Igor Rouzine\, Institut für Theoretische Physik\, Universitä
t zu Köln\n\nTraveling wave of asexual evolution: no longer solitary\n\nM
odern evolution theory is focussed on interference (linkage) of adaptive m
utations emerging at different DNA locations. Interference effects emerge
even in the absence of biochemical interaction of proteins at different si
tes ("epistasis"\, "complex fitness landscape") and are a simple consequen
ce of competition of emerging lineages for space in population. Mathematic
al description of these effects proved to be not so simple. Interference i
s strong in populations in which recombination between genomes\, such as o
ccurs due to sexual reproduction\, is rare or absent. The examples inclu
de bacteria\, viruses\, yeast\, Y-chromosome\, mitochondrial DNA\, as well
any genomic segment in any organism with densely located evolving sites.
I will compare two historical models of interference: one where pairs of b
eneficial mutations differ in fitness effect\, and another where genomes c
arry multiple mutations of similar effect but variable in number.\n
LOCATION:Institute for Genetics\, Zülpicher Str. 47a\, Lecture Hall\, gro
und floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Christoph Brüne
DTSTART;VALUE=DATE-TIME:20111123T100000
DTEND;VALUE=DATE-TIME:20111123T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000127@events.thp.uni-koeln.de
DESCRIPTION:Christoph Brüne\, Universität Würzburg\n\nStrained bulk HgT
e as a 3-dimensional topological insulator\n\nThe prediction and discovery
of topological insulators (TIs) generated a large interest in the physics
community during the past years. This new state of mater is characterized
by conducting Dirac type surface states while the bulk of the material re
mains insulating. These surface states have been observed so far in\, e.g.
\, Bi2Te3\, Bi2Se3 and Sb2Te3. These materials do however exhibit large de
fect densities paired with low arrier mobilities. So far this prevented tr
ansport studies in the quantum Hall regime of 3D TIs. Recently\, however\,
we succeeded in using strained bulk HgTe as 3D TI. This enabled us to mea
sure the quantum Hall effect from the 3D TI surface state in transport exp
eriments. The samples were fabricated by molecular beam epitaxy of HgTe la
yers on top of CdTe substrates. The strain induced by the lattice mismatch
between HgTe and CdTe results in opening a gap in the HgTe band structure
which makes the TI state observable.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Inga Fischer
DTSTART;VALUE=DATE-TIME:20111125T140000
DTEND;VALUE=DATE-TIME:20111125T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000128@events.thp.uni-koeln.de
DESCRIPTION:Inga Fischer\, Universität Stuttgart\n\nSome Silicon-based co
ncepts beyond Moore: Towards Spintronics\, Tunneling-FETs\, and Plasmonic
Interconnects\n\nSilicon-based complementary metal-oxide-semiconductor (CM
OS) devices are the basic building blocks of integrated electronic logic a
nd memory devices. Their continuous downscaling which\, as described by Mo
ore’s law\, leads to a doubling of the number of transistors on a chip e
very two years\, cannot go on indefinitely: Today’s smallest transistors
function despite quantum mechanics\; their metal-wire interconnects will
also face scaling limits. New design paradigms that make use of quantum me
chanics instead of trying to avoid its effects will be necessary. In this
talk\, I will present some current work on spin injection into SiGe-hetero
structures\, tunneling field effect transistors (FETs)\, and electrical de
tection of plasmons.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Andreas Schnyder
DTSTART;VALUE=DATE-TIME:20111209T140000
DTEND;VALUE=DATE-TIME:20111209T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000129@events.thp.uni-koeln.de
DESCRIPTION:Andreas Schnyder\, MPI for Solid State Research\, Stuttgart\n\
nGapped and gapless topological phases in condensed matter systems\n\nOne
of the defining properties of topological insulators and superconductors\,
which are topological phases with a full gap in the bulk\, is the appeara
nce of topologically protected zero-energy surface or edge states\, some o
f which are of Majorana type. Boundary modes of topological nature can als
o occur in (semi-)metallic systems that exhibit topologically stable Fermi
surfaces or in nodal superconductors with non-trivial topology. For insta
nce\, dispersionless boundary states exist on the (110) surface of a d_{x^
2-y^2}-wave superconductor (e.g.\, in high-temperature superconductors)\,
or at the zig-zag edge in graphene. In this talk I present a classificatio
n of both gapped and gapless topological phases in terms of symmetry and s
patial dimension. As a consequence of the non-trivial bulk topology all of
these systems exhibit topologically stable surface states\, which are eit
her dispersionless or show a linear dispersion as a function of edge or su
rface momentum. As a concrete example\, superconductors without inversion
symmetry are discussed in detail. Three different types of topologically p
rotected surface states are identified in these systems\, namely Kramers-d
egenerate Majorana modes\, arc surface states\, and surface flat bands\, w
hose stability is guaranteed by the conservation of three different types
of topological invariants. I examine the signatures of the Majorana modes\
, the arc surface states and the zero-energy surface flat bands in tunneli
ng-conductance spectra and other experimental probes.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Poulumi Dey
DTSTART;VALUE=DATE-TIME:20111216T140000
DTEND;VALUE=DATE-TIME:20111216T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000130@events.thp.uni-koeln.de
DESCRIPTION:Poulumi Dey\, IIT Guwahati\n\nDisorder induced exotic phases i
n weakly coupled s-wave superconductors\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Dr. Ingo Lohmar
DTSTART;VALUE=DATE-TIME:20111221T100000
DTEND;VALUE=DATE-TIME:20111221T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000133@events.thp.uni-koeln.de
DESCRIPTION:Dr. Ingo Lohmar\, Racah Institute of Physics\, Jerusalem\n\nEx
tinction of Bacterial Populations: A Change of Paradigm?\n\nIt is now well
-established that individual bacteria of many types switch\nstochastically
between two phenotypes: fast-growing "normals"\nsusceptible to antibiotic
s\, and slowly-growing "persisters" hardly\naffected by the drug. In the
competition of species during exponential\ngrowth\, persisters are a burde
n\, but they may become beneficial when\nintroducing "stress" phases like
drug treatment.\nWe suggest to shift the focus to the persistence of an\ne
stablished population. Due to fluctuations\, the population will (after\n
a long time) eventually go extinct\; persisters act as a life insurance\na
gainst this. We study a simple stochastic model of these processes.\nUsin
g a WKB approximation\, we find the most likely path to extinction\nand qu
antify the extinction risk under both favorable and adverse\nconditions.
Analytical results are obtained both in the biologically\nrelevant regime
when the switching is rare compared with the birth and\ndeath processes\,
and in the opposite regime of frequent switching. We\nexplain how persist
ers strongly reduce the extinction risk and show that\nrare switches are m
ost beneficial to this end.\n
LOCATION:Konferenzraum des Instituts für Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Guido Sonnabend
DTSTART;VALUE=DATE-TIME:20120113T130000
DTEND;VALUE=DATE-TIME:20120113T134500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000134@events.thp.uni-koeln.de
DESCRIPTION:Guido Sonnabend\, 1. Physikalisches Institut\, Universität zu
Köln\n\nDynamical properties of planetary atmospheres from high-resoluti
on infrared spectroscopy \n\nThis talk is one of a series of presentations
of research groups organized\nby the Bonn-Cologne Graduate School of Phys
ics and Astronomy. The\naim is to provide insights into the research done
at physics institutes in \nBonn and Cologne.\nInterested students (Bachelo
r\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Thomas Michely
DTSTART;VALUE=DATE-TIME:20120127T121500
DTEND;VALUE=DATE-TIME:20120127T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000135@events.thp.uni-koeln.de
DESCRIPTION:Thomas Michely\, 2. Physikalisches Institut\, Universität zu
Köln\n\nGraphene: a journey through carbon flatland \n\nThis talk is one
of a series of presentations of research groups organized\nby the Bonn-Col
ogne Graduate School of Physics and Astronomy. The\naim is to provide insi
ghts into the research done at physics institutes in \nBonn and Cologne.\n
Interested students (Bachelor\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Jacopo Viti
DTSTART;VALUE=DATE-TIME:20111208T104500
DTEND;VALUE=DATE-TIME:20111208T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000136@events.thp.uni-koeln.de
DESCRIPTION:Jacopo Viti\, SISSA\n\nUniversal properties of two-dimensional
percolation\n\nPercolation is the best known example of geometrical phas
e transition. In two dimensions a plethora of exact results were derived a
t criticality (critical exponents\, crossing probabilities) using Conforma
l Field Theory. In this talk I will discuss a possible field theoretical d
escription for the scaling region of off-critical percolation\, exploitin
g the $q\\rightarrow 1$ limit of the integrable q-color Potts field theory
. I will apply the formalism to the computation of universal amplitude ra
tios and off-critical crossing probabilities. All the predictions can be
checked by numerical simulations.
LOCATION:Trieste
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Achim Rosch
DTSTART;VALUE=DATE-TIME:20111209T121500
DTEND;VALUE=DATE-TIME:20111209T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000137@events.thp.uni-koeln.de
DESCRIPTION:Achim Rosch\, Institut für Theoretische Physik\, Universität
zu Köln\n\nExcursions into the quantum world\n\nThis talk is one of a se
ries of presentations of research groups organized\nby the Bonn-Cologne Gr
aduate School of Physics and Astronomy. The\naim is to provide insights in
to the research done at physics institutes in \nBonn and Cologne.\nInteres
ted students (Bachelor\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Simon Trebst
DTSTART;VALUE=DATE-TIME:20120120T163000
DTEND;VALUE=DATE-TIME:20120120T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000138@events.thp.uni-koeln.de
DESCRIPTION:Prof. Simon Trebst\, University of Cologne\n\nInteractions and
disorder in topological quantum matter\n\nThe emergence of topological or
der is one of the most intriguing phenomena in quantum many-body physics a
nd one of possibly far reaching relevance - topological quantum matter is\
nincreasingly appreciated as possible medium for quantum computation purpo
ses. In this talk\, I will discuss the stability of topological quantum ma
tter when considering the effects of\ninteractions and disorder on the col
lective quantum state formed by a set of topological excitations\, so-call
ed anyons. In particular\, I will discuss the formation of a thermal metal
of\nMajorana fermions in a two-dimensional system of interacting non-Abel
ian anyons in the presence of moderate disorder. This bulk metallic phase
occurs for various proposed systems\nsupporting Majorana fermion zero mode
s when disorder induces the random pinning of a finite density of vortices
. This includes all two-dimensional topological superconductors in\nso-cal
led symmetry class D. A distinct experimental signature of the thermal met
al phase is the presence of bulk heat transport down to zero temperature.
I will finish by discussing\nimplications for topological quantum computin
g proposals.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Mario Kieburg
DTSTART;VALUE=DATE-TIME:20111222T104500
DTEND;VALUE=DATE-TIME:20111222T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000139@events.thp.uni-koeln.de
DESCRIPTION:Mario Kieburg\, Stony Brook University\n\nRandom Matrix Theory
for the Wilson-Dirac operator\n\nSince the 90's random matrix theory (RMT
) was successfully applied to quantum chromodynamics (QCD). In particular
the low lying spectrum of the Dirac operator can be exactly mapped to chir
al RMT. The same applies to lattice QCD. One particular modification of th
e Dirac operator on the lattice is the one introduced by Wilson. This modi
fication explicitly breaks chiral symmetry even though the quark masses ar
e set to zero. Recently a random matrix model was introduced which lies in
the same universality class as the Wilson-Dirac operator. The aim is to i
nvestigate the lattice artifacts in data of lattice simulations with RMT a
s strongly simplified model. Quite recently we derived the joint probabili
ty density and\, in particular\, the level density of the so called Wilson
random matrix ensemble. I will present these new results in my talk. More
over I will show that the Wilson random matrix ensemble lies in a new clas
s of ensembles related to a mixing of orthogonal and skew-orthogonal polyn
omials. Hence it is a new kind of interpolations between universality clas
ses.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Dr. J. Schmalian
DTSTART;VALUE=DATE-TIME:20120113T163000
DTEND;VALUE=DATE-TIME:20120113T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000140@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. J. Schmalian\, KIT Karlsruhe\n\nDiscrete scale invar
iance and non-Ginzburg-Landau criticality near quantum percolation transit
ions\n\nWe analyze the low-energy excitations of diluted Josephson-junctio
ns arrays\, XY-quantum antiferromagnets\, and interacting bosons near the
percolation threshold. We then show that the\ncritical behavior of these
systems is dramatically altered by the presence of a Berry phase that lead
s to an order parameter precession and\, depending on the system\, is caus
ed by an\nexternal magnetic field or an external gate voltage. Most intere
stingly\, the low energy excitations become spinless fermions with a fract
al spectrum. As a result\, critical properties not\ncaptured by the usual
Ginzburg-Landau-Wilson description of phase transitions emerge\, such as c
omplex critical exponents\, log-periodic oscillations and dynamically brok
en scale-invariance.\n[Rafael M. Fernandes\, Jörg Schmalian\, Phys.Rev.Le
tt.106\, 067004 (2011)]\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Alexander Ludwig
DTSTART;VALUE=DATE-TIME:20120203T163000
DTEND;VALUE=DATE-TIME:20120203T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000141@events.thp.uni-koeln.de
DESCRIPTION:Prof. Alexander Ludwig\, Center for Macroeconomic Re
search\, Cologne \n\nOn the Welfare Effects of Social Security in a Mo
del with Aggregate and Idiosyncratic Risk\n\nWe study the welfare effects
of social security in an overlapping\ngenerations general equilibrium mod
el with aggregate and idiosyncratic\nrisk. Prior research on social securi
ty has only considered either\naggregate or idiosyncratic risk. We show an
alytically that the\naggregate and idiosyncratic risks interact due to the
life-cycle structure\nof the economy. This interaction increases the welf
are gains of a\nmarginal introduction of an unfunded social security syste
m. Adding\na second interaction by making the variance of the idiosyncrati
c risk\ncountercyclical further increases the welfare gains. In our quanti
tative\nexperiment\, raising the contribution rate from zero to two percen
t\nleads to long-run welfare gains of 3.5% of life-time consumption on ave
rage\,\neven though the economy experiences substantial crowding out\nof c
apital. Approximately one third of these gains can be attributed\nto the i
nteractions between idiosyncratic and aggregate risk.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Dr. Rahul Marathe
DTSTART;VALUE=DATE-TIME:20120118T100000
DTEND;VALUE=DATE-TIME:20120118T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000142@events.thp.uni-koeln.de
DESCRIPTION:Dr. Rahul Marathe\, MPI for Colloids and Interfaces\, Golm\n\n
Twitching Motility of Bacteria\n\nBacteria perform various kinds of motion
based on a variety of molecular mechanisms. We are studying the twitching
motility of bacteria such as Neisseria gonorrhoeae\, which use so called
type IV pili to propel themselves over surfaces. Pili are long polymeric s
tructures given out of the bacterial body which adhere to the surface and
then retract\, thus pulling the cell body. Recent experiments performed on
these bacteria suggest that several pili co-operate in bacterial motion a
nd that their co-ordination may be based on a tug-of-war between pili pull
ing in different directions. We are studying the Twitching Motility of bac
teria\, by a stochastic tug-of-war model\, with a strong connection\nto ex
periments. The system is modeled by taking into consideration the stochast
ic nature of different processes. We describe the system as a tug-of-war b
etween the pili\, pulling a bacterium in different direction\, to test whe
ther this idea\, together with known properties of individual pili can exp
lain the observed patterns of bacterial motion.\n
LOCATION:Konferenzraum des Instituts für Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Simon Trebst
DTSTART;VALUE=DATE-TIME:20120127T130000
DTEND;VALUE=DATE-TIME:20120127T134500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000143@events.thp.uni-koeln.de
DESCRIPTION:Simon Trebst\, Institut für Theoretische Physik\, Universitä
t zu Köln\n\nKollektive Phänomene in der Quantenwelt: Spinflüssigkeiten
\, topologische Ordnung und exotische Phasenübergänge\n\nThis talk is on
e of a series of presentations of research groups organized\nby the Bonn-C
ologne Graduate School of Physics and Astronomy. The\naim is to provide in
sights into the research done at physics institutes in \nBonn and Cologne.
\nInterested students (Bachelor\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Dr. Andrew Mitchell\, Priv.-Doz. Dr. Ralf Bulla\, Prof. Dr.
Simon Trebst
DTSTART;VALUE=DATE-TIME:20120305T093000
DTEND;VALUE=DATE-TIME:20120305T110000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000144@events.thp.uni-koeln.de
DESCRIPTION:Dr. Andrew Mitchell\, Priv.-Doz. Dr. Ralf Bulla\, Prof. Dr. Si
mon Trebst\, Institut für Theoretische Physik\, Universität zu Köln\n\n
BCGS Intensive Week: Numerical methods for many-particle systems\n\n5-9th
March 2012\; Mo-Fr 9:30 - 17:00\, SR THP/CIP-Pool.\n \nThis intens
ive week is intended to provide both a working understanding\nand real han
ds-on experience with the essential numerical techniques of\nsolid state m
any-body physics. Rather than a 'black-box' philosophy\, the\ncourse aims
to discuss the theory and physics underpinning numerical\napproaches. Lect
ures will introduce three models of central importance:\nthe Ising model\,
the Anderson impurity model\, and the Hubbard model.\nUsing these as conc
rete examples\, the Monte Carlo\, Numerical\nRenormalization Group and De
nsity Matrix Renormalization Group\ntechniques will be discussed. Students
will also gain supervised\npractical hands-on experience writing\, using
and modifying simple\ncomputer codes to solve real problems.\n
\nSee website for more details and registration information: \nht
tp://www.thp.uni-koeln.de/~mitchell/intensive.html\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Oskar Hallatschek
DTSTART;VALUE=DATE-TIME:20120208T084500
DTEND;VALUE=DATE-TIME:20120208T093000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000145@events.thp.uni-koeln.de
DESCRIPTION:Oskar Hallatschek\, MPI for Dynamics and Self-Organization\, G
öttingen\n\nLife at the front of expanding populations\n\n
LOCATION:Institute for Genetics\, Ground Floor Lecture Hall
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Malte Wachsmuth
DTSTART;VALUE=DATE-TIME:20120208T093000
DTEND;VALUE=DATE-TIME:20120208T101500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000146@events.thp.uni-koeln.de
DESCRIPTION:Malte Wachsmuth\, EMBL\, Heidelberg\n\nLive from the scene - q
uantitative microscopy of diffusion and binding in vivo\n\n
LOCATION:Institute for Genetics\, Ground Floor Lecture Hall
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Ralf Seidel
DTSTART;VALUE=DATE-TIME:20120208T104500
DTEND;VALUE=DATE-TIME:20120208T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000147@events.thp.uni-koeln.de
DESCRIPTION:Ralf Seidel\, TU Dresden\n\nBiomolecular machines on DNA\n\n
LOCATION:Institute for Genetics\, Ground Floor Lecture Hall
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Kay-Eberhard Gottschalk
DTSTART;VALUE=DATE-TIME:20120208T113000
DTEND;VALUE=DATE-TIME:20120208T121500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000148@events.thp.uni-koeln.de
DESCRIPTION:Kay-Eberhard Gottschalk\, Universität Ulm\n\nMechanics and cr
osstalk in cellular systems\n\n
LOCATION:Institute for Genetics\, Ground Floor Lecture Hall
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Doris Heinrich
DTSTART;VALUE=DATE-TIME:20120209T084500
DTEND;VALUE=DATE-TIME:20120209T093000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000149@events.thp.uni-koeln.de
DESCRIPTION:Doris Heinrich\, LMU München\n\nControl and functions of cell
ular nanoarchitecture\n\n
LOCATION:Biocenter\, Ground Floor Lecture Hall
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Matthias Schneider
DTSTART;VALUE=DATE-TIME:20120209T093000
DTEND;VALUE=DATE-TIME:20120209T101500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000150@events.thp.uni-koeln.de
DESCRIPTION:Matthias Schneider\, Boston University\n\nA physicist's 2D per
spective on biology: Flat microfluidics\, blood clotting and the integrati
ng interface of the cell \n\n
LOCATION:Biocenter\, Ground Floor Lecture Hall
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Frank Schleifenbaum
DTSTART;VALUE=DATE-TIME:20120209T104500
DTEND;VALUE=DATE-TIME:20120209T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000151@events.thp.uni-koeln.de
DESCRIPTION:Frank Schleifenbaum\, Universität Tübingen\n\nSpectro-micros
copy: From physics to applied biology\n\n
LOCATION:Biocenter\, Ground Floor Lecture Hall
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Axel Rosenhahn
DTSTART;VALUE=DATE-TIME:20120209T113000
DTEND;VALUE=DATE-TIME:20120209T121500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000152@events.thp.uni-koeln.de
DESCRIPTION:Axel Rosenhahn\, Karlsruhe Institute of Technology\n\nPhysical
and chemical cues in biofouling\n\n
LOCATION:Biocenter\, Ground Floor Lecture Hall
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Gerard C.L. Wong
DTSTART;VALUE=DATE-TIME:20120213T170000
DTEND;VALUE=DATE-TIME:20120213T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000153@events.thp.uni-koeln.de
DESCRIPTION:Gerard C.L. Wong\, California NanoSystems Institute\, UCLA\n\n
Soft matter physics and bacteria\n\nOne of the long term challenges in hu
man health and disease is the control of pathogens\,\nsuch as antibiotic-r
esistant forms of bacteria. In this talk\, we will briefly describe two\nd
irections where materials science based approaches have been useful.\n1) B
acterial biofilms are structured multi-cellular communities that are notor
iously\nresistant to antibiotics. We translate bacteria movies into search
able databases of\nbacterial behavior and find an unexpected diversity in
motility driven by Type IV pili\nacross different bacterial species. The a
ssociated phenomena include ‘stick-slip’\nmotion analogous to earthqua
ke dynamics\, and self-organized distribution of\nresources in early biofi
lm development reminiscent of capitalist economies.\n2) We examine the mec
hanism of a range of pore-forming polypeptides\, including\nantimicrobial
peptides\, cell penetrating peptides\, viral fusion peptides\, and apoptos
is\nproteins\, and show how a combination of topology\, coordination chemi
stry\, and\nmaterials science can be used to approach a unified understand
ing.
LOCATION:Institute for Genetics\, New Seminar Room\, Ground Floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Dr. Shamik Gupta
DTSTART;VALUE=DATE-TIME:20120309T100000
DTEND;VALUE=DATE-TIME:20120309T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000154@events.thp.uni-koeln.de
DESCRIPTION:Dr. Shamik Gupta\, ENS Lyon\n\nRelaxation dynamics of systems
with long-range interactions\n\nSystems with long-range interactions have
interaction\npotentials that decay slower than 1/r^d at large distances r
in\nd dimensions. Common examples are self-gravitating systems\,\nnon-neut
ral plasmas\, dipolar ferroelectrics and ferromagnets\, etc.\nLong-range i
nteracting systems are non-additive. This leads to unusual\nproperties\, b
oth thermodynamic (e.g.\, negative microcanonical specific\nheat\, ensembl
e inequivalence) and dynamic (e.g.\, slow relaxation\,\nbreaking of ergodi
city). After a brief review\, I will discuss a\nparadigmatic example\, the
Hamiltonian Mean-Field model\, involving XY\nspins with mean-field intera
ctions. For this model\, relaxation of some\ninitial states towards equili
brium proceeds through intermediate\nquasistationary states characterized
by a slow variation of\nmacroscopic observables over time. The life time o
f these states\ndiverges with the system size. These states are observed i
n\ndeterministic microcanonical evolution within a certain energy\ninterva
l. Our recent study suggests that in presence of noise\,\nquasistationary
states occur only as a crossover phenomenon depending\non the relative mag
nitudes of two timescales set by the system size\nand the level of noise i
n the evolution. Our proposed scaling form for\nthe relaxation time to equ
ilibrium is verified in simulations by a\nscheme of piecewise deterministi
c evolution for the model.\n
LOCATION:Konferenzraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Dr. Tridib Sadhu
DTSTART;VALUE=DATE-TIME:20120227T100000
DTEND;VALUE=DATE-TIME:20120227T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000155@events.thp.uni-koeln.de
DESCRIPTION:Dr. Tridib Sadhu\, Weizmann Institute of Science\, Rehovot\n\n
Pattern formation in growing sandpiles\n\nBeautiful spatial patterns can b
e formed in a cellular automaton known as Abelian Sandpile Model (ASM)\, b
y dropping large N number of particles at a single site and then redistrib
uting them according to ASM toppling rules. The patterns are usually compo
sed of large number of macroscopic regions with sharp boundaries\, all of
which grow at the same rate with N\, keeping the overall shape unchanged.
This proportionate growth makes the patterns important in the context of b
iology where such ability to adapt to size variations is common in growing
animals. The patterns are also a good example of analytically tractable c
omplex structures generated using simple local rules. I will present exact
characterization of few asymptotic (N→∞) patterns on two dimensional
lattices\, which involve some intriguing connection to the mathematics of
discrete analytic functions. I will also discuss robustness of the pattern
s against different types of noise.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Prof. Dr. Hans-Thomas Elze
DTSTART;VALUE=DATE-TIME:20120316T100000
DTEND;VALUE=DATE-TIME:20120316T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000156@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Hans-Thomas Elze\, Università di Pisa\n\nQuantum-cl
assical hybrid dynamics\n\nA new formulation of quantum-classical hybrid d
ynamics is presented\, which concerns the direct coupling of classical and
quantum mechanical degrees of freedom - of interest for approximation sch
emes and for the foundations of quantum mechanics\, in particular at the q
uantum-classical border. The present linear theory differs from the nonlin
ear ensemble theory of Hall and Reginatto\, but shares with it to fulfill
all consistency requirements discussed in the literature\, while earlier a
ttempts failed to do this. Our work is based on a representation of quantu
m mechanics in the framework of classical analytical mechanics\, showing t
hat notions of states in phase space\, observables\, Poisson brackets\, an
d related canonical transformations can be naturally extended to quantum m
echanics and generalized for quantum-classical hybrids (arXiv:1111.2276 an
d 1202.3448). Classically induced decoherence\, backreaction\, separable i
nteractions\, enlarged algebra of observables\, (non)locality\, and “fre
e will” can be discussed here.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Sabine Lennartz
DTSTART;VALUE=DATE-TIME:20120518T163000
DTEND;VALUE=DATE-TIME:20120518T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000157@events.thp.uni-koeln.de
DESCRIPTION:Dr. Sabine Lennartz\, University of Edinburgh\n\nInverse power
-law like crack growth in earth materials and its possible origin as an em
ergent property of localisation\n\nThe origin and development of cracks in
earth materials is a subject of\ngeneral interest and wide application: f
rom seismologists studying\nearthquakes to engineers studying the strength
of materials. Therefore\nmany laboratory experiments have been carried ou
t to investigate the\nresponse of rocks to an applied differential stress\
, often using\nacoustic emissions (AE) to track intermittent crack growth
inside the\nrock specimen prior to system-sized sample failure. Under a co
nstant\napplied stress in double-torsion tensile tests with a guide groove
and a\nsingle dominant crack\, independent observations of the stress int
ensity\nfactor and crack growth velocity imply the size of the largest (su
b-)\ncritical crack grows with time t according to an inverse power-law. \
nA similar law holds for the mean crack length in a\npopulation of micro-c
racks growing under compressional stress with no\npre-defined fault plane\
, often treated using mean field models that\nignore localisation of damag
e clearly seen in the experiments. Here I\npresent a new hypothesis for th
e origin of this formula by combining\nexpressions for crack population gr
owth and localisation in a single\nmodel. The model is tested and some of
its parameters inferred from\nanalysis of the AE rate and the spatial clus
tering of its source\nlocations from laboratory data.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Alexander Altland
DTSTART;VALUE=DATE-TIME:20120420T163000
DTEND;VALUE=DATE-TIME:20120420T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000158@events.thp.uni-koeln.de
DESCRIPTION:Prof. Alexander Altland\, University of Cologne\n\nQuantum the
rmalization\n\nIn this talk\, I will discuss mechanisms by which (nonlinea
r) quantum systems effectively 'thermalize' into long time stationary dist
ributions. \nFocusing on the paradigmatic example of the Dicke model (a la
rge spin coupled to a boson mode)\, I will demonstrate how a constructive
description of the thermalization process is\nfacilitated by the Glauber Q
or Husimi function\, for which the evolution equation turns out to be of
Fokker-Planck type. The equation describes a competition of classical inst
abilities\nand quantum diffusion. By this mechanism the system follows a "
quantum smoothened" approach to equilibrium\, which avoids the notorious s
ingularities inherent to classical chaotic flows.\nI will touch upon the r
elevance of the above picture to recent experiments in cold atom physics.\
n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Dr. I. Müller
DTSTART;VALUE=DATE-TIME:20120525T163000
DTEND;VALUE=DATE-TIME:20120525T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000159@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. I. Müller\, TU Berlin\n\nThe terroristic nimbus of
entropy - on the history of thermodynamics\n\nThe development of thermodyn
amics in the second half of the \n19th century has had a strong impact on
both technology and \nnatural philosophy.\nIt is true that the steam engin
e for the conversion of heat \ninto work existed before thermodynamics was
developed as a \nbranch of physics. However\, the systematic theory impro
ved \nthe conversion process\, and it succeeded in developing other \nproc
esses essential to modern life\, notably refrigeration and \nrectification
. So\, altogether thermodynamics has provided \nhumanity with cheap energy
\, and cheap fuel\, - consequently \nwith cheap\, and abundant\, and unspo
iled food. Thus \nthermodynamics has made populations grow\, and life expe
ctancy \nincrease beyond anything people could possibly have imagined \n20
0 years ago. \nAt the same time thermodynamics has uncovered the precariou
s \nbalance between determinism and stochasticity which is essential \nto
processes on earth\, including life. The competition of those \nintentions
is described by the doctrine of energy and entropy \nin thermodynamics\;
energy tends to force a system into one \nsingle state\, and entropy tends
to spread the system evenly \nover all possible states. These competing t
endencies are weighed by\ntemperature such that minimal energy determines
cold systems and\nmaximal entropy determines hot systems.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Boris Gutkin
DTSTART;VALUE=DATE-TIME:20120413T163000
DTEND;VALUE=DATE-TIME:20120413T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000160@events.thp.uni-koeln.de
DESCRIPTION:Dr. Boris Gutkin\, University of Duisburg-Essen\n\nClustering
of periodic orbits in chaotic systems\n\nStatistics of energy levels in Ha
miltonian systems with classically\nchaotic dynamics belong to one of thre
e Wigner-Dyson symmetry classes. By\nthe semiclassical approach this remar
kable universality can be attributed\nto the systematic correlations betwe
en actions of periodic orbits. The\ncorrelating periodic orbits do not exi
st as independent individuals\nbut rather come in closely packed bunches.
We demonstrate how this\nbunching phenomena can be rigorously described us
ing symbolic\ndynamics of the system.\n\nFor systems with Markov partition
we introduce an ultrametric\ndistance between periodic orbits and organiz
e them into clusters.\nEach cluster is composed of periodic orbits passin
g through\n(approximately) the same points of the phase space. We then stu
dy the\ndistribution of cluster sizes in the asymptotic limit of long\ntra
jectories. In the case of the baker's map this problem turns out to be\neq
uivalent to the one of counting degeneracies in the length spectrum\nof de
Bruijn graphs.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Prof. Dr. Albrecht Beutelspacher
DTSTART;VALUE=DATE-TIME:20120417T164500
DTEND;VALUE=DATE-TIME:20120417T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000161@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Albrecht Beutelspacher\, Mathematisches Institut\, J
ustus-Liebig-Universitä\;t Gieß\;en\n\nMathematische Experimente\
n\nIn dem Vortrag "Mathematische Experimente" fü\;hrt Professor Beutel
spacher\nmit Hilfe einfachster Materialien faszinierende Experimente vor \
nund erlä\;utert deren mathematische Bedeutung. All diese Experimente\
nkö\;nnen von den Zuhö\;rern zu Hause direkt nachgemacht werden.\n
\nProfessor Beutelspacher ist Professor für Geometrie und Diskrete\nMathe
matik am Mathematischen Institut der Justus-Liebig-Universitä\;t\nGie
ßen und Leiter des Mathematikums in Gieß\;en. Dort hat auch die\nbek
annte Wanderausstellung "Mathematik zum Anfassen" ihren\nAusgangspunkt. P
rofessor Beutelspacher wurde mehrfach ausgezeichnet\,\nunter anderem mit d
em Communicator Preis für herausragende Leistungen\nin der Vermittlung se
iner Wissenschaft in die Ö\;ffentlichkeit.
LOCATION:Lecture Hall 1
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Prof. Dr. Karsten Kruse
DTSTART;VALUE=DATE-TIME:20120424T164500
DTEND;VALUE=DATE-TIME:20120424T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000162@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Karsten Kruse\, Theoretische Biologische Physik\, Un
iversitaä\;t des Saarlandes\n\nCellular protein self-organization\n\nT
o understand the emergence of spatiotemporal structures in biological syst
ems \nremains a major challenge to this day. Self-organization of a limite
d number\nof different agents has been found to account for structure form
ation in \nsea shells\, slime mold aggregation\, and bee colonies. On a su
bcellular level\,\nhowever\, the importance of self-organization of prote
ins and other molecules \nfor forming vital structures is still debated. I
n this talk\, I will discuss recent \nexperimental and theoretical advance
s that indicate that self-organization plays \nan important role in cellul
ar processes like cell division and cell locomotion.\nSpecifically\, I wil
l discuss patterns formed by the Min proteins in the \nbacterium Escherich
ia coli as well as cytoskeletal polymerization waves in animal cells. \nTo
gether these results show how physical concepts and methods can help\nus t
o understand life.
LOCATION:Lecture Hall 3
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Mark Oliver Goerbig
DTSTART;VALUE=DATE-TIME:20120504T163000
DTEND;VALUE=DATE-TIME:20120504T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000163@events.thp.uni-koeln.de
DESCRIPTION:Dr. Mark Oliver Goerbig\, Universite Paris Sud\n\nGraphene Fra
ctional Quantum Hall Effect and Internal Symmetries\n\nA milestone in grap
hene research was the 2005 discovery of an \ninteger quantum Hall effect.
In contrast to its manifestation \nin conventional two-dimensional (2D) el
ectron systems\, such \nas in semiconductor heterostructures\, the graphen
e quantum \nHall effect reflects the "ultra-relativistic" character of \nt
he underlying carriers\, via a particular sequence of plateaus \nin the tr
ansverse Hall resistance.\n\nIn view of the fractional cousin of the integ
er quantum Hall \neffect in 2D electron systems\, one may thus naturally a
sk the \nquestion about a fractional quantum Hall effect in graphene. \nDo
es it also reflect the ultra-relativistic character of the \ncharge carrie
rs? To what extent is it different from the \nfractional quantum Hall effe
ct in (non-relativistic) \nsemiconductor heterostructures? Many of these q
uestions remain \nopen from an experimental point of view\, although some
\nfractional states have recently been observed in transport \nand spectro
scopic measurements.\n\nThis talk aims at a theoretical perspective on the
fractional \nquantum Hall effect in graphene\, namely in view of its \nmu
lti-component character due to the fourfold spin-valley \ndegeneracy\, whi
ch gives rise to an internal SU(4) symmetry \nand that is approximately re
spected by the underlying \nelectron-electron interactions. This theoretic
al perspective \nwill be confronted with recent experimental advances.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Wojciech De Roeck
DTSTART;VALUE=DATE-TIME:20120427T163000
DTEND;VALUE=DATE-TIME:20120427T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000164@events.thp.uni-koeln.de
DESCRIPTION:Dr. Wojciech De Roeck\, University of Cologne\n\nA rigorous ap
proach to quantum Brownian motion\n\nThis talk concerns the rigorous deriv
ation of diffusion\, thermalization and decoherence in simple quantum syst
ems: a spin or a particle interacting with phonons.\nOur approach takes th
e Markovian description (Pauli master equation or quantum Boltzmann equati
on) as a starting point. However\, since such a Markovian description is o
nly valid in a\ncertain scaling limit (vanishing coupling constant and lon
g time)\, we develop an expansion around the Markovian description to cont
rol the behavior at finite coupling constant. This\nexpansion consists of
a controlled renormalization group flow with Brownian motion as the fix-p
oint solution.\n\nThe long-range nature of the velocity-velocity correlati
on function is an example of a physical quantity that is not described cor
rectly within the Markovian description (cfr. Alder-Wainwright)\, but that
is captured by our approach.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Bela Bauer
DTSTART;VALUE=DATE-TIME:20120502T100000
DTEND;VALUE=DATE-TIME:20120502T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000165@events.thp.uni-koeln.de
DESCRIPTION:Bela Bauer\, Station Q\n\nEffect of thermal fluctuations in to
pological p-wave superconductors\n\nWe study the effect of thermal fluctua
tions on the topological properties of chiral p-wave superconductors. In p
articular\, we allow for thermally excited topological defects – vortice
s and anti-vortices. We find that the topological degeneracy remains robus
t as long as topological excitations remain paired. Above the KT transitio
n\, disorder-driven low-energy modes give rise to either a thermal metal o
r a non-topological thermal insulating phase\, which have a drastically di
fferent splitting of the topological degeneracy. We can relate these resul
ts from the point of view of localization-delocalization transition studie
d in the context of disordered superconductors breaking time-reversal and
spin symmetry.\n
LOCATION:Seminarraum II. Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Emanuel Gull
DTSTART;VALUE=DATE-TIME:20120427T140000
DTEND;VALUE=DATE-TIME:20120427T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000166@events.thp.uni-koeln.de
DESCRIPTION:Emanuel Gull\, MPI PKS Dresden\n\nSuperconductivity and the Ps
eudogap in the 2d Hubbard model\n\nUsing a numerically exact continuous-ti
me quantum Monte Carlo impurity solver and the DCA cluster dynamical mean
field method with cluster sizes up to 16\, we have been able to access the
superconducting phase of the two dimensional Hubbard model for parameters
believed to be relevant to high temperature copper oxide superconductivit
y. We present results for the phase diagram\, the gap to transition temper
ature ratio\, and the interplay of the pseudogap and the superconducting g
ap. The gap results are obtained by direct inference from imaginary freque
ncy data and analytically continued spectral functions.\nWork done in coll
aboration with Olivier Parcollet and Andrew J. Millis\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Prof. Dr. Stefan Rahmstorf
DTSTART;VALUE=DATE-TIME:20120507T170000
DTEND;VALUE=DATE-TIME:20120507T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000167@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Stefan Rahmstorf\, Potsdam-Institut für Klimafolgen
forschung\n\nZunahme von Temperaturextremen durch die globale Klimaerwärm
ung\n\nWie beeinflusst die globale Klimaerwärmung die Häufigkeit von\nW
ärmerekorden? Diese Frage wird oft auch in der Öffentlichkeit\ndiskutier
t. Dabei sind Rekorde nicht nur für die Medien interessant\,\nsondern auc
h wissenschaftlich eine besonders dankbare Art der Extreme\,\nda über Rek
orde einige statistische Aussagen möglich sind ohne die\nVerteilungsfunkt
ion zu kennen. Das unterscheidet Rekorde von Extremen\,\ndie z.B. als Übe
rschreitung eines vorgegebenen Temperaturwertes\ndefiniert sind. Wir haben
das Auftreten von Rekorden in der globalen\nDurchschnittstemperatur analy
siert ebenso wie in lokalen\nMonatsmitteltemperaturen. Dabei zeigt sich\,
dass weltweit die Häufigkeit\nvon Wärmerekorden in lokalen Monatstempera
turen heute rund fünf mal so\nhoch ist\, wie sie in einem stationären Kl
ima (also ohne Klimaerwärmung)\nwäre.\n
LOCATION:Geo-Bio Hörsaal
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Kirill Shtengel
DTSTART;VALUE=DATE-TIME:20120511T163000
DTEND;VALUE=DATE-TIME:20120511T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000168@events.thp.uni-koeln.de
DESCRIPTION:Prof. Kirill Shtengel\, UC Riverside\n\nNon-Abelian anyons: Ne
w particles for less than a billion\n\nStates of matter are conventionally
classified according to broken\nsymmetries. Topologically ordered phases
fall outside of this paradigm:\nwith no local order parameter\, they never
theless have many peculiar\nproperties setting them apart from disordered
phases. In 2D\, such\nphases may support anyons - quasiparticles that are
neither bosons\nnor fermions. Moreover\, anyons with non-Abelian statistic
s are\nexpected to occur in certain fractional quantum Hall systems as wel
l\nas materials supporting topological superconductivity (intrinsic or\nin
duced).\nIn this talk\, I will discuss various approaches designed to\ndet
ect such exotic statistics. I will also describe our recent\nproposal for
novel physical systems supporting unusual non-Abelian\nanyons. I will also
mention potential applications of such systems for\ntopological quantum c
omputation.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Gunnar Möller
DTSTART;VALUE=DATE-TIME:20120504T140000
DTEND;VALUE=DATE-TIME:20120504T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000169@events.thp.uni-koeln.de
DESCRIPTION:Gunnar Möller\, Cambridge University\n\nNeutral Fermion Excit
ations in the Moore-Read State at Filling Factor &nu\;=5/2\n\nWe present e
vidence supporting the weakly paired Moore-Read phase in the half-filled s
econd Landau level\, focusing on some of the qualitative features of its e
xcitations. Based on numerical studies\, we show that systems with odd par
ticle number at the flux N_&phi\;=2N-3 can be interpreted as a neutral fer
mion mode of one unpaired fermion\, which is gapped. The mode is found to
have two distinct minima\, providing a signature that could be observed by
photoluminescence (PL). In this context\, we briefly review the role of s
kyrmion excitations in PL experiments. In the presence of two quasiparticl
es the same neutral fermion excitation is shown to be gapless\, confirming
expectations for non-Abelian statistics of the Ising model with degenerat
e fusion channels 1 and &psi\;.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Subir Sachdev
DTSTART;VALUE=DATE-TIME:20120608T163000
DTEND;VALUE=DATE-TIME:20120608T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000170@events.thp.uni-koeln.de
DESCRIPTION:Prof. Subir Sachdev\, Harvard\n\nStrange metals: field theory
versus gauge-gravity duality\n\nThe description of non-Fermi liquid metals
is one of the central problems in the theory of correlated electron syste
ms. I present a holographic theory which builds on general features of the
thermal entropy density and the entanglement entropy. Remarkable connecti
ons emerge between the holographic approach\, and the postulated strong-co
upling behavior of the field theory.\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Kai P. Schmidt
DTSTART;VALUE=DATE-TIME:20120601T140000
DTEND;VALUE=DATE-TIME:20120601T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000171@events.thp.uni-koeln.de
DESCRIPTION:Kai P. Schmidt\, TU Dortmund\n\nEffective models for spin liqu
id phases in Hubbard models\n\nThe Hubbard model is one of the most studie
d microscopic models in condensed matter physics. It describes on a very s
imple level the interplay between the kinetics and the Coulomb interaction
of electrons in solid state systems. Generically\, one expects at half fi
lling a metallic phase for large kinetics while a Mott insulator is presen
t for large interactions. In most cases the Mott phase shows additionally
long-range spin order\, since the Hubbard model can be mapped to a Heisenb
erg model in the strong-coupling limit. A direct transition between the me
tal and the long-range ordered Mott insulator was considered to be the sta
ndard case for a long time.\n\nBut in recent years there are more and more
evidences that especially on frustrated lattices there is the possibility
of exotic and insulating intermediate phases without long range order. It
is therefore an obviously relevant question what kind of effective low-en
ergy theory describes such Mott phases and how to derive them. This is par
ticular complicated when the spin liquid is located close to the metal-ins
ulator transition as for the recently discovered spin liquid of the Hubbar
d model on the honeycomb lattice. In this talk we discuss these issues for
the Mott phase of the Hubbard model on the triangular and on the honeycom
b lattice.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Lode Pollet
DTSTART;VALUE=DATE-TIME:20120511T140000
DTEND;VALUE=DATE-TIME:20120511T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000172@events.thp.uni-koeln.de
DESCRIPTION:Lode Pollet\, LMU München\n\nBose-Fermi mixtures: The Cooper
problem and beyond in Bose-Fermi mixtures\n\nWe calculate the phase diagra
m of the Bose-Fermi Hubbard model on the 3d cubic lattice at fermionic hal
f filling and bosonic unity filling by means of single-site dynamical mean
-field theory (DMFT). For fast bosons\, this is the Cooper problem in whic
h the bosons can induce s-wave pairing\, even between repulsively interact
ing fermions. Superfluid and supersolid phases are found\, depending on th
e interspecies coupling strength. The modifications in the phase diagram c
ompared to the purely fermionic case are well explained by renormalized ho
ppings and on-site interactions. Slow bosons favor fermionic charge densit
y wave structures for attractive fermionic interactions.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Yoshio Kuramoto
DTSTART;VALUE=DATE-TIME:20120518T140000
DTEND;VALUE=DATE-TIME:20120518T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000173@events.thp.uni-koeln.de
DESCRIPTION:Yoshio Kuramoto\, Tohoku University\n\n Exotic orders in heavy
electron systems\n\nSome f-electron systems such as URu2Si2 and PrFe4P12
show ordered phases where the order parameter is difficult to identify. Th
ese systems are characterized by the non-Kramers configuration where the n
umber of f -electrons per site is even. We have studied generalized Kondo
lattice models for such non-Kramers systems\, and have found a new kind of
orders by combining the dynamical mean-field theory and the continuous-ti
me quantum Monte Carlo calculation. In the case of two-channel Kondo latti
ce with two conduction electrons per site\, for example\, a strange order
emerges where the one-body quantities such as magnetization and charge den
sity remain the same as in the high- temperature phase. The (hidden) order
parameter Ψ at each site is given by Ψ = ⟨S · (s1 − s2)⟩ where S
is the localized pseudo spin and si (i = 1\, 2) is the pseudo spin of con
duction channel i at the same site. This order can be interpreted as itine
rant higher multipoles of electrons\, and also as analogue of the composit
e superconducting order with odd frequency pairing amplitude. We also disc
uss other exotic orders and implication of our results in actual f-electro
n systems.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Gregor Wergen
DTSTART;VALUE=DATE-TIME:20120515T121500
DTEND;VALUE=DATE-TIME:20120515T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000174@events.thp.uni-koeln.de
DESCRIPTION:Gregor Wergen\, Institute for Theoretical Physics\, Cologne\n\
nRecord Statistics for Multiple Random Walks\n\nI will discuss the statist
ics of the number of records for N identical\nand independent symmetric di
screte-time random walks. At each time step\,\neach walker jumps by a rand
om length drawn independently from a\nsymmetric and continuous distributio
n. One has to distinguish between\ntwo cases: (I) when the variance of the
jump distribution is finite and\n(II) when it is divergent as in the case
of Levy flights. In both\ncases the mean record number grows universally
with the square root of n\nfor large n\, but with a very different behavio
r of the amplitude in the\ntwo cases. For a finite variance I will argue\,
and this is confirmed by\nnumerical simulations\, that the full distribut
ion of the record number\nconverges to a Gumbel law for large n. In case I
I\, numerical simulations\nindicate that the distribution of the record nu
mber converges\, for large\nn and N\, to a universal nontrivial distributi
on\, independently of the\nLevy index. I also discuss an application of th
ese results to the\nstudy of the record statistics of daily stock prices.
LOCATION:Konferenzraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Steffen Karalus
DTSTART;VALUE=DATE-TIME:20120605T120000
DTEND;VALUE=DATE-TIME:20120605T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000175@events.thp.uni-koeln.de
DESCRIPTION:Steffen Karalus\, Institute for Theoretical Physics\, Cologne\
n\nNetwork evolution towards optimal dynamical behavior\n\nUnderstanding t
he mutual interdependence between the behavior of dynamical processes on n
etworks and the underlying topologies promises new insight for a large cla
ss of empirical networks. We present a generic approach to investigate thi
s relationship which is applicable to a wide class of dynamics\, namely to
evolve networks using a performance measure based on the whole spectrum o
f the dynamics' time evolution operator. As an example\, we consider the g
raph Laplacian describing diffusion processes\, and we evolve the network
structure such that a given sub-diffusive behavior emerges.\n
LOCATION:Konferenzraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Thomas Quella
DTSTART;VALUE=DATE-TIME:20120529T164500
DTEND;VALUE=DATE-TIME:20120529T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000176@events.thp.uni-koeln.de
DESCRIPTION:Thomas Quella\, Universität zu Köln\n\nConformal superspace
sigma-models\n\nMany physical phenomena such as quark confinement and the
fractional quantum Hall effect arise at strong coupling\, thus making a pe
rturbative treatment impossible. Occasionally\, a good description can nev
ertheless be found which involves effective degrees of freedom - different
from the fundamental ones and adapted to the specific situation at hand.
In such a situation one would speak about a duality. In 1+1 or 2 dimension
s there is a wealth of dualities\, some of which are extremely well unders
tood. In higher dimensions\, the best known duality is the celebrated AdS/
CFT correspondence\, a concrete realization of the holographic principle.\
n\nThe "conformal superspace sigma-models" featuring in the title are a sp
ecial class of strongly coupled supersymmetric 2D quantum field theories w
hich naturally arise in the context of the AdS/CFT correspondence (but als
o in the theory of disordered systems). As will be discussed\, the underly
ing supergeometry allows for the derivation of exact partition functions b
ut it also leads to a few unusual peculiarities. As an application\, we co
nclude with arguments in favor of a supersymmetric duality which generaliz
es the well-known bosonization of a Luttinger liquid.
LOCATION:Hörsaal 3
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Jakub Otwinowski
DTSTART;VALUE=DATE-TIME:20120619T130000
DTEND;VALUE=DATE-TIME:20120619T140000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000177@events.thp.uni-koeln.de
DESCRIPTION:Jakub Otwinowski\, Department of Physics\, Emory University\n\
nFitness landscape of an E. coli lac promoter\n\nWe infer a large fitness
landscape from high-throughput sequence data\nfrom the E. coli lac promote
r region with ~200k sequences. The\nsequences are associated with measurem
ents of transcriptional\nactivity. Utilizing linear regression and L1 regu
larization (LASSO)\,\nwe find the best linear and quadratic approximations
to fit the data.\nWe find the fitness landscape to be largely smooth and
additive\, with\na small amount of epistasis. Our method also reveals the
locations of\nbinding sites\, and their interactions without any prior kno
wledge and\nwithout any difficult optimization steps.
LOCATION:Konferenzraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Dr. Heiko Rieger
DTSTART;VALUE=DATE-TIME:20120615T163000
DTEND;VALUE=DATE-TIME:20120615T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000178@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Heiko Rieger\, Universität des Saarlandes\n\nBiophy
sical models for tumor growth\n\nTumor growth is a multifactorial process
that surely emerges from molecular and genetic abnormalities\, but also de
pends strongly on cell-cell and cell-extracellular matrix macroscopic\nreg
ulations and interactions. Numerous models have been developed to understa
nd the mechanisms controlling solid tumor morphogenesis: While the earlies
t efforts were focusing on cell\nproliferation kinetics\, modulated by the
availability of supplied nutrients\, new approaches emphasize the crucial
role of several biophysical processes\, including local matrix\nremodelin
g\, active cell migration and traction\, and reshaping of the host tissue
blood vessel network. In this talk a brief review over a number of represe
ntative models will be given\,\nin particular those predicting the emergen
ce of invasive behavior through growth instabilities at the tumor-host int
erface. Then the focus will be put on the analysis of vascular\nremodeling
during tumor growth within a theoretical model including angiogenesis\, c
ooption and regression of blood vessels. The physical mechanisms determini
ng the morphological and\nhydrodynamical characteristics of the emerging t
umor vasculature are analyzed and implications for blood borne drug delive
ry are discussed.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Dr. Eva Hackmann
DTSTART;VALUE=DATE-TIME:20120522T120000
DTEND;VALUE=DATE-TIME:20120522T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000179@events.thp.uni-koeln.de
DESCRIPTION:Dr. Eva Hackmann\, Universität Bremen\n\nStructure and analyt
ical solutions of orbits in axially symmetric space-times \n\nThe structur
e of solutions of the geodesic equations in general axially symmetric spac
e-times can be very complex and differs significantly from the plane conic
sections of Newtonian gravity. Each space-time exhibits an individual set
of geodesics which allows to conclude from the observation of orbits on t
he physical properties of the underlying space-time. The complete set of s
olutions of the geodesic equation in a given space-time can be studied mos
t conveniently by using analytical methods. In the case of type D space-ti
mes with separable Hamilton-Jacobi equation the analytical solutions can b
e constructed in terms of elliptic or the more general hyperelliptic funct
ions. In this talk the structure of orbits and the construction of analyti
cal solutions will be exemplified in some type D space-times.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Prof. Ofer Biham
DTSTART;VALUE=DATE-TIME:20120706T144500
DTEND;VALUE=DATE-TIME:20120706T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000180@events.thp.uni-koeln.de
DESCRIPTION:Prof. Ofer Biham\, Racah Institute of Physics\, Hebrew Univers
ity of Jerusalem\n\nCompetition\, feedback and fluctuations in genetic reg
ulatory modules\n\nI will describe the modeling of several genetic regulat
ory modules\nin cells and analyze the effects of competition\, feedback an
d\nfluctuations in these systems using deterministic and stochastic\nmetho
ds. The genetic networks to be considered involve a combination\nof transc
riptional regulation\, regulation by small non-coding RNA's\nand protein-p
rotein interactions. The effects of competition\, feedback\nand fluctuatio
ns on each one of these regulation mechanisms will be\ndiscussed. I will p
resent results obtained using a\ncombination of deterministic and stochast
ic methods\, including\nrate equations\, direct integration of the master
equation and\nMonte Carlo simulations.\n
LOCATION:Institute for Genetics\, New Seminar Room\, Ground Floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Martin Evans
DTSTART;VALUE=DATE-TIME:20120713T163000
DTEND;VALUE=DATE-TIME:20120713T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000181@events.thp.uni-koeln.de
DESCRIPTION:Prof. Martin Evans\, University of Edinburgh\n\nDiffusion with
stochastic resetting\n\n"Stochastic resetting" is a rather common process
in everyday\nlife. Consider searching for some target such as\, for examp
le\, a face in a\ncrowd or one's misplaced keys at home. A natural tendenc
y is\, on having\nsearched unsuccessfully for a while\, to return to the s
tarting point and\nrecommence the search. In this talk I explore the conse
quences of such\nresetting on perhaps the most simple and common process i
n nature\, namely\,\nthe diffusion of a single or a multiparticle system.
It turns out that a\nnonzero rate of resetting has a rather rich and drama
tic effect on the\ndiffusion process\, strongly affecting the behaviour of
mean first passage\ntimes and survival probabilities.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB608 | Dr. Martin Galpin
DTSTART;VALUE=DATE-TIME:20120629T140000
DTEND;VALUE=DATE-TIME:20120629T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000182@events.thp.uni-koeln.de
DESCRIPTION:Dr. Martin Galpin\, Oxford University\n\nThe local moment appr
oach to quantum impurity models\n\nThe local moment approach (LMA) has bee
n successfully applied to a\nnumber of quantum impurity models over the la
st 15 years. In this talk I shall\ngive a pedagogical review of the techni
que\, focusing on its basic underlying\nideas and the insights it can prov
ide into the Anderson impurity model and\ngeneralizations thereof.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Pascal Simon
DTSTART;VALUE=DATE-TIME:20120706T163000
DTEND;VALUE=DATE-TIME:20120706T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000183@events.thp.uni-koeln.de
DESCRIPTION:Pascal Simon\, Université Paris Sud\n\nMajorana polarization
and transport properties in 1D topological superconductors\n\nI will prese
nt recent results on a one-dimensional wire with strong Rashba\nand Dresse
lhaus spin-orbit coupling (SOC)\, which supports Majorana\nfermions when s
ubject to a Zeeman magnetic field and in proximity of a\nsuperconductor. B
y introducing a new local quantity dubbed as "Majorana\npolarization"\, I
will argue that it can be used as a local order\nparameter to characteriz
e the topological transition between a trivial\nsystem and a system exhibi
ting Majorana bound modes. We have found that\nthe local "Majorana polariz
ation" is correlated to the transverse spin\npolarization\, and we propose
to test the presence of Majorana fermions in\na 1D system by a spin-polar
ized density of states measurement. Such\nquantity turns out to be very us
eful to analyze one-dimensional\ntopological SN and SNS long junctions obt
ained by placing a topological\ninsulating nanowire in the proximity of ei
ther one or two superconducting\nfinite-size leads: for a finite-size SN j
unction the Andeev Bound States\n(ABS) spectrum exhibits a zero-energy ext
ended state which carries a full\nMajorana fermion\, while the ABS of long
SNS junctions with phase\ndifference pi transform into two zero-energy st
ates carrying two\nMajorana fermions.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Prof. Martin Bojowald
DTSTART;VALUE=DATE-TIME:20120703T120000
DTEND;VALUE=DATE-TIME:20120703T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000184@events.thp.uni-koeln.de
DESCRIPTION:Prof. Martin Bojowald\, Penn State University\, USA\n\nSignatu
re change in loop quantum gravity\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | André Großardt
DTSTART;VALUE=DATE-TIME:20120710T120000
DTEND;VALUE=DATE-TIME:20120710T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000185@events.thp.uni-koeln.de
DESCRIPTION:André Großardt \, Universität Bremen\n\nSchrödinger–Newt
on equation as a model for self-gravitating systems\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Prof. Dr. Mathias Kläui
DTSTART;VALUE=DATE-TIME:20120710T164500
DTEND;VALUE=DATE-TIME:20120710T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000186@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Mathias Kläui\, Institut für Physik\, Johannes Gut
enberg-Universität Mainz\n\nNew spintronics devices for green informati
on technology\n\nA key step to reducing power consumption of \nmobile devi
ces is to replace volatile memory \nby fast non-volatile spintronic memory
. \nNovel low power memories with switching by \nspin-polarized currents h
ave been proposed. \nWe study the rich physics of the interaction \nbetwee
n magnetization and spin currents as \nwell as photons\, and we use these
to excite \nspin dynamics and manipulate the magnetization \non ultrafast
timescales. We are probing \nthe magnetization dynamics to gauge the ultim
ate speed \nlimits of spin angular momentum transfer that governs device s
witching speed.
LOCATION:Lecture Theatre 3
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Prof. James M. Nester
DTSTART;VALUE=DATE-TIME:20120709T174500
DTEND;VALUE=DATE-TIME:20120709T190000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000187@events.thp.uni-koeln.de
DESCRIPTION:Prof. James M. Nester\, National Central University\, Chung-li
\, Taiwan\n\nGood dynamical torsion modes of spin zero: some cosmological
exploration\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Prof. Su-Chan Park
DTSTART;VALUE=DATE-TIME:20120719T140000
DTEND;VALUE=DATE-TIME:20120719T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000188@events.thp.uni-koeln.de
DESCRIPTION:Prof. Su-Chan Park\, Catholic University of Korea\n\nDynamic S
caling Behavior of a Directional Generalized Voter Model\n\nWe study the n
on-equilibrium dynamics of a one-dimensional\n directional voter model wit
h opinion exchange. The opinion of an individual\n at site i is denoted by
σi which can take either +1 or -1. If\n σi =+1 and σi+1 =-1 (+- domai
n wall)\, the opinion of\n both individuals can be either ++ or -- with pr
obability (1-α/2)\n [voter dynamics]\, but with probability α both indiv
iduals just\n exchange opinions without attaining a consensus [simple excl
usion process].\n Note that -+ domain wall does not induce any configurati
onal change. When\n α < 1\, the whole population eventually reaches a ful
l consensus. The\n way how the consensus is reached is described by decayi
ng behavior of the\n domain wall density ρ. For any α < 1\, ρ is found
to show a\n power-law decay behavior. Quite interestingly\, however\, the
exponent varies\n continuously with α\, from 0.5 (pure voter dynamics) to
0 (ASEP case).\n These results are obtained from both Monte-Carlo simulat
ions and spectral\n analysis of the time evolution operator.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Prof. Jeong-Man Park
DTSTART;VALUE=DATE-TIME:20120724T140000
DTEND;VALUE=DATE-TIME:20120724T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000189@events.thp.uni-koeln.de
DESCRIPTION:Prof. Jeong-Man Park\, Catholic University of Korea\n\nPopulat
ion Size Dependence of Evolutionary Paths in Bacteria\n\nWe consider the e
volution of large but finite populations on arbitrary\nfitness landscapes.
We describe the evolutionary process by a Markov\,\nMoran process. We sho
w that to O(1/N)\, the time-averaged fitness is\nlower for the finite popu
lation than it is for the infinite population. We also\nshow that fluctuat
ions in the number of individuals for a given genotype\ncan be proportiona
l to a power of the inverse of the mutation rate. Finally\,\nwe show that
the probability for the system to take a given path through\nthe fitness l
andscape can be non-monotonic in system size.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Paolo Politi
DTSTART;VALUE=DATE-TIME:20121123T163000
DTEND;VALUE=DATE-TIME:20121123T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000190@events.thp.uni-koeln.de
DESCRIPTION:Dr. Paolo Politi\, Istituto dei Sistemi Complessi\, Firenze\n\
nCoarsening: some answers to when and how it occurs\n\nMany out-of-equilib
rium systems undergo an instability when an order parameter is suitably tu
ned\, giving rise to well known and widespread processes: growth\, convect
ion\, phase separation\, and so on. A common feature is the emergence of a
nontrivial spatial structure\, whose typical scale L may display differen
t dynamics. We are specially interested in understanding when L increases
in time (coarsening process) and how. \nUsing a continuum modelling and a
multiscale approach\, for several equations we are able to obtain a phase
diffusion equation describing the dynamics of the emerging pattern and to
predict when and how coarsening proceeds.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:DIS | Simon Dettmer
DTSTART;VALUE=DATE-TIME:20120726T140000
DTEND;VALUE=DATE-TIME:20120726T143000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000191@events.thp.uni-koeln.de
DESCRIPTION:Simon Dettmer\, University of Cologne\n\nConvergence of the Pl
efka Expansion in 1D\n\nThe Plefka expansion is a method for approximately
analyzing complicated probabilistic systems such as those consisting of m
any interacting particles. In principle\, it consists of an expansion in t
he interaction strength around the non-interacting case. Important applic
ations are the calculation of expectation values of observables as well as
the problem of statistical inference encountered for example in the inver
se Ising problem. In order to assess the applicability of the expansion
to a specific system\, it is important to know the radius of convergence.
Unfortunately\, this radius is only known for very few systems\, the Sherr
ington-Kirkpatrick model of a spin glass being the most prominent one. Thi
s talk will introduce the general concept of the Plefka expansion applied
to the Ising model as well as explicitly derive the radius of convergence
for the 1D ferromagnet.
LOCATION:Conference Room THP
END:VEVENT
BEGIN:VEVENT
SUMMARY:DIS | Benjamin Schmiegelt
DTSTART;VALUE=DATE-TIME:20120726T143000
DTEND;VALUE=DATE-TIME:20120726T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000192@events.thp.uni-koeln.de
DESCRIPTION:Benjamin Schmiegelt\, University of Cologne\n\nEffects of neig
hborhood choice in NK fitness landscapes\n\nThe structure of fitness lands
capes\, which determine the behaviour of evolutionary processes through mu
tation and natural selection\, is an current issue of theoretical biology.
In this colloquium one aspect of the NK-model\, which is a biologically m
otivated construction for complex correlated fitness landscapes\, is analy
zed with regard to some typical characteristics of fitness landscapes. Thi
s aspect is tthe choice of the neighborhood describing the interaction bet
ween mutations at different genetic loci. It is shown by simulation that\,
although the fitness correlation does not depend on the choice of neighbo
rhood\, some global measures like the number of maxima and the number of e
volutionary accessible paths to the global maximum depend\, sometimes stro
ngly\, on that choice. Tested examples for choice of neighborhood are rand
om\, adjacent and block neighborhood. Also\, the distribution of evolution
ary accessible paths in the block model is derived from the distribution i
n the random energy model (House-of-Cards model).\n
LOCATION:Conference room THP
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Dr. Holger Hennig
DTSTART;VALUE=DATE-TIME:20120911T103000
DTEND;VALUE=DATE-TIME:20120911T120000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000193@events.thp.uni-koeln.de
DESCRIPTION:Dr. Holger Hennig\, Department of Physics\, Harvard University
\n\nThe nature of fluctuations in human musical rhythms\n\nAlthough human
musical performances represent one of the most valuable achievements of ma
nkind\, the best musicians perform imperfectly. Musical rhythms are not en
tirely accurate and thus\ninevitably deviate from the ideal beat pattern.
Nevertheless\, computer generated perfect beat patterns are frequently dev
alued by listeners due to a perceived lack of\nhuman touch. Professional a
udio editing software therefore offers a humanizing feature which artifici
ally generates rhythmic fluctuations. However\, the built-in humanizing un
its are\nessentially random number generators producing only simple uncorr
elated fluctuations. The nature of temporal fluctuations in complex human
musical rhythms has never been scrutinized as\nyet. Here\, I will show tha
t long-range correlations are an inevitable natural companion of both simp
le and complex human rhythmic performances. Moreover\, it will be demonstr
ated that\nlisteners strongly prefer long-range correlated fluctuations in
musical rhythms. Thus\, the favorable fluctuation type for humanizing int
erbeat intervals coincides with the one\ngenerically inherent in human mus
ical performances.
LOCATION:Seminarraum I. Physikalisches Institut
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Dirk Witthaut
DTSTART;VALUE=DATE-TIME:20121102T163000
DTEND;VALUE=DATE-TIME:20121102T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000194@events.thp.uni-koeln.de
DESCRIPTION:Dr. Dirk Witthaut\, Max Planck Institute for Dynamics and Self
-Organization\n\nSynchronization and Braess' paradox in an oscillator mode
l for power grid operation\n\nPower grids\, which form the cornerstone our
technical infrastructure\, will undergo a revolutionary change in the upc
oming decades driven by the advancement of renewable energy sources. Large
centralized power plants are put out of operation in favor of many small\
, distributed and potentially fluctuating generators. To face this enormou
s challenge for the reliable operation of the power grid\, both the struct
ure and control of the grid must undergo a radical change. This developmen
t must be supported by a great advancement of our theoretic understanding
of complex networked systems.\n\nIn this talk I discuss the collective dyn
amics of power grids using an idealized oscillator model that model grid d
ynamics on coarse scales. This model bridges the gap between abstract larg
e-scale\, basically structural network models from physics on the one hand
and detailed simulations of small electric engineering systems on the oth
er. I analyze self-organized synchronization of the grid depending on the
network topology and study the impact of dynamical perturbations and the i
nfluence of topological changes. I find that\, contrary to common intui
tion\, the addition of new transmission lines may reduce the overall grid
capacity and explain this phenomenon by geometric frustration in the oscil
lator model. \n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Miles Stoudenmire
DTSTART;VALUE=DATE-TIME:20120911T090000
DTEND;VALUE=DATE-TIME:20120911T100000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000195@events.thp.uni-koeln.de
DESCRIPTION:Miles Stoudenmire\, UC Irvine\n\nNew Tools for Simulating Real
istic Systems with the Density Matrix Renormalization Group (DMRG)\n\nThe
density matrix renormalization group (DMRG) is an extremely powerful techn
ique for solving interacting many-body systems\, but most applications of
DMRG have been to lattice models on one-dimensional chains or ladder geome
tries.\nI will describe recent advances in DMRG that make it practical to
explore richer classes of systems.\nIn one dimension\, we can now treat co
ntinuum models with long-range interactions with applications to electroni
c structure theory (especially density functional theory) and cold atom ex
periments.\nFor two-dimensional systems\, a new method for parallelizing D
MRG means we can apply an order of magnitude more power to reach new syste
m sizes.\nIf time permits\, I will also describe a promising extension of
DMRG for finite temperature systems.
LOCATION:Seminarraum II. Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Roger Melko
DTSTART;VALUE=DATE-TIME:20120914T100000
DTEND;VALUE=DATE-TIME:20120914T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000196@events.thp.uni-koeln.de
DESCRIPTION:Roger Melko\, Waterloo\, Canada\n\nSpin Liquid and Deconfined
Criticality in a Kagome Lattice Bose-Hubbard Model\n\nWe present quantum M
onte Carlo simulations on a sign-problem free Bose-Hubbard model on the ka
gome lattice.\nThis model supports a quantum Z2 spin liquid phase with fra
ctional excitations and topological order\, which can be characterized def
initively through calculation of the topological entanglement entropy.\nI
will outline how the entanglement entropy can be measured in general using
a direct implementation of the ``replica trick'' which allows for the stu
dy of entanglement scaling in a variety of other models amenable to study
by QMC.\nFinally\, I will examine the kagome model's superfluid/spin-liqui
d transition\, which is an example of an exotic deconfined quantum critica
l point called XY*\, mediated by the fractional charges.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Lars Fritz
DTSTART;VALUE=DATE-TIME:20121012T163000
DTEND;VALUE=DATE-TIME:20121012T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000197@events.thp.uni-koeln.de
DESCRIPTION:Dr. Lars Fritz\, University of Cologne\n\nTopological insulato
rs: magnetic fields\, disorder\, and interactions\n\nIn an introductory pa
rt I will discuss the relation between topological insulators and the arch
itectural challenge of building a bridge between Hongkong and mainland Chi
na. \nThen I discuss how a magnetic field induces one-dimensional edge cha
nnels when the two-dimensional surface states of three-dimensional topolog
ical insulators become gapped. Remarkably\, the Hall effect remains quanti
zed even in situations\, where the theta-term characteristic of the bulk a
nd the associated surface Hall conductivities are not quantized due to the
breaking of time-reversal symmetry. The quantization arises as the theta-
term changes by integer multiples along a loop around n edge channels. Mod
el calculations show how an interplay of orbital and Zeeman effects leads
to quantum Hall transitions\, where channels get redistributed along the e
dges of the crystal. The network of edges opens new possibilities to inves
tigate the coupling of edge channels.\nIn a last part I will shortly discu
ss aspects of strongly disordered topological insulators as well as intera
ction effects on the surfaces.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Prof. Dr. Immanuel Bloch
DTSTART;VALUE=DATE-TIME:20121016T164500
DTEND;VALUE=DATE-TIME:20121016T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000198@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Immanuel Bloch\, MPI für Quantenoptik\n\nErforschun
g der Quantenmaterie auf atomarer Ebene\n\nUltrakalte Gase bieten bemerken
swerte Möglichkeiten um das Verhalten stark korrelierter \nQuantensysteme
zu erforschen. In diesem Vortrag zeige ich\, wie es möglich ist solche G
ase \nin optischen Gittern auf der Ebene einzelner \nAtome abzubilden und
zu manipulieren. Diese Techniken haben uns erlaubt Higgs-artige \nAnregung
en in Vielteilchensystemen zu beobachten. Weitere Themen sind künstliche
\nEichfelder in ultrakalten Gasen\, mit denen magnetische Felder von mehre
ren tausend Tesla erzeugt werden können und Bose-Einstein \nKondensate be
i negativen Temperaturen.
LOCATION:Hörsaal 3
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Prof. Dr. Gil Refael
DTSTART;VALUE=DATE-TIME:20121030T164500
DTEND;VALUE=DATE-TIME:20121030T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000199@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Gil Refael\, Caltech\n\nMessy magnets and dirty supe
rfluids\n\nMagnets and superfluids provide the simplest \nexamples of symm
etry breaking and correlations in interacting quantum systems. When \ndiso
rder is thrown into the mix\, particularly in low-dimensional quantum syst
ems\, novel and universal behavior often emerges. In \nmy talk I will firs
t explore some surprising \neffects of disorder in systems of non-interact
ing electrons\, and magnetic chains. I will \nthen focus on the superfluid
-insulator transition for interacting bosons in a disordered \nenvironment
. Recent research on this system \nhas brought about a new understanding o
f \nsuperfluidity and its demise in low-dimensional disordered bosonic sys
tems
LOCATION:HS 3
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Prof. Dr. Rudolf Merkel
DTSTART;VALUE=DATE-TIME:20121127T164500
DTEND;VALUE=DATE-TIME:20121127T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000200@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Rudolf Merkel\, Institute of Complex Systems\, Jüli
ch\n\nMechanics and Living Cells - A Forceful Relation\n\nAt the microscop
ic level the correct working \nof our organism vitally depends on chemical
\nand physical signals. It was shown recently that signals of mechanical
nature result in \nvery profound effects on animal cells. Here\, \nconcept
s and techniques from physics are \nprofoundly changing the understanding
of \nbiological phenomena. We have developed \nmethods to apply defined me
chanical stimuli to cells and quantify their mechanical responses and acti
vity. Using such techniques \nwe\, and others\, are approaching the princi
ples underlying the intricate interplay of cells and forces.
LOCATION:Hörsaal 3
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Prof. Dr. E.F. van Dishoeck
DTSTART;VALUE=DATE-TIME:20121019T163000
DTEND;VALUE=DATE-TIME:20121019T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000201@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. E.F. van Dishoeck\, Sterrewacht Leiden\n\nBuilding s
tars\, planets and the ingredients for life between the stars\n\nOne of th
e most exciting developments in astronomy is the discovery of planets\naro
und stars other than our Sun. Nearly 1000 exo-planets have now been\ndetec
ted. But how do these planets form\, and why are they so different from\no
ur own solar system? Which ingredients are available to build them? How ar
e\ntheir parent stars formed?\nThanks to powerful new telescopes\, in part
icular the Herschel Space\nObservatory and pioneering ground-based and air
borne telescopes at infrared\nand millimeter wavelengths\, astronomers are
starting to address these age-old\nquestions scientifically. In this talk
\, an overview will be given of how stars and\nplanets are born in the ext
remely cold and tenuous clouds between the stars in\nthe Milky Way. Specia
l attention will be given to the formation of\nprotoplanetary disks in the
embedded phase and their evolution. These clouds\nalso contain water and
a surprisingly rich variety of organic material. How and\nwhere was the wa
ter formed that is now in our oceans on Earth? Can these\norganic molecule
s end up on new planets and form the basis for pre-biotic\nmaterial and ev
entually life?\nThe Atacama Large Millimeter/submillimeter Array (ALMA)\,
under construction\nin Chile and planned to be fully operational by late 2
013\, will be able to zoom\ninto the planet-forming zones of disks around
young stars and revolutionize\nthis field in the near future.\n
LOCATION:Hörsaal 1
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Madeleine Leiser
DTSTART;VALUE=DATE-TIME:20121122T163000
DTEND;VALUE=DATE-TIME:20121122T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000202@events.thp.uni-koeln.de
DESCRIPTION:Madeleine Leiser\, LMU\n\nChemical warfare and survival strate
gies in bacterial range expansions\n\n
LOCATION: Institute for Genetics\, Zülpicher Str. 47a\, Lecture Hall\, Gr
ound Floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Ilka Bischofs
DTSTART;VALUE=DATE-TIME:20130124T163000
DTEND;VALUE=DATE-TIME:20130124T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000203@events.thp.uni-koeln.de
DESCRIPTION:Ilka Bischofs\, BioQuant\, Heidelberg\n\nDesign principles fo
r quorum sensing networks\n\n
LOCATION:Institute for Genetics\, Zülpicher Str. 47a\, Lecture Hall\, Gro
und Floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Guido Sonnabend
DTSTART;VALUE=DATE-TIME:20121026T120000
DTEND;VALUE=DATE-TIME:20121026T124500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000204@events.thp.uni-koeln.de
DESCRIPTION:Guido Sonnabend\, 1. Physikalisches Institut\, Universität zu
Köln\n\nObservation of planetary atmospheres with
high-resolution infrared spectroscopy\n\nThis talk is on
e of a series of presentations of research groups organized by the Bonn-Co
logne Graduate School of Physics and Astronomy. The aim is to provide insi
ghts into the research done at physics institutes in Cologne. Interested s
tudents (Bachelor\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Professor Steven H. Simon
DTSTART;VALUE=DATE-TIME:20121109T163000
DTEND;VALUE=DATE-TIME:20121109T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000205@events.thp.uni-koeln.de
DESCRIPTION:Professor Steven H. Simon\, Rudolf Peierls Centre for Theoreti
cal Physics\, Oxford\n\nTopological Matter and Why You Should Be Intereste
d\n\nIn two dimensional topological phases of matter\, processes depend \n
on gross topology rather than detailed geometry. Thinking in 2+1 \ndimensi
ons\, particle world lines can be interpreted as knots or \nlinks\, and th
e amplitude for certain processes becomes a topological \ninvariant of tha
t link. While sounding rather exotic\, we believe \nthat such phases of ma
tter not only exist\, but have actually been \nobserved in quantum Hall ex
periments\, and could provide a uniquely \npractical route to building a q
uantum computer. Possibilities \nhave also been proposed for creating simi
lar physics in systems \nranging from superfluid helium to strontium ruthe
nate to \nsemiconductor-superconductor junctions to quantum wires to spin
\nsystems to cold atoms.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. K. Wolff
DTSTART;VALUE=DATE-TIME:20121116T163000
DTEND;VALUE=DATE-TIME:20121116T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000206@events.thp.uni-koeln.de
DESCRIPTION:Dr. K. Wolff\, TU Berlin \n\nActive particles and fluid flow\n
\nActive motion of particles in aqueous solution may lead to interesting \
ncollective phenomena such as pattern formation or macroscopic fluid flows
. I \nwill discuss two examples where this can be observed. First\, I will
present \nlattice Boltzmann simulations of a microscopic model for cytopl
asmic\nstreaming in algal cells. Here\, myosin motors entrain the surround
ing fluid by \nwalking along actin filaments while dragging vesicles or ot
her organelles. I \nwill pay particular attention to how the high speeds o
bserved in experiments can \nbe achieved by assuming a layer of lower visc
osity at the outer wall of the \nsimulated compartment. The second example
is a system of sedimenting \nself-propelled particles with the additional
property of bottom-heaviness\, which \nresults in a tendency of particles
to swim upwards. I will give analytical \nresults for the dilute limit an
d numerical results for the interacting case \nwhere particles form vortic
es and columns.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Prof. Berenike Maier
DTSTART;VALUE=DATE-TIME:20121123T120000
DTEND;VALUE=DATE-TIME:20121123T124500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000207@events.thp.uni-koeln.de
DESCRIPTION:Prof. Berenike Maier\, Institut für Theoretische Physik\, Uni
versität zu Köln\n\nThe biophysics of molecular motors \n\nThi
s talk is one of a series of presentations of research groups organized by
the Bonn-Cologne Graduate School of Physics and Astronomy. The aim is to
provide insights into the research done at physics institutes in Cologne.
Interested students (Bachelor\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Dr. Hideki Ohta
DTSTART;VALUE=DATE-TIME:20121204T120000
DTEND;VALUE=DATE-TIME:20121204T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000208@events.thp.uni-koeln.de
DESCRIPTION:Dr. Hideki Ohta\, University Paris-Sud\n\nDynamics of zero-tem
perature random-field Ising model on the Bethe lattice and its application
s\n\nI would like to talk about the zero-temperature Glauber dynamics of\n
a random-field Ising model on Bethe lattices. With a special initial condi
tion\,\nwe can exactly derive a macroscopically closed evolution equation\
,\nwhich determines a dynamical phase diagram related to avalanche phenome
na.\nI will mention a possible application of this analysis for epidemic n
etworks.\n
LOCATION:Konferenzraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Prof. A. Zilges
DTSTART;VALUE=DATE-TIME:20121207T124500
DTEND;VALUE=DATE-TIME:20121207T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000209@events.thp.uni-koeln.de
DESCRIPTION:Prof. A. Zilges\, Institut für Kernphysik\, Universität zu K
öln\n\n"Melting pots of the Universe" - Nuclear Astrophy
sics and Nuclear Structure\n\nThis talk is one of a series of pres
entations of research groups organized by the Bonn-Cologne Graduate School
of Physics and Astronomy. The aim is to provide insights into the researc
h done at physics institutes in Cologne. Interested students (Bachelor\, M
aster\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Mikel Fernández Méndez
DTSTART;VALUE=DATE-TIME:20121113T120000
DTEND;VALUE=DATE-TIME:20121113T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000210@events.thp.uni-koeln.de
DESCRIPTION:Mikel Fernández Méndez\, Instituto de Estructura de la Mater
ia\, CSIC\, Madrid\n\nQuantum cosmological perturbations in a Loop Quantum
Cosmology background\n\nWe introduce scalar perturbations in a homogeneou
s and isotropic universe with compact spatial sections filled with a massi
ve scalar field. The gauge freedom is then almost entirely removed by impo
sing two different sets of gauge-fixing conditions\, which lead to consist
ent results. We quantize completely the model by combining a polymer repre
sentation for the homogeneous degrees of freedom and a Fock representation
for the perturbations. Criteria of symmetry and unitary dynamics determin
e the latter uniquely. We also present an equivalent quantization in terms
of gauge-invariant variables. Moreover\, we propose a quantum implementat
ion of the Hamiltonian constraint whose solutions are totally characterize
d by their initial value on the minimum-volume section.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Silvia De Bianchi
DTSTART;VALUE=DATE-TIME:20121127T120000
DTEND;VALUE=DATE-TIME:20121127T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000211@events.thp.uni-koeln.de
DESCRIPTION:Silvia De Bianchi\, University College London\n\nKant’s cosm
ology and theory of matter: an answer to the 18th century astronomical rid
dles?\n\nBy taking into account Kant’s scientific background in the pre-
Critical writings\, it is possible to show the impact of traditional parad
oxes and dilemmas that grounded his cosmology and cosmogony. In the first
part of my contribution\, I shall expound the relevance of the Kepler and
Halley’s riddle\, better known as the starry-dark-sky paradox\, which ha
s been later discussed and formalized by Olbers in the 19th century. In th
e second part\, I shall clarify which elements of Kant’s cosmology can b
e read as an answer to this riddle\, involving a specific hierarchical str
ucture of the universe\, which is represented as an expanding sphere. In o
rder to highlight this conception\, I shall refer to the influence exerted
by Sir William Herschel on Kant’s Critical writings on natural science
and theory of matter\, as well as to the development of Kant’s transcend
ental philosophy that provided useful tools in order to clarify and solve
paradoxes and dilemmas of natural science.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Benjamin Eltzner
DTSTART;VALUE=DATE-TIME:20121204T120000
DTEND;VALUE=DATE-TIME:20121204T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000212@events.thp.uni-koeln.de
DESCRIPTION:Benjamin Eltzner\, Universität Leipzig\n\nLocal Thermal Equil
ibrium in Quantum Field Theory on Curved Spacetimes\n\nStates that describ
e thermodynamic equilibrium in the thermodynamic limit of infinite volume
cannot be described by density matrices in vacuum Fock space because of th
eir everywhere finite energy density. In the framework of algebraic quantu
m field theory on Minkowski spacetime\, such states can be readily describ
ed as expectation functionals with certain analyticity properties. In curv
ed spacetimes\, a globally defined temperature cannot generally be expecte
d to exist\, if the metric is not static. Therefore the description of the
rmal states is more difficult in this case. This talk explores the propose
d concept of local thermal equilibrium states and discusses problems that
arise even for the free scalar field in simple spacetime models.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Dr. M. Sornig
DTSTART;VALUE=DATE-TIME:20121123T124500
DTEND;VALUE=DATE-TIME:20121123T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000213@events.thp.uni-koeln.de
DESCRIPTION:Dr. M. Sornig\, 1. Physikalisches Institut\, Universität zu
Köln\n\nAtmospheres - Venus\, Earth\, Mars & Co\n\nThis talk is
one of a series of presentations of research groups organized by the Bonn-
Cologne Graduate School of Physics and Astronomy. The aim is to provide in
sights into the research done at physics institutes in Cologne. Interested
students (Bachelor\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | PD Dr. Th. Lorenz
DTSTART;VALUE=DATE-TIME:20121214T120000
DTEND;VALUE=DATE-TIME:20121214T124500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000214@events.thp.uni-koeln.de
DESCRIPTION:PD Dr. Th. Lorenz\, 2. Physikalisches Institut\, Universität
zu Köln\n\nQuantum spin systems: crystal growth\, thermodyna
mics and transport properties \n\nThis talk is one of a series of
presentations of research groups organized by the Bonn-Cologne Graduate Sc
hool of Physics and Astronomy. The aim is to provide insights into the res
earch done at physics institutes in Cologne. Interested students (Bachelor
\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | PD Dr. V. Ossenkopf
DTSTART;VALUE=DATE-TIME:20121214T124500
DTEND;VALUE=DATE-TIME:20121214T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000215@events.thp.uni-koeln.de
DESCRIPTION:PD Dr. V. Ossenkopf\, 1. Physikalisches Institut\, Universitä
t zu Köln\n\nSubmm-astronomy: observations and modellin
g\n\nThis talk is one of a series of presentations of research groups orga
nized by the Bonn-Cologne Graduate School of Physics and Astronomy. The ai
m is to provide insights into the research done at physics institutes in C
ologne. Interested students (Bachelor\, Master\, and PhD) are most welcome
.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. F. Assaad
DTSTART;VALUE=DATE-TIME:20130426T163000
DTEND;VALUE=DATE-TIME:20130426T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000241@events.thp.uni-koeln.de
DESCRIPTION:Prof. F. Assaad\, Universität Würzburg\n\nCorrelated topolog
ical insulators\n\nThe interplay of spin-orbit coupling and correlations o
pens a new \nplayground to study a variety of effects ranging from helical
\nLuttinger liquids to quantum spin systems generated by threading \npi-fl
uxes through correlated topological insulators. In this talk\, \nI will co
ncentrate on the Kane-Mele model supplemented by a Hubbard \nU. After disc
ussing the salient features of the non-interacting \nmodel - topological i
nvariants and edge states - I will concentrate\non the above mentioned cor
relations driven effects. The results \nobtained are based on large scale
quantum Monte Carlo simulations \nwhich turn out to be free of the infamou
s sign problem for this \nspecific class of models. \n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Prof. J. Krug
DTSTART;VALUE=DATE-TIME:20121207T120000
DTEND;VALUE=DATE-TIME:20121207T124500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000217@events.thp.uni-koeln.de
DESCRIPTION:Prof. J. Krug\, Institut für Theoretische Physik\, Universit
ät zu Köln\n\nBiological evolution and extreme value theory\n\nThis talk
is one of a series of presentations of research groups organized by the B
onn-Cologne Graduate School of Physics and Astronomy. The aim is to provid
e insights into the research done at physics institutes in Cologne. Intere
sted students (Bachelor\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Manuel Rabold
DTSTART;VALUE=DATE-TIME:20121218T120000
DTEND;VALUE=DATE-TIME:20121218T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000218@events.thp.uni-koeln.de
DESCRIPTION:Manuel Rabold\, Karlsruher Institut für Technologie\n\nProbin
g the Sensitivities of future Weak Lensing Surveys on cosmological Paramet
ers\n\nWeak gravitational lensing will be one of the key methods in the fu
ture of\ncosmology\, for the determination of cosmological parameters. Its
way of\nextracting statistical information from the formation of cosmic\n
structures\, poses a hybrid between the methods applied to the CMB and the
\nones applied to the matter density contrast\, in the mathematical\ndescr
iption. Since the deflection of light by mass through its gravity\,\ndoes
not distinguish between baryonic and dark matter\, an increased\nsensitivi
ty towards the latter one is expected\, compared to the\ntraditional sourc
es of information\, on a first point of view. Moreover\nthrough the applic
ation of tomographic binning in redshift space\, it is\nalso expected that
weak lensing will offer profound insights into the late\ntime evolution o
f cosmic structures\, therefore allowing for a closer\ndetermination of pa
rameters characterizing dark energy and neutrinos. At\nthe moment several
weak lensing surveys are planned. Among them the Large\nSynoptic Survey Te
lescope and the Euclid space probe. It is therefore\nimportant to a priori
evaluate their sensitivities on the cosmological\nparameters of interest.
A very nice way of doing this is through the\nFisher matrix method.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Florian Knorr
DTSTART;VALUE=DATE-TIME:20121218T120000
DTEND;VALUE=DATE-TIME:20121218T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000219@events.thp.uni-koeln.de
DESCRIPTION:Florian Knorr\, University of Duisburg-Essen\n\nCounting the c
orners of a random walk and its application to traffic flow\n\nMotivated b
y heterogeneous traffic flow with communicating and\nnon-communicating veh
icles\, I will address a combinatorial problem in in\nmy talk: if communic
ating vehicles can detect the vehicle ahead (and\nbehind) by front (and re
ar) sensors\, I ask how many non-communicating\nvehicles are on average de
tected by communicating ones.\nRelating the problem to a discrete random w
alk in one dimension with a\nfixed number of steps allows to determine the
detected vehicles for both\nopen and periodic boundary conditions as well
as for the case where\ncommunicating vehicles detect both or only one ne
ighboring vehicle(s).\nIn the random walk picture\, where the two vehicles
types stand for steps\nin opposite directions\, non-communicating vehicle
s are detected whenever\nthe resulting path has a corner.\n
LOCATION:Konferenzraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Mikhail A. Skvortsov
DTSTART;VALUE=DATE-TIME:20121130T163000
DTEND;VALUE=DATE-TIME:20121130T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000220@events.thp.uni-koeln.de
DESCRIPTION:Dr. Mikhail A. Skvortsov\, Landau Institute of Theoretical Phy
sics\, Chernogolovka \n\nSuperconducting proximity effect in quantum wires
without time-reversal symmetry\n\nWe study the superconducting proximity
effect in a quantum wire with\nbroken time-reversal (TR) symmetry connecte
d to a superconductor. We\nconsider the situation of a strong TR-symmetry
breaking\, so that\nCooper pairs entering the wire from the superconductor
are immediately\ndestroyed. Nevertheless\, some traces of the proximity e
ffect survive:\nfor example\, the local electronic density of states (LDOS
) is\ninfluenced by the proximity to the superconductor\, provided that\nl
ocalization effects are taken into account. With the help of the\nsupersym
metric sigma model\, we calculate the average LDOS in such a\nsystem. The
LDOS in the wire is strongly modified close to the\ninterface with the sup
erconductor at energies near the Fermi\nlevel. The relevant distances from
the interface are of the order of\nthe localization length\, and the size
of the energy window around the\nFermi level is of the order of the mean
level spacing at the\nlocalization length. Remarkably\, the sign of the ef
fect is sensitive\nto the way the TR symmetry is broken: In the spin-symme
tric case\n(orbital magnetic field)\, the LDOS is depleted near the Fermi
energy\,\nwhereas for the broken spin symmetry (magnetic impurities)\, the
LDOS\nat the Fermi energy is enhanced.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. B. Rosenow
DTSTART;VALUE=DATE-TIME:20121207T160000
DTEND;VALUE=DATE-TIME:20121207T171500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000221@events.thp.uni-koeln.de
DESCRIPTION:Prof. B. Rosenow\, Universität Leipzig\n\nNon-equilibrium ste
ady states and charge fractionalization in Luttinger liquids\n\nIn many ca
ses\, interacting fermions in one spatial dimension are described by the L
uttinger model of free bosonic density excitations. Due to the absence of
an interaction between these\nbosonic degrees of freedom\, the model is in
tegrable. As a consequence\, it does not relax back to equilibrium when on
e excites it via the local injection of electrons. Instead\, it reaches\na
non-equilibrium steady state with a peculiar electronic distribution func
tion and spectral density. In the case of two co-propagating chiral channe
ls\, the non-perturbative method of\nnon-equilibrium bosonization allows t
o characterize the electron distribution by a fractional Fano factor and i
nterpret it in terms of charge fractionalization. \n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Prof. A. Schadschneider
DTSTART;VALUE=DATE-TIME:20130111T120000
DTEND;VALUE=DATE-TIME:20130111T124500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000222@events.thp.uni-koeln.de
DESCRIPTION:Prof. A. Schadschneider\, Institut für Theoretische Physik\,
Universität zu Köln\n\nStatistical physics of pedestrian d
ynamics and other traffic systems\n\nThis talk is one of a series
of presentations of research groups organized by the Bonn-Cologne Graduate
School of Physics and Astronomy. The aim is to provide insights into the
research done at physics institutes in Cologne. Interested students (Bache
lor\, Master\, and PhD) are most welcome.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Dr. Stefan Klumpp
DTSTART;VALUE=DATE-TIME:20121204T160000
DTEND;VALUE=DATE-TIME:20121204T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000223@events.thp.uni-koeln.de
DESCRIPTION:Dr. Stefan Klumpp\, MPI for Colloids and Interfaces\n\nMechani
sms and cellular economy of molecular machines\n\nCells contain billions o
f molecular machines that drive processes such as directed transport and p
rocessing of the genetic information. The talk will address theoretical ap
proaches to\nthe mechanisms of such machines and to their cellular economy
. I will discuss how the stochastic dynamics of several molecular motors c
an be coordinated by mechanical forces through a\ntug-of-war mechanism and
how a global picture of the machines that process the genetic information
(RNA polymerases and ribosomes) reveals the different economic principles
that underlie\ntheir use in a bacterial cell.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Silke Weinfurtner
DTSTART;VALUE=DATE-TIME:20121214T160000
DTEND;VALUE=DATE-TIME:20121214T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000224@events.thp.uni-koeln.de
DESCRIPTION:Dr. Silke Weinfurtner\, SISSA\, Trieste\n\nQuantum Gravity Lab
oratory\n\nA major problem of quantum field theory in curved spacetime\,\n
and quantum gravity more generally\, is the lack of sufficient\nobservatio
nal and experimental guidance. To address this issue I am\nproposing to ex
plore various phenomena of semi-classical gravity and\nquantum gravity in
table-top experiments. The overall programme is\nbased on the existence of
analogue gravity models for semi-classical\nquantum gravity\, demonstrati
ng that certain effects predicted within\nquantum field theory in curved s
pacetimes can be mimicked in\neasy-to-access physical systems\, such as fl
uids and superfluids. In\naddition\, I will explore the possibility of ada
pting the general\nprinciples underlying analogue gravity models to full q
uantum gravity\,\ncombining tools and concepts from quantum information th
eory with\ndiscrete quantum gravity. In contrast to many other proposals i
n\nquantum gravity\, the project objectives are not only theoretical\n(ana
lytical and numerical studies)\, but also of experimental nature.\nThe sp
ecific scientific goals are to study the robustness and\nuniversality of (
rotating) black hole phenomena in water channel\nflows\, cosmological part
icle production in Bose-Einstein condensate\,\nand the emergence of a smoo
th geometry as an ensemble average of\nbinary encodings of triangulated ma
nifolds.\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Prof. Dr. Corinna Kollath
DTSTART;VALUE=DATE-TIME:20121206T140000
DTEND;VALUE=DATE-TIME:20121206T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000225@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Corinna Kollath\, Universität Genf\n\nDynamics in s
trongly correlated ultracold gases\n\nAtomic gases cooled to Nanokelvin te
mperatures are a new exciting tool to\nstudy a broad range of quantum phen
omena. In particular\, an outstanding and\nrapid control over the fundamen
tal parameters\, such as interaction strength\,\nspin composition\, and di
mensionality allows to realize and observe many\ndifferent situations far
from equilibrium. Long-standing questions such as the\nthermalization dyna
mics can be investigated. Theoretical studies of this question\nhave a lon
g history\, in particular\, in the classical Fermi-Pasta-Ulam-Tsingou\npro
blem\, a coupled chain of harmonic oscillators under the influence of furt
her\nhigher order couplings. Even though a lot of progress has been made\,
up to day\,\na complete understanding is missing. In the first part of my
talk\, I will report on\nrecent progress on the investigation of relaxati
on dynamics in isolated quantum\nsystems in connection with experimental s
tudies. In the second part of my talk\, I\nwill address the question of th
e influence of a coupling to an environment on the\nsystem dynamics. We fi
nd that the environment can cause complex relaxation\ndynamics often descr
ibed by spatially dependent classical diffusion equations.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Prof. Dr. Ilya Eremin
DTSTART;VALUE=DATE-TIME:20121212T143000
DTEND;VALUE=DATE-TIME:20121212T154500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000226@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Ilya Eremin\, Ruhr-Universität Bochum\n\nSupercondu
ctivity in Fe-based superconductors: competing orders and pairing fluctuat
ions\n\nThe discovery of superconductivity in Fe-based superconductors in
2008 with Tc\nreaching almost 60K is among the most significant breakthrou
ghs in\ncontemporary condensed matter physics. The experimental data on\ns
uperconductivity show rich behavior\, with potentially different symmetry
of a\nsuperconducting state for different compositions of the same materia
l.\nFurthermore\, the phase diagram reveal a complex interplay between mag
netism\nand superconductivity typical for other exotic superconductors suc
h as cuprates\nor heavy fermions. In my talk I will present an introductio
n to various aspects of\nthe theory of iron-based superconductors. In part
icular\, I will discuss general\naspects of the Cooper-pairing in Fe-based
superconductors. I will argue that the\nphysics is universal and that all
pairing states obtained so far can be understood\nwithin the same univers
al pairing scenario. Then I will review the magnetic\nordering in the iron
-based parent compounds. I will first analyze the selection of\nthe experi
mentally observed magnetic order out of the degenerate manifold\nwhich occ
urs due to frustration associated with multiple nesting wave vectors. In\n
addition\, in analogy to the J1-J2 model of the localized spins\, I will d
iscuss the\npossibility of an Ising nematic order to form above the actual
Neel temperature\nand its coupling to orbital and lattice degrees of free
dom.\n
LOCATION:Seminarraum des II. Physikalischen Instituts
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Prof. Dr. Sebastian Diehl
DTSTART;VALUE=DATE-TIME:20121214T134500
DTEND;VALUE=DATE-TIME:20121214T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000227@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Sebastian Diehl\, Universität Innsbruck\n\nQuantum
States and Phases in Driven Open Many-Body Systems\n\nIn ultracold atomic
gases\, the areas of quantum optics and many-body quantum\nphysics increas
ingly merge together\, giving rise to non-equilibrium scenarios\nwhere coh
erent and dissipative dynamics appear on an equal footing.\nControlled dis
sipation allows for counter-intuitive effects such as dissipatively\ninduc
ed long-range phase coherence. We discuss several aspects of new\nmany-bod
y physics in such systems: This includes phases of lattice bosons with\nco
mpeting coherent and tailored dissipative dynamics\, and a purely dissipat
ive\npairing mechanism for fermions\, operative in the absence of attracti
ve\nconservative forces. We show how this mechanism can be used for coolin
g into\ntopologically ordered states and point out a possible physical rea
lization. We\nanalyze the nature of topological order and Majorana edge st
ates in such non-\nequilibrium systems\, highlighting properties without i
mmediate counterpart in\nequilibrium.\nFinally\, we report on first result
s on non-equilibrium criticality in driven open\nquantum systems subject t
o particle loss and pumping. We identify an\nadditional\, independent crit
ical exponent witnessing the driven nature of these\nsystems.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Dr. Brian Swingle
DTSTART;VALUE=DATE-TIME:20121218T160000
DTEND;VALUE=DATE-TIME:20121218T171500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000228@events.thp.uni-koeln.de
DESCRIPTION:Dr. Brian Swingle\, Harvard University\n\nEntanglement and the
Fermi surface\n\nI will describe my work characterizing quantum entanglem
ent in systems with\na Fermi surface. This class includes everything from
Fermi liquids to exotic spin\nliquids in frustrated magnets and perhaps ev
en holographic systems. I review\nmy original scaling argument and then de
scribe in detail a number of new\nprecise results on entanglement in Fermi
liquids. I will discuss recent quantum\nMonte Carlo calculations of Renyi
entropies and will argue that we now have a\nrather complete agreement be
tween theory and numerics\nfor Fermi liquid entanglement. I will also exhi
bit universal crossover functions\nbetween thermal and entanglement entrop
y and a class of solvable interacting\nmodels where I have proved the univ
ersality of the Widom formula\nfor Fermi surface entanglement. I will conc
lude by discussing some of the\nlessons learned and by giving a glimpse of
the wider world of many-body\nentanglement.\n
LOCATION:Hörsaal III
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Dr. S. Schadmand
DTSTART;VALUE=DATE-TIME:20130111T124500
DTEND;VALUE=DATE-TIME:20130111T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000229@events.thp.uni-koeln.de
DESCRIPTION:Dr. S. Schadmand\, IKP - FZ Jülich\n\nTests of Fundamen
tal Symmetries and Hadron Physics\n\nThis talk is one of a series
of presentations of research groups organized by the Bonn-Cologne Graduate
School of Physics and Astronomy. The aim is to provide insights into the
research done at physics institutes in Cologne. Interested students (Bache
lor\, Master\, and PhD) are most welcome.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Dr. Oskar Hallatschek
DTSTART;VALUE=DATE-TIME:20121221T134500
DTEND;VALUE=DATE-TIME:20121221T151500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000230@events.thp.uni-koeln.de
DESCRIPTION:Dr. Oskar Hallatschek\, MPI for Dynamics and Self-Organization
\n\nPredicting evolutionary change using statistical physics\n\nThe spread
ing of discrete entities occurs in many complex systems\, and controls for
instance the speed of chemical reactions\, species invasions\, epidemic o
utbreaks or biological\nadaptation. Unless population are well-mixed (li
ke bacteria in a shaken test tube)\, the spreading dynamics not only depe
nds on reaction rates but also on the dispersal behavior of the\nspecies.
Spreading at a constant speed is generally predicted when dispersal is s
ufficiently short-ranged. I present a recent exactly solvable model for th
is wave-like spread and the\nassociated genealogical trees\, which are gen
erated by a coalescent process with frequent multiple mergers. Spreading
in the presence of rare long-range dispersal (e.g. triggered by\naviatio
n) has been unresolved so far: While it is clear that even rare long-rang
e jumps can lead to a drastic speedup\, it has been difficult to quantify
the ensuing stochastic growth\nprocess. I present a simple self-consiste
nt argument supported by simulations that accurately predicts the asympto
tic spreading dynamics for fat-tailed jump distributions. I discuss our
\nresults in the light of population genetics\, and show how they can be u
sed to predict evolutionary change in simple microbial experiments. \n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Dr. Richard Neher
DTSTART;VALUE=DATE-TIME:20130116T100000
DTEND;VALUE=DATE-TIME:20130116T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000231@events.thp.uni-koeln.de
DESCRIPTION:Dr. Richard Neher\, MPI for Developmental Biology\n\nPopulatio
n genetics of rapid adaptation\n\nPopulation genetics provides a theoretic
al frame work to interpret genetic diversity and make inferences about the
evolutionary process. Traditional population genetics models assume\nthat
adaptation\, i.e. change for the better\, is rare. However\, adaptive evo
lution is pervasive in many organisms and other models are needed to study
their evolution. I will show that\nmany models of asexual adaptive evolut
ion give rise to a universal genealogical process known as Bolthausen-Szni
tman coalescent. The Bolthausen-Sznitman coalescent\, first described in\n
spin-glass physics\, makes concrete predictions for patterns of genetic di
versity that can be compared against data and used for inference. I will c
lose by discussing how these results\nfor asexual evolution carry over to
sexual populations.
LOCATION:Seminarraum I. Physikalisches Institut
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Prof. Marc Timme
DTSTART;VALUE=DATE-TIME:20130118T134500
DTEND;VALUE=DATE-TIME:20130118T151500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000232@events.thp.uni-koeln.de
DESCRIPTION:Prof. Marc Timme\, MPI for Dynamics and Self-Organization\n\nB
ridging Statistical Physics and Nonlinear Dynamics of Networks\n\nNetworks
of interacting units dominate our everyday lives\, from the\ndynamics of
neural circuits that control our behaviors to the power\ngrids that provid
e us with electric energy. Over the last 15 years\,\nresearchers furthered
our understanding of complex networks by analyzing\ntheir connectivity st
ructure and collective dynamics\, mostly using\nperspectives from either g
raph theory\, statistical physics or nonlinear\ndynamics. Recent progress
shows that features from the statistical physics and the\nnonlinear dynami
cs of networks are often intimately related\; I discuss\ntwo main examples
: Many different neural circuits exhibit\nspatio-temporal activity patter
ns\, but the dynamic origin of such\npatterns remains unknown. I link the
nonlinear deterministic dynamics of\nsuch systems to a statistical descrip
tion. The results indicate that\nnon-additive coupling\, recently found in
neuro-physiological\nexperiments\, enable the generation of spike pattern
s in circuits\nconsistent with anatomy. In a second example\, I identify a
type of percolation transition that\nwas unknown so far. Analyzing the mi
croscopic dynamics of link additions\nreveals that the transition is conti
nuous in the thermodynamics limit\nbut discontinuous features prevail even
for macroscopic finite systems.\nFinally\, I briefly mention a new concep
t of universal computation via\nswitching in complex networks of states an
d the intriguing\nself-organized dynamics of power grids.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Dr. Thilo Gross
DTSTART;VALUE=DATE-TIME:20130109T100000
DTEND;VALUE=DATE-TIME:20130109T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000233@events.thp.uni-koeln.de
DESCRIPTION:Dr. Thilo Gross\, University of Bristol\n\nNetworks as a unify
ing approach to complex systems: a food web example\n\nDescribing a given
system as a network means reducing it to set of discrete nodes\nconnected
by links. This reduction often leads to a considerable simplification\,\nb
ut preserves the complex pattern of interactions among the system's consti
tuents.\nNetwork models thus lend themselves naturally to the analysis of
complex systems\nin which the interactions between constituents give rise
to emergent properties and phenomena.\nHere\, the hope is that a properly
constructed network model can simplify the system such\nthat these propert
ies and phenomena can be understood analytically. In this talk I \nillust
rate this approach by several short examples from my work and a study on t
he\nstability of ecological food webs that I present in greater detail. I
conclude with a\nforward looking discussion arguing that recent successes
follow a certain pattern\nthat could lead to a conceptual unification of c
omplex systems research.\n
LOCATION:Seminarraum I. Physikalisches Institut
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Prof. Peter Sollich
DTSTART;VALUE=DATE-TIME:20130115T160000
DTEND;VALUE=DATE-TIME:20130115T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000234@events.thp.uni-koeln.de
DESCRIPTION:Prof. Peter Sollich\, King's College London\n\nFrom learning o
n networks to non-equilibrium dynamics on networks and elsewhere\n\nI will
give an overview of recent work on understanding learning processes\non n
etworks\, specifically inference of a function: imagine trying to predict\
nbiochemical reactivity of a protein based on noisy measurements for\n"sim
ilar" molecules\, where similarity is represented by links on a network\nw
hose nodes are the various proteins. In a Bayesian framework and using\nfl
exible priors (Gaussian processes) on the function to be learned\, I will\
nshow that the cavity or replica methods can be used to predict the learni
ng\ncurve (mean squared error versus number of data points)\, exactly so i
n the\nlimit of large random networks with some imposed degree distributio
n.\nI will then trace an arc from this research to my work on dynamics of\
nprotein interaction networks\, glasses and dynamical phase transitions\,
and\nsoft matter physics.\n
LOCATION:Hörsaal III der Physikalischen Institute
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Prof. L. Labadie
DTSTART;VALUE=DATE-TIME:20130125T120000
DTEND;VALUE=DATE-TIME:20130125T124500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000235@events.thp.uni-koeln.de
DESCRIPTION:Prof. L. Labadie\, 1. Physikalisches Institut\, Universit
ät zu Köln\n\nHigh-angular resolution in astronomy: a
microscope for the Universe\n\nThis talk is one of a series of pre
sentations of research groups organized by the Bonn-Cologne Graduate Schoo
l of Physics and Astronomy. The aim is to provide insights into the resear
ch done at physics institutes in Cologne. Interested students (Bachelor\,
Master\, and PhD) are most welcome.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Dr. Maria Daghofer
DTSTART;VALUE=DATE-TIME:20130109T143000
DTEND;VALUE=DATE-TIME:20130109T154500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000236@events.thp.uni-koeln.de
DESCRIPTION:Dr. Maria Daghofer\, IFW Dresden\n\nCorrelations and Topology
in multi-orbital models\n\nElectronic correlations have long been known to
fundamentally affect a\nmaterial's property. I will discuss situations\,
where they can induce topologically\nnontrivial electronic states. Interac
tion between itinerant carriers and localized\nspins on frustrated lattice
s can stabilize phases that are in many respects similar\nto a Landau leve
l\, as a non-coplanar spin background gives the electrons a\ncomplex phase
analogous to that induced by a magnetic field. If the bands are\nnearly f
lat\, longer-range Coulomb repulsion can then induce states that are like\
nlattice-analogs of fractional Quantum-Hall states\, but do not require an
external\nmagnetic field.\nI will also discuss Mott insulators with spin-
orbit coupling\, where excitations then\nhave combined spin and orbital ch
aracter. We have investigated effective\nclassical spin model for spin-orb
it coupled Mott insulators. The ground state has\nturned out to support a
vortex lattice of topological defects\, Z2 vortices\, whose\ndensity is de
termined by the strength of the spin-orbit coupling.\n
LOCATION:Seminarraum des II. Physikalischen Instituts
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Dr. Pasquale Calabrese
DTSTART;VALUE=DATE-TIME:20130111T160000
DTEND;VALUE=DATE-TIME:20130111T171500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000237@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Pasquale Calabrese\, Universität Pisa\n\nQuantum Qu
enches in one dimensional systems\n\nNon-equilibrium quantum systems repre
sent one of the most promising\npossibilities for realizing novel states o
f matter. I will consider the non\nequilibrium situation known as quantum
quench\, in which a closed system\nevolves from an initial state that is n
ot a Hamiltonian eigenstate such as those\nachieved by suddenly switching
a control parameter. An important question is\nunder what conditions the s
ystem reaches a stationary state and in which\ncircumstances this state is
characterized by an effective “thermal”\, i.e.\nequilibrium\, distrib
ution. I will discuss how to obtain the time evolution of\nobservables and
correlation functions with a variety of theoretical techniques\nincluding
quantum field theory (in particular CFT) and integrability. These\napproa
ches allow to have a rather complete understanding of the relaxation\ndyna
mics and the most challenging open problems will be presented.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Prof. Dr. Andreas Ludwig
DTSTART;VALUE=DATE-TIME:20130107T120000
DTEND;VALUE=DATE-TIME:20130107T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000238@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Andreas Ludwig\, University of California\, Santa Ba
rbara\n\nTopological insulators and superconductors\n\n
LOCATION:Seminarraum des II. Physikalischen Instituts
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Prof. Dr. Simon Trebst
DTSTART;VALUE=DATE-TIME:20130125T124500
DTEND;VALUE=DATE-TIME:20130125T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000239@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Simon Trebst\, University of Cologne\n\nCollective
phenomena in the quantum world: spin liquids\, topologica
l order\, and exotic phase transitions\n\nThis talk is one of a se
ries of presentations of research groups organized by the Bonn-Cologne Gra
duate School of Physics and Astronomy. The aim is to provide insights into
the research done at physics institutes in Cologne. Interested students (
Bachelor\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Dr. Jan von Delft
DTSTART;VALUE=DATE-TIME:20130118T160000
DTEND;VALUE=DATE-TIME:20130118T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000240@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Jan von Delft\, LMU München\n\nMicroscopic Origin o
f the 0.7-Anomaly in Quantum Point Contacts\n\nQuantum point contacts are
elementary building blocks of numerous\nsemiconducting nanodevices. Despit
e their simple structure\, however\, their\nconductance properties exhibit
anomalous features\, collectively known as the\n"0.7-anomaly"\, whose ori
gin is still subject to controversial discussions. We\noffer a detailed mi
croscopic explanation for the 0.7-anomaly and the zero-bias\npeak that typ
ically accompanies it: the common origin of both is a smeared van\nHove si
ngularity in the local density of states at the bottom of the lowest one-\
ndimensional subband of the point contact\, which causes an anomalous\nenh
ancement in the Hartree potential barrier\, magnetic spin susceptibility a
nd\ninelastic scattering rate. We present theoretical calculations and exp
erimental\nresults that show good qualitative agreement for the dependence
of the\nconductance on gate voltage\, magnetic field\, temperature\, sour
ce-drain voltage\n(including the zero-bias peak) and interaction strength.
For low energies we\npredict and observe Fermi-liquid behavior analogous
to that known for the\nKondo effect in quantum dots. At high energies\, ho
wever\, the analogy between\n0.7-anomaly and Kondo effect ceases to be app
licable.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Stefan Scheel
DTSTART;VALUE=DATE-TIME:20130419T163000
DTEND;VALUE=DATE-TIME:20130419T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000242@events.thp.uni-koeln.de
DESCRIPTION:Prof. Stefan Scheel\, Universität Rostock\n\nMacroscopic quan
tum electrodynamics - quantum optics with macroscopic bodies\n\nIn this ta
lk I will briefly review the basic principles of\nelectromagnetic field qu
antisation in the presence of macroscopic\nmatter\, and explain its releva
nce to the quantum interaction between\n(isolated) microscopic particles a
nd macroscopic surfaces. As a first\nexample\, I will review some aspects
of propagation of nonclassical light\nthrough absorbing optical devices. I
will then concentrate on two\naspects of atom-surface interactions --- de
coherence and dispersion\nforces (Casimir\, Casimir-Polder and van der Waa
ls forces). Both effects\ncan be understood within the framework of macros
copic QED as spatially\ndependent relaxation processes and line shift mech
anisms\, respectively.\nI will present examples of highly excited atoms an
d weakly bound\nmolecules that are particularly susceptible to changes in
dispersion forces.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Bartlomiej Waclaw
DTSTART;VALUE=DATE-TIME:20130503T163000
DTEND;VALUE=DATE-TIME:20130503T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000243@events.thp.uni-koeln.de
DESCRIPTION:Dr. Bartlomiej Waclaw\, University of Edinburgh\n\nPhysics in
the evolution of microbes\n\nBiological evolution is a fascinating subject
which can be fully understood\nonly if it is approached from many differe
nt angles. In this talk I will\npresent my personal point of view on how p
hysics can advance our\nunderstanding of biological evolution. I will focu
s on three problems in the\nevolution of bacteria I have been working on r
ecently. I will begin with a\nsimple\, statistical-physics model of the ev
olution of antibiotic resistance.\nThis is a timely and important problem
because drug-resistant\, pathogenic\nbacteria are becoming a major health
hazard. I will show that resistant\nbacteria can rapidly emerge in environ
ments with spatially non-uniform drug\nconcentration such as our bodies du
ring antibiotic treatment. Towards the\nend of my talk\, I will briefly di
scuss the evolution of metabolic networks\nin bacteria and biological evol
ution in bacterial colonies growing on solid\nsubstrates.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Anton Iakovlev
DTSTART;VALUE=DATE-TIME:20130315T110000
DTEND;VALUE=DATE-TIME:20130315T120000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000244@events.thp.uni-koeln.de
DESCRIPTION:Anton Iakovlev\, Universität Bonn\n\nStatistical Mechanics of
Quasi-One-Dimensional Coupled Complex Ginzburg-Landau Classical Fields wi
th Non-Gaussian Fluctuations\n\nI present an investigation of non-Gaussian
\nfluctuations of complex classical Ginzburg-Landau (GL) order parameter\n
fields.\nThe transfer-matrix formalism enables an exact treatment of the\n
non-Gaussian fluctuations.\nAccording to this formalism the generalized GL
energy functional is\nconsidered as an energy associated with a particula
r order parameter\nconfiguration.\nTherefore the partition function can be
represented as a functional\nintegral over all possible configurations of
the order parameters. In\nthe cases of a single and two competing order p
arameters the\nfunctional integration is formally analogous to an eigenval
ue problem\nof a single and two quantum particles in an an-harmonic potent
ial\nrespectively.\nTo solve the problem we use such techniques as the pat
h integral Monte\nCarlo and the Lanczos method. The results obtained via b
oth techniques\nare compared with each other and with known results for th
e single\norder parameter case. Afterwards the results for the competing o
rder\nparameters are computed.
LOCATION:Konferenzraum THP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Eugene V. Koonin
DTSTART;VALUE=DATE-TIME:20130430T120000
DTEND;VALUE=DATE-TIME:20130430T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000245@events.thp.uni-koeln.de
DESCRIPTION:Eugene V. Koonin\, National Center for Biotechnology Informati
on\, NIH\, Bethesda\, Maryland\, USA \n\nThe Virus World: Evolution of vi
ruses and antivirus defense\n\nEmergence of genetic parasites is germane t
o evolving systems of replicators\, and accordingly\, virus-like selfish a
gents most likely antedate full-fledged cells in the evolution of life. Vi
ruses have comprised one of the two fundamental types of organisms through
out the course of evolution\, and so the entire history of life is a story
of virus-host arms race and cooperation. The genomic and biological dive
rsity of viruses is still under-appreciated as illustrated by the recent d
iscovery of giant viruses and their own distinct mobilomes. All cellular l
ife forms have evolved complex\, multilayer systems of antivirus defense t
hat account for a substantial portion of the genome even in simple prokary
otes. These diverse defense systems function on one of the three general p
rinciples: i) innate\, non-specific immunity\; ii) adaptive\, specific imm
unity\; iii) programmed cell suicide or dormancy induced by infection. Co
mparative genomic analysis shows that in bacterial and archaeal genomes\,
genes encoding innate and adaptive immune systems are invariably associate
d with genes encoding toxin-antitoxin systems that induce dormancy or suic
ide. Hence the immunity-dormancy/suicide coupling hypothesis according to
which antivirus response in prokaryotes involves key decision-making steps
when the cell chooses the path to follow by sensing the course of virus i
nfection. The recently discovered CRISPR-Cas system of adaptive immunity p
resents a clear-cut case of an environmental sensor that evolves under the
Lamarckian evolutionary paradigm. I will present results of mathematical
modeling that identify the conditions under which Lamarckian evolution is
feasible.
LOCATION:Institute for Genetics\, Zülpicher Str. 47a\, Lecture Hall\, 4th
Floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Eugene V. Koonin
DTSTART;VALUE=DATE-TIME:20130430T153000
DTEND;VALUE=DATE-TIME:20130430T163000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000246@events.thp.uni-koeln.de
DESCRIPTION:Eugene V. Koonin\, National Center for Biotechnology Informati
on\, NIH\, Bethesda\, Maryland\, USA\n\nMathematical modeling of the evolu
tion of adaptive immunity in prokaryotes\n\n
LOCATION:Institute for Genetics\, Zülpicher Str. 47a\, New Seminar Room 0
.46\, ground floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Johanna Erdmenger
DTSTART;VALUE=DATE-TIME:20130412T163000
DTEND;VALUE=DATE-TIME:20130412T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000247@events.thp.uni-koeln.de
DESCRIPTION:Dr. Johanna Erdmenger\, Werner-Heisenberg-Institut München\n\
nGauge/Gravity Duality: New methods from string theory for strongly couple
d systems\n\nWe give an introduction to the area of gauge/gravity duality
and its\napplications. Based on string theory\, gauge/gravity duality maps
strongly\ncoupled quantum field theories to weakly coupled gravity theori
es and thus\nprovides a new framework for studying physical phenomena in s
trongly\ncoupled systems. We describe the main features of this approach a
nd\ndiscuss its range of applicability. Moreover\, we give examples of\nap
plications in both elementary particle/nuclear physics and condensed\nmatt
er physics. The examples presented include the quark-gluon plasma\,\nmeson
s\, quantum phase transitions as well as superfluids and\nsuperconductors.
\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Peter Hegarty and Anders Martinsson
DTSTART;VALUE=DATE-TIME:20130506T160000
DTEND;VALUE=DATE-TIME:20130506T183000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000248@events.thp.uni-koeln.de
DESCRIPTION:Peter Hegarty and Anders Martinsson\, Chalmers University of T
echnology and University of Gothenburg\n\nOn the existence of accessible p
aths in various models of fitness landscapes\n\nWe present rigorous analy
ses of a number of well-known mathematical models for genetic mutations. I
n these models\, the genome is represented by a vertex of the n-dimensiona
l binary hypercube\, for some n\, a mutation involves the flipping of a si
ngle bit\, and each vertex is assigned a real number\, called its fitness\
, according to some rules. The study of such models has a long tradition\,
both in mathematical biology and in statistical physics\, where the same
models arise in the study of spin glasses. The field has been recently gal
vanised by the increasing availability of empirical genetic data. In this
context\, Weinreich and others introduced the notion of an accessible evol
utionary pathway\, that is a path along which fitness is monotonically inc
reasing or\, in the case of spin glasses\, along which energy is monotonic
ally decreasing. Our main results resolve open questions about three such
models\, which in the biophysics literature are known as House of Cards (H
oC)\, Constrained House of \nCards (CHoC) and Rough Mount Fuji (RMF). We p
rove that the probability of there being at least one accessible path acro
ss the directed n-hypercube tends\, in the case of HoC and CHoC respective
ly\, \nto 0 and 1\, as n tends to infinity. In the case of RMF\, we prove
that the probability of accessible \npaths existing tends to 1 for a wide
class of underlying fitness distributions.
LOCATION:Lecture Hall\, Cologne Biocenter
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Debashish Chowdhury
DTSTART;VALUE=DATE-TIME:20130614T163000
DTEND;VALUE=DATE-TIME:20130614T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000249@events.thp.uni-koeln.de
DESCRIPTION:Prof. Debashish Chowdhury\, Indian Institute of Technology\,
Kanpur\n\nStochastic kinetics of a self-organized complex molecular machin
e: microtubule-chromosome coupling by ring-rod-hook device\n\nBefore cell
division\, two identical copies of chromosome need to\nbe segregated accur
ately. Each chromosome is connected to a "nano-ring"\n(dam1) by "rods" (Nd
c80). For accurate chromosome segregation\, the two\nchromosomes are pulle
d apart in the opposite directions by two sets of\n"nano-hooks"\, formed b
y microtubules (MTs)\, that are inserted into these\nrings. An externally
applied tension can lead to detachment of the hooks\nfrom the ring\; the m
ean lifetime of such an attachment is essentially a\nmean first-passage ti
me. Recent pioneering in-vitro experiments with\nreconstituted nano hook-
ring device established that the mean lifetimes of\nsuch attachments vary
non-monotonically with increasing tension. In this\ntalk I'll explain the
counter-intuitive stabilization of the attachments by\nsmall tension with
a unified model that we have developed very\nrecently. The catch-bond-lik
e mechanism emerges naturally in this model\nfrom the interplay of tension
-dependence of (i) the potential landscape and\n(ii) MT depolymerization r
ate. I'll also show how the distribution of\nlifetimes of the hook-ring at
tachment depends on (a) the structure\, (b)\nenergetics\, and (c) kinetics
of the coupling.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Matias Dahl
DTSTART;VALUE=DATE-TIME:20130507T120000
DTEND;VALUE=DATE-TIME:20130507T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000250@events.thp.uni-koeln.de
DESCRIPTION:Matias Dahl\, Aalto-yliopisto\, Finland\n\nClassification of e
lectromagnetic media from the behaviour of phase velocity\n\nIf we are giv
en an electromagnetic medium tensor we can compute the speed of a propagat
ing signal. For example\, in a homogeneous medium we can compute the phase
velocity using plane waves. A less well understood question is the conver
se: If we know the behaviour of phase velocity in all possible directions
for an unknown medium\, how much can we say about the anisotropic structur
e of that medium? In this talk we describe a number of results on this que
stion in the setting of linear\, local\, and non-dissipative (skewon-free)
media. In particular\, we discuss the classification of medium tensors wh
ere wave propagation is determined by one or two Lorentz null cones.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Magdalena Zych
DTSTART;VALUE=DATE-TIME:20130514T120000
DTEND;VALUE=DATE-TIME:20130514T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000251@events.thp.uni-koeln.de
DESCRIPTION:Magdalena Zych\, Universität Wien\n\nQuantum Mass-Energy Equi
valence Principle\n\nMass-energy equivalence principle is considered an im
portant consequence of General Relativity. I will reverse the usual approa
ch and take the validity of the mass-energy equivalence principle as a pos
tulate within the non-relativistic mechanics. In the classical case this y
ields special and general relativistic time dilation effects (to lowest or
der) and Nordtvedt’s quantitative version of the Schiff’s conjecture
– a relation between the violations of the universality of free fall and
deviations from the gravitational redshift. However\, these results do no
t necessarily extend to quantum mechanics. Various semiclassical extension
s of the mass-energy equivalence principle will be presented that correspo
nd to theories in which the free fall and/or the time dilation effects are
modified in the presence of quantum effects. These theories in general vi
olate Schiff’s conjecture\, yet\, in the scenario considered by Nordtved
t\, they all agree with the classical result. I will explain this apparent
“paradox” and derive a quantum version of the Nordtvedt’s relation
from a fully quantum extension of the mass-energy equivalence principle. I
n the end I briefly discuss experimental scenarios that allow distinguishi
ng between these various formulations of the mass-energy equivalence princ
iple.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Nicolas Boulanger
DTSTART;VALUE=DATE-TIME:20130528T120000
DTEND;VALUE=DATE-TIME:20130528T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000252@events.thp.uni-koeln.de
DESCRIPTION:Nicolas Boulanger\, Université de Mons\, Belgium\n\nA brief i
ntroduction to higher-spin gauge theory\n\nWe would like to explain the ba
sic mechanisms underlying fully interacting higher-spin theory\, aiming at
giving a flavor of Vasiliev’s equations. We will start from the lineari
sed theory\, explain the Fradkin-Vasiliev procedure for cubic interactions
and arrive at Vasiliev’s equations if time allows.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Prof. Charles Marcus
DTSTART;VALUE=DATE-TIME:20130508T143000
DTEND;VALUE=DATE-TIME:20130508T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000253@events.thp.uni-koeln.de
DESCRIPTION:Prof. Charles Marcus \, Center for Quantum Devices\, Copenhage
n\n\nHas Majorana returned\, and why we should care\n\nOpening Colloquium
of the key profile area "Quantum Matter and Materials".\nAfter the talk th
ere will be a reception in the foyer.\n\nAbstract: This talk will review r
ecent experiments by several groups\, including ours\, aimed at identifyin
g signatures of Majorana fermions in condensed matter systems. To date\, t
he experiments are very suggestive\, but uncertainties remain. What can fu
ture experiments do to make the case air-tight? As time allows\, I will al
so discuss how such states might be valuable to topological quantum inform
ation processing.
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. M. Troyer
DTSTART;VALUE=DATE-TIME:20130607T163000
DTEND;VALUE=DATE-TIME:20130607T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000254@events.thp.uni-koeln.de
DESCRIPTION:Prof. M. Troyer\, ETH Zürich\n\nQuantum annealing on five hun
dred qubits?\n\nQuantum technology is maturing to the point where quantum
devices\,\nsuch as quantum communication systems\, quantum random number \
ngenerators and quantum simulators\, may be built with powers \nexceeding
the performance of classical computers. A quantum \nannealer\, in particul
ar\, finds solutions to hard optimization \nproblems by evolving a known i
nitial configuration towards the \nground state of a Hamiltonian that enco
des an optimisation \nproblem. In this talk I will present results from ex
periments \non a 108 qubit D-Wave One device based on superconducting flux
\nqubits and will provide evidence that the device indeed performs \nquan
tum anealing. To assess the computational power of the \nquantum annealer
I compare it to optimised classical algorithms \nand will present first pr
eliminary results for a D-Wave Two \nsystem with more than five hundred qu
bits.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Prof. Steven N. Evans
DTSTART;VALUE=DATE-TIME:20130610T160000
DTEND;VALUE=DATE-TIME:20130610T183000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000255@events.thp.uni-koeln.de
DESCRIPTION:Prof. Steven N. Evans\, University of California at Berkeley\n
\nMathematical perspectives on the evolution of aging\n\nIt is a challenge
to explain biological phenomena that appear to arise from the complex\nin
teraction of many genes in response to natural selection acting through th
e mechanisms of\nmutation and recombination. The proportions of a large po
pulation that have various\ngenotypes form a probability measure on the sp
ace of possible genotypes and\, under suitable\nassumptions\, it is reason
able to model this probability measure as evolving in time according\nto a
relativelysimple\, continuous-time\, measure-valued dynamical system. I w
ill explore the\nstructure of this dynamical system and its equilibria wit
h a view to shedding light on\nevolutionary explanations of the similar pa
tterns of senescence and mortality seen in many\nmulti-cellular organisms.
In particular\, I will point out how the non-linear nature of the\ndynami
cal system causes problems with a popular explanation of the Gompertz-Make
ham\nmortality curve and requires a reformulation of Haldane's Principle\,
one of the cornerstones of\nthe theory of mutation accumulation. This is
joint work with David Steinsaltz (Oxford)\nand Kenneth W. Wachter (Berkele
y).\n
LOCATION:Lecture Hall\, Cologne Biocenter
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Prof. Herbert Spohn
DTSTART;VALUE=DATE-TIME:20130605T143000
DTEND;VALUE=DATE-TIME:20130605T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000256@events.thp.uni-koeln.de
DESCRIPTION:Prof. Herbert Spohn\, TU München\n\nNonlinear fluctuating hyd
rodynamics and anharmonic chains\n\nRather commonly\, Hamiltonian systems
at nonzero temperature\nin one spatial dimension have short range static c
orrelations\, but\nlong-lived excitations. The slowest modes are the local
ly conserved fields.\nTo capture their universal behavior we develop a non
linear version of\nfluctuating hydrodynamics. The best studied systems are
classical\nanharmonic chains. We compare with MD simulations.\n\n\nContac
t Person: Markus Kunze
LOCATION:Seminar room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Prof. Nicolai Reshetikhin
DTSTART;VALUE=DATE-TIME:20130529T143000
DTEND;VALUE=DATE-TIME:20130529T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000257@events.thp.uni-koeln.de
DESCRIPTION:Prof. Nicolai Reshetikhin\, Berkeley\n\nOn semiclassical quant
ization of gauge theories on space time manifolds with boundary\n\nIt is w
ell known how to construct a formal semiclassical (or perturbative) quanti
zation of a classical field theory on $\\R^n$. The answer is given by form
al power series in Feynman diagrams. In this talk we will focus on how to
do it for space time manifolds with boundary. The main example is Chern-Si
mons classical field theory. The talk is based on joint work with A. Catta
neo and P. Mnev. \n\nContact Person: Peter Littelmann
LOCATION:Seminar room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Prof. Dr. Simon Trebst
DTSTART;VALUE=DATE-TIME:20130709T164500
DTEND;VALUE=DATE-TIME:20130709T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000258@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Simon Trebst\, ITP\, Universitä\;t Kö\;ln\n\
nEmergenz nahe des Temperaturnullpunktes: Topologische Quantenflü\;ssi
gkeiten\n\nDie Quantenmechanik hä\;lt viele Ü\;berraschungen berei
t – eine immer wiederkehrende Erfahrung\, die nicht nur Physik-Studieren
de in den ersten Semestern machen\, sondern auch eine\, die der aktuellen
Forschung immer wieder neuen Antrieb verleiht. Etwa dann\, wenn das Zusamm
enspiel einer groß\;en Zahl quantenmechanischer Freiheitsgrade in sub
tiler Weise konspiriert und zu qualitativ völlig neuen Effekten und Mater
ialeigenschaften fü\;hrt. Ein besonders faszinierendes emergentes Ph&a
uml\;nomen dieser Art ist die Entstehung topologischer Ordnung. In diesem
Kolloquium werde ich berichten von der aktuellen Suche nach topologischer
Ordnung in einer Vielzahl von physikalischen Systemen\, den Hoffnungen auf
den Einsatz topologischer Materie in Quantencomputern\, sowie all den kle
inen und großen Hü\;rden auf dem Weg dorthin – etwa in Form all jen
er Instabilitä\;ten topologischer Ordnung\, die durch Unordnung hervor
gerufen werden\, und dabei neuer Quell eben jener Faszination der Quantenm
echanik sind.
LOCATION:HS3
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Himani Sachdeva
DTSTART;VALUE=DATE-TIME:20130613T140000
DTEND;VALUE=DATE-TIME:20130613T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000259@events.thp.uni-koeln.de
DESCRIPTION:Himani Sachdeva\, Tata Institute of Fundamental Research\, Mum
bai\, India\n\nPhase Transitions in an Open-Boundary Aggregation-Fragmenta
tion Model\n\nMotivated by the phenomenology of traffic inside the Golgi a
pparatus of cells\,\nwe study a one-dimensional aggregation-fragmentation
model in an open\nsystem where the total mass is not conserved due to infl
ux and outflux at the\nboundaries. As influx is increased\, the system und
ergoes a phase transition to\nan unusual condensate phase in which the tot
al mass shows giant fluctuations\nas well as strong temporal intermittency
\, as in the turbulence phenomena.\nThese properties are established analy
tically in the absence of fragmentation\nand numerically for non-zero frag
mentation. We have also studied a multi-\nspecies generalisation of this m
odel which allows for interconversion between\ndifferent species: in a cer
tain limit\, the system exists in a phase characterised by\nformation of l
ocalised\, indefinitely growing aggregates of different species in\ndiffer
ent regions of the system. The broad relevance of this sort of a model in\
nthe context of Golgi structure and traffic will be briefly discussed.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. V. L. Pokrovsky
DTSTART;VALUE=DATE-TIME:20130719T163000
DTEND;VALUE=DATE-TIME:20130719T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000260@events.thp.uni-koeln.de
DESCRIPTION:Prof. V. L. Pokrovsky\, Texas A&M University\n\nCoherence and
reflection symmetry breaking in the Bose-Einstein condensate of spin waves
\n\nIn 2006 the phenomenon of Bose-Einstein condensation at room temperatu
re was discovered in a ferromagnet YIG (Yttrium-Iron garnet) by the group
of experimenters from University of\nMünster leaded by S. Demokritov. Th
ey also presented a theoretical explanation of their experiment. In my tal
k I will first describe this experiment and its explanation. Recently (Jun
e\n2012) the same group discovered a low-contrast interference pattern in
the intensity of Brillouin light scattering. The spectrum of spin waves in
a thin film of YIG has two minima at\nfinite values of momentum + Q and -
Q. The interference demonstrates that the two condensates have very differ
ent densities despite complete symmetry of the system to space inversion.
In\nour work (Fuxiang Li\, W.M. Saslow and V.L. P.) we propose a theory ex
plaining why and how this symmetry is violated. Our theory predicts that i
n thinner films it is possible to observe a\nsymmetric state of condensate
s. The transition between these two states can be driven by magnetic field
. The theory also predicts a new type of the collective oscillations. The
dipolar\ninteraction plays a special role trapping the sum of the two cond
ensate phases at the values 0 or pi. Transition between these two states i
s possible in non-symmetric phase and can be\nobserved as a cusp in the pl
ot of contrast vs. magnetic field.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Leonid Mirny
DTSTART;VALUE=DATE-TIME:20130612T110000
DTEND;VALUE=DATE-TIME:20130612T120000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000261@events.thp.uni-koeln.de
DESCRIPTION:Leonid Mirny\, Institute for Medical Engineering and Science\,
and Department of Physics\, MIT\n\nThe Genome Folding Problem: Bridging P
hysics and Biology\n\nDNA of the human genome is two meters long and is fo
lded inside a cell nucleus\, which is just 5 microns in diameter. Revealin
g genome organization in 3D and understanding physical principles that gov
ern its folding constitute the Genome Folding Problem. Recently developed
Chromosome Conformation Capture technique\, Hi-C\, provides comprehensive
information about spatial genome organization. Our analysis of these data
and polymer simulations suggest that the genome is folded into a non-equil
ibrium polymer state\, called the fractal globule. Yeast genome\, on the c
ontrary\, resembles an equilibrium polymer brush. I will discuss intriguin
g properties of these polymer states and other major features of the human
and yeast genome organization.
LOCATION:Seminar Room 1st Physical Institute
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Dr. Florian Marquardt
DTSTART;VALUE=DATE-TIME:20130621T163000
DTEND;VALUE=DATE-TIME:20130621T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000262@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Florian Marquardt\, Universität Erlangen-Nürnberg\
n\nDynamics of optomechanical arrays\n\nOptomechanical systems\, that coup
le light to nanomechanical motion\,\nhave seen rapid progress during the p
ast few years and have now\nentered the quantum regime of motion. In addit
ion\, it is now\nbecoming possible to build optomechanical arrays\, i.e.\n
arrays of many interacting localized optical and mechanical modes.\nThis o
pens up several new areas for optomechanical systems\,\nsuch as quantum in
formation processing with many mechanical modes\,\ncollective dynamics\, a
nd quantum simulations.\nIn this talk I will focus on the nonlinear collec
tive dynamics in such arrays.\nIn the classical regime\, mechanical oscill
ations\ncan synchronize. The evolution of the mechanical oscillation\nphas
e field can display interesting phenomena\, such as vortices.\nThe transit
ion from the incoherent regime to a synchronized regime\ncan be determined
either by static disorder or by noise.\nIn particular\, I will describe w
hat happens under the influence\nof quantum noise.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Daniel Becker
DTSTART;VALUE=DATE-TIME:20130618T120000
DTEND;VALUE=DATE-TIME:20130618T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000263@events.thp.uni-koeln.de
DESCRIPTION:Daniel Becker\, Universität Mainz\n\nAsymptotic Safety and Bl
ack Hole Thermodynamics\n\nThe goal of the Asymptotic Safety program consi
sts in finding a nonperturbatively renormalizable quantum field theory of
gravity and analyzing its properties. The ideas\, the motivation and the c
oncepts of Asymptotic Safety will be explained in the first part of this t
alk. Then\, we focus on Quantum Einstein Gravity in case spacetime has bou
ndaries and consider a specific example of a renormalization group calcula
tion including scale dependent boundary terms. In the third part I show th
e impact of these results on black hole thermodynamics.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Tobias Galla
DTSTART;VALUE=DATE-TIME:20130628T163000
DTEND;VALUE=DATE-TIME:20130628T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000264@events.thp.uni-koeln.de
DESCRIPTION:Dr. Tobias Galla\, University of Manchester\n\nEffects of intr
insic noise in individual-based systems\n\nInteracting particle systems in
biology\, chemistry and the social sciences are\ntraditionally described
by ordinary or partial differential equations. These\nare purely determini
stic and based on the assumption that effects of noise can\nsafely be negl
ected. Such approaches are no doubt chosen for their mathematical\nsimplic
ity\, the theory of differential equations is well developed\, whereas\nex
isting theories of non-equilibrium stochastic dynamics are more complex an
d\nlargely incomplete. In this talk I will consider systems of a finite nu
mber of\ninteracting particles\, their intrinsic stochasticity can then no
longer be\nignored. I will discuss noise-induced phenomena such as quasi-
cyles\,\nquasi-Turing patterns and travelling quasi waves\, and explain ho
w they can be\ncharacterised analytically within the so-called linear nois
e approximation.\nExamples where this is relevant include systems in evolu
tionary dynamics\, game\ntheory and chemical reaction systems. One focus o
f the talk will be on models\nwith delay dynamics\, important for example
in gene regulatory systems or in\nepidemiology. I will show how path-integ
ral approaches can be used to derive\ngeneral results for their chemical L
angevin equation and linear-noise\napproximation.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Dr. Reinhold Egger
DTSTART;VALUE=DATE-TIME:20130705T163000
DTEND;VALUE=DATE-TIME:20130705T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000265@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Reinhold Egger \, Heinrich-Heine Universität Düsse
ldorf \n\nMesoscopic transport properties of multiterminal Coulomb Majoran
a junctions\n\nIn this talk\, the low-energy quantum transport prope
rties of the Coulomb-Majorana junction will be discussed\, whe
re several helical nanowires are coupled to a joint mesoscopic superconduc
tor with finite charging energy. By virtue of the proximity effect\,
Majorana bound states are formed near the ends of the superconducti
ng wire parts\, which are coupled together by charging effects. F
or sufficiently weak but finite charging energy\, this system generi
cally approaches an isotropic SO(M) Kondo fixed point with non-Fermi
liquid behavior observable in quantum transport observables such as the t
emperature-dependent conductance tensor or the fluctuating current noise c
orrelator. The latter quantities follow from the Keldysh formulatio
n of an effective phase action approach.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Peter Finch
DTSTART;VALUE=DATE-TIME:20130715T140000
DTEND;VALUE=DATE-TIME:20130715T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000266@events.thp.uni-koeln.de
DESCRIPTION:Peter Finch\, Hannover University\n\nIntegrablity in the so(5)
_2 anyon chain\n\n
LOCATION:Conference Room THP
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Jorgen Rasmussen
DTSTART;VALUE=DATE-TIME:20130731T141500
DTEND;VALUE=DATE-TIME:20130731T151500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000267@events.thp.uni-koeln.de
DESCRIPTION:Jorgen Rasmussen\, University of Queensland\n\nSolvable model
of critical dense polymers\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Prof. Erik Verlinde
DTSTART;VALUE=DATE-TIME:20131022T164500
DTEND;VALUE=DATE-TIME:20131022T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000268@events.thp.uni-koeln.de
DESCRIPTION:Prof. Erik Verlinde\, University of Amsterdam\n\nTowards an En
tropic Theory for Gravity\, Dark Energy and Dark Matter\n\nDevelopments in
string theory and black hole physics indicate that gravity should be view
ed as an emergent phenomenon that is derived from an underlying microscopi
c description. Following these insights I illuminate the basic mechanisms
responsible for the emergence of gravity. I will argue that space time\,
matter and gravity originate from a highly entangled quantum mechanical s
ystem\, whose energy contains the dark energy. Gravity\, or rather inertia
\, appears as an adiabatic reaction force\, while non-adiabatic correction
s due to slow relaxation processes lead to the phenomena attributed to dar
k matter. These considerations lead to a universal formula for the dark
matter distribution which explains the observed velocity profiles for all
types of galaxies and galaxy clusters and agrees with the cosmic dark matt
er density obtained from the WMAP and Planck-data. \n\nContact Person: Jo
hannes Berg
LOCATION:HS 2
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Test Speaker
DTSTART;VALUE=DATE-TIME:20130907T100000
DTEND;VALUE=DATE-TIME:20130907T120000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000269@events.thp.uni-koeln.de
DESCRIPTION:Test Speaker\, Test Affiliation\n\nTest talk\n\ntest test test
test\n\nContact Person: Contact Test
LOCATION:nowhere
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Anatoly Konechny
DTSTART;VALUE=DATE-TIME:20131018T163000
DTEND;VALUE=DATE-TIME:20131018T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000270@events.thp.uni-koeln.de
DESCRIPTION:Anatoly Konechny\, Heriot-Watt University\, Edinburgh\n\nBound
ary entropy and its properties\n\nBoundary entropy of boundaries in one-d
imensional critical systems was defined by I. Affleck and A. Ludwig in 199
1. A classic example of such systems is a conduction defect at low tempera
ture as described by the Kondo model.\n\nBoundary entropy has a number of
peculiar properties\, for example it can be negative.\n\nIn this talk we w
ill discuss how this quantity is defined and what are its known properties
.\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Rochus Klesse
DTSTART;VALUE=DATE-TIME:20131025T163000
DTEND;VALUE=DATE-TIME:20131025T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000271@events.thp.uni-koeln.de
DESCRIPTION:Dr. Rochus Klesse\, University of Cologne\, Institute for Theo
retical Physics\n\nProbability assignment and maximum entropy principles\n
\nThe assignment of adequate probabilities to the basic\noutcomes of some
random experiment under consideration is a\nprerequisite of a probabilisti
c description. The maximum entropy\nprinciple of Statistical Mechanics sol
ves this problem by stating that\namong all probability distributions that
satisfy some given constraints\nthe one of maximum Boltzmann-Gibbs-Shanno
n entropy must be chosen.\nBeing an indisputable principle of Statistical
Mechanics\,\nits status outside physics as a general method of statistical
\ninference is less clear.\n\nWe present a foundation of the maximum entro
py principle that is based\non probabilistic arguments. It deliberately a
voids reference to\nnotions of information and it does not appeal to physi
cally motivated\nproperties of entropy. This is achieved by formalizing pr
obability\nassignment as a certain symmetric\, continuous mapping that add
itionally\nsatisfies a condition of self-consistency. We show that any suc
h mapping\ncan be expressed as a variational principle\, i.e. as a general
ized\nmaximum entropy principle with an a priori unspecified entropy funct
ion.\nAdding a condition of statistical independence\, an earlier result o
f\nShore and Johnson shows that the entropy function must be essentially\n
the standard Boltzmann-Gibbs-Shannon entropy.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Dr. Arkady Krashenninikov
DTSTART;VALUE=DATE-TIME:20130515T143000
DTEND;VALUE=DATE-TIME:20130515T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000272@events.thp.uni-koeln.de
DESCRIPTION:Dr. Arkady Krashenninikov\, University of He
lsinki\n\nNative and irradiation-induced defects in
two-dimensional materials: graphene\, boron-nitride\
, transition metal dichacolgenides\, and silica\n\n\n\nC
ontact Person: Thomas Michely
LOCATION:Seminar room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Dr. Oleg Petracic
DTSTART;VALUE=DATE-TIME:20130619T143000
DTEND;VALUE=DATE-TIME:20130619T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000273@events.thp.uni-koeln.de
DESCRIPTION:Dr. Oleg Petracic\, Forschungszentrum Jülich\n\nStructural an
d magnetic correlations of self-assembled nanoparticle superlattices\n\nNa
noparticle superlattices can be considered as novel type of materials with
controllable electronic\, optical and magnetic properties. Their building
blocks are nanoparticles (or 'nanocrystals') from a metallic\, metal-oxid
e\, or semiconducting material or hybrid between different materials. I wi
ll report about the structural and magnetic properties of 2- or 3-dimensio
nal 'superlattices' of magnetic nanoparticles. Depending on the substrate
and the self-assembly technique we can fabricate either 'superlattice film
s' showing various growth modes as known from classical thin films or 3d m
esocrystals. The lateral ordering is quantified using electron microscopy
and grazing incidence small angle X-ray scattering (GISAXS). The magnetic
behavior and correlations are investigated by magnetometry\, polarized neu
tron reflectometry (PNR) and grazing incidence small-angle neutron scatter
ing (GISANS).\n\nContact Person: Markus Grüninger
LOCATION:Seminar room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Manuel Brando
DTSTART;VALUE=DATE-TIME:20130717T143000
DTEND;VALUE=DATE-TIME:20130717T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000274@events.thp.uni-koeln.de
DESCRIPTION:Manuel Brando\, MPI CPfS Dresden\n\nFerromagnetic quantum crit
icality in heavy fermion systems\n\nHeavy fermion (HF) systems are metals
where the weak hybridisation between nearly localized f-electrons and the
mobile conduction electrons\, i.e. the Kondo eect\, leads to a Fermi liqu
id (FL) ground state with narrow bands and quasiparticles with strongly en
hanced eective electronic masses. When the magnetic RKKY interaction beco
mes comparable to the Kondo interaction\, magnetic order can appear\, most
ly at very low T. The magnetic order can be suppressed by an external para
meter\, e.g. pressure or magnetic eld\, inducing a quantum phase transiti
on (QPT) at T = 0. If this QPT is continuous\, the associated quantum crit
ical point (QCP) is surrounded by a non- FL regime of quantum critical fuc
tuations where unconventional superconductivity or novel phases of matter
may arise [1].\n\nThe unambiguous observation of antiferromagnetic (AFM) Q
CPs in HF systems [2] has led to an increasing number of theoretical and e
xperimental works in order to understand QPTs as deeply as their classical
counterpart. Although it has been demonstrated that in antiferromagnets Q
CPs exist\, in ferromagnets there is still no clear evidence. Intensive in
vestigations have shown that metallic ferromagnets are inherently unstable
[3\, 4] and do not exhibit a FM QCP.\n\nHowever\, in the recently discove
red HF system YbNi4P2\, a quasi-1D ferromagnet with a remarkably-low TC =
0:15K [5\, 6]\, the T-divecgence in the Grüneisen ratio [7] points to the
presence of a FM QCP. I will present a general overview of the state of t
he art of FM quantum criticality in HF systems\, discussing in particular
the cases of YbNi4P2 [5\, 6]\, CeFePO [8]\, CePd1-xRhx [9] as well as the
AFM system YbRh2Si2 [10] where FM order is induced by chemical pressure [1
1].\n\n \n\nContact Person: Markus Garst
LOCATION:Seminar room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Sandipan Sengupta
DTSTART;VALUE=DATE-TIME:20131022T120000
DTEND;VALUE=DATE-TIME:20131022T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000275@events.thp.uni-koeln.de
DESCRIPTION:Sandipan Sengupta\, Raman Research Institute\, Bangalore\, Ind
ia\n\nTopological parameters in gravity\n\nGravity theory in four dimensio
ns has three independent topological parameters. In the Lagrangian\, these
show up as coefficients of three topological densities\, namely Nieh-Yan\
, Pontryagin and Euler. We analyse the Hamiltonian theory based on this ge
neralized Lagrangian. The resulting theory develops a nontrivial dependenc
e on all three parameters\, and is shown to admit a SU(2) gauge theoretic
interpretation with a set of seven first class constraints corresponding t
o three SU(2) rotations\, three spatial diffeomorphism and one to evolutio
n in a timelike direction.\n\nWe also study how the topological parameters
affect the gravity action with or without a cosmological constant for man
ifolds with boundaries. For both Dirichlet and locally AdS asymptotia\, th
e Barbero-Immirzi parameter is shown to appear as the only independent top
ological coupling constant in the action principle.\n\nOur analyses indica
te that there might be nontrivial implications of the topological paramete
rs in the quantum theory of gravity.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Biswajit Paul
DTSTART;VALUE=DATE-TIME:20131112T120000
DTEND;VALUE=DATE-TIME:20131112T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000276@events.thp.uni-koeln.de
DESCRIPTION:Biswajit Paul\, S. N. Bose National Centre for Basic Sciences\
, Kolkata\, India\n\nSymmetries in the Regge–Teitelboim Type Cosmology\n
\nSince their introduction\, theories with higher derivatives are unavoida
ble and frequently arise in different contexts. Hamiltonian formulation fo
r Higher derivative theories become necessary and is discussed in the firs
t order formalism. This Hamiltonian formulation is applied to the minisupe
rspace cosmology following from the geodetic brane gravity model introduce
d by Regge and Teitelboim. The analysis is done using the equivalent first
order approach. The constraint algebra is shown to realize a truncated Vi
rasoro algebra. The gauge generator containing the exact number of gauge p
arameters is constructed. Equivalence between the gauge and reparametrizat
ion symmetries has been demonstrated. Complete gauge fixed computations ha
ve been provided and formal quantization is indicated.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Friedrich W. Hehl
DTSTART;VALUE=DATE-TIME:20131203T120000
DTEND;VALUE=DATE-TIME:20131203T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000277@events.thp.uni-koeln.de
DESCRIPTION:Friedrich W. Hehl\, Universität zu Köln and University of Mi
ssouri-Columbia\n\nOn Energy–Momentum & Spin: the inertial currents in c
lassical field theory\n\nIn special relativity\, quantum matter can be cla
ssified according to mass-energy and spin. The corresponding field-theoret
ical notions are the energy-momentum-stress tensor T and the spin angular
momentum tensor S. Since each object in physics carries energy and\, if fe
rmionic\, also spin\, the notions of T and S can be spotted in all domains
of physics\, starting from the mechanical stress in engineering mechanics
\, over the Maxwell stress in electrodynamics to the energy-momentum tenso
r of matter in special and in general relativity. We discuss\, in particul
ar\, asymmetric stress tensors\, spin fluids\, the Belinfante-Rosenfeld sy
mmetrization of T\, the improved energy-momentum of Callan\, Coleman\, and
Jackiw. We discuss in how far Weyl's dictum that only general relativity
leads to a proper definition of the energy concept is appropriate. This se
minar is open ended and tries to build bridges to relativistic themodynami
cs.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Erez Berg
DTSTART;VALUE=DATE-TIME:20131106T143000
DTEND;VALUE=DATE-TIME:20131106T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000278@events.thp.uni-koeln.de
DESCRIPTION:Erez Berg\, Weizmann Institute\n\nThere's Life at Absolute Zer
o: Exotic Phases of Quantum Matter\n\nTraditionally\, condensed matter phy
sicists have classified phases of\nmatter according to their symmetries. O
ver the last few decades\, it\nbecame clear that near zero temperature\, t
here are plenty of phases\nwhich lie beyond this classification scheme. Th
ese intrinsically\nquantum mechanical states of matter lack any ordinary o
rder parameter\;\nthey can be thought of as a strongly fluctuating quantum
liquids.\nNevertheless\, they posses a hidden underlying order\, known as
\n"topological order". The quantum Hall effect is a celebrated example\nof
such a phase\; several others have been discovered recently\, and\nmany m
ore have been predicted theoretically. The elementary\nexcitations of topo
logically ordered states can be thought of as\nemergent particles\; intrig
uingly\, these particles can obey unusual\nexchange statistics rules which
resemble neither those of bosons nor\nof fermions. This property makes to
pological phases potentially useful\nas building blocks for future decoher
ence-free quantum processing\ndevices. In this talk\, I will describe some
modern insights into the\nnature of these phases\, and their characteriza
tion in term of their\nquantum entanglement. I will also discuss a new rou
te to realize novel\nphases that arise on the boundaries of other\, previo
usly known\ntopologically ordered states.\n\n\nContact Person: Simon Trebs
t
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Joachim Hemberger
DTSTART;VALUE=DATE-TIME:20131108T120000
DTEND;VALUE=DATE-TIME:20131108T124500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000279@events.thp.uni-koeln.de
DESCRIPTION:Joachim Hemberger\, 2. Physikalisches Institut\, Univers
ität zu Köln\n\nLinear and Non-linear Dielectric Spectrosco
py from mHz to THz: Control & Dynamics of Complex Matter\n\nTh
is talk is one of a series of presentations of research groups organized b
y the Bonn-Cologne Graduate School of Physics and Astronomy. The aim is to
provide insights into the research done at physics institutes in Cologne.
Interested students (Bachelor\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Hans Ströher
DTSTART;VALUE=DATE-TIME:20131108T124500
DTEND;VALUE=DATE-TIME:20131108T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000280@events.thp.uni-koeln.de
DESCRIPTION:Hans Ströher\, IKP - FZ Jülich\n\nSpin Physik an COSY un
d anderswo\n\nThis talk is one of a series of presentations of researc
h groups organized by the Bonn-Cologne Graduate School of Physics and Astr
onomy. The aim is to provide insights into the research done at physics in
stitutes in Cologne. Interested students (Bachelor\, Master\, and PhD) are
most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Peter Schilke
DTSTART;VALUE=DATE-TIME:20131122T120000
DTEND;VALUE=DATE-TIME:20131122T124500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000281@events.thp.uni-koeln.de
DESCRIPTION:Peter Schilke\, 1. Physikalisches Institut\, Universität zu
Köln\n\nStar Formation\n\nThis talk is one of a series of presentations
of research groups organized by the Bonn-Cologne Graduate School of Physic
s and Astronomy. The aim is to provide insights into the research done at
physics institutes in Cologne. Interested students (Bachelor\, Master\, an
d PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Anton Akhmerov
DTSTART;VALUE=DATE-TIME:20131113T143000
DTEND;VALUE=DATE-TIME:20131113T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000282@events.thp.uni-koeln.de
DESCRIPTION:Anton Akhmerov\, TU Delft\n\nCoulomb manipulation of Majorana
fermions with superconducting circuits\n\nCreation of isolated Majorana fe
rmions\, the simplest type of\nnon-Abelian anyons\, in one out of many sup
erconductor-semiconductor\nhybrid systems seems reachable within a few yea
rs time.\nI will introduce a scheme for manipulation of Majorana fermions
using\nexistent superconducting circuits\, namely transmon qubits.\nWithin
this framework I will consider in particular the minimal setup\nrequired
to measure the unusual properties of Majorana fermions\, and a\npossible i
mplementation of a scalable quantum computer that relies on\nthe topologic
al properties of Majorana fermions.\n\n\nContact Person: Simon Trebst
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Montu Saxena
DTSTART;VALUE=DATE-TIME:20131118T100000
DTEND;VALUE=DATE-TIME:20131118T103000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000283@events.thp.uni-koeln.de
DESCRIPTION:Montu Saxena\, University of Cambridge\n\nQuantum Criticality
and Superconductivity in Spin and Charge Systems\n\nThis talk will focus o
n experimental search and discovery of novel forms of quantum order in met
allic and insulating magnets\, intercalated compounds\, ferroelectric syst
ems and multi-ferroic materials. Particularly discussed will be the pressu
re-induced superconductivity and critical phenomena in the vicinity of qua
ntum\nphase transitions.\n\nMaterials tuned to the neighbourhood of a zero
temperature phase transition often show the emergence of novel quantum ph
enomena. Much of the effort to study these new emergent effects\, like the
breakdown\nof the conventional Fermi-liquid theory in metals has been foc
used in narrow band electronic systems. But Spin or Charge ordered phases
in insulating systems can also be tuned to absolute zero using hydrostatic
pressure. Close to such a zero temperature phase transition\, physical qu
antities like resistivity\, magnetisation and dielectrics constant change
into radically unconventional forms due to the fluctuations experienced in
this region giving rise to new kinds ordered states including superconduc
tivity in the metallic systems\n\n\nContact Person: Paul H.M. van Loosdrec
ht
LOCATION:Seminar Room A\, Institute of Chemistry
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Alexander Brinkmann
DTSTART;VALUE=DATE-TIME:20131127T143000
DTEND;VALUE=DATE-TIME:20131127T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000284@events.thp.uni-koeln.de
DESCRIPTION:Alexander Brinkmann\, University of Twente\n\nTransport and su
perconductivity at topological surfaces and interfaces\n\nDue to the locki
ng of the electron spin to the momentum at the conducting surface of a 3D
topological insulator\, new physical phenomena arise in transport and supe
rconductivity. The topological nature of surface states can be evidenced b
y measuring the Berry phase of quantum oscillations in magnetotransport. I
will quickly review the current status of the Bi-based class of 3D topolo
gical insulators in terms of how good a topological insulator one can make
nowadays. Also the conducting interface between insulating LaAlO3 and SrT
iO3 bears great resemblance to these topological surfaces.\nWhen supercond
uctivity is induced into a topological state by using the proximity effect
or a Josephson junction configuration\, the superconducting order paramet
er can have a large p-wave component\, leading to Andreev bound states at
zero energy\, the so-called Majorana states. I will review the status of o
ur experiments on topological Josephson junctions based on the Bi-based 3D
topological insulators\, as well as conducting interfaces between LaAlO3
and SrTiO3.\n\nContact Person: Paul H.M. van Loosdrecht
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Steve Zelditch
DTSTART;VALUE=DATE-TIME:20131211T143000
DTEND;VALUE=DATE-TIME:20131211T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000285@events.thp.uni-koeln.de
DESCRIPTION:Steve Zelditch\, Northwestern University\n\nShapes and Sizes o
f Eigenfunctions \n\nEigenfunctions of the Schrodinger operator (or a La
placian on a domain or manifold)\nrepresent modes of vibrations of drums a
nd membranes. In quantum mechanics\nthey represent stationary states of a
toms. Understanding shapes and sizes of\neigenfunctions allows one to visu
alize these objects. An intriguing problem\nis to relate the shapes and si
zes of eigenfunctions to the underlying classical mechanics\,\nsuch as the
geodesic flow of (M\, g) or the dynamics of billiard trajectories\non a b
illiard table. \n\nIn this talk we will explain the role of eigenfunctions
in quantum mechanics\nand discuss both classic and new results describing
nodal (zero) sets\nof eigenfunctions. The new results relate nodal sets
to classical dynamics. \nNo prior knowledge of quantum mechanics is assume
d. \n\n\nContact Person: George Marinescu
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Sebastian Schmittner
DTSTART;VALUE=DATE-TIME:20130424T140000
DTEND;VALUE=DATE-TIME:20130424T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000294@events.thp.uni-koeln.de
DESCRIPTION:Sebastian Schmittner\, Institut für Theoretische Physik\n\nSp
herical Representations of Reductive Lie Supergroups\n\n
LOCATION:Seminar room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Michael Kiessling
DTSTART;VALUE=DATE-TIME:20140115T143000
DTEND;VALUE=DATE-TIME:20140115T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000287@events.thp.uni-koeln.de
DESCRIPTION:Michael Kiessling\, Rutgers University\n\nAtoms with Bosonic '
Electrons'\n\nAtoms with bosonic `electrons' have always been more of a\nt
heoretical fancy than a model of real physical matter\, at best suited to\
nillustrate how important the Pauli principle is in our world\, but mainly
\nof only academic interest to mathematical physicists. All this is about
to\nchange in the not-too-distant future if the recently discovered anti-a
lpha\nparticles (anti-He nuclei which are twice positively charged bosons
in\ntheir nuclear ground state) can be produced in sufficiently large numb
ers\,\ncaptured\, and substituted for the conventional electrons in the at
omic\nhull around conventional nuclei (a similar feat has already been\nac
complished with anti-protons\, but these are fermions\, not bosons). In my
\ntalk I will try to survey what is mathematically rigorously known about\
natoms with bosonic `electrons' and\, more importantly\, present a list of
\ninteresting open problems which still await their solution.\n\n\nContact
Person: Markus Kunze
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Andew Mackenzie
DTSTART;VALUE=DATE-TIME:20140226T143000
DTEND;VALUE=DATE-TIME:20140226T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000288@events.thp.uni-koeln.de
DESCRIPTION:Andew Mackenzie\, University of St. Andrews\n\nt.b.a.\n\n\n\nC
ontact Person: Markus Braden
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Charles M. Marcus
DTSTART;VALUE=DATE-TIME:20130508T143000
DTEND;VALUE=DATE-TIME:20130508T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000289@events.thp.uni-koeln.de
DESCRIPTION:Charles M. Marcus\, Center for Quantum Devices\, Unive
rsity of Copenhagen\n\nHas Majorana returned\, and why we should c
are\n\nThis talk will review recent experiments by several groups\, includ
ing ours\, aimed at identifying signatures of Majorana fermions in condens
ed matter systems. To date\, the experiments are very suggestive\, but unc
ertainties remain. What can future experiments do to make the case air-tig
ht? As time allows\, I will also discuss how such states might be valuable
to topological quantum information processing. \n\nContact Person: Achim
Rosch
LOCATION:Lecture Hall 3
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Arkady Krashenninikov
DTSTART;VALUE=DATE-TIME:20130515T143000
DTEND;VALUE=DATE-TIME:20130515T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000290@events.thp.uni-koeln.de
DESCRIPTION:Arkady Krashenninikov\, Aalto University and University of Hel
sinki\n\nNative and irradiation-induced defects in two-dimensional materia
ls: graphene\, boron-nitride\, transition metal dichacolgenides\, and sili
ca\n\nIsolation of a single sheet of graphene indicated that strictly two-
dimensional (2D) materials can exist at finite temperatures. Indeed\, inor
ganic 2D systems such as hexagonal BN sheets\, transition metal dichalcoge
nides (TMD) with a common structural formula MeX2\, where Me stands for tr
ansition metals (Mo\, W\, Ti\, etc.)\, X for chalcogens (S\, Se\, Te)\, an
d SiO2 layers were later manufactured by various methods. All these materi
als have defects\, which naturally affect their properties. Moreover\, def
ects can deliberately be introduced by ion and electron irradiation to tai
lor the properties of the system [1].\n\nIn my talk\, I will summarize our
knowledge about defects [2] in graphene and other 2D materials. I will al
so touch upon defect production in 2D systems under impacts of energetic i
ons [3] and electrons [4\,7] and present theoretical data obtained in coll
aboration with several experimental groups [3\,6]. I will also dwell upon
defect-mediated engineering of the electronic structure of 2D materials su
ch as BN [5] or TMDs [7]. \n\nBesides\, I will discuss mixed TMDs\, such a
s MoS2x Se2(1−x)\, which can be referred to as 2D random alloys [8]. Our
simulations indicate that 2D mixed ternary MoS2/MoSe2/MoTe2 compounds are
thermodynamically stable at room temperature\, so that such materials can
be manufactured by CVD or exfoliation techniques that the direct gap in t
hese material can continuously be tuned. I will further present advanced f
irst-principles calculations of the electronic structure of TMDs [9].\n\n1
. A.V. Krasheninnikov and F. Banhart\, Nature Materials\, 6 (2007) 723.\n2
. F. Banhart\, J. Kotakoski and A. V. Krasheninnikov\, ACS Nano\, 5 (2011)
26.\n3. M. Kalbac\, et al.\, Advanced Materials 25 (2013) 1004.\n4. J.C.
Meyer\, et al.\, Phys. Rev. Lett. 108 (2012) 196102.\n5. N. Berseneva\, A.
V. Krasheninnikov\, and R.M. Nieminen\, Phys. Rev. Lett. 107 (2011) 03550
1.\n6. R. R. Nair\, et al.\, Nature Physics 8 (2012) 199.\n7. H.-P. Komsa\
, et al.\, Phys. Rev. Lett. 109 (2012) 035503.\n8. H.-P. Komsa and A. V. K
rasheninnikov\, J. Phys. Chem. Lett. 3 (2012) 3652. \n9. H.-P. Komsa and
A. V. Krasheninnikov\, Phys. Rev. B (Rapid Comm.) 86 (2012) 241201. \n\nC
ontact Person: Thomas Michely
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Peter Hirschfeld
DTSTART;VALUE=DATE-TIME:20140205T143000
DTEND;VALUE=DATE-TIME:20140205T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000292@events.thp.uni-koeln.de
DESCRIPTION:Peter Hirschfeld\, University of Florida\n\nNovel Disorder Eff
ects in Fe-Based Superconductors\n\n\n\nContact Person: Achim Rosch
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Jure Demsar
DTSTART;VALUE=DATE-TIME:20131120T143000
DTEND;VALUE=DATE-TIME:20131120T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000293@events.thp.uni-koeln.de
DESCRIPTION:Jure Demsar\, Ilmenau University of Technology\n\nThe interpla
y between the electronic and lattice degrees of freedom in Density Waves
probed with femtosecond real-time probes\n\nIn many of the advanced solids
exhibiting macroscopic quantum phenomena (e.g. superconductivity) their f
unctional properties arise from a delicate balance between interactions am
ong different degrees of freedom (electrons\, phonons\, spins). An example
of such is the appearance of Charge Density Wave (CDW) ground state in se
veral quasi one- or two-dimensional metals. According to the standard Peie
rls’ scenario the appearance of the CDW phase is driven by the divergent
static electronic susceptibility at a wave vector q=2kF. This classical
description has been challenged [1]\, arguing that the appearance of CDWs
\, in particular in the transition-metal dichalcogenides\, is due to stron
g (q-dependent) electron-phonon coupling [1].\n\nI will review some recent
studies where some of the open questions were addressed utilizing femtose
cond time-resolved optical [2] and structural probes [3-5]. Using femtosec
ond electron diffraction we were able to directly follow the photo-trigger
ed dynamics of the periodic lattice distortion (order parameter) in dichal
cogenides [3\,4]\, point out the importance of three-dimensionality for th
e existence of CDWs in these quasi-2D systems [4]\, and to track the diffe
rent stages of the photo-induced phase transition between different CDW ph
ases [5].\n\n[1] e.g. M. Johannes and I. Mazin\, Phys. Rev. B 77 (2008)\;
L. Gor'kov\, Phys. Rev. B 85\, 165142 (2012)\; H-M. Eiter\, PNAS 110\, 64
(2013).\n[2] H. Schäfer\, et al.\, Phys. Rev. Lett. 105\, 066402 (2010)\;
H. Schäfer\, et al.\, EPJ-ST 222\, 1005 (2013).\n[3] M. Eichberger\, et
al.\, Nature 468\, 799 (2010).\n[4] N. Erasmus\, et al.\, Phys. Rev. Lett.
109\, 167402 (2012)\; E. Eichberger\, et al.\, APL 102\, 121106 (2013).\n
[5] K. Haupt\, et al.\, in preparation.\n\nContact Person: Paul H.M. van L
oosdrecht
LOCATION:Seminar Room\, Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nEnvironment-assisted invariance\, entan
glement\, and probabilities in quantum mechanics\nWojciech Zurek
DTSTART;VALUE=DATE-TIME:20130417T140000
DTEND;VALUE=DATE-TIME:20130417T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000295@events.thp.uni-koeln.de
DESCRIPTION:Wojciech Zurek\n\nEnvironment-assisted invariance\, entangleme
nt\, and probabilities in quantum mechanics\n\n
LOCATION:Seminar room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Peter Wölfle
DTSTART;VALUE=DATE-TIME:20131129T163000
DTEND;VALUE=DATE-TIME:20131129T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000296@events.thp.uni-koeln.de
DESCRIPTION:Peter Wölfle\, KIT\n\nCritical fermionic quasiparticles near
quantum critical points of antiferromagnetic metals\n\nA theory of the sca
ling behavior of the thermodynamic\, transport and \ndynamical properties
of a three-dimensional metal at an \nantiferromagnetic (AFM) critical poin
t is presented. It is show how\nthe critical spin fluctuations at the AFM
wavevector q = Q induce energy \nfluctuations at small q\, giving rise to
a diverging quasiparticle \neffective mass over the whole Fermi surface. T
he coupling\nof the fermionic and bosonic degrees of freedom leads to a \n
self-consistent relation for the effective mass\, which has a strong \ncou
pling solution in addition to the well-known weak-coupling \nspin-density
wave solution. We thereby use the recently introduced \nconcept of critica
l quasiparticles\, employing a scale dependent \neffective mass ratio m*/m
and quasiparticle weight factor Z. We \nspecifically assume a scale depen
dent vertex correction boosting the \ncoupling of fermions and spin fluctu
ations. The ensuing spin fluctuation \nspectrum obeys E/T-scaling. Our res
ults are in good agreement with\nexperimental data on the heavy fermion co
mpounds YbRh2Si2 and CeCu6-xAux \nassuming 3D and 2D spin fluctuations\, r
espectively.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Dr. Luca Ferretti
DTSTART;VALUE=DATE-TIME:20131118T160000
DTEND;VALUE=DATE-TIME:20131118T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000297@events.thp.uni-koeln.de
DESCRIPTION:Dr. Luca Ferretti\, Universite Pierre et Marie Curie and Colle
ge de France\n\nEvolution in the protein universe and epistasis in fitness
landscapes\n\nOur understanding of the structure of real genotype fitness
landscapes at\ndifferent scales is still incomplete and requires new meth
ods and models. We\npresent a model of long-term protein evolution that\,
once fitted to data from\nprokaryotic protein alignments\, shed light on t
he large-scale epistatic structure\nof the protein universe. We also propo
se a natural measure of epistasis inspired\nby this model\, namely the cor
relation of fitness differences\, and show how it can\nbe used both to mea
sure local and global epistasis in experimental landscapes\nand to discrim
inate between theoretical models. Finally we discuss how chains\,\ni.e. co
nstrained paths in the landscape\, are related to the epistasis and the\ns
tructure of the interactions.\n
LOCATION:Biocentre\, Ground Floor Lecture Hall
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Peter Reiter
DTSTART;VALUE=DATE-TIME:20131122T124500
DTEND;VALUE=DATE-TIME:20131122T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000298@events.thp.uni-koeln.de
DESCRIPTION:Peter Reiter\, Institut für Kernphysik\, Universität zu K
öln\n\nPhysics with exotic nuclei - A journey to terra incogn
ita\n\nThis talk is one of a series of presentations of research groups
organized by the Bonn-Cologne Graduate School of Physics and Astronomy. Th
e aim is to provide insights into the research done at physics institutes
in Cologne. Interested students (Bachelor\, Master\, and PhD) are most wel
come.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Lucas Labadie
DTSTART;VALUE=DATE-TIME:20131206T120000
DTEND;VALUE=DATE-TIME:20131206T124500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000299@events.thp.uni-koeln.de
DESCRIPTION:Lucas Labadie\, 1. Physikalisches Institut\, Universität
zu Köln\n\nHigh-angular resolution in astronomy: a mi
croscope for the Universe\n\nThis talk is one of a series of present
ations of research groups organized by the Bonn-Cologne Graduate School of
Physics and Astronomy. The aim is to provide insights into the research d
one at physics institutes in Cologne. Interested students (Bachelor\, Mast
er\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Alfred Dewald
DTSTART;VALUE=DATE-TIME:20131206T124500
DTEND;VALUE=DATE-TIME:20131206T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000300@events.thp.uni-koeln.de
DESCRIPTION:Alfred Dewald\, Institut für Kernphysik\, Universität zu
Köln\n\nAccelerator mass spectrometry: Isotopic-rati
os measured with extremely high sensitivity are used i
n various applications\n\nThis talk is one of a series of pres
entations of research groups organized by the Bonn-Cologne Graduate School
of Physics and Astronomy. The aim is to provide insights into the researc
h done at physics institutes in Cologne. Interested students (Bachelor\, M
aster\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Achim Rosch
DTSTART;VALUE=DATE-TIME:20131220T120000
DTEND;VALUE=DATE-TIME:20131220T124500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000301@events.thp.uni-koeln.de
DESCRIPTION:Achim Rosch\, Institut für Theoretische Physik\, Universität
zu Köln\n\nFieldtheory and Condensed Matter physics\n\nT
his talk is one of a series of presentations of research groups organized
by the Bonn-Cologne Graduate School of Physics and Astronomy. The aim is t
o provide insights into the research done at physics institutes in Cologne
. Interested students (Bachelor\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Andres Zilges
DTSTART;VALUE=DATE-TIME:20140117T120000
DTEND;VALUE=DATE-TIME:20140117T124500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000302@events.thp.uni-koeln.de
DESCRIPTION:Andres Zilges\, Institut für Kernphysik\, Universität zu
Köln\n\nFrom giants\, pygmies and a cauldron in the cosmos: Nucl
ear Structure and Nuclear Astrophysics\n\nThis talk is one
of a series of presentations of research groups organized by the Bonn-Col
ogne Graduate School of Physics and Astronomy. The aim is to provide insig
hts into the research done at physics institutes in Cologne. Interested st
udents (Bachelor\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Paul van Loosdrecht
DTSTART;VALUE=DATE-TIME:20140117T124500
DTEND;VALUE=DATE-TIME:20140117T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000303@events.thp.uni-koeln.de
DESCRIPTION:Paul van Loosdrecht\, 2. Physikalisches Institut\, Universit
ät zu Köln\n\nUltrafast Science\n\nThis talk is one of a series
of presentations of research groups organized by the Bonn-Cologne Graduate
School of Physics and Astronomy. The aim is to provide insights into the
research done at physics institutes in Cologne. Interested students (Bache
lor\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Christian Maes
DTSTART;VALUE=DATE-TIME:20131213T163000
DTEND;VALUE=DATE-TIME:20131213T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000304@events.thp.uni-koeln.de
DESCRIPTION:Prof. Christian Maes\, KU Leuven\n\nFluctuations determining r
esponse in nonequilibrium systems\n\nIn or close-to-equilibrium response t
o external stimuli and statistical forces are primarily entropic and gove
rned by the standard thermodynamic potentials.\nWe report on a program of
identifying a unifying kinetic feature\, called the frenetic contribution\
, to complement entropy considerations in the study of\nnonequilibrium beh
avior. We therefore present extensions of the first and second fluctuation
-dissipation relation for driven systems or for probes in contact with non
equilibrium\n(active) baths.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Jan Jolie
DTSTART;VALUE=DATE-TIME:20140131T120000
DTEND;VALUE=DATE-TIME:20140131T124500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000305@events.thp.uni-koeln.de
DESCRIPTION:Jan Jolie\, Institut für Kernphysik\, Universität zu Köln\n
\nFemtophysics with atomic nuclei\n\nThis talk is one of a serie
s of presentations of research groups organized by the Bonn-Cologne Gradua
te School of Physics and Astronomy. The aim is to provide insights into th
e research done at physics institutes in Cologne. Interested students (Bac
helor\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Stefanie Walch
DTSTART;VALUE=DATE-TIME:20140131T124500
DTEND;VALUE=DATE-TIME:20140131T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000306@events.thp.uni-koeln.de
DESCRIPTION:Stefanie Walch\, 1. Physikalisches Institut\, Universität
zu Köln\n\nAstrophysics with computer simulations\n\nT
his talk is one of a series of presentations of research groups organized
by the Bonn-Cologne Graduate School of Physics and Astronomy. The aim is t
o provide insights into the research done at physics institutes in Cologne
. Interested students (Bachelor\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Prof. Dr. Dieter Braun
DTSTART;VALUE=DATE-TIME:20140107T163000
DTEND;VALUE=DATE-TIME:20140107T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000307@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Dieter Braun\, Ludwig-Maximilians-Universitä\;t
Mü\;nchen\n\nLiving Nonequilibrium? Towards a thermally driven Darwin
Process\n\nThe origin of life is one of the fundamental\, unsolved riddles
of modern science. Life as we know it is a stunningly complex non-equilib
rium process\, keeping its entropy low against the second law of thermod
ynamics. Therefore it is straightforward to argue that first living system
s had to start in a natural non-equilibrium settings.\n\nRecent experiment
s with non-equilibrium microsystems suggest that geological conditions sho
uld be able to drive molecular evolution\, i.e. the combined replication a
nd selection of genetic molecules towards ever increasing complexity.\n\nA
s a start\, we explored the non-equilibrium setting of natural thermal gra
dients. Temperature differences across rock fissures accumulate small mono
mers more than millionfold by thermophoresis and convection. Longer mole
cules are exponentially better accumulated\, hyperexponentially shifting t
he polymerization equilibrium towards long RNA strands. The same setting i
mplements convective temperature oscillations which overcome template pois
oning and yield length-insensitive\, exponential replication kinetics. Acc
umulation and thermally driven replication was demonstrated in the same ch
amber\, driven by the same temperature gradient. Protein-free\, non-ligati
ng replication schemes can be driven by thermal convection. For example\,
the hairpins of tRNA can be used for reversible codon-sequence replication
\, bridging from replication of genes to the translation of proteins. Non-
templated polymerization and hybridization-dependent degradation leads to
replication-like information transmission. Replication and trapping of DNA
persist over long time in a constant influx of monomers\, closely approac
hing the criteria for an autonomous Darwin process.\n\nBesides temperature
gradients\, many more non-equilibrium settings can be imagined and become
increasingly accessible to experimentation. For example\, geological pH
gradients\, geological redox potentials or the optical excitation of geolo
gical nanoparticles should drive metabolic reactions in a very peculiar wa
y. \n\n
LOCATION:HS 3
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Dr. Florian Marquardt
DTSTART;VALUE=DATE-TIME:20131206T163000
DTEND;VALUE=DATE-TIME:20131206T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000308@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Florian Marquardt\, Universität Erlangen-Nürnberg\
n\nPhotons and phonons interacting on a lattice\n\nNanomechanical structur
es can be coupled to light in order\nto control their mechanical vibration
s. Recent experimental developments\nin this field of "cavity optomechanic
s" have led to\nlaser-cooling of such vibrations to their quantum ground s
tate\nand entanglement between mechanics and the radiation field.\nA parti
cularly promising platform consists in photonic crystal\nstructures with o
ptical and vibrational modes localized at\ndefect sites. If these sites we
re to be arranged periodically\,\nthey would form an "optomechanical array
" that can be described via\na tight-binding model of interacting photons
and phonons.\nI will describe our theoretical predictions\, including\nlig
ht-induced synchronization of mechanical oscillators\,\nquantum many-body
dynamics of photons and phonons\,\nDirac physics on an optomechanical hone
ycomb lattice\, and\nthe possibility of generating artificial photonic gau
ge fields.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Yakov Itin
DTSTART;VALUE=DATE-TIME:20131203T120000
DTEND;VALUE=DATE-TIME:20131203T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000309@events.thp.uni-koeln.de
DESCRIPTION:Yakov Itin\, Hebrew University of Jerusalem and Jerusalem Coll
ege of Technology\n\nWave propagation in electromagnetic systems with a li
near response\n\nA covariant description of a generic electromagnetic medi
um requires a set of 36 independent parameters\, instead of two ordinary m
aterial parameters\, &epsilon\; and &mu\;. Such a set is arranged in a 4-t
h order constitutive tensor. Due to the group theory\, this tensor is irre
ducibly decomposed into the sum of three independent sub-tensors. The firs
t principal part is a substitution of the classical set of parameters. Two
other tensors\, skewon and axion\, have no classical analogs and may repr
esent some novel properties of media or artificial materials.\n\nIn my tal
k\, I will describe how the generalized covariant dispersion relation is d
erived. The result is in a correspondence with the formula proposed by Heh
l\, Obukhov and Rubilar. I define the notion of optic tensor (an analog of
acoustic tensor from elasticity) and describe its properties. With this n
ew device\, I show some new results about the skewon modified media. The m
ost visual outcome is a proof that in the skewon modified vacuum the wave
propagation is necessary superluminal. It means that the skewon is probabl
y forbidden in vacuum\, but not in material media.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Klas Lindfors
DTSTART;VALUE=DATE-TIME:20140219T143000
DTEND;VALUE=DATE-TIME:20140219T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000318@events.thp.uni-koeln.de
DESCRIPTION:Klas Lindfors\, Universität zu Köln\n\nOptical antennas for
controlling light \n\nResonant plasmonic metal nanoparticles allow manipul
ating optical fields on the nanoscale. In analogy to the radio frequency d
omain such particles are called optical antennas. They have led to a multi
tude of breakthroughs\, e.g.\, in enhancement of light emission and radiat
ion engineering of single photons\, as well as ultrasensitive sensing. I w
ill present the results of our work on enhancing the optical properties of
single solid-state quantum emitters using optical antennas and on applyin
g plasmonic nanoantennas in point-to-point links. Coupling a quantum emitt
er to the antenna allows enhancing both its absorption efficiency as well
as emission rate. Meanwhile\, point-to-point links based on optical antenn
as are a promising concept to transmit optical signals between nano-object
s. I will show the first realization of such a link.
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Anton Zeitlin
DTSTART;VALUE=DATE-TIME:20140116T101500
DTEND;VALUE=DATE-TIME:20140116T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000315@events.thp.uni-koeln.de
DESCRIPTION:Anton Zeitlin\, Columbia University\n\nContinuous series of af
fine sl(2\,R) and beyond\n\nI will talk about the construction of the cont
inuous series of sl(2\,R) and its possible relation to modular double repr
esentations of quantum sl(2\,R). The relations to physical models will be
overviewed.\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Christopher Max
DTSTART;VALUE=DATE-TIME:20131212T101500
DTEND;VALUE=DATE-TIME:20131212T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000316@events.thp.uni-koeln.de
DESCRIPTION:Christopher Max\, University of Cologne\n\nFourier analysis on
the supersphere\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nRenormalization in quantum field theory
and the Riemann-Hilbert problem I: the Hopf algebra structure of graphs a
nd the main theorem\nConnes and Kreimer
DTSTART;VALUE=DATE-TIME:20131205T101500
DTEND;VALUE=DATE-TIME:20131205T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000317@events.thp.uni-koeln.de
DESCRIPTION:Connes and Kreimer\n\nRenormalization in quantum field theory
and the Riemann-Hilbert problem I: the Hopf algebra structure of graphs an
d the main theorem\n\nWe discuss the paper "Renormalization in quantum fie
ld theory and the Riemann-Hilbert problem I: the Hopf algebra structure of
graphs and the main theorem" by Connes and Kreimer. Modus operandi: The d
ice will determine who will lead the discussion\, so every seminar partici
pant is kindly asked to prepare the paper in advance.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Maxim Eingorn
DTSTART;VALUE=DATE-TIME:20140121T120000
DTEND;VALUE=DATE-TIME:20140121T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000311@events.thp.uni-koeln.de
DESCRIPTION:Maxim Eingorn\, North Carolina Central University\, CREST and
NASA Research Centers\n\nDiscrete cosmology: scalar perturbations and dyna
mics of galaxies\n\nThe mechanical approach to cosmological problems insid
e the cell of\nuniformity represents a very promising scientific research
direction in\nmodern cosmology. It may be also associated with discrete co
smology in the\nnonrelativistic limit. In its framework the observable inh
omogeneous\nUniverse is described in the first order approximation with re
spect to its\ndeviation from the averaged homogeneous FLRW one\, the gravi
tational\npotentials of separate inhomogeneities (galaxies) are found and
their\nrelative motion (particularly\, the motion of the Milky Way and And
romeda as\nwell as the dwarf galaxies around our Local Group) is investiga
ted in\ndetail. It turns out that the characteristic features of scalar\np
erturbations (including\, for example\, singularities in the places of\ngr
avitating masses locations and beyond them) are sensitive to spatial\ntopo
logy and composition of the Universe. Thus\, the discrete cosmology\nscree
ns powerfully different cosmological models and sheds light on the\nspacet
ime structure and its filling.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Colin Russell
DTSTART;VALUE=DATE-TIME:20131219T141500
DTEND;VALUE=DATE-TIME:20131219T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000312@events.thp.uni-koeln.de
DESCRIPTION:Colin Russell\, University of Cambridge\n\nThe global circulat
ion of seasonal influenza viruses\n\n\n\nContact Person: Michael Lässig
LOCATION:Institute of Genetics\, 0.46
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Dr. Jeroen Custers
DTSTART;VALUE=DATE-TIME:20140129T143000
DTEND;VALUE=DATE-TIME:20140129T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000314@events.thp.uni-koeln.de
DESCRIPTION:Dr. Jeroen Custers\, Charles University\, Prague\n\nSupercondu
ctivity emerging in the magnetic state in heavy fermion materials Ce3PdIn1
1 and Ce3PtIn11 at ambient pressure\n\nThe present focus on quantum critic
al phenomena in correlated matter is driven by the puzzling enigma concern
ing the origin of unconventional superconductivity (SC). In a weak couplin
g picture\, the magnetic ordering is a spin density wave (SDW) induced by
Fermi surface (FS) nesting of itinerant electrons. Consequently\, supercon
ductivity results from pair scattering between the electron - and holelike
FS pockets. A drastically different viewpoint proposes that magnetism and
superconductivity develop out of localized moments which are generated by
strong electron - electron correlations (strong coupling limit). The simi
larities in the superconducting phase diagrams of correlated materials tem
pt us to believe that there may be a certain fundamental aspects shared be
tween the iron pnictides\, chalcogenides\, cuprate superconductors and the
HF materials. Against this backdrop\, heavy Fermion (HF) materials acquir
e a new significance.\n\nThis class of materials is inherent close to a ma
gnetic quantum phase transition frequently in conjunction with emergence o
f unconventional superconductivity [1]. Recently it was shown that strong
and weak coupling scenarios are complementary if taking into account the "
dimensionality" of the critical fluctuations which in most cases mirrors t
he structural dimensionality of the compound [2-4]. In this presentation I
will discuss the global phase diagram of heavy fermions with an experimen
tal focus on the CenTmIn3n+2m (T = transition metal\, n = 1\, 2\,..\; m =
0\, 1\,..) family. This family is predestinated in order to understand how
magnetism and superconductivity is influenced when going from 3D to 2D HF
structures. CenTmIn3n+2m compounds display both attributes with cubic CeI
n3 at the 3D and CeCoIn5 as an example of the opposite (2D) end of the ser
ies. I will present first results on single crystals of two new members Ce
3PdIn11 and Ce3PtIn11 located in between [5]. At ambient pressure supercon
ductivity emerges in the complex antiferromagnetic state below Tc = 0.42 K
(Tc = 0.32 K) in Ce3PdIn11 (Ce3PtIn11). Both phenomena coexist in a wide
range of the pressure - temperature phase diagrams. The critical pressure
where TN -> 0 and Tc is maximum equals pc ~= 1.6 GPa.\n\n[1] H. von Löhne
ysen et al.\, Rev. Mod. Phys. 79\, 1015 - 1075 (2007).\n[2] Q. Si\, Physic
a B 378-380\, 23 (2008)\n[3] J. Custers et al. Phys. Rev. Lett. 104\, 1864
02 (2010)\n[4] J. Custers et al. Nature Mat. 11\, 189 (2012)\n[5] J. Prokl
eska et al. submitted to Science (2013)\n\n\nContact Person: Mohsen Abd-El
meguid
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Fulvio Parmigiani
DTSTART;VALUE=DATE-TIME:20141008T143000
DTEND;VALUE=DATE-TIME:20141008T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000457@events.thp.uni-koeln.de
DESCRIPTION:Fulvio Parmigiani\, University of Trieste\n\nSpin and time res
olved photoelectron spectroscopy in the momentum space of archetypal topol
ogical insulators\n\nThe interaction between light and the topologically p
rotected spin polarized Dirac particles at the surface of topological insu
lators (TIs) constitutes the key issue for the development of opto-spintro
nics devices. Laser-based time and angle resolved photoelectron spectrosco
py (tr-ARPES) in the sub-ps time domain represents an important experiment
al tool to investigate the ultrafast light-induced modification of the ele
ctronic properties in TIs. Several studies recently disclosed a very rich
scenario\, characterized by long-lived electronic population [ref. Sobota]
\, Floquet-Bloch states [ref. Gedik science]\, reduction of the electron-p
honon coupling [ref Crepaldi2] and the possibility to tune the Schottky ba
rrier [ref. Marsi]. Despite the large number of experimental investigation
s of the out-of-equilibrium electronic properties [ref. Sobota JP\, Chulko
v\, Perfetti\, Crepaldi1]\, a detailed description of the microscopic scat
tering mechanisms within the surface state and between the bulk conduction
band and the surface state is lacking\, so far. Here an overview of the m
ost recent discoveries relevant to the evolution of the electron populatio
n optically-injected in the topologically protected state at the surface i
s reported. In particular\, we prove that only by measuring the spin-inten
sity signal over several orders of magnitude in spin- time- and angle reso
lved photoemission spectroscopy (s-tr-ARPES) experiments it is possible to
comprehensively describe the optically excited electronic states in TIs m
aterials. Remarkably\, the experimental data\, interpreted on the base of
ab-initio fully relativistic spin resolved photoemission calculations and
spin dynamics modeling\, unambiguously show that two non-interacting elect
ronic systems\, derived from the excited surface and bulk states\, are cha
racterizing the non-equilibrium electronic properties of the archetypal TI
\, Bi2Se3.\n\nContact Person: Paul H.M. van Loosdrecht
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Frank Ferrari
DTSTART;VALUE=DATE-TIME:20140521T143000
DTEND;VALUE=DATE-TIME:20140521T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000458@events.thp.uni-koeln.de
DESCRIPTION:Frank Ferrari\, Université libre de Bruxelles\n\nOn Quantum B
lack Holes\n\n\n\nContact Person: Semyon Klevtsov
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Bum Joon Kim
DTSTART;VALUE=DATE-TIME:20140702T143000
DTEND;VALUE=DATE-TIME:20140702T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000459@events.thp.uni-koeln.de
DESCRIPTION:Bum Joon Kim\, MPI FKF Stuttgart\n\nThe quest for novel high-t
emperature superconductors\n\nAfter nearly three decades of research on hi
gh temperature superconductivity\, the transition temperature remains stag
nant and our understanding incomplete. In this talk\, I will argue that fi
nding a novel material system that mimics the cuprate physics can provide
a breakthrough. Ruddelsden-popper series iridates display remarkable simil
arity to high-Tc cuprates in terms of crystal\, lattice\, and magnetic str
uctures\, which lead to similarity in the effective low-energy physics as
manifested by the unique cuprate fermiology reproduced in Sr2IrO4. How sup
erconductivity emerges or fails in this new class of materials will reveal
essential features of high temperature superconductivity\; in particular
the long-sought connection between the pseudogap and superconductivity.\n\
nContact Person: Simon Trebst
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Roderick MacKenzie
DTSTART;VALUE=DATE-TIME:20140313T143000
DTEND;VALUE=DATE-TIME:20140313T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000460@events.thp.uni-koeln.de
DESCRIPTION:Roderick MacKenzie\, Nottingham University\n\nSimulating organ
ic electrons - from fullerenes to whole devices\n\n\n\nContact Person: Pau
l H.M. van Loosdrecht
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nSoluble models of turbulent transport\n
Krzysztof Gawedzki
DTSTART;VALUE=DATE-TIME:20140306T101500
DTEND;VALUE=DATE-TIME:20140306T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000461@events.thp.uni-koeln.de
DESCRIPTION:Krzysztof Gawedzki\n\nSoluble models of turbulent transport\n\
nWe discuss Lectures 2 and 3 of the lecture notes "Soluble models of turbu
lent transport" by Krzysztof Gawedzki. Modus operandi: The dice will deter
mine who will lead the discussion\, so every seminar participant is kindly
asked to prepare the paper in advance. (Contact me to get the paper.)\n\n
Contact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Jacobus Verbaarschot
DTSTART;VALUE=DATE-TIME:20140110T163000
DTEND;VALUE=DATE-TIME:20140110T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000320@events.thp.uni-koeln.de
DESCRIPTION:Prof. Jacobus Verbaarschot\, Stony Brook University\n\nDirac S
pectra\, Tail States and Spontaneous Symmetry Breaking\n\nBecause of spont
aneous symmetry breaking and a mass gap\, Dirac spectra \nshow universal b
ehavior that can be understood by means of random matrix \ntheory. We dis
cuss the effect of a nonzero lattice spacing on QCD \nDirac spectra and
find tail states that have been observed before \nin disordered condensed
matter systems. Despite the Coleman-Mermin-Wagner \ntheorem Dirac spectra
also show universal behavior in two dimensions\, \nbut the unversality cl
asses are different from those in four dimensions\nand depend on the pari
ty of the lattice. A complete classification \nof two dimensional lattice
QCD Dirac spectra in terms of the ten fold \nclassification of random matr
ix theories is given.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Dr. Andreas Läuchli
DTSTART;VALUE=DATE-TIME:20140117T163000
DTEND;VALUE=DATE-TIME:20140117T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000321@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Andreas Läuchli\, Universität Innsbruck\n\nEntangl
ement spectra: A novel spectroscopic tool to investigate quantum many body
wave functions\n\nThe entanglement spectrum\, i.e. the logarithm of the e
igenvalues of reduced density matrices of \nquantum many body wave functio
ns\, has been the focus of a rapidly expanding research endeavor recently.
Initially introduced by Li & Haldane in the context of the fractional qua
ntum Hall effect\, its usefulness has been shown to extend to many more fi
elds\, such as topological insulators\, fractional Chern insulators\, spin
liquids\, continuous symmetry breaking states\, etc. After a general intr
oduction to the field we review some of our own contributions to the field
\, in particular the perturbative structure of the entanglement spectrum i
n gapped phases\, the entanglement spectrum across the Mott-insulator tran
sition in the Bose-Hubbard model\, and the relation of the entanglement sp
ectrum of (1+1) dimensional quantum critical systems to the operator cont
ent of their underlying CFT.\n\n\nContact Person: Simon Trebst
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Karl Leo
DTSTART;VALUE=DATE-TIME:20141028T140000
DTEND;VALUE=DATE-TIME:20141028T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000322@events.thp.uni-koeln.de
DESCRIPTION:Karl Leo\, TU Dresden\n\nRecent progress in organic light-emit
ting diodes and solar cells\n\n\n\nContact Person: Achim Rosch
LOCATION:HS 2\, Institute of Chemistry
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Jan Seidel
DTSTART;VALUE=DATE-TIME:20140114T120000
DTEND;VALUE=DATE-TIME:20140114T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000324@events.thp.uni-koeln.de
DESCRIPTION:Jan Seidel\, Universität New South Wales\n\nDomain wall funct
ionality in complex oxides\n\n\n\nContact Person: Paul
LOCATION:Seminarraum Kernphysik
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Prof. Dr. Peter Stadler
DTSTART;VALUE=DATE-TIME:20140203T160000
DTEND;VALUE=DATE-TIME:20140203T183000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000331@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Peter Stadler\, University of Leipzig\n\nEnergy Land
scapes and the Dynamics of RNA Folding\n\nRNA molecules are quite well rep
resented in terms of their secondary\nstructure. In this discrete model\,
which considers only base pair stacking\,\nground state energies as well a
s properties of the equilibrium ensemble can\nbe computed efficiently by m
eans of exact dynamic programming\nalgorithms. In addition\, it allows a v
ery detailed analysis of the entire\nenergy landscapes and therefore acces
s to details of the processes of\nstructural change. To this end\, however
\, the huge space of all secondary\nstructures needs to be condensed to a
coarse grained representation that is\nsmall enough to allow detailed dyna
mical analyses. Examples are barrier\ntrees and the more accurate 'base ho
pping graph'. These condensed graph\nstructures can be computed exactly fo
r moderate size molecules making use\nby enumeration and admit rather effe
ctive sampling techniques for larger\nRNAs. Kinetic parameters can be esti
mated with acceptable accuracy in this\nmanner providing insights into the
folding and refolding dynamics of RNAs.\nThe landscape paradigm can be ex
tended to co-transcriptional folding as\nwell as a variety of settings in
which environmental conditions lead to\nsmall changes in the RNA itself or
in underlying parametrization. In this\npicture\, intricate effects\, as
they occur e.g. in kinetically controlled\nriboswitches can be modelled. \
n\n\nContact Person: Joachim Krug
LOCATION:Biocentre\, Ground Floor Lecture Hall
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Yoichi Ando
DTSTART;VALUE=DATE-TIME:20140212T100000
DTEND;VALUE=DATE-TIME:20140212T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000330@events.thp.uni-koeln.de
DESCRIPTION:Yoichi Ando\, Universität Osaka\n\nTopological Insulators and
Superconductors: Materials Frontier\n\n\n\nContact Person: Paul H.M. van
Loosdrecht
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Sebastian Gönnewein
DTSTART;VALUE=DATE-TIME:20140122T150000
DTEND;VALUE=DATE-TIME:20140122T163000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000329@events.thp.uni-koeln.de
DESCRIPTION:Sebastian Gönnewein\, TU München\n\nSpin Currents in Ferroma
gnet / Normal Metal Hybrid Structures\n\n\n\nContact Person: Paul H.M. van
Loosdrecht
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Dr. Jens Eisert
DTSTART;VALUE=DATE-TIME:20140207T163000
DTEND;VALUE=DATE-TIME:20140207T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000332@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Jens Eisert\, FU Berlin\n\nTaming the non-equilibriu
m\n\nComplex quantum systems out of equilibrium are at the basis of a\n
number of the most intriguing puzzles in physics. This talk will be\n
concerned with recent progress on understanding how quantum many-body\
n systems out of equilibrium eventually come to rest and thermalise.
The\n first part of the talk will highlight theoretical progress on t
his\n question\, taking in several ways a quantum information view -\
n employing ideas of Lieb-Robinson bounds\, quantum central limit\n
theorems and of concentration of measure. These findings will be\n
complemented by experimental work with ultra-cold atoms in optical\n
lattices\, in setups constituting dynamical "quantum simulators"\,\n
allowing to probe physical questions that are not only out of reach\n
for state-of-the-art numerical techniques based on matrix-product\n
states\, but also relate to classically computationally hard problems.\n
\n\nContact Person: Alexander Altland
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Dr. Piet Brouwer
DTSTART;VALUE=DATE-TIME:20140124T163000
DTEND;VALUE=DATE-TIME:20140124T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000333@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Piet Brouwer\, FU Berlin\n\nDisordered Majorana wire
s\n\nA one dimensional spinless p-wave superconductor may be in a topologi
cal nontrivial state\, in which it has a zero energy Majorana bound state
at each end. Although no known materials are spinless p-wave superconducto
rs\, such a system can be realized in principle in spin-orbit coupled nano
wires with proximity-induced pairing from a nearby s-wave superconductor.
After introducing the topological phase\, I will discuss how non-idealitie
s\, such as potential disorder and deviations from a strict one-dimensiona
l limit\, affect the topological phase and its signatures in a current-vol
tage measurement.\n\n\nContact Person: Alexander Altland
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Prof. Dr. Peter Grassberger
DTSTART;VALUE=DATE-TIME:20140131T163000
DTEND;VALUE=DATE-TIME:20140131T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000334@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Peter Grassberger\, Jülich Supercomputing Centre\n\
nCooperativity in complex epidemics\n\nThere are two standard "Ising" mode
ls for the spreading of epidemics\, the "SIS" (susceptible-infected-suscep
tible) epidemic and the "SIR" (susceptible-infected-removed) model. Both a
re related to percolation - the first to directed\, the second to undirect
ed - and thus both show continuous ("second-order") phase transitions when
the conditions for spreading are critical. Recently\, much interest has b
een roused by models which show first order transitions. After giving a sh
ort overview I will concentrate on first order transitions in models with
cooperativity. This cooperativity can be of two very different types. On t
he one hand\, several agents on neighboring nodes in a network (or sites o
n a lattice) can cooperate in infecting a new node (like three friends who
convince you more easily than any single one of them to adopt a political
opinion). On the other hand\, also two pathogens (like HIV and TB) can co
operate in the sense that one of them lowers the resistance to the other.
In the first case the transition from a continuous to a discontinuous phas
e transition is a standard tricritical point (with higher n-point interact
ions in a field theoretic formalism)\, while in the second one one has a m
ulti-component order parameter. In several instances\, the resulting first
order transitions are actually "hybrid"\, i.e. they involve also features
of second-order transitions like scaling. In one case\, one even finds th
at two order parameter definitions which coincide for ordinary percolation
display different transition orders.\n\nContact Person: Joachim Krug
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Dionisios Margetis
DTSTART;VALUE=DATE-TIME:20140224T143000
DTEND;VALUE=DATE-TIME:20140224T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000335@events.thp.uni-koeln.de
DESCRIPTION:Dionisios Margetis\, University of Maryland at College Park \n
\nBose-Einstein condensation: Pair excitation and many-body bound state of
periodic microstructure \n\nThis talk focuses on aspects of Bose-Einstein
condensation in a trapped\, dilute atomic gas beyond the Gross-Pitaevskii
mean field regime. By use of the formalism of pair excitation introduced
by Wu\, based on earlier works by Lee\, Huang and Yang\, the description o
f many-body bound states is\naddressed via formal asymptotics. There are t
wo related questions to be discussed. \n(i) What is a plausible modeling o
f pair correlations by use of Partial Differential Equations\, beyond the
Gross-Pitaevskii limit? \n(ii) What is the effective depletion of the macr
oscopic quantum state (condensate) for a spatially varying scattering leng
th having a periodic microstructure? \n\nContact Person: Joachim Krug
LOCATION:Seminar Room of the Institute for Theoretical Physics
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Kamran Behnia
DTSTART;VALUE=DATE-TIME:20140213T130000
DTEND;VALUE=DATE-TIME:20140213T143000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000336@events.thp.uni-koeln.de
DESCRIPTION:Kamran Behnia\, ESPCI Paris\n\nSuperconductivity in dilute met
als\n\n
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nHow (not) to teach Lorentz covariance o
f the Dirac equation\nHrvoje Nikolic
DTSTART;VALUE=DATE-TIME:20140123T101500
DTEND;VALUE=DATE-TIME:20140123T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000337@events.thp.uni-koeln.de
DESCRIPTION:Hrvoje Nikolic\n\nHow (not) to teach Lorentz covariance of the
Dirac equation\n\nWe discuss the paper "How (not) to teach Lorentz covari
ance of the Dirac equation" by Hrvoje Nikolic. Modus operandi: The dice wi
ll determine who will lead the discussion\, so every seminar participant i
s kindly asked to prepare the paper in advance.\n\nContact Person: Thomas
Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nGeometry of physical dispersion relatio
ns\nDennis Raetzel\, Sergio Rivera\, Frederic P. Schuller
DTSTART;VALUE=DATE-TIME:20140206T101500
DTEND;VALUE=DATE-TIME:20140206T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000338@events.thp.uni-koeln.de
DESCRIPTION:Dennis Raetzel\, Sergio Rivera\, Frederic P. Schuller\n\nGeome
try of physical dispersion relations\n\nWe read and discuss the paper "Geo
metry of physical dispersion relations" by Dennis Raetzel\, Sergio Rivera
and Frederic P. Schuller. Modus operandi: The dice will determine who will
lead the discussion\, so every seminar participant is kindly asked to pre
pare the paper in advance.\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Abhishek Roy
DTSTART;VALUE=DATE-TIME:20140130T101500
DTEND;VALUE=DATE-TIME:20140130T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000340@events.thp.uni-koeln.de
DESCRIPTION:Abhishek Roy\, University of Cologne\n\nAnyons and twists\n\n\
n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Bernard Kippelen
DTSTART;VALUE=DATE-TIME:20140320T100000
DTEND;VALUE=DATE-TIME:20140320T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000466@events.thp.uni-koeln.de
DESCRIPTION:Bernard Kippelen\, Georgia Institute of Technology\n\nAdvances
in Organic Flexible Optolectronics\n\n\n\nContact Person: Klaus Meerholz
LOCATION:Seminarraum 147\, Institut für Physikalische Chemie
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Ricardo Kennedy
DTSTART;VALUE=DATE-TIME:20140213T101500
DTEND;VALUE=DATE-TIME:20140213T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000341@events.thp.uni-koeln.de
DESCRIPTION:Ricardo Kennedy\, University of Cologne\n\nStrong vs. weak top
ological insulators\n\nThe difference between strong and weak topological
insulators is rooted in the difference between homotopy classes of maps fr
om a sphere as opposed to maps from a torus. I will give a simple proof th
at the former constitute a subset of the latter\, which I use to give a de
finition of "strong".\n\nAnother aspect I will address is the possibility
of stacking lower dimensional systems into higher dimensions. I will give
two examples that demonstrate that not all weak topological insulators com
e from stacking and - vice versa - that stacking insulators can give more
topological phases than one might guess from considering only the lower di
mension.\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Honghao Tu
DTSTART;VALUE=DATE-TIME:20140320T101500
DTEND;VALUE=DATE-TIME:20140320T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000342@events.thp.uni-koeln.de
DESCRIPTION:Honghao Tu\, MPQ Garching\n\nProjected entangled-pair states c
an describe chiral topological states\n\nProjected entangled-pair states (
PEPS)\, higher-dimensional generalizations of matrix-product states in one
dimension\, provide a useful representation for topological states. Many
examples of nonchiral topological states\, such as toric code and short-ra
nge resonating valence-bond states\, allow exact PEPS representations. One
of the challenging question in this field is to understand whether PEPS c
an describe chiral topological states with broken time-reversal symmetry.
In this talk\, I will present our recent results on constructing explicit
examples of PEPS\, which belong to Chern insulators and topological superc
onductors with nonzero Chern number. These provide a proof-of-principle re
sult that PEPS can describe chiral topological states.\n\nContact Person:
Thomas Quella
LOCATION:Physik-Container
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Mairi Sakellariadou
DTSTART;VALUE=DATE-TIME:20140220T140000
DTEND;VALUE=DATE-TIME:20140220T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000343@events.thp.uni-koeln.de
DESCRIPTION:Mairi Sakellariadou\, King’s College London\n\nParticle Phys
ics and Cosmology from Almost Commutative Manifolds\n\nThe unification of
the four fundamental forces remains one of the most important issues in th
eoretical particle physics. In this talk\, I will first give a short intro
duction to noncommutative spectral geometry\, a bottom-up approach that un
ifies the (successful) Standard Model of high energy physics with Einstein
's General theory of Relativity. The model is build upon almost-commutativ
e spaces and I will discuss the physical implications of the choice of suc
h manifolds. I will show that even though the unification has been obtaine
d only at the classical level\, the doubling of the algebra may incorporat
e the seeds of quantisation. I will then briefly review the particle physi
cs phenomenology and highlight open issues and current proposals. In the l
ast part of my talk\, I will explore consequences of the gravitational-Hig
gs part of the spectral action formulated within such almost-commutative m
anifolds. In particular\, I will study modifications of the Friedmann equa
tion\, propagation of gravitational waves and the onset of inflation. I wi
ll show how current measurements (Gravity Probe B and pulsars) can constra
in free parameters of the model. I will conclude with a short discussion o
n open questions.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Hans-Thomas Elze
DTSTART;VALUE=DATE-TIME:20140220T160000
DTEND;VALUE=DATE-TIME:20140220T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000344@events.thp.uni-koeln.de
DESCRIPTION:Hans-Thomas Elze\, University of Pisa\n\nAction principle for
cellular automata and the linearity of quantum mechanics\n\nWe introduce a
n action principle for a class of integer valued cellular automata and obt
ain Hamiltonian equations of motion. Employing sampling theory\, these dis
crete deterministic equations are invertibly mapped on continuum equations
for a set of bandwidth limited harmonic oscillators\, which encode the Sc
hroedinger equation. Thus\, the linearity of quantum mechanics is related
to the action principle of such cellular automata and its conservation law
s to discrete ones.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nMeasures on Closed Subspaces of a Hilbe
rt Space\nA.M. Gleason
DTSTART;VALUE=DATE-TIME:20131122T101500
DTEND;VALUE=DATE-TIME:20131122T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000345@events.thp.uni-koeln.de
DESCRIPTION:A.M. Gleason\n\nMeasures on Closed Subspaces of a Hilbert Spac
e\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Moritz Ernst
DTSTART;VALUE=DATE-TIME:20131115T101500
DTEND;VALUE=DATE-TIME:20131115T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000346@events.thp.uni-koeln.de
DESCRIPTION:Moritz Ernst\n\nFinding the characteristic function of input-o
utput fidelities in the case of infinite Pauli (or even Gellmann) channels
\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Jochen Peschutter
DTSTART;VALUE=DATE-TIME:20131101T101500
DTEND;VALUE=DATE-TIME:20131101T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000347@events.thp.uni-koeln.de
DESCRIPTION:Jochen Peschutter\n\nFinite size scaling\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nCardy's formula on the triangular latti
ce\, the easy way\nVincent Beffara
DTSTART;VALUE=DATE-TIME:20131025T101500
DTEND;VALUE=DATE-TIME:20131025T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000348@events.thp.uni-koeln.de
DESCRIPTION:Vincent Beffara\n\nCardy's formula on the triangular lattice\,
the easy way\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Josua Groeger
DTSTART;VALUE=DATE-TIME:20131011T101500
DTEND;VALUE=DATE-TIME:20131011T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000349@events.thp.uni-koeln.de
DESCRIPTION:Josua Groeger\n\nNoether theorems in superharmonic field theor
ies\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nLandau Damping\nCédric Villani
DTSTART;VALUE=DATE-TIME:20130927T101500
DTEND;VALUE=DATE-TIME:20130927T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000350@events.thp.uni-koeln.de
DESCRIPTION:Cédric Villani\n\nLandau Damping\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nTopological Field Theory\, Higher Categ
ories\, and Their Applications\nAnton Kapustin
DTSTART;VALUE=DATE-TIME:20130913T101500
DTEND;VALUE=DATE-TIME:20130913T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000351@events.thp.uni-koeln.de
DESCRIPTION:Anton Kapustin\n\nTopological Field Theory\, Higher Categories
\, and Their Applications\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Charles Guggenheim
DTSTART;VALUE=DATE-TIME:20130906T101500
DTEND;VALUE=DATE-TIME:20130906T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000352@events.thp.uni-koeln.de
DESCRIPTION:Charles Guggenheim\n\nStrong and weak topological insulators\n
\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nTwo simple proofs of the Kochen–Speck
er theorem\nA. Peres
DTSTART;VALUE=DATE-TIME:20130830T101500
DTEND;VALUE=DATE-TIME:20130830T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000353@events.thp.uni-koeln.de
DESCRIPTION:A. Peres\n\nTwo simple proofs of the Kochen–Specker theorem\
n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Martin Zirnbauer
DTSTART;VALUE=DATE-TIME:20130823T101500
DTEND;VALUE=DATE-TIME:20130823T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000354@events.thp.uni-koeln.de
DESCRIPTION:Martin Zirnbauer\n\nPure Scaling Operators at the IQHE plateau
transition\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nRenormalization group running of the en
tanglement entropy of a circle\nH. Casini\, M. Huerta
DTSTART;VALUE=DATE-TIME:20130816T101500
DTEND;VALUE=DATE-TIME:20130816T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000355@events.thp.uni-koeln.de
DESCRIPTION:H. Casini\, M. Huerta\n\nRenormalization group running of the
entanglement entropy of a circle\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nChiral kinetic theory\nM.A. Stephanov\,
Y. Yin
DTSTART;VALUE=DATE-TIME:20130809T101500
DTEND;VALUE=DATE-TIME:20130809T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000356@events.thp.uni-koeln.de
DESCRIPTION:M.A. Stephanov\, Y. Yin\n\nChiral kinetic theory\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Jorgen Rasmussen
DTSTART;VALUE=DATE-TIME:20130801T101500
DTEND;VALUE=DATE-TIME:20130801T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000357@events.thp.uni-koeln.de
DESCRIPTION:Jorgen Rasmussen\n\nSolvable model of critical dense polymers\
n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Mike Mücke
DTSTART;VALUE=DATE-TIME:20130725T101500
DTEND;VALUE=DATE-TIME:20130725T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000358@events.thp.uni-koeln.de
DESCRIPTION:Mike Mücke\n\nFrom homogeneous distributions to the super loc
al zetafunction on the super vector space S^2(V)\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Kevin Coulembier
DTSTART;VALUE=DATE-TIME:20130718T101500
DTEND;VALUE=DATE-TIME:20130718T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000359@events.thp.uni-koeln.de
DESCRIPTION:Kevin Coulembier\n\nBott-Borel-Weil theory for basic classical
Lie superalgebras\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Peter Finch
DTSTART;VALUE=DATE-TIME:20130716T101500
DTEND;VALUE=DATE-TIME:20130716T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000360@events.thp.uni-koeln.de
DESCRIPTION:Peter Finch\n\nIntegrablity in the so(5)_2 anyon chain\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Alexander Alldridge
DTSTART;VALUE=DATE-TIME:20130711T101500
DTEND;VALUE=DATE-TIME:20130711T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000361@events.thp.uni-koeln.de
DESCRIPTION:Alexander Alldridge\n\nGlobalisation of Harish-Chandra supermo
dules\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Daniel Wieczorek
DTSTART;VALUE=DATE-TIME:20130704T101500
DTEND;VALUE=DATE-TIME:20130704T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000362@events.thp.uni-koeln.de
DESCRIPTION:Daniel Wieczorek\n\n2n-point conductances in the Chalker-Coddi
ngton model\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Rochus Klesse
DTSTART;VALUE=DATE-TIME:20130627T101500
DTEND;VALUE=DATE-TIME:20130627T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000363@events.thp.uni-koeln.de
DESCRIPTION:Rochus Klesse\n\nProbability assignments and maximum entropy p
rinciples\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Wolfgang Palzer
DTSTART;VALUE=DATE-TIME:20130613T101500
DTEND;VALUE=DATE-TIME:20130613T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000364@events.thp.uni-koeln.de
DESCRIPTION:Wolfgang Palzer\n\nThe Fourier transformation on symmetric sup
erspaces – The rank one case\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Artur Swiech
DTSTART;VALUE=DATE-TIME:20130608T101500
DTEND;VALUE=DATE-TIME:20130608T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000365@events.thp.uni-koeln.de
DESCRIPTION:Artur Swiech\n\nApplications of generalized free addition and
multiplication laws\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Hadi Salmasian
DTSTART;VALUE=DATE-TIME:20130601T101500
DTEND;VALUE=DATE-TIME:20130601T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000366@events.thp.uni-koeln.de
DESCRIPTION:Hadi Salmasian\n\nGNS construction for Lie supergroups\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nThe finite group velocity of quantum sp
in systems\nElliott W. Lieb\, Derek W. Robinson
DTSTART;VALUE=DATE-TIME:20130523T101500
DTEND;VALUE=DATE-TIME:20130523T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000367@events.thp.uni-koeln.de
DESCRIPTION:Elliott W. Lieb\, Derek W. Robinson\n\nThe finite group veloci
ty of quantum spin systems\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Ricardo Kennedy
DTSTART;VALUE=DATE-TIME:20130516T101500
DTEND;VALUE=DATE-TIME:20130516T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000368@events.thp.uni-koeln.de
DESCRIPTION:Ricardo Kennedy\n\nEquivariant homotopy theory of topological
insulators\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Sebastian Schmittner
DTSTART;VALUE=DATE-TIME:20130424T101500
DTEND;VALUE=DATE-TIME:20130424T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000369@events.thp.uni-koeln.de
DESCRIPTION:Sebastian Schmittner\n\nSpherical Representations of Reductive
Lie Supergroups\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nEnvironment-assisted invariance\, entan
glement\, and probabilities in quantum mechanics\nWojciech Zurek
DTSTART;VALUE=DATE-TIME:20130417T101500
DTEND;VALUE=DATE-TIME:20130417T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000370@events.thp.uni-koeln.de
DESCRIPTION:Wojciech Zurek\n\nEnvironment-assisted invariance\, entangleme
nt\, and probabilities in quantum mechanics\n\nhttp://prl.aps.org/abstract
/PRL/v90/i12/e120404
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Jochen Peschutter
DTSTART;VALUE=DATE-TIME:20130410T101500
DTEND;VALUE=DATE-TIME:20130410T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000371@events.thp.uni-koeln.de
DESCRIPTION:Jochen Peschutter\n\nQuantum spin Hamiltonians from Wess-Zumin
o-Witten models\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nIs there life beyond quantum mechanics?
\nAnton Kapustin
DTSTART;VALUE=DATE-TIME:20130404T101500
DTEND;VALUE=DATE-TIME:20130404T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000372@events.thp.uni-koeln.de
DESCRIPTION:Anton Kapustin\n\nIs there life beyond quantum mechanics?\n\nh
ttp://arxiv.org/pdf/1303.6917.pdf
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Roberto Bondesan
DTSTART;VALUE=DATE-TIME:20130328T101500
DTEND;VALUE=DATE-TIME:20130328T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000373@events.thp.uni-koeln.de
DESCRIPTION:Roberto Bondesan\n\nTopological and symmetry broken phases of
Z(N) parafermions in one dimension\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nLoop Groups\nGraeme Segal
DTSTART;VALUE=DATE-TIME:20130321T101500
DTEND;VALUE=DATE-TIME:20130321T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000374@events.thp.uni-koeln.de
DESCRIPTION:Graeme Segal\n\nLoop Groups\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\n"Fractional Statistics and Quantum Theo
ry"\, Chapter 2: Fractional Statistics in Two Dimensions\nKhare
DTSTART;VALUE=DATE-TIME:20130307T101500
DTEND;VALUE=DATE-TIME:20130307T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000375@events.thp.uni-koeln.de
DESCRIPTION:Khare\n\n"Fractional Statistics and Quantum Theory"\, Chapter
2: Fractional Statistics in Two Dimensions\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Eldad Betelheim
DTSTART;VALUE=DATE-TIME:20130228T101500
DTEND;VALUE=DATE-TIME:20130228T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000376@events.thp.uni-koeln.de
DESCRIPTION:Eldad Betelheim\n\nConformal restriction in Anderson transitio
ns\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nDecoherence and the foundations of quan
tum mechanics\nMax Schlosshauer\, Arthur Fine
DTSTART;VALUE=DATE-TIME:20130214T101500
DTEND;VALUE=DATE-TIME:20130214T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000377@events.thp.uni-koeln.de
DESCRIPTION:Max Schlosshauer\, Arthur Fine\n\nDecoherence and the foundati
ons of quantum mechanics\n\nhttp://www.maxschlosshauer.com/publications/de
coherence_book.pdf\nhttp://www.maxschlosshauer.com/publications/decoherenc
e_book.pdf\nhttp://www.maxschlosshauer.com/publications/decoherence_book.p
df\nhttp://www.maxschlosshauer.com/publications/decoherence_book.pdf\nhttp
://www.maxschlosshauer.com/publications/decoherence_book.pdf\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Thomas Quella
DTSTART;VALUE=DATE-TIME:20130207T101500
DTEND;VALUE=DATE-TIME:20130207T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000378@events.thp.uni-koeln.de
DESCRIPTION:Thomas Quella\n\nCold atom realization of non-trivial topologi
cal phases of PSU(N) spin chains\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nDUALITY IN MATHEMATICS AND PHYSICS\nM.F
. Atiyah
DTSTART;VALUE=DATE-TIME:20130131T101500
DTEND;VALUE=DATE-TIME:20130131T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000379@events.thp.uni-koeln.de
DESCRIPTION:M.F. Atiyah\n\nDUALITY IN MATHEMATICS AND PHYSICS\n\nhttp://ww
w.fme.upc.edu/arxius/butlleti-digital/riemann/071218_conferencia_atiyah-d_
article.pdf
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nDiscrete Holomorphicity at Two-Dimensi
onal Critical Points\nJohn Cardy
DTSTART;VALUE=DATE-TIME:20130124T101500
DTEND;VALUE=DATE-TIME:20130124T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000380@events.thp.uni-koeln.de
DESCRIPTION:John Cardy\n\nDiscrete Holomorphicity at Two-Dimensional Crit
ical Points\n\nhttp://link.springer.com/article/10.1007%2Fs10955-009-9870-
6
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Yuriy Stepanov
DTSTART;VALUE=DATE-TIME:20130110T101500
DTEND;VALUE=DATE-TIME:20130110T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000381@events.thp.uni-koeln.de
DESCRIPTION:Yuriy Stepanov\n\nPrice Dynamics and Market States\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Mike Mücke
DTSTART;VALUE=DATE-TIME:20121220T101500
DTEND;VALUE=DATE-TIME:20121220T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000382@events.thp.uni-koeln.de
DESCRIPTION:Mike Mücke\n\nPrehomogenous super vector spaces\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Semyon Klevtsov
DTSTART;VALUE=DATE-TIME:20121206T101500
DTEND;VALUE=DATE-TIME:20121206T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000383@events.thp.uni-koeln.de
DESCRIPTION:Semyon Klevtsov\n\nIntroduction to random metrics\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nThe moment map and equivariant cohomolo
gy\nMichael F. Atiyah\, Raoul Bott
DTSTART;VALUE=DATE-TIME:20121129T101500
DTEND;VALUE=DATE-TIME:20121129T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000384@events.thp.uni-koeln.de
DESCRIPTION:Michael F. Atiyah\, Raoul Bott\n\nThe moment map and equivaria
nt cohomology\n\nhttp://dx.doi.org/10.1016/0040-9383(84)90021-1
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Moritz Ernst
DTSTART;VALUE=DATE-TIME:20121122T101500
DTEND;VALUE=DATE-TIME:20121122T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000385@events.thp.uni-koeln.de
DESCRIPTION:Moritz Ernst\n\nCalculating Input-Output-Fidelity-Moments usin
g the Representation Theory of S_n\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Peter Rønne
DTSTART;VALUE=DATE-TIME:20121025T101500
DTEND;VALUE=DATE-TIME:20121025T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000386@events.thp.uni-koeln.de
DESCRIPTION:Peter Rønne\n\nHigher spin AdS/CFT duality\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nGauge theory of topological phases of m
atter\nJürg Fröhlich\, Philipp Werner
DTSTART;VALUE=DATE-TIME:20121018T101500
DTEND;VALUE=DATE-TIME:20121018T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000387@events.thp.uni-koeln.de
DESCRIPTION:Jürg Fröhlich\, Philipp Werner\n\nGauge theory of topologica
l phases of matter\n\nhttp://arxiv.org/abs/1207.5304
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Wolfgang Palzer
DTSTART;VALUE=DATE-TIME:20120726T101500
DTEND;VALUE=DATE-TIME:20120726T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000388@events.thp.uni-koeln.de
DESCRIPTION:Wolfgang Palzer\n\nSpherical superfunction asymptotics - the r
ank one case\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nA geometric theory of swimming: Purcell
's swimmer and its symmetrized cousin\nJ.E. Avron and O. Raz
DTSTART;VALUE=DATE-TIME:20120719T101500
DTEND;VALUE=DATE-TIME:20120719T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000389@events.thp.uni-koeln.de
DESCRIPTION:J.E. Avron and O. Raz\n\nA geometric theory of swimming: Purce
ll's swimmer and its symmetrized cousin\n\nhttp://iopscience.iop.org/1367-
2630/10/6/063016/
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nQuantization is a Mystery\nIvan Todorov
DTSTART;VALUE=DATE-TIME:20120628T101500
DTEND;VALUE=DATE-TIME:20120628T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000390@events.thp.uni-koeln.de
DESCRIPTION:Ivan Todorov\n\nQuantization is a Mystery\n\nhttp://de.arxiv.o
rg/abs/1206.3116
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Wojciech de Roeck (Heidelberg)
DTSTART;VALUE=DATE-TIME:20120621T101500
DTEND;VALUE=DATE-TIME:20120621T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000391@events.thp.uni-koeln.de
DESCRIPTION:Wojciech de Roeck (Heidelberg)\n\nMicroscopic origins of DMPK
theory and universal conductance fluctuations\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nThe quantum phases of matter\nSubir Sac
hdev
DTSTART;VALUE=DATE-TIME:20120614T101500
DTEND;VALUE=DATE-TIME:20120614T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000392@events.thp.uni-koeln.de
DESCRIPTION:Subir Sachdev\n\nThe quantum phases of matter\n\nhttp://de.arx
iv.org/abs/1203.4565
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nHow I Learned to Stop Worrying and Love
QFT (part 2)\nMario Flory\, Robert C. Helling\, Constantin Sluka
DTSTART;VALUE=DATE-TIME:20120510T101500
DTEND;VALUE=DATE-TIME:20120510T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000393@events.thp.uni-koeln.de
DESCRIPTION:Mario Flory\, Robert C. Helling\, Constantin Sluka\n\nHow I
Learned to Stop Worrying and Love QFT (part 2)\n\nhttp://arxiv.org/abs/arX
iv:1201.2714
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Zain Shaikh
DTSTART;VALUE=DATE-TIME:20120503T101500
DTEND;VALUE=DATE-TIME:20120503T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000394@events.thp.uni-koeln.de
DESCRIPTION:Zain Shaikh\n\nA representation theoretic approach to superbos
onization\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nThe Geometry of the Master Equation and
Topological Quantum Field Theory\nM. Alexandrov\, M. Kontsevich\, A. Schw
arz\, O. Zaboronsky
DTSTART;VALUE=DATE-TIME:20120426T101500
DTEND;VALUE=DATE-TIME:20120426T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000395@events.thp.uni-koeln.de
DESCRIPTION:M. Alexandrov\, M. Kontsevich\, A. Schwarz\, O. Zaboronsky\n\n
The Geometry of the Master Equation and Topological Quantum Field Theory\n
\nhttp://arxiv.org/abs/hep-th/9502010
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Amin Abbasloo
DTSTART;VALUE=DATE-TIME:20120419T101500
DTEND;VALUE=DATE-TIME:20120419T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000396@events.thp.uni-koeln.de
DESCRIPTION:Amin Abbasloo\n\nOptimizing Regularized Channel Fidelity over
Matrix Product State\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Kaspar Duivenvoorden
DTSTART;VALUE=DATE-TIME:20120412T101500
DTEND;VALUE=DATE-TIME:20120412T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000397@events.thp.uni-koeln.de
DESCRIPTION:Kaspar Duivenvoorden\n\ntba\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nPolynomial-Time Algorithms for Prime Fa
ctorization and Discrete Logarithms on a Quantum Computer\nPeter W. Shor
DTSTART;VALUE=DATE-TIME:20120405T101500
DTEND;VALUE=DATE-TIME:20120405T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000398@events.thp.uni-koeln.de
DESCRIPTION:Peter W. Shor\n\nPolynomial-Time Algorithms for Prime Factoriz
ation and Discrete Logarithms on a Quantum Computer\n\nhttp://arxiv.org/ab
s/quant-ph/9508027
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nHearing shapes of drums - mathematical
and physical aspects of isospectrality\nOlivier Giraud\, Koen Thas
DTSTART;VALUE=DATE-TIME:20120329T101500
DTEND;VALUE=DATE-TIME:20120329T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000399@events.thp.uni-koeln.de
DESCRIPTION:Olivier Giraud\, Koen Thas\n\nHearing shapes of drums - mathem
atical and physical aspects of isospectrality\n\nhttp://rmp.aps.org/abstra
ct/RMP/v82/i3/p2213_1
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Harm Michalski
DTSTART;VALUE=DATE-TIME:20120322T101500
DTEND;VALUE=DATE-TIME:20120322T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000400@events.thp.uni-koeln.de
DESCRIPTION:Harm Michalski\n\nValence bond states in 1D spin chains\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nHow I Learned to Stop Worrying and Love
QFT (part 1)\nMario Flory\, Robert C. Helling\, Constantin Sluka
DTSTART;VALUE=DATE-TIME:20120315T101500
DTEND;VALUE=DATE-TIME:20120315T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000401@events.thp.uni-koeln.de
DESCRIPTION:Mario Flory\, Robert C. Helling\, Constantin Sluka\n\nHow I
Learned to Stop Worrying and Love QFT (part 1)\n\nhttp://arxiv.org/abs/arX
iv:1201.2714
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Nezhla Aghaei
DTSTART;VALUE=DATE-TIME:20120301T101500
DTEND;VALUE=DATE-TIME:20120301T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000402@events.thp.uni-koeln.de
DESCRIPTION:Nezhla Aghaei\n\nWZW model with a boundary term in the Lagrang
ian\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nAn introduction to the Batalin-Vilkovis
ky formalism\nDomenico Fiorenza
DTSTART;VALUE=DATE-TIME:20120209T101500
DTEND;VALUE=DATE-TIME:20120209T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000403@events.thp.uni-koeln.de
DESCRIPTION:Domenico Fiorenza\n\nAn introduction to the Batalin-Vilkovisky
formalism\n\nhttp://xxx.lanl.gov/abs/math.QA/0402057
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nBRST-antifield Quantization: a Short Re
view\nAndrea Fuster\, Marc Henneaux\, Axel Maas
DTSTART;VALUE=DATE-TIME:20120202T101500
DTEND;VALUE=DATE-TIME:20120202T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000404@events.thp.uni-koeln.de
DESCRIPTION:Andrea Fuster\, Marc Henneaux\, Axel Maas\n\nBRST-antifield
Quantization: a Short Review\n\nhttp://arxiv.org/abs/hep-th/0506098
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Alexander Alldridge
DTSTART;VALUE=DATE-TIME:20120126T101500
DTEND;VALUE=DATE-TIME:20120126T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000405@events.thp.uni-koeln.de
DESCRIPTION:Alexander Alldridge\n\nSuperbosonisation and Riesz integrals\n
\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nOn Wigner's theorem\nDan Freed
DTSTART;VALUE=DATE-TIME:20120119T101500
DTEND;VALUE=DATE-TIME:20120119T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000406@events.thp.uni-koeln.de
DESCRIPTION:Dan Freed\n\nOn Wigner's theorem\n\nhttp://arxiv.org/abs/1112.
2133
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Roberto Bondesan (ENS)
DTSTART;VALUE=DATE-TIME:20121215T101500
DTEND;VALUE=DATE-TIME:20121215T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000407@events.thp.uni-koeln.de
DESCRIPTION:Roberto Bondesan (ENS)\n\nEdge states in the spin quantum Hall
effect\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Jacopo Viti (SISSA)
DTSTART;VALUE=DATE-TIME:20121208T101500
DTEND;VALUE=DATE-TIME:20121208T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000408@events.thp.uni-koeln.de
DESCRIPTION:Jacopo Viti (SISSA)\n\nUniversal properties of two-dimensional
percolation\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Andreas Deuchert (Heidelberg)
DTSTART;VALUE=DATE-TIME:20121201T101500
DTEND;VALUE=DATE-TIME:20121201T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000409@events.thp.uni-koeln.de
DESCRIPTION:Andreas Deuchert (Heidelberg)\n\nDynamics of Repulsively Bound
Atom Pairs\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nInfinite conformal symmetry in two-dime
nsional quantum field theory\nA.A. Belavin\, A.M. Polyakov\, A.B. Zamolo
dchikov
DTSTART;VALUE=DATE-TIME:20111117T101500
DTEND;VALUE=DATE-TIME:20111117T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000410@events.thp.uni-koeln.de
DESCRIPTION:A.A. Belavin\, A.M. Polyakov\, A.B. Zamolodchikov\n\nInfinit
e conformal symmetry in two-dimensional quantum field theory\n\nhttp://dx.
doi.org/10.1016/0550-3213(84)90052-X
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nMaking sense of non-Hermitian Hamiltoni
ans\n Carl M. Bender
DTSTART;VALUE=DATE-TIME:20111020T101500
DTEND;VALUE=DATE-TIME:20111020T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000411@events.thp.uni-koeln.de
DESCRIPTION: Carl M. Bender\n\nMaking sense of non-Hermitian Hamiltonians
\n\nhttp://dx.doi.org/10.1088/0034-4885/70/6/R03
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Liza Vishnyakova (MPIM)
DTSTART;VALUE=DATE-TIME:20111006T101500
DTEND;VALUE=DATE-TIME:20111006T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000412@events.thp.uni-koeln.de
DESCRIPTION:Liza Vishnyakova (MPIM)\n\nVector bundles over supermanifolds\
n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Martin Zirnbauer
DTSTART;VALUE=DATE-TIME:20110929T101500
DTEND;VALUE=DATE-TIME:20110929T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000413@events.thp.uni-koeln.de
DESCRIPTION:Martin Zirnbauer\n\nConformal fields with circle bundle target
\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nTopological quantum field theories\nMic
hael F. Atiyah
DTSTART;VALUE=DATE-TIME:20110915T101500
DTEND;VALUE=DATE-TIME:20110915T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000414@events.thp.uni-koeln.de
DESCRIPTION:Michael F. Atiyah\n\nTopological quantum field theories\n\nhtt
p://www.springerlink.com/content/365574223623w045/
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nClifford modules\nMichael F. Atiyah\, R
aoul Bott\, Arnold Shapiro
DTSTART;VALUE=DATE-TIME:20110908T101500
DTEND;VALUE=DATE-TIME:20110908T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000415@events.thp.uni-koeln.de
DESCRIPTION:Michael F. Atiyah\, Raoul Bott\, Arnold Shapiro\n\nClifford mo
dules\n\nhttp://dell5.ma.utexas.edu/users/dafr/Index/ABS.pdf
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Zain Shaikh
DTSTART;VALUE=DATE-TIME:20110901T101500
DTEND;VALUE=DATE-TIME:20110901T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000416@events.thp.uni-koeln.de
DESCRIPTION:Zain Shaikh\n\nIntroduction to K-Theory\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nMorse Theory\, Chapters 20-23\nJohn Mil
nor
DTSTART;VALUE=DATE-TIME:20110811T101500
DTEND;VALUE=DATE-TIME:20110811T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000417@events.thp.uni-koeln.de
DESCRIPTION:John Milnor\n\nMorse Theory\, Chapters 20-23\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Alexander Alldridge
DTSTART;VALUE=DATE-TIME:20110804T101500
DTEND;VALUE=DATE-TIME:20110804T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000418@events.thp.uni-koeln.de
DESCRIPTION:Alexander Alldridge\n\nHarmonic analysis on the Clifford super
group\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nNon-Abelian anyons and topological quan
tum computation\nChetan Nayak et al.
DTSTART;VALUE=DATE-TIME:20110724T101500
DTEND;VALUE=DATE-TIME:20110724T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000419@events.thp.uni-koeln.de
DESCRIPTION:Chetan Nayak et al.\n\nNon-Abelian anyons and topological quan
tum computation\n\nhttp://link.aps.org/doi/10.1103/RevModPhys.80.1083
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nConsistent histories and quantum reason
ing\nRobert B. Griffiths
DTSTART;VALUE=DATE-TIME:20110711T101500
DTEND;VALUE=DATE-TIME:20110711T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000420@events.thp.uni-koeln.de
DESCRIPTION:Robert B. Griffiths \n\nConsistent histories and quantum reas
oning\n\nhttp://link.aps.org/doi/10.1103/PhysRevA.54.2759
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Rochus Klesse
DTSTART;VALUE=DATE-TIME:20110707T101500
DTEND;VALUE=DATE-TIME:20110707T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000421@events.thp.uni-koeln.de
DESCRIPTION:Rochus Klesse\n\nThe Principle of Maximum Entropy and its just
ifications in Statistical Mechanics and elsewhere\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nSLE for theoretical physicists\nJohn Ca
rdy
DTSTART;VALUE=DATE-TIME:20110617T101500
DTEND;VALUE=DATE-TIME:20110617T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000422@events.thp.uni-koeln.de
DESCRIPTION:John Cardy\n\nSLE for theoretical physicists\n\nhttp://dx.doi.
org/10.1016/j.aop.2005.04.001
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Abbas Saberi
DTSTART;VALUE=DATE-TIME:20110609T101500
DTEND;VALUE=DATE-TIME:20110609T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000423@events.thp.uni-koeln.de
DESCRIPTION:Abbas Saberi\n\n2D Criticality in a 3D Ising model\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nLectures on the renormalization group
(part 3)\nDavid C. Brydges
DTSTART;VALUE=DATE-TIME:20110525T101500
DTEND;VALUE=DATE-TIME:20110525T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000424@events.thp.uni-koeln.de
DESCRIPTION:David C. Brydges\n\nLectures on the renormalization group (pa
rt 3)\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Jan Schmidt
DTSTART;VALUE=DATE-TIME:20110519T101500
DTEND;VALUE=DATE-TIME:20110519T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000425@events.thp.uni-koeln.de
DESCRIPTION:Jan Schmidt\n\nLandau-Zener formula (part 2)\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nLectures on the renormalization group
(part 2)\nDavid C. Brydges
DTSTART;VALUE=DATE-TIME:20110512T101500
DTEND;VALUE=DATE-TIME:20110512T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000426@events.thp.uni-koeln.de
DESCRIPTION:David C. Brydges\n\nLectures on the renormalization group (pa
rt 2)\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Mike Mücke
DTSTART;VALUE=DATE-TIME:20110505T101500
DTEND;VALUE=DATE-TIME:20110505T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000427@events.thp.uni-koeln.de
DESCRIPTION:Mike Mücke\n\nGeneralisation of Prehomogeneous Vector Spaces
to the Super Case\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nLectures on the renormalization group
(part 1)\nDavid C. Brydges
DTSTART;VALUE=DATE-TIME:20110428T101500
DTEND;VALUE=DATE-TIME:20110428T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000428@events.thp.uni-koeln.de
DESCRIPTION:David C. Brydges\n\nLectures on the renormalization group (pa
rt 1)\n\nhttp://www.math.ubc.ca/~db5d/Seminars/PCMILectures/
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Jan Schmidt
DTSTART;VALUE=DATE-TIME:20110421T101500
DTEND;VALUE=DATE-TIME:20110421T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000429@events.thp.uni-koeln.de
DESCRIPTION:Jan Schmidt\n\nLandau-Zener formula (part 1)\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nThe information paradox: a pedagogical
introduction\nSamir D Mathur
DTSTART;VALUE=DATE-TIME:20110414T101500
DTEND;VALUE=DATE-TIME:20110414T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000430@events.thp.uni-koeln.de
DESCRIPTION:Samir D Mathur\n\nThe information paradox: a pedagogical intro
duction\n\nhttp://dx.doi.org/10.1088/0264-9381/26/22/224001
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Ricardo Kennedy
DTSTART;VALUE=DATE-TIME:20110407T101500
DTEND;VALUE=DATE-TIME:20110407T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000431@events.thp.uni-koeln.de
DESCRIPTION:Ricardo Kennedy\n\nClassification of topological insulators ba
sed on non-interacting/meanfield Hamiltonians\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nEven Partitions in Plethysms\nPeter Bü
rgisser\, Matthias Christandl\, Christian Ikenmeyer
DTSTART;VALUE=DATE-TIME:20110331T101500
DTEND;VALUE=DATE-TIME:20110331T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000432@events.thp.uni-koeln.de
DESCRIPTION:Peter Bürgisser\, Matthias Christandl\, Christian Ikenmeyer\n
\nEven Partitions in Plethysms\n\nhttp://dx.doi.org/10.1016/j.jalgebra.201
0.10.031
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Kaspar Duivenvoorden
DTSTART;VALUE=DATE-TIME:20110424T101500
DTEND;VALUE=DATE-TIME:20110424T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000433@events.thp.uni-koeln.de
DESCRIPTION:Kaspar Duivenvoorden\n\nClassification of 'Symmetric' 1-D Topo
logical Insulators (part 2)\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nThe supersymmetry method of random matr
ix theory\nMartin Zirnbauer
DTSTART;VALUE=DATE-TIME:20110417T101500
DTEND;VALUE=DATE-TIME:20110417T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000434@events.thp.uni-koeln.de
DESCRIPTION:Martin Zirnbauer\n\nThe supersymmetry method of random matrix
theory\n\nhttp://arxiv.org/abs/math-ph/0404057
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Victor Gurarie (Boulder)
DTSTART;VALUE=DATE-TIME:20110303T101500
DTEND;VALUE=DATE-TIME:20110303T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000435@events.thp.uni-koeln.de
DESCRIPTION:Victor Gurarie (Boulder)\n\nSingle-particle Green's functions
and topological insulators\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Peter Rønne
DTSTART;VALUE=DATE-TIME:20110224T101500
DTEND;VALUE=DATE-TIME:20110224T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000436@events.thp.uni-koeln.de
DESCRIPTION:Peter Rønne\n\nSuper target spaces from twisted 2d supersymme
try\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Kaspar Duivenvoorden
DTSTART;VALUE=DATE-TIME:20110203T101500
DTEND;VALUE=DATE-TIME:20110203T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000437@events.thp.uni-koeln.de
DESCRIPTION:Kaspar Duivenvoorden\n\nClassification of 'Symmetric' 1-D Topo
logical Insulators (part 1)\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nA New Look At The Path Integral Of Quan
tum Mechanics \nEdward Witten
DTSTART;VALUE=DATE-TIME:20110127T101500
DTEND;VALUE=DATE-TIME:20110127T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000438@events.thp.uni-koeln.de
DESCRIPTION:Edward Witten\n\nA New Look At The Path Integral Of Quantum Me
chanics \n\nhttp://www.slac.stanford.edu/spires/find/hep/www?eprint=arXiv
:1009.6032
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Daniel Wieczorek
DTSTART;VALUE=DATE-TIME:20110118T101500
DTEND;VALUE=DATE-TIME:20110118T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000439@events.thp.uni-koeln.de
DESCRIPTION:Daniel Wieczorek\n\nGround States and Mass Gaps of Symmetric S
paces Spin Chains\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nSymplectic geometry of entanglement\nAd
am Sawicki\, Alan Huckleberry\, Marek Kuś
DTSTART;VALUE=DATE-TIME:20110113T101500
DTEND;VALUE=DATE-TIME:20110113T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000440@events.thp.uni-koeln.de
DESCRIPTION:Adam Sawicki\, Alan Huckleberry\, Marek Kuś\n\nSymplectic geo
metry of entanglement\n\nhttp://de.arxiv.org/abs/1007.1844
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Jakob Müller-Hill
DTSTART;VALUE=DATE-TIME:20101216T101500
DTEND;VALUE=DATE-TIME:20101216T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000441@events.thp.uni-koeln.de
DESCRIPTION:Jakob Müller-Hill\n\nContinuous Dyson-Maleev representations\
n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nOn the Origin of Gravity and the Laws o
f Newton \nEric Verlinde
DTSTART;VALUE=DATE-TIME:20101209T101500
DTEND;VALUE=DATE-TIME:20101209T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000442@events.thp.uni-koeln.de
DESCRIPTION:Eric Verlinde \n\nOn the Origin of Gravity and the Laws of New
ton \n\nhttp://www.slac.stanford.edu/spires/find/hep/www?eprint=arXiv:100
1.0785
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Moritz Ernst
DTSTART;VALUE=DATE-TIME:20101202T101500
DTEND;VALUE=DATE-TIME:20101202T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000443@events.thp.uni-koeln.de
DESCRIPTION:Moritz Ernst\n\nOptimizing Fidelities\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nTopological defects and gapless modes i
n insulators and superconductors\nJeffrey C. Y. Teo\, C. L. Kane
DTSTART;VALUE=DATE-TIME:20101125T101500
DTEND;VALUE=DATE-TIME:20101125T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000444@events.thp.uni-koeln.de
DESCRIPTION:Jeffrey C. Y. Teo\, C. L. Kane \n\nTopological defects and ga
pless modes in insulators and superconductors\n\nhttp://prb.aps.org/abstra
ct/PRB/v82/i11/e115120
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Max Schäfer
DTSTART;VALUE=DATE-TIME:20101118T101500
DTEND;VALUE=DATE-TIME:20101118T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000445@events.thp.uni-koeln.de
DESCRIPTION:Max Schäfer\n\nOn the R-transform in free probability theory\
n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nGeometrisierung dreidimensionaler Manni
gfaltigkeiten und Ricci-Fluß/Recent progress on the Poincaré conjecture
and the classification of 3-manifolds\nBernhard Leeb/John W. Morgan
DTSTART;VALUE=DATE-TIME:20101111T101500
DTEND;VALUE=DATE-TIME:20101111T111500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000446@events.thp.uni-koeln.de
DESCRIPTION:Bernhard Leeb/John W. Morgan\n\nGeometrisierung dreidimensiona
ler Mannigfaltigkeiten und Ricci-Fluß/Recent progress on the Poincaré co
njecture and the classification of 3-manifolds\n\nhttp://www.ams.org/journ
als/bull/2005-42-01/S0273-0979-04-01045-6/home.html
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Alpha N'Diaye
DTSTART;VALUE=DATE-TIME:20140514T143000
DTEND;VALUE=DATE-TIME:20140514T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000447@events.thp.uni-koeln.de
DESCRIPTION:Alpha N'Diaye\, Lawrence Berkeley National Laboratory\n\nTunin
g chirality in magnetic thin films through interface engineering\n\n\n\nCo
ntact Person: Thomas Michely
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Christian Rüegg
DTSTART;VALUE=DATE-TIME:20140416T143000
DTEND;VALUE=DATE-TIME:20140416T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000448@events.thp.uni-koeln.de
DESCRIPTION:Christian Rüegg\, Paul Scherrer Institute\, University of Gen
eva\n\nQuantum Phase Transitions in Model Magnets\n\nSome magnets are exce
ptional solid-state model systems for high-precision studies of fundamenta
l quantum phenomena in physics like Bose-Einstein condensates and Tomonaga
-Luttinger liquids [1\,2]. Further examples include complex ground states
and correlations realized in low-dimensional and frustrated systems [3\,4]
\, exciting physics of impurities and quenched disorder [5]\, and dramatic
events near quantum phase transitions [6]. In this colloquium studies of
model oxides and halides by neutron scattering and complementary experimen
tal techniques will be presented. Classical phase transitions in such comp
ounds can be controlled easily by temperature\, interactions and quantum f
luctuations by chemistry and pressure application\, and correlations and p
article numbers by magnetic field. The experimental results will be discus
sed in the context of recent developments of powerful computational method
s enabling fully quantitative analysis and of related work on other model
systems like gases of ultracold atoms.\n[1] T. Giamarchi et al.\, Nature P
hysics 4\, 198 (2008).\n[2] B. Thielemann et al.\, Phys. Rev. Lett. 102\,
107204 (2009).\n[3] Y. Kohama et al.\, Phys. Rev. Lett. 109\, 167204 (2012
).\n[4] F. Casola et al.\, Phys. Rev. Lett. 110\, 187201 (2013).\n[5] S. W
ard et al.\, J. Phys.: Condens. Matter 25\, 014004 (2013).\n[6] P. Merchan
t et al.\, Nature Physics\, in press (2014).\n\n\nContact Person: Simon Tr
ebst
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Matthias Sperl
DTSTART;VALUE=DATE-TIME:20140411T163000
DTEND;VALUE=DATE-TIME:20140411T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000449@events.thp.uni-koeln.de
DESCRIPTION:Dr. Matthias Sperl\, DLR Cologne\n\nNon-Equilibrium Dynamics i
n Granular Matter\n\nThe dynamics in granular matter is inherently out-of-
equilibrium\, as \ntime-reversal symmetry is broken by the energy loss dur
ing interparticle \ncollisions. This presents challenges to both theory an
d experiment: \nExperimentally\, granular systems need to be agitated stro
ngly to achieve \nsteady states or need to be measured in microgravity to
avoid sedimentation. \nFor the theoretical treatment\, suitable ensembles
need to be assumed or \ninferred from experiments.\n\nExperiments from par
abolic-flight and drop-tower campaigns shall be shown for \nthe dilute reg
ime of granular gases where homogeneous steady states and \ngranular cooli
ng are observed. For dense granular fluids\, the derivation of \ngranular
rheology from first principles shall be presented as well as new \nexperim
ental techniques for the characterization of granular states such as \nX-r
ay radiography and tomography\, and terahertz scattering.\n\n\nContact Per
son: Joachim Krug
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Artur Swiech
DTSTART;VALUE=DATE-TIME:20140227T101500
DTEND;VALUE=DATE-TIME:20140227T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000450@events.thp.uni-koeln.de
DESCRIPTION:Artur Swiech\, University of Cologne\n\nFree Probability and S
upersymmetric Laplace Transform\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Alexander Alldridge
DTSTART;VALUE=DATE-TIME:20140313T101500
DTEND;VALUE=DATE-TIME:20140313T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000451@events.thp.uni-koeln.de
DESCRIPTION:Alexander Alldridge\, University of Cologne\n\nThe wave front
functor and its application to left-invariant (super) distributions\n\n\n\
nContact Person: Thomas Quella
LOCATION:Seminarraum II. Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Rochus Klesse
DTSTART;VALUE=DATE-TIME:20140410T101500
DTEND;VALUE=DATE-TIME:20140410T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000452@events.thp.uni-koeln.de
DESCRIPTION:Rochus Klesse\, University of Cologne\n\nProbability assignmen
ts and maximum entropy principles: details\n\n\n\nContact Person: Thomas Q
uella
LOCATION:Seminarraum Container
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Semyon Klevtsov
DTSTART;VALUE=DATE-TIME:20140508T101500
DTEND;VALUE=DATE-TIME:20140508T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000453@events.thp.uni-koeln.de
DESCRIPTION:Semyon Klevtsov\, University of Cologne\n\nQuantum Hall effect
and Kähler metrics\n\nIn physics\, important information about a system
sometimes can be obtained by studying its response to geometry. Recently\,
the gravitational response of the Quantum Hall effect on Riemann surfaces
attracted considerable attention. I will begin by explaining that the pro
blem can be formulated naturally using Kähler metrics\, line bundles and
projective embeddings. Then I will explain how to fully constrain the larg
e N expansion of the QHE partition function on Riemann surfaces (and on K
ähler manifolds) by relating it to the Bergman kernel\, extending previou
s math (S. Donaldson\, R. Berman) and physics (P. Wiegmann – A. Zabrodin
) results. Then I will discuss the meaning of Liouville and Mabuchi functi
onals\, appearing in the large N expansion. I will also discuss possible e
xtension of these results to the case of fractional QHE.\n\nContact Person
: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Christian Heß
DTSTART;VALUE=DATE-TIME:20140618T143000
DTEND;VALUE=DATE-TIME:20140618T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000455@events.thp.uni-koeln.de
DESCRIPTION:Christian Heß\, IFW Dresden\n\nUnconventional superconductivi
ty in LiFeAs as seen by scanning tunneling microscopy and spectroscopy\n\n
In this talk\, I will present recent results on the unconventional superco
nductor LiFeAs obtained by scanning tunneling micrsopcopy/spectroscopy (S
TM/STS). STM. STM/STS is an important probe for studying such superconduct
ors. On the one hand it provides the possibility to directly measure the s
patial variation of the order parameter in the presence of a magnetic vort
ex lattice\, and thus the coherence length. On the other hand\, the quasip
article interference (QPI) which arises from quasiparticle scattering off
impurities\, and which sensitively depends on the superconducting wave fun
ction can be probed directly. LiFeAs belongs to the class of iron arsenide
superconductors which have been discovered in 2008. This material possess
es very clean and charge neutral cleaved surfaces without a surface state
and is thus perfectly suited for STM/STS. Our QPI data are perfectly cons
istent with band structure data derived from angular reolved photoemission
spectroscopy [1].\nHowever\, the further analysis yields incompatibility
with elementary s- or d-wave order parameters\, suggestive of a more compl
ex scenario [2]. I will discuss these findings in the context of further e
xperimental data and theoretical results.\n\n[1] C. Hess\, S. Sykora\, T.
Hänke\, R. Schlegel\, D. Baumann\, V. B. Zabolotnyy\, L. Harnagea\, S. Wu
rmehl\, J. van den Brink\, B. Büchner\, Phys. Rev. Lett. 110\, 017006 (
2013)\n[2] T. Hänke\, S. Sykora\, R. Schlegel\, D. Baumann\, L. Harnagea\
, S. Wurmehl\, M. Daghofer\, B. Büchner\, J. van den Brink\, C. Hess\,
Phys. Rev. Lett. 108\, 127001 (2012) \n\n\nContact Person: Paul H.M. van L
oosdrecht
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Claudio Castelnovo
DTSTART;VALUE=DATE-TIME:20140604T143000
DTEND;VALUE=DATE-TIME:20140604T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000456@events.thp.uni-koeln.de
DESCRIPTION:Claudio Castelnovo\, University of Cambridge\n\nDynamics of fr
actionalised excitations in spin ice materials\n\nSpin ice materials such
as Dy2Ti2O7 and Ho2Ti2O7 provide a rare instance of emergent gauge symmetr
y and fractionalisation in three dimensions. Their elementary excitations
carry a fraction of the magnetic moment of the microscopic spin degrees of
freedom and they can be thought of as magnetic monopoles. Spin ice ground
states are highly degenerate yet locally constrained and in the absence o
f monopole excitations\, effectively no dynamics is possible. At low tempe
ratures\, the monopoles are sparse and dynamics becomes very slow. These s
ystems are therefore prone to falling out of equilibrium at low temperatur
es\, for instance following comparatively rapid changes in temperature or
applied magnetic field. In this regime\, a wealth of dynamical phenomena o
ccur\, including reaction diffusion behaviour\, slow dynamics due to kinem
atic constraints\, as well as behaviour that mimic the deposition of inter
acting dimers on a lattice. The situation is further complicated by the pr
esence of disorder that\, even at small\n densities\, appears to have a si
zeable effect on the low-temperature dynamics of these systems. Here we in
vestigate some of these phenomena and we propose how to effectively extend
existing theories to describe spin ice out of equilibrium. Nonequilibrium
physics in spin ice is a novel setting which combines kinematic constrain
ts\, emergent topological defects\, and magnetic long range Coulomb intera
ctions. \n\n\nContact Person: Simon Trebst
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Yoshio Kuramoto
DTSTART;VALUE=DATE-TIME:20140314T140000
DTEND;VALUE=DATE-TIME:20140314T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000462@events.thp.uni-koeln.de
DESCRIPTION:Yoshio Kuramoto\, Tohoku University\n\nSuperconductivity and m
ultipoles of electron-spin composites in two-channel Kondo lattice\n\nThe
Kondo lattice model\, if properly generalized\, provides microscopic under
standing of rich varieties of ordering phenomena in strongly correlated el
ectrons. Moreover\, the model can predict new orders that can be tested e
xperimentally. We demonstrate novel electronic orders in the Kondo lattic
e by including multi-bands of conduction electrons. The resultant two-cha
nnel Kondo lattice at zero temperature cannot remain disordered because of
the remaining fractional entropy at each site\, and unconventional orders
are realized. The hidden symmetry SO(5) of the model at half-filling of c
onduction bands causes degeneracy between multipole composite orders with
three components\, and an odd-frequency superconducting order with a compl
ex order parameter. Detailed numerical calculation shows that deviation f
rom the half-filling makes the superconductivity most stable for a certain
range of the density. We discuss peculiar features of the order paramet
ers.\n\n\nContact Person: Achim Rosch
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dr. Regine Frank
DTSTART;VALUE=DATE-TIME:20140509T163000
DTEND;VALUE=DATE-TIME:20140509T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000463@events.thp.uni-koeln.de
DESCRIPTION:Dr. Regine Frank\, Eberhard Karls Universität Tübingen\n\nSi
gnatures of Anderson Localization of Light in Real World Disordered Sample
s\n\nTo derive Anderson localization of light is one of the holy grails of
our time. I show in this talk theoretical results derived by Vollhardt-W
ölfle theory of photons in a novel time dependent approach. The results a
re given for 3D disordered\, finite sized real world systems of poly-dispe
rse powders consisting of TiO_2 Mie spheres. Signatures of Anderson loca
lized states\, namely interference effects\, are determined and they can b
e clearly distinguished from long living light-matter bound states as well
as frequency converted photons and losses. Influences of different types
of non-linear effects are discussed.\n\nContact Person: Alexander Altland
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Various speakers
DTSTART;VALUE=DATE-TIME:20140328T140000
DTEND;VALUE=DATE-TIME:20140328T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000464@events.thp.uni-koeln.de
DESCRIPTION:Various speakers\n\nRehearsals for DPG-Tagung\n\nWe are going
to have rehearsals for the DPG-Tagung.\n\nSpeakers and titles:\n1. Roberto
Bondesan: "Critical theory of the spin quantum Hall transition"\n2. Danie
l Wieczorek: "Pure scaling operators at the integer quantum Hall plateau t
ransition"\n3. Thomas Quella: "The Cirac-Sierra construction and long rang
e SU(N) spin models"\n4. Jochen Peschutter: "The gl(1|1) Lie superalgebra
as a basis for the Nielsen-Cirac-Sierra construction"\n5. Thomas Quella: "
Haldane phases of SU(N) spin chains and their realization in ultra-cold at
om gases"\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Container
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Andrzej Jarosz
DTSTART;VALUE=DATE-TIME:20140605T101500
DTEND;VALUE=DATE-TIME:20140605T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000465@events.thp.uni-koeln.de
DESCRIPTION:Andrzej Jarosz\, University of Cologne\n\nQuaternion free prob
ability\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Container
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Xenophon Zotos
DTSTART;VALUE=DATE-TIME:20140328T140000
DTEND;VALUE=DATE-TIME:20140328T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000467@events.thp.uni-koeln.de
DESCRIPTION:Xenophon Zotos\, University of Crete\n\nSome new insights in 1
D quantum magnets\n\n\n\nContact Person: Paul H.M. van Loosdrecht
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Heiko Wende
DTSTART;VALUE=DATE-TIME:20140528T143000
DTEND;VALUE=DATE-TIME:20140528T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000468@events.thp.uni-koeln.de
DESCRIPTION:Heiko Wende\, University of Essen-Duisburg\n\nMagnetic Hybrid
Systems: from Molecules and Graphene to Multiferroic Nanocomposites\n\nIn
the on-going process of electronic device miniaturization new concepts are
developed by utilizing hybrid systems. For this purpose the tailoring of
the magnetic properties in these nanoscale systems is essential. We make u
se of hybrid systems that consist of a combination of magnetic molecules\,
graphene\, thin films as well as magnetic nanopillars. Surface and interf
ace effects are crucial to achieve new functionalities in these structures
. This shall be demonstrated by means of two examples: 1) The magnetic cou
pling of paramagnetic molecules to ferromagnetic surfaces can be tailored
by the help of an intermediate layer of atomic oxygen or graphene [1-4]. T
he fundamental understanding of the relevant interactions for the coupling
is possible by combination of experimental and theoretical results utiliz
ing ab initio calculations. 2) Ferrimagnetic CoFe2O4 (CFO) nanopillars emb
edded in a ferroelectric BaTiO3 (BTO) matrix are an example for a two-phas
e magnetoelectrically coupled system [5]. In particular\, the\n \n
[1] H. Wende et al.\, Substrate-induced magnetic ordering and
switching of iron porphyrin molecules\, Nature Materials 6\, 516 (2007).\n
[2] H. Wende\, Molecular magnets: How a nightmare turn
s into a vision\, \nNature Materials 8\, 165 (2009).\n [3]
M. Bernien et al.\, Tailoring the Nature of Magnetic Coupling of Fe-Po
rphyrin Molecules to Ferromagnetic Substrates\, Phys. Rev. Lett. 102\, 047
202 (2009).\n [4] S. Bhandary et al.\, Graphene as a Re
versible Spin Manipulator of Molecular Magnets\, Phys. Rev. Lett. 107\, 25
7202 (2011).\n [5] C. Schmitz-Antoniak et al.\, Electri
c in-plane polarization in multiferroic CoFe2O4/BaTiO3 nanocomposite tuned
by magnetic fields\, Nature Communications 4:2051 doi: 10.1038/ncomms3051
(2013).\n\n\nContact Person: Thomas Michely
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Christoph Tegenkamp
DTSTART;VALUE=DATE-TIME:20140709T143000
DTEND;VALUE=DATE-TIME:20140709T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000469@events.thp.uni-koeln.de
DESCRIPTION:Christoph Tegenkamp\, Universität Hannover\n\n“Edge science
”: electronic states in geometrically and electronically confined surfa
ce structures\n\nFascinating phenomena such as superconductivity\, charge
density waves\, Luttinger liquids or topologically protected edge states\,
can be realized on surfaces with atomic precision. Strongest correlation
effects are expected in 1D structures and I will present in this talk two
recent examples of geometrically and electronically confined systems fabri
cated by lithography and self-assembly\, respectively\, where the spectros
copic signatures and transport properties are determined by their edges an
d step structures: \nPb adsorbed on Si(557) leads to formation of long ra
nge ordered quantum wire ensembles. At temperatures below 78K the system u
ndergoes a refacetting transition accompanied by a metal-insulator transit
ion. The insulating behavior found in the direction across the wires can b
e explained in terms of Fermi nesting [1]. Recently\, the spin-orbit coupl
ing in this system and its impact to magneto-transport measurements have b
een analyzed in detail. The spin polarization of the Fermi surface\, manif
ested already in the suppression of spin-orbit coupling along the wires wi
thin the 1D transport regime\, has been confirmed by spin-resolved ARPES m
easurements. The magnitude of the Rashba-splitting in this strongly anisot
ropic system evidences the formation of a spin density wave\, which is the
ground state of a CDW system electron-electron interaction [2]. \nThe reg
ime of mesoscopic transport physics has been entered with graphene nanorib
bon structures (GNR) grown on SiC-MESAs. By means of a 4-tip STM/SEM syste
m ballistic transport channels with mean free path lengths up to 10 µm at
room temperature have been identified [3]. The existence of edge-localize
d states near the zig-zag edges have been confirmed by first STS spectra t
aken across the ribbon [4]. \n[1] C. Tegenkamp\, et.al. PRL 95\, 176804 (2
005)\n[2] C. Tegenkamp\, et.al. PRL 109\, 266401 (2012) \n[3] J. Baringhau
s \,et.al.\, Nature 506\, 349 (2014)\n[4] J. Baringhaus et.al. JPCM\, 25\
, 392001 (2013).\n\nContact Person: Carsten Busse
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | M. Lässig
DTSTART;VALUE=DATE-TIME:20140425T163000
DTEND;VALUE=DATE-TIME:20140425T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000470@events.thp.uni-koeln.de
DESCRIPTION:M. Lässig\, Institut für Theoretische Physik\, Universität
zu Köln\n\nEvolution of influenza: Statistical genetics far from equilibr
ium\n\nThe human flu virus undergoes rapid evolution\, which is driven by
interactions with its host immune system. We describe the evolution of vir
al genomes in terms of a non-equilibrium statistical mechanics model. This
model successfully predicts the evolution of influenza one year into the
future. Thus\, evolutionary analysis transcends its traditional role of re
constructing past history. This has important consequences for public heal
th: evolutionary predictions can inform the selection of influenza vaccine
strains. We discuss the conditions of predictability and its links to coo
perative phenomena and universality. These links highlight the key role of
statistical mechanics in making evolutionary biology a predictive science
.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Antonin Coutant
DTSTART;VALUE=DATE-TIME:20140408T120000
DTEND;VALUE=DATE-TIME:20140408T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000471@events.thp.uni-koeln.de
DESCRIPTION:Antonin Coutant\, Max-Planck-Institut für Gravitationsphysik\
, Potsdam\n\nUnitary and non-unitary transitions around a cosmological bou
nce\n\nIn this presentation\, we will discuss the notion of time and unita
rity in the vicinity of a bounce in quantum cosmology\, that is\, a turnin
g point for the scale factor. This starts from the Vilenkin approach to th
e interpretation of the solutions of the Wheeler-DeWitt equation. In this
approach\, unitarity is defined through the conserved current and is by na
ture an approximate concept. In minisuperspace it amounts to using the sca
le factor as a time variable. A unitary evolution is recovered when the la
tter becomes semi-classical enough.\n\nUnfortunately\, WKB methods drastic
ally fail near a turning point and the scale factor cannot play the role o
f time in scenarios with a bounce or a recollapsing phase for the universe
. In this work\, we extend the results of Vilenkin Massar and Parentani to
momentum representation. For this\, we investigate the dynamics of matter
transitions when using its conjugate momentum as a time. In a first part\
, we describe the precise conditions so as to recover unitarity\, and henc
e\, a consistent notion of probability. In a second part\, we discuss a co
ncrete example in the vicinity of a bounce.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Paul van Loosdrecht
DTSTART;VALUE=DATE-TIME:20140527T164500
DTEND;VALUE=DATE-TIME:20140527T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000484@events.thp.uni-koeln.de
DESCRIPTION:Paul van Loosdrecht\, University of Cologne\n\nUltrafast Conde
nsed Matter Science\n\n
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Achim Rosch
DTSTART;VALUE=DATE-TIME:20140617T164500
DTEND;VALUE=DATE-TIME:20140617T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000485@events.thp.uni-koeln.de
DESCRIPTION:Achim Rosch\, University of Cologne\n\nMagnetic whirls in chir
al magnets: skyrmions and monopoles\n\n
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Mark Huyse
DTSTART;VALUE=DATE-TIME:20140701T164500
DTEND;VALUE=DATE-TIME:20140701T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000486@events.thp.uni-koeln.de
DESCRIPTION:Mark Huyse\, University of Leuven\n\nRadioactive ion beams\n\n
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Philippe André
DTSTART;VALUE=DATE-TIME:20140715T164500
DTEND;VALUE=DATE-TIME:20140715T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000487@events.thp.uni-koeln.de
DESCRIPTION:Philippe André\, CEA Saclay\n\nFrom Filamentary Networks to P
rotostellar Cores in Giant Molecular Clouds\n\n
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Tim Wehling
DTSTART;VALUE=DATE-TIME:20140523T163000
DTEND;VALUE=DATE-TIME:20140523T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000488@events.thp.uni-koeln.de
DESCRIPTION:Tim Wehling\, Universität Bremen\n\nElectronic structure of l
ow dimensional materials: from graphene to quantum impurities\n\nLow dimen
sional structures combine pronounced surface effects with distinct\nmany b
ody interactions. Both affect material properties decisively\, as they\nde
termine excitations and boundaries between different electronic as well as
\nstructural phases. Here\, we discuss how the electronic structure of low
\ndimensional materials can be understood based on microscopic theory alon
g\nwith three examples of how interactions affect material properties. Fir
st\, we\nconsider chemically functionalized graphene and show how doping t
riggers\nadsorbate phase transitions including tendencies towards sublatti
ce symmetry\nbreaking. Regarding the electrons in layered materials\, loca
l "Hubbard\ninteractions" generally compete with large non-local Coulomb i
nteractions. We\nwill discuss the "two-faced" nature of these non-local in
teractions: while they\ncontribute to strong renormalizations of electroni
c excitations\, non-local\nCoulomb terms turn out to weaken ground state e
lectronic correlations\nfrequently. Finally\, we will turn to quantum impu
rity problems and show how\nelectronic interactions shape excitation spect
ra in magnetic nanostructures.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Fernanda Pinheiro
DTSTART;VALUE=DATE-TIME:20140415T150000
DTEND;VALUE=DATE-TIME:20140415T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000473@events.thp.uni-koeln.de
DESCRIPTION:Fernanda Pinheiro\, Stockholm University and Nordita\n\nOrbita
l physics in excited bands of optical lattices\n\nOrbital physics in excit
ed bands of optical lattices\n\nAfter numerous advances in manipulation an
d detection techniques\, cold atoms in optical lattices have become a prim
ary candidate for studies of mesoscopic quantum phenomena. The possibility
of accessing both the weakly and strongly correlated regimes\, allows for
investigation of a variety of phenomena which include quantum phase trans
itions.\n\nAfter a brief introduction to the field of cold atoms\, here we
will explore the physics in excited bands of optical lattices - the p ban
d. Due to an additional orbital degree of freedom\, the physics in the p b
and is qualitatively different from the physics of the usual systems in th
e ground band. We will start by defining these orbital states and describi
ng mean field properties of the system\, with particular emphasis on the c
ondensation (in the p band) of a confined system. We will then move to the
strongly correlated regime to show that under specific circumstances\, th
e physics of bosons in the p band can be described by the spin-1/2 quantum
XYZ Heisenberg model in an external field\, that is one of the paradigmat
ic models in the study of quantum magnetism.\n
LOCATION:Institute for Genetics\, Zülpicher Str. 47a\, New Seminar Room 0
.46\, ground floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nThe Excitation Spectrum for Bose Fluids
with Weak Interactions\nRobert Seiringer
DTSTART;VALUE=DATE-TIME:20140417T153000
DTEND;VALUE=DATE-TIME:20140417T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000474@events.thp.uni-koeln.de
DESCRIPTION:Robert Seiringer\n\nThe Excitation Spectrum for Bose Fluids wi
th Weak Interactions\n\nWe discuss the paper "The Excitation Spectrum for
Bose Fluids with Weak Interactions" by Robert Seiringer. Modus operandi: T
he dice will determine who will lead the discussion\, so every seminar par
ticipant is kindly asked to prepare the paper in advance. \n\nContact Pers
on: Thomas Quella
LOCATION:Seminarraum Physik-Container
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Viktor Zolyomi
DTSTART;VALUE=DATE-TIME:20140611T143000
DTEND;VALUE=DATE-TIME:20140611T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000475@events.thp.uni-koeln.de
DESCRIPTION:Viktor Zolyomi\, Lancaster University\n\nBeyond Graphene: The
future of two-dimensional nanomaterials\n\nNanoscale materials science has
been dominated by graphene for the past ten\nyears. The presentation will
discuss the way forward by looking at a number of\nemerging novel materia
ls that are expected to define the next decade of\nresearch in two-dimensi
onal materials. The presentation will focus on two\nclasses of semiconduc
ting nanomaterials: hexagonal chalcogenides and\nsilicene/germanene deriva
tives.\n\nHexagonal gallium chalcogenides and indium chalcogenides are str
ucturally\nquite similar to transition metal dichalcogenides while exhibit
ing very unique\nelectronic properties. Their valence band will be discuss
ed with emphasis on\ntheir use to engineer a very robust Lifshitz transiti
on\, and their optical\nproperties will be examined to project their futur
e use as UV photodetectors\n[1\,2\,3].\n\nSilicane and germanane are fully
hydrogenated covalent derivatives of silicene\nand germanene\, respective
ly. Their stability will be discussed and their\nelectronic structure pres
ented. The talk will show that a tight-binding\ndescription of their valen
ce and conduction bands requires the inclusion of\nsecond-nearest neighbor
interaction and present a model with parameters\nobtained from first prin
ciples [4\,5].\n\n\n[1] Zólyomi\, V.\; Drummond\, N. D.\; Fal'ko\, V. I.\
; Phys. Rev. B 87\, 195403\n(2013)\n\n[2] Liu\, F. C.\; Shimotani\, H.\; S
hang\, H.\; Kanagasekaran\, T.\; Zólyomi\, V.\;\nDrummond\, N. D.\; Fal'k
o\, V. I.\; Tanigaki\, K.\; ACS Nano 8\, 752-760 (2014)\n\n[3] Zólyomi\,
V.\; Drummond\, N. D.\; Fal'ko\, V. I.\; arXiv:1403.4389\n\n[4] Drummond\,
N. D.\; Zólyomi\, V.\; Fal'ko\, V. I.\; Phys. Rev. B 85\, 075423\n(2012)
\n\n[5] Zólyomi\, V.\; Wallbank\, J. R.\; Fal'ko\, V. I.\; 2D Mater. 1\,
011005 (2014)\n\n\nContact Person: Alexander Grueneis
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Gianni Profeta
DTSTART;VALUE=DATE-TIME:20140626T160000
DTEND;VALUE=DATE-TIME:20140626T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000476@events.thp.uni-koeln.de
DESCRIPTION:Gianni Profeta\, CNR-SPIN and University of L'Aquila\n\nPhysic
al properties of superconductors from Density Functional Theory\n\nThe rec
ent discovery of superconductivity at high temperature in\niron-based mate
rials have highly\nrenewed the interest in the scientific community for th
e comprehension of\nthe physical properties of\nsuperconductors and their
applications.\nIn this talks\, we will give an overview of some new experi
mental results\nin this field and their theoretical interpretations\nby me
ans of density functional theory calculations.\nIn particular\, we will pr
esent results on the effects of charge doping\,\npressure and reduced dime
nsionality on the electronic\,\nFermi surface topology and magnetic proper
ties in conventional and\nnon-conventional superconductors\,\nhighlighting
their debated role in the appearance of the superconducting\nphase.\n\n\n
Contact Person: Alexander Grueneis
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Daniel Grumiller
DTSTART;VALUE=DATE-TIME:20140507T141500
DTEND;VALUE=DATE-TIME:20140507T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000477@events.thp.uni-koeln.de
DESCRIPTION:Daniel Grumiller\, Vienna University of Technology\n\nHolograp
hy: From (flat space) gravity to quantum matter\n\nThe description of stro
ngly coupled systems presents a challenge for theoretical physics\, since
usual weak-coupling methods based upon perturbation theory typically fail.
Therefore\, new tools are required to describe strongly interacting quant
um matter\, like the quark gluon plasma created in heavy ion collisions or
cold fermionic atoms at unitarity. Holographic correspondences between gr
avity theories and quantum field theories can provide such tools. I review
basic aspects of holography and summarize our recent results in flat spac
e holography\n\nContact Person: Thomas Nattermann
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nThe entropy concept for non-equilibrium
states\nLieb and Yngvason
DTSTART;VALUE=DATE-TIME:20140424T101500
DTEND;VALUE=DATE-TIME:20140424T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000478@events.thp.uni-koeln.de
DESCRIPTION:Lieb and Yngvason\n\nThe entropy concept for non-equilibrium s
tates\n\nWe discuss the paper "The entropy concept for non-equilibrium sta
tes" by Lieb and Yngvason. Modus operandi: The dice will determine who wil
l lead the discussion\, so every seminar participant is kindly asked to pr
epare the paper in advance. \n\nContact Person: Thomas Quella
LOCATION:Seminarraum Container
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Jerome Dubail
DTSTART;VALUE=DATE-TIME:20140430T160000
DTEND;VALUE=DATE-TIME:20140430T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000479@events.thp.uni-koeln.de
DESCRIPTION:Jerome Dubail\, University of Nancy\n\nThe problem of construc
ting Tensor Product States for chiral topological phases\n\nIn this inform
al talk\, I will discuss the question whether it is possible to find a Ten
sor Product State which is the ground state of a gapped\, local\, Hamilton
ian lying inside a chiral topological phase. Prominent examples of such ch
iral phases are quantum Hall states\, Chern bands\, or complex (e.g.\, p+i
p) paired states. This question appears to have been mentioned by various
people\, but so far only a handful of papers have tackled it directly. I w
ill start with a preprint from last year (JD-Read\, 2013\, see also Wahl-T
u-Schuch-Cirac\, 2013 and Hastings\, 2014) and elaborate on some subsequen
t developments (unpublished). Only basic knowledge of quantum Hall trial w
ave functions (the approach of Moore-Read\, 1991) and of conformal field t
heory will be required.\n\nContact Person: Thomas Quella
LOCATION:Seminarraum 303 (II. Physik)
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Philipp Werner
DTSTART;VALUE=DATE-TIME:20140516T163000
DTEND;VALUE=DATE-TIME:20140516T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000480@events.thp.uni-koeln.de
DESCRIPTION:Philipp Werner\, Fribourg\n\nDynamical mean field approach to
correlated lattice systems in and out of equilibrium\n\nOver the past 25 y
ears\, the dynamical mean field (DMFT) formalism has been extended from fe
rmionic Hubbard-type models to realistic multi-band materials\, bosonic la
ttice systems and even quantum field theories. It has also been developed
into a powerful and versatile tool for the study of nonequilibrium phenome
na in correlated lattice models. I will provide an overview of the key dev
elopments in the field and explain the most recent addition to the DMFT fa
mily - the DMFT treatment of quantum field theories. In the second part of
the talk I will discuss two predictions from nonequilibrium DMFT studies:
the possibility to switch the Coulomb repulsion into an effective attract
ive interaction through the application of periodic electric fields\, and
the existence of nonthermal critical points\, which control the relaxation
dynamics of the antiferromagnetic or superconducting order parameter on i
ntermediate time-scales.\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Paul Wiegmann
DTSTART;VALUE=DATE-TIME:20140723T143000
DTEND;VALUE=DATE-TIME:20140723T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000481@events.thp.uni-koeln.de
DESCRIPTION:Paul Wiegmann\, University of Chicago\n\nt.b.a.\n\n\n\nContact
Person: Seymon Klevtsov
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Priv.-Doz. Dr. Johanna Erdmenger
DTSTART;VALUE=DATE-TIME:20140515T130000
DTEND;VALUE=DATE-TIME:20140515T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000482@events.thp.uni-koeln.de
DESCRIPTION:Priv.-Doz. Dr. Johanna Erdmenger\, MPI Munich\n\nGauge/Gravity
Duality: Foundations and applications to strongly coupled systems \n\nBas
ed on string theory\, gauge/gravity duality maps strongly coupled quantum\
nfield theories to weakly coupled gravity theories. It thus provides a new
\napproach for studying physical phenomena in strongly coupled systems. We
\ndescribe the main features of this approach and discuss selected example
s.\nThese include new results for relativistic hydrodynamics and for anoma
lous\ntransport\, with possible implications for Dirac matter and for Weyl
semimetals.\nAs a further example\, we present a new Kondo model within g
auge/gravity\nduality\, which amounts to a Luttinger liquid coupled to a m
agnetic impurity.\n\nContact Person: Nattermann
LOCATION:Seminarraum des Instituts für Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nConsistent thermostatistics forbids neg
ative absolute temperatures\nJ. Dunkel and S. Hilbert
DTSTART;VALUE=DATE-TIME:20140515T101500
DTEND;VALUE=DATE-TIME:20140515T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000483@events.thp.uni-koeln.de
DESCRIPTION:J. Dunkel and S. Hilbert\n\nConsistent thermostatistics forbid
s negative absolute temperatures\n\nWe discuss the paper "Consistent therm
ostatistics forbids negative absolute temperatures" by Dunkel and Hilbert.
Modus operandi: The dice will determine who will lead the discussion\, so
every seminar participant is kindly asked to prepare the paper in advance
. \n\nContact Person: Thomas Quella
LOCATION:Seminarraum Container
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | David Gross
DTSTART;VALUE=DATE-TIME:20140606T160000
DTEND;VALUE=DATE-TIME:20140606T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000489@events.thp.uni-koeln.de
DESCRIPTION:David Gross\, Universität Freiburg\n\nQuantum cellular automa
ta\, the Pauli principle\, and vintage movies\n\nThe output files of a dig
ital camera are typically only 10% the size of the raw data.\nCan one desi
gn a physical process that only records the relevant information to\nbegin
with? The recently developed field of "compressed sensing" achieves this\
ntrick for certain signals. Building on tools from mathematical physics\,
we have\nintroduced new methods to the theory which have since found appli
cations in\nareas as diverse as face recognition\, despeckling of movie fr
ames\, and large\ndeviation bounds for non commutative processes.\nIn a se
cond\, unrelated part\, I will talk about the one-body quantum marginal\np
roblem. Here\, the task is to decide which set of local reduced density ma
trices\nare compatible with a globally pure state. Known to be non-trivial
since the 70s\,\nonly recent developments in symplectic geometry and asym
ptotic representation\ngeometry have made the problem tractable. I will re
port on our work that connects\nthese methods to the study of multi-partit
e entanglement and fermionic many-body\nsystems.\nLastly\, I will mention
some results related to the classification of time evolutions in\ndiscrete
quantum lattice systems (otherwise known as quantum cellular\nautomata).\
n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Sebastian Diehl
DTSTART;VALUE=DATE-TIME:20140620T160000
DTEND;VALUE=DATE-TIME:20140620T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000490@events.thp.uni-koeln.de
DESCRIPTION:Sebastian Diehl\, Universität Innsbruck\n\nAspects of Univers
ality in Driven Open Quantum Systems\n\nRecent experimental developments i
n diverse areas - ranging from cold atomic\ngases over light-driven semico
nductors to microcavity arrays - move systems\ninto the focus\, which are
located on the interface of quantum optics\, many-body\nphysics and statis
tical mechanics. They share in common that coherent and\ndriven-dissipativ
e quantum dynamics occur on an equal footing\, creating\nscenarios without
immediate counterpart in condensed matter. A key challenge\nis to identif
y universal macroscopic phenomena\, which manifestly witness\nmicroscopic
non-equilibrium conditions.\nHere\, we will report on three results in thi
s direction. First\, we show that\ndynamical Bose criticality in driven sy
stems lies beyond the equilibrium Halperin-\nHohenberg classification. Sec
ond\, we argue that driven open systems in two\ndimensions\, realized by e
nsembles of exciton-polaritons\, cannot support\nsuperfluidity and quasi-l
ong range order. Third\, we reveal new\, manifestly non-\nequilibrium scal
ing behavior in the short time heating dynamics of interacting\,\nultracol
d atomic quantum wires.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Jie Ren
DTSTART;VALUE=DATE-TIME:20140627T160000
DTEND;VALUE=DATE-TIME:20140627T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000491@events.thp.uni-koeln.de
DESCRIPTION:Jie Ren\, Massachusetts Institute of Technology\n\nSpin Seebec
k diode and transistor: smart control of energy and information in nano-de
vices\n\nEnergy waste is a severe bottleneck in the supply of sustainable
energy to any\nmodern economy. Besides developing new energy sources\, the
global energy\ncrisis can be alleviated by re-utilizing the waste heat. I
n this talk\, I will first\nintroduce some background of harnessing the th
ermal energy by the\nthermoelectrics\, spin caloritronics\, and phononics.
Then\, in the second part\, I\nwould like to share with you some of my re
cent discoveries about the\nrectification and negative differential spin S
eebeck effects\, exemplified in\nmetal/magnetic insulator interfaces and m
agnon tunneling junctions. These\nproperties lead us to the novel devices\
, such as thermal-driven spin diode and\ntransistor in the absence of elec
tric transports. I call them spin Seebeck diode\nand transistor. These fin
dings imply that a spin computer driven by waste heat\nmight not be a drea
m in the future\, which offer us new opportunities to achieve\nthe smart c
ontrol of energy and information at nanoscale.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Maria Hermanns
DTSTART;VALUE=DATE-TIME:20140704T160000
DTEND;VALUE=DATE-TIME:20140704T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000492@events.thp.uni-koeln.de
DESCRIPTION:Maria Hermanns\, University of Cologne\n\nMajorana metals and
quantum spin liquids\n\nOne of the most intriguing phenomena in strongly c
orrelated systems is\nthe fractionalization of quantum numbers - familiar
examples include \nthe spin-charge separation in one-dimensional metallic
systems\, \nthe fractionalization of the electron in certain quantum Hall
states \nor the emergence of monopoles in spin ice.\n\nIn this talk\, I wi
ll discuss the fractionalization of magnetic \nmoments in a certain class
of Mott insulators\, in which the emergent \ndegrees of freedom are Majora
na fermions that form an (almost) \nconventional metal. The origin of such
a dichotomous state is \nelucidated by a family of exactly solvable model
s of frustrated \nquantum magnets in three dimensions\, which might be rea
lized in \na class of recently synthesized Iridate compounds. These models
\nthereby provide the first analytical tractable examples of long \nsough
t-after quantum spin liquids with a spinon Fermi surface and \neven an ent
ire new class of quantum spin liquids - a so-called Weyl \nspin liquid\, i
n which the fractionalized degrees of freedom form \na topological semi-me
tal.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Dominik Ostermayr
DTSTART;VALUE=DATE-TIME:20140522T101500
DTEND;VALUE=DATE-TIME:20140522T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000493@events.thp.uni-koeln.de
DESCRIPTION:Dominik Ostermayr\, Universität Köln\n\nAutomorphism supergr
oups of supermanifolds\n\nWe introduce the notion of a G-structure on a su
permanifold\nM and indicate a proof that the automorphisms of such a struc
ture\nconstitute a Lie supergroup\, provided it is of finite type. This re
lies\non a representability criterion for subsheaves of certain representa
ble\nsheaves on supermanifolds. Examples include the cases of even and odd
\nRiemannian metrics as well as G-structures (G a suitable Poincare\nsuper
group) on spinor supermanifolds as constructed by Cortes et al.
LOCATION:Seminarraum Container
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Martin Zirnbauer
DTSTART;VALUE=DATE-TIME:20140612T101500
DTEND;VALUE=DATE-TIME:20140612T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000494@events.thp.uni-koeln.de
DESCRIPTION:Martin Zirnbauer\, University of Cologne\n\nBott periodicity f
or Z_2 symmetric ground states of gapped free-fermion systems with disorde
r\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Thomas Quella
DTSTART;VALUE=DATE-TIME:20140703T101500
DTEND;VALUE=DATE-TIME:20140703T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000495@events.thp.uni-koeln.de
DESCRIPTION:Thomas Quella\, University of Cologne\n\nProtection of topolog
ical phases by quantum group symmetries\n\n\n\nContact Person: Thomas Quel
la
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Roberto Bondesan
DTSTART;VALUE=DATE-TIME:20140710T101500
DTEND;VALUE=DATE-TIME:20140710T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000496@events.thp.uni-koeln.de
DESCRIPTION:Roberto Bondesan\, University of Cologne\n\nInfinite Matrix Pr
oduct States for long range SU(N) spin models\n\nSee http://arxiv.org/abs/
1405.2971\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Sebastian Schmittner
DTSTART;VALUE=DATE-TIME:20140724T101500
DTEND;VALUE=DATE-TIME:20140724T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000497@events.thp.uni-koeln.de
DESCRIPTION:Sebastian Schmittner\, University of Cologne\n\nThe final mode
l for disordered solids?\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nTBA\nTBA
DTSTART;VALUE=DATE-TIME:20140918T101500
DTEND;VALUE=DATE-TIME:20140918T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000498@events.thp.uni-koeln.de
DESCRIPTION:TBA\n\nTBA\n\nWe discuss the paper "" by . Modus operandi: The
dice will determine who will lead the discussion\, so every seminar parti
cipant is kindly asked to prepare the paper in advance.\n\nContact Person:
Thomas Quella
LOCATION:Seminarraum Container
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nGauge symmetry and spontaneous breaking
of gauge symmetry: philosophical approach\nPascal Lederer
DTSTART;VALUE=DATE-TIME:20140626T101500
DTEND;VALUE=DATE-TIME:20140626T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000499@events.thp.uni-koeln.de
DESCRIPTION:Pascal Lederer\n\nGauge symmetry and spontaneous breaking of g
auge symmetry: philosophical approach\n\nWe discuss the paper "Gauge symme
try and spontaneous breaking of gauge symmetry: philosophical approach" by
Pascal Lederer. Modus operandi: The dice will determine who will lead the
discussion\, so every seminar participant is kindly asked to prepare the
paper in advance.\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Eran Sela
DTSTART;VALUE=DATE-TIME:20140716T143000
DTEND;VALUE=DATE-TIME:20140716T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000501@events.thp.uni-koeln.de
DESCRIPTION:Eran Sela\, University of Tel Aviv\n\nFractional helical liqui
ds in quantum wires\n\n\nIn this talk I will argue that the physics of the
fractional quantum Hall effect my arise\, under certain conditions and li
mitations\, directly in one dimensional systems. \n\nThe primary example t
hat will be discussed is that of one dimensional wires with spin-orbit cou
pling. We will show that in the presence of Zeeman field and strong elect
ron-electron interaction\, a clean wire may form fractional helical liquid
\nstates with phenomenology similar to fractional quantum Hall liquids. Mo
st notably\, the wire's\ntwo terminal conductance is predicted to show fra
ctional quantized conductance plateaus at low\nelectron density. The eleme
ntary charge excitation of the wire is fractional and affects the shot noi
se in a nontrivial way. When the system is proximity-coupled to a superco
nductor\, fractional Majorana\nbound states may be stabilized\, giving ris
e to 1D analog of non-abelian anyons. I will discuss how\ndisorder destabi
lizes these fractional phases. Possible numerical checks of the predicted
effects will be discussed.\n\n\nContact Person: Simon Trebst
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Christian Teichert
DTSTART;VALUE=DATE-TIME:20140827T143000
DTEND;VALUE=DATE-TIME:20140827T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000502@events.thp.uni-koeln.de
DESCRIPTION:Christian Teichert\, Montanuniversität Loeben\, Austria\n\nOr
ganic thin film growth on graphene\n\nCrystalline films of small organic s
emiconductors offer attractive potential for electronic and optoelectronic
applications. To realize such applications on flexible substrates\, graph
ene as a transparent electrode material comes into play. We studied the g
rowth of the rod-like oligophenylene molecule para-hexaphenyl (6P) on meta
l supported as well as on exfoliated graphene. On clean graphene\, the mol
ecules grow in a lying fashion on the substrate whereas contaminations cau
se the molecules to stand up. Islands of upright 6P molecules are also obs
erved on ion-bombarded surfaces. We found recently that on ion bombarded r
utile(110) under oblique incidence the resulting nanometer surface ripples
significantly change the shape of the 6P islands.\n\nContact Person: Thom
as Michely
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Robert Pitz-Paal
DTSTART;VALUE=DATE-TIME:20141014T164500
DTEND;VALUE=DATE-TIME:20141014T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000503@events.thp.uni-koeln.de
DESCRIPTION:Robert Pitz-Paal\, DLR\n\nSolarthermische Kraftwerke zur Energ
ieversorgung im Sonnengürtel\n\n\n\nContact Person: Simon Trebst
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Dimitri Argyriou
DTSTART;VALUE=DATE-TIME:20141028T164500
DTEND;VALUE=DATE-TIME:20141028T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000504@events.thp.uni-koeln.de
DESCRIPTION:Dimitri Argyriou\, European Spallation Source \n\nThe European
Spallation Source: A Source for Discovery\n\n\n\nContact Person: Simon Tr
ebst
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Stefanie Walch
DTSTART;VALUE=DATE-TIME:20141111T164500
DTEND;VALUE=DATE-TIME:20141111T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000505@events.thp.uni-koeln.de
DESCRIPTION:Stefanie Walch\, University of Cologne\n\nThe full life-cycle
of molecular clouds\n\n\n\nContact Person: Simon Trebst
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Achim Richter
DTSTART;VALUE=DATE-TIME:20141125T164500
DTEND;VALUE=DATE-TIME:20141125T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000506@events.thp.uni-koeln.de
DESCRIPTION:Achim Richter\, TU Darmstadt\n\nSchrödinger- and Dirac Microw
ave Billiards\, Photonic Crystals and Graphene\n\n\n\nContact Person: Simo
n Trebst
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Albert Fert
DTSTART;VALUE=DATE-TIME:20141209T164500
DTEND;VALUE=DATE-TIME:20141209T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000507@events.thp.uni-koeln.de
DESCRIPTION:Albert Fert\, Université Paris-Sud\, Orsay\n\nSpin-orbitronic
s\, a new direction for spintronics\n\n\n\nContact Person: Achim Rosch
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Jocelyn Bell-Burnell
DTSTART;VALUE=DATE-TIME:20150113T164500
DTEND;VALUE=DATE-TIME:20150113T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000508@events.thp.uni-koeln.de
DESCRIPTION:Jocelyn Bell-Burnell\, Oxford University\n\nAn introduction to
pulsar physics\n\n\n\nContact Person: Lucas Labadie
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Michael Köhl
DTSTART;VALUE=DATE-TIME:20150127T164500
DTEND;VALUE=DATE-TIME:20150127T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000509@events.thp.uni-koeln.de
DESCRIPTION: Michael Köhl\, University of Bonn\n\nUltracold atomic Fermi
gases\n\n\n\nContact Person: Simon Trebst
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Gregor Mussler
DTSTART;VALUE=DATE-TIME:20140903T143000
DTEND;VALUE=DATE-TIME:20140903T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000510@events.thp.uni-koeln.de
DESCRIPTION:Gregor Mussler\, FZ Jülich\n\nt.b.a.\n\n\n\nContact Person: M
arkus Grüninger
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nGeometry and Empirical Science\nC.G. He
mpel
DTSTART;VALUE=DATE-TIME:20140717T101500
DTEND;VALUE=DATE-TIME:20140717T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000512@events.thp.uni-koeln.de
DESCRIPTION:C.G. Hempel\n\nGeometry and Empirical Science\n\nWe discuss th
e paper "Geometry and Empirical Science" by C.G. Hempel. Modus operandi: T
he dice will determine who will lead the discussion\, so every seminar par
ticipant is kindly asked to prepare the paper in advance.\n\nContact Perso
n: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Wolfgang Lechner
DTSTART;VALUE=DATE-TIME:20140930T100000
DTEND;VALUE=DATE-TIME:20140930T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000513@events.thp.uni-koeln.de
DESCRIPTION:Wolfgang Lechner\, University of Innsbruck\n\nQuantum Soft Mat
ter with Cold Polar Molecules: Glass and the Hexatic Phase\n\nThe realizat
ion of cold ensembles of polar molecules has opened a new pathway to explo
re the dynamics of quantum many body systems with strong\, long-range and
anisotropic dipolar interactions. While theoretical studies have so far fo
cused on the equilibrium phases in the highly degenerate quantum regime \,
I will focus in my talk on non-equilibirum dynamics in the regime where q
uantum and thermal fluctuations are of the same order of magnitude. I will
present two proposals: i.) a study on the glass transition in the presenc
e of quantum fluctuations and ii.) a study on quantum fluctuations in the
hexatic phase. i.) I will show\, how the glass phase can be prepared in a
bilayer system of ultracold dipolar molecules and present results on class
ical and quantum glassy behavior\, characterized by long tails in the rela
xation time and dynamical heterogeneity. I will also present experimental
accessible order parameters based on marker molecules\, distinguished by p
roperly chosen internal levels\, and find quantum features of dynamical he
terogeneity. ii.) The hexatic phase is an intermediate phase in two dimen
sional systems when going from the crystal to the liquid phase. I will pre
sent results on the influence of quantum fluctuations on the nature of the
hexatic phase and methods that allow one to measure these effects in a se
tup with polar molecules. \n\n\n\nContact Person: Philipp Strack
LOCATION:Seminar Room of the Institute for Theoretical Physics
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Denis Vyalikh
DTSTART;VALUE=DATE-TIME:20141015T143000
DTEND;VALUE=DATE-TIME:20141015T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000514@events.thp.uni-koeln.de
DESCRIPTION:Denis Vyalikh\, Institute of Solid State Physics\, University
of Technology Dresden\, D-01062 Dresden\, Germany\n\nARPES insight into th
e properties of f-electrons in rare-earth intremetallics\n\nFor a long tim
e\, rare-earth (RE) intermetallic materials have attracted considerable in
terest be-cause of their exotic properties at low temperatures which inclu
de complex magnetic phases\, valence fluctuations\, heavy-fermion states\,
Kondo behavior and many others. It is widely believed that all of these p
roperties stem from the delicate interplay between almost localized 4f ele
ctrons and itinerant valence band states.\nOur experiments aim to disclose
details of this interaction\, and reveal the fine electronic struc-ture o
f such materials near the Fermi level. To this end\, we apply Angle-Resolv
ed Photoemission Spectroscopy (ARPES) technique\, which in spite of its su
rface sensitivity when working in UV mode\, indeed\, allows to gain deep i
nsight not only into surface electron structure\, but to probe the bulk de
-rived states\, too. In that regard\, the particular point of our experime
nts is the proper discrimination of (sub-) surface and bulk related phenom
ena. \nIn the past years we performed extensive ARPES studies on the RERh2
Si2 (RE = Ce\, Eu and Yb) series of compound as well as on YbIr2Si2 With o
ur approach we were able to address some of the topics at the core of stro
ngly correlated 4f electron systems: (i) observation of crystal-electric f
ield (CEF) splitting of the 4f states and their fine dispersion induced by
f-d hybridization\; (ii) insight into the Fermi surface and manifestation
of its strong 4f character. Disclosing its topology and features reflecti
ng f-d coupling at the surface and bulk of the material. Studying its temp
erature dependence for a Kondo lattice (YbRh2Si2)\; (iii) clear evidence o
f the interplay of Dirac fermions and heavy quasi-particles\; (iv) manifes
tation of unusual and strong ferromagnetism at the Si-terminated surface o
f an antiferromagnet (EuRh2Si2) caused by buried 4f magnetic moments of Eu
lying 4-layers below the surface.\n\n[1] A. Chikina et al.\, Strong ferro
magnetism at the surface of an antiferromagnet caused by buried magnetic m
oments\, Nature Communications 5\, 3171 (2014).\n\n[2] M. Höppner et al.\
, Interplay of Dirac fermions and heavy quasiparticles in solids\, Nature
Commu-nications 4\, 1646 (2013).\n\n[3] S. Danzenbächer et al.\, Insight
into the f-derived Fermi surface of the heavy-fermion compound YbRh2Si2\,
Phys. Rev. Lett. 107\, 267601 (2011).\n\n[4] D.V. Vyalikh et al.\, k-depen
dence of the crystal-field splittings of 4f states in rare-earth systems\,
Phys. Rev. Lett. 105\, 237601 (2010).\n\n[5] D.V. Vyalikh et al.\, Tuning
the hybridization at the surface of a heavy-fermion system\,\nPhys. Rev.
Lett.\, 103\, 137601 (2009).\n\n\nContact Person: Alexander Grueneis
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Jean-Marie Stephan
DTSTART;VALUE=DATE-TIME:20141024T140000
DTEND;VALUE=DATE-TIME:20141024T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000515@events.thp.uni-koeln.de
DESCRIPTION:Jean-Marie Stephan\n\nEntropy and Mutual information in low-di
mensional classical and quantum systems\n\n\nIn studies of quantum phases
of matter\, the\nentanglement entropy has established itself as an importa
nt practical\nresource. For example it is universal at one-dimensional qua
ntum critical\npoints: the leading term can be used to extract the central
charge\nc of the underlying conformal field theory\, and thus identify th
e\nuniversality class. I will show how an analogous\ninformation theoretic
quantity defined for classical systems\, the\nRenyi Mutual Information (R
MI)\, can be used to access universality\nclasses in 2d. In particular for
a rectangle cut into two rectangles\,\nthe shape\ndependence of the RMI c
an be computed exactly and is proportional to c.\n\nI will also discuss ho
w this Mutual information is related to the\nentanglement entropy of certa
in Resonating valence bond states in\n2d\, as well as other basis-dependen
t entropies in 1d quantum\nsystems. In all cases\, the information theoret
ic approach\nprovides an efficient way of identifying the various competin
g orders\nin a given classical or quantum system.\n\n\nContact Person: Joh
annes Helmes
LOCATION:Seminar Room of the Institute for Theoretical Physics
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Christian Teichert
DTSTART;VALUE=DATE-TIME:20140911T130000
DTEND;VALUE=DATE-TIME:20140911T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000516@events.thp.uni-koeln.de
DESCRIPTION:Christian Teichert\, Montanuniversität Leoben\n\nAFM Tutorial
: Nanostructure Characterization by Atomic Force Microscopy\n\n
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Christian Teichert
DTSTART;VALUE=DATE-TIME:20140912T130000
DTEND;VALUE=DATE-TIME:20140912T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000517@events.thp.uni-koeln.de
DESCRIPTION:Christian Teichert\, Montanuniversität Leoben\n\nAFM Tutorial
: Nanostructure Characterization by Atomic Force Microscopy\n\n
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Elisabeth Sörgel
DTSTART;VALUE=DATE-TIME:20141112T143000
DTEND;VALUE=DATE-TIME:20141112T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000518@events.thp.uni-koeln.de
DESCRIPTION:Elisabeth Sörgel\, Universität Bonn\n\nExploiting the capabi
lities of scanning probe microscopy for the investigation of ferroelectri
cs\n\nFerroelectrics exhibit a spontaneous dipole moment whose orientation
can be determined by the application of electric fields. This allows for
the controlled fabrication of ferroelectric domain patterns which are\, fo
r instance\, in use for efficient frequency doubling using quasi phase mat
ching. Although known since more than fifty years\, and intensively invest
igated for applications\, lots of basic knowledge and understanding of fer
roelectrics is still missing. \nTo start with\, I will briefly introduce f
erroelectrics as a material itself\, and in particular show the potential
of domain-structured ferroelectrics. In the main part of my talk I will di
scuss the possibilities of scanning probe microscopy (SFM) for a better un
derstanding of ferroelectrics and also ferroelectric domains. Finally\, I
will present our results on structuring lithium niobate surfaces. \n\n\nCo
ntact Person: Thomas Michely
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Bela Bauer
DTSTART;VALUE=DATE-TIME:20140916T140000
DTEND;VALUE=DATE-TIME:20140916T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000519@events.thp.uni-koeln.de
DESCRIPTION:Bela Bauer\, Microsoft Station Q\n\nArea laws in a many-body l
ocalized state and its implications for topological order\n\nThe question
whether Anderson insulators can persist to finite-strength interactions -
a scenario dubbed many-body localization - has received a great deal of in
terest. We formulate a precise sense in which a single energy eigenstate o
f a Hamiltonian can be adiabatically connected to a state of a non-interac
ting Anderson insulator\, and define a many-body localized phase based on
this. We explore the possible consequences of this\; the most striking is
an area law for the entanglement entropy of almost all excited states in a
many-body localized phase. We present the results of numerical calculatio
ns for a one-dimensional system of spinless fermions. Furthermore\, we stu
dy the implications that many-body localization may have for topological p
hases and identify scenarios in which many-body localization can help to s
tabilize topological order at non-zero energy density. We also explore the
ways in which a relatively small quantum computer could be leveraged to s
tudy many-body localization. We show that\, in addition to studying time-e
volution\, a quantum computer can\, in polynomial time\, obtain eigenstate
s at arbitrary energies to sufficient accuracy that localization can be ob
served.\n\nContact Person: Simon Trebst
LOCATION:Seminar Room\, Conainer Building
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Stefan Wolff
DTSTART;VALUE=DATE-TIME:20141112T103000
DTEND;VALUE=DATE-TIME:20141112T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000520@events.thp.uni-koeln.de
DESCRIPTION:Stefan Wolff\n\nMaster colloquium\n\n
LOCATION:Seminar room 03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Kevin O'Brien
DTSTART;VALUE=DATE-TIME:20141119T100000
DTEND;VALUE=DATE-TIME:20141119T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000521@events.thp.uni-koeln.de
DESCRIPTION:Kevin O'Brien\n\nMaster colloquium\n\n
LOCATION:Conference Room (Institute for Theoretical Physics)
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Karla Loida
DTSTART;VALUE=DATE-TIME:20141210T100000
DTEND;VALUE=DATE-TIME:20141210T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000522@events.thp.uni-koeln.de
DESCRIPTION:Karla Loida\, University of Bonn\n\nMaster colloquium\n\n
LOCATION:Seminar Room of the Institute for Theoretical Physics
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Oksana Sukhostavets
DTSTART;VALUE=DATE-TIME:20140912T140000
DTEND;VALUE=DATE-TIME:20140912T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000523@events.thp.uni-koeln.de
DESCRIPTION:Oksana Sukhostavets\, University of San Sebastian\n\nLinear an
d nonlinear vortex dynamics in single and coupled magnetic discs\n\n\n\n
Contact Person: Achim Rosch
LOCATION:Seminar Room of the Institute for Theoretical Physics
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Lih-King Lim
DTSTART;VALUE=DATE-TIME:20140925T140000
DTEND;VALUE=DATE-TIME:20140925T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000524@events.thp.uni-koeln.de
DESCRIPTION:Lih-King Lim\, Institut d'Optique\, Palaiseau\n\nDirac cones m
erging transition and geometric phase in Stuckelberg interferometer with c
old atoms\n\n\n\nContact Person: Achim Rosch
LOCATION:Seminar Room of the Container Building
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Lukas Janssen
DTSTART;VALUE=DATE-TIME:20140917T100000
DTEND;VALUE=DATE-TIME:20140917T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000525@events.thp.uni-koeln.de
DESCRIPTION:Lukas Janssen\, Simon Fraser University\n\nQuadratic band touc
hing points in 3D: NFL phase versus topological Mott instability\n\n\n\nCo
ntact Person: Achim Rosch
LOCATION:Seminar room of the Institute for Theoretical Physics
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nString-net condensation: A physical mec
hanism for topological phases\nM. Levin and X.-G. Wen
DTSTART;VALUE=DATE-TIME:20140925T101500
DTEND;VALUE=DATE-TIME:20140925T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000526@events.thp.uni-koeln.de
DESCRIPTION:M. Levin and X.-G. Wen\n\nString-net condensation: A physical
mechanism for topological phases\n\nWe discuss the paper "String-net conde
nsation: A physical mechanism for topological phases" by M. Levin and X.-G
. Wen. Modus operandi: The dice will determine who will lead the discussio
n\, so every seminar participant is kindly asked to prepare the paper in a
dvance.\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nOn 2d TQFTs whose values are holomorphi
c symplectic varieties\nG. Moore and Y. Tachikawa
DTSTART;VALUE=DATE-TIME:20141009T101500
DTEND;VALUE=DATE-TIME:20141009T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000527@events.thp.uni-koeln.de
DESCRIPTION:G. Moore and Y. Tachikawa\n\nOn 2d TQFTs whose values are holo
morphic symplectic varieties\n\nWe discuss the paper "On 2d TQFTs whose va
lues are holomorphic symplectic varieties" by G. Moore and Y. Tachikawa. M
odus operandi: The dice will determine who will lead the discussion\, so e
very seminar participant is kindly asked to prepare the paper in advance.\
n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Daniel Wieczorek
DTSTART;VALUE=DATE-TIME:20141030T100000
DTEND;VALUE=DATE-TIME:20141030T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000528@events.thp.uni-koeln.de
DESCRIPTION:Daniel Wieczorek\, University of Cologne\n\nBoundary exponents
at the IQHE transition\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nRecovering low-rank matrices from few c
oefficients in any basis\nDavid Gross
DTSTART;VALUE=DATE-TIME:20141023T100000
DTEND;VALUE=DATE-TIME:20141023T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000529@events.thp.uni-koeln.de
DESCRIPTION:David Gross\n\nRecovering low-rank matrices from few coefficie
nts in any basis\n\nWe discuss the paper "Recovering low-rank matrices fro
m few coefficients in any basis" by David Gross. Modus operandi: The dice
will determine who will lead the discussion\, so every seminar participant
is kindly asked to prepare the paper in advance.\n\nContact Person: Thoma
s Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Kevin Coulembier
DTSTART;VALUE=DATE-TIME:20141016T101500
DTEND;VALUE=DATE-TIME:20141016T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000530@events.thp.uni-koeln.de
DESCRIPTION:Kevin Coulembier\, University of Cologne\n\nThe primitive spec
trum for Lie superalgebras\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Johannes Helmes
DTSTART;VALUE=DATE-TIME:20141022T100000
DTEND;VALUE=DATE-TIME:20141022T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000546@events.thp.uni-koeln.de
DESCRIPTION:Johannes Helmes\n\nTopological phase transitions in the classi
cal toric code model\n\n
LOCATION:Institute for Theoretical Physics
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Oliver Rader
DTSTART;VALUE=DATE-TIME:20141126T143000
DTEND;VALUE=DATE-TIME:20141126T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000547@events.thp.uni-koeln.de
DESCRIPTION:Oliver Rader\, Helmholtz-Zentrum Berlin\n\nExperiments on band
gap opening and spin manipulation in graphene and toplogical insulators \
n\nGraphene as two-dimensional conductor and topologial insulators which p
ossess two-dimensional metallic surface states around an insulating volume
share also quasirelativistic properties of their charge carriers. Their c
haracteristic linear E(k) band dispersions can be observed as so-called Di
rac cones in angle-resolved photoelectron spectroscopy. In graphene\, they
are caused by pseudospin properties\, in topological insulators such as B
i2Se3 by the electron spin. This opens the possibility to manipulate trans
port properties by opening a surface band gap at the Dirac crossing point
through breaking of the sublattice symmetry of graphene or the time-revers
al symmetry of topological insulators. In the talk\, examples are shown wh
ere these attempts lead to surprising results. In a further step\, graphen
e is made spin dependent by an extrinsic spin orbit interaction. The resul
ting spin polarization is in the surface plane - the same is the case with
topological insulators. The opening of the Dirac point by symmetry breaki
ng should in both cases turn the spin perpendicular to the surface. This i
s demonstrated for graphene. For topological insulators\, we show that the
spin can be turned out of the plane by polarized light in the photoemissi
on process.\n\nContact Person: Thomas Michely
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nQuantum Master Equations\nH.P. Breuer a
nd F. Petruccione
DTSTART;VALUE=DATE-TIME:20141106T100000
DTEND;VALUE=DATE-TIME:20141106T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000531@events.thp.uni-koeln.de
DESCRIPTION:H.P. Breuer and F. Petruccione\n\nQuantum Master Equations\n\n
We discuss the beginning of the chapter "Quantum Master Equations" from th
e book "The theory of open quantum systems" by Breuer and Petruccione. Mod
us operandi: The dice will determine who will lead the discussion\, so eve
ry seminar participant is kindly asked to prepare the paper in advance.\n\
nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Josua Groeger
DTSTART;VALUE=DATE-TIME:20141113T100000
DTEND;VALUE=DATE-TIME:20141113T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000532@events.thp.uni-koeln.de
DESCRIPTION:Josua Groeger\, University of Cologne\n\nHolonomy and Superhol
onomy\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Fulvio Parmigiani
DTSTART;VALUE=DATE-TIME:20141104T160000
DTEND;VALUE=DATE-TIME:20141104T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000566@events.thp.uni-koeln.de
DESCRIPTION:Fulvio Parmigiani\, University of Trieste\n\nScience driven re
quirements for seeded soft X-ray free electron lasers\n\nStarting from the
archetypal FERMI externally seeded FEL\, recent theoretical and experimen
tal progress has shown the possibility of producing fully coherent\, varia
ble polarization and tunable\, soft-X-ray\, ultra-short pulses at high rep
etition rate. \n\nThis ultimate achievement will unlock the gate for perfo
rming X-ray-based experiments that are qualitatively different from those
available at any current or planned X-ray source.\n\nHere we will review t
he experiments and the ideas that represent the science frontier in soft X
-ray\, time-resolved spectroscopy\, coherent imaging and scattering experi
ments.\n\nThese studies will lead to an understanding of fundamental dynam
ics\, occurring on the ultrafast time and nanometer spatial scales\, neede
d for addressing a broad range of science essential for resolving our comp
lex and long-term energy challenges\, environmentally urgent questions and
demanding problems in bioscience and novel materials. \n\nContact Person
: Paul H.M. van Loosdrecht
LOCATION:Seminar room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nRelating Field Theories via Stochastic
Quantization\nR. Dijkgraaf\, D. Orlando\, S. Reffert
DTSTART;VALUE=DATE-TIME:20141120T100000
DTEND;VALUE=DATE-TIME:20141120T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000533@events.thp.uni-koeln.de
DESCRIPTION:R. Dijkgraaf\, D. Orlando\, S. Reffert\n\nRelating Field Theor
ies via Stochastic Quantization\n\nWe discuss the paper "Relating Field Th
eories via Stochastic Quantization" by Dijkgraaf\, Orlando\, Reffert. Modu
s operandi: The dice will determine who will lead the discussion\, so ever
y seminar participant is kindly asked to prepare the paper in advance.\n\n
Contact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Roberto Bondesan
DTSTART;VALUE=DATE-TIME:20141127T100000
DTEND;VALUE=DATE-TIME:20141127T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000534@events.thp.uni-koeln.de
DESCRIPTION:Roberto Bondesan\, University of Cologne\n\nChiral SU(2)_k cur
rents as local operators in vertex models and spin chains\n\n\n\nContact P
erson: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Natan Andrei
DTSTART;VALUE=DATE-TIME:20150119T140000
DTEND;VALUE=DATE-TIME:20150119T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000565@events.thp.uni-koeln.de
DESCRIPTION:Natan Andrei\, Rutgers University\n\nQuench dynamics in integr
able quantum many body systems\n\n\n\nContact Person: Achim Rosch
LOCATION:Seminarraum 0.03 Gebaeude TP
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nQuantum information and computation\nCh
arles Bennett and David DiVincenzo
DTSTART;VALUE=DATE-TIME:20141204T100000
DTEND;VALUE=DATE-TIME:20141204T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000535@events.thp.uni-koeln.de
DESCRIPTION:Charles Bennett and David DiVincenzo\n\nQuantum information an
d computation\n\nWe discuss the paper "Quantum information and computation
" by Charles Bennett and David DiVincenzo. Modus operandi: The dice will d
etermine who will lead the discussion\, so every seminar participant is ki
ndly asked to prepare the paper in advance.\n\nContact Person: Thomas Quel
la
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Stephan Kleinbölting
DTSTART;VALUE=DATE-TIME:20141211T100000
DTEND;VALUE=DATE-TIME:20141211T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000536@events.thp.uni-koeln.de
DESCRIPTION:Stephan Kleinbölting\n\nThermalization via a microscopic bath
\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Andriy Shevchenko
DTSTART;VALUE=DATE-TIME:20150114T143000
DTEND;VALUE=DATE-TIME:20150114T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000588@events.thp.uni-koeln.de
DESCRIPTION:Andriy Shevchenko\, Aalto Universität\n\nSpatially dispersive
optical metamaterials: Design and applications\n\nThe presentation concer
ns spatially dispersive optical metamaterials\, for which the refractive i
ndex and impedance depend on the wave propagation direction. This dependen
ce – often considered as unwanted – can as I will show bring new inter
esting applications to the field of metamaterials. In particular\, it can
be used to control the propagation characteristics of optical beams. I wil
l also present a model that allows describing the interaction of optical b
eams with spatially dispersive metamaterials by making use of a vector ang
ular-spectrum representation. Then\, by applying the model\, I will show t
hat metamaterial slabs can be designed to have quite demanding functional
abilities\, for example\, to act as an apertureless spatial filter or a di
ffraction-cancelling beam waveguide. \n\nContact Person: Klas Lindfors
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nSpin Ice\, Fractionalization and Topolo
gical Order\nC. Castelnovo\, R. Moessner\, S.L. Sondhi
DTSTART;VALUE=DATE-TIME:20141218T100000
DTEND;VALUE=DATE-TIME:20141218T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000537@events.thp.uni-koeln.de
DESCRIPTION:C. Castelnovo\, R. Moessner\, S.L. Sondhi\n\nSpin Ice\, Fracti
onalization and Topological Order\n\nWe discuss the paper "Spin Ice\, Frac
tionalization and Topological Order" by C. Castelnovo\, R. Moessner\, S.L.
Sondhi. Modus operandi: The dice will determine who will lead the discuss
ion\, so every seminar participant is kindly asked to prepare the paper in
advance.\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Jochen Guck
DTSTART;VALUE=DATE-TIME:20150623T164500
DTEND;VALUE=DATE-TIME:20150623T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000628@events.thp.uni-koeln.de
DESCRIPTION:Jochen Guck\, TU Dresden\n\nDo biological cells care about phy
sics?\n\nWhile most current biological research focuses on molecular\, bio
chemical\naspects of cell and their functioning\, we are interested in the
ir global\nphysical properties. I will discuss our recent findings that th
e mechanical\nproperties of cells determine the physical limits of cell fu
nction\, for example\nin cell migration. Cell mechanics can therefore be u
sed to characterize\ncells\, to monitor physiological changes and to diagn
ose pathological alterations\,\nsuch as cancer progression. Another exampl
e for the importance\nof physics in biology are the optical properties of
cells\, specifically in the\nretina. We have shown that there are cells in
the retina that act as optical\nfibers and that photoreceptor cells even
invert their usual nuclear chromatin\narrangement to turn them into micro-
lenses. Both aspects improve\nthe light transmission through the retina an
d help to mitigate the disadvantage\nof its inverted structure. These resu
lts provide novel insight into\nthe importance of physics for biological f
unction and even offer new diagnostic\nand therapeutic avenues for further
exploration.\n\nContact Person: Berenike Maier
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Artur Swiech
DTSTART;VALUE=DATE-TIME:20150115T100000
DTEND;VALUE=DATE-TIME:20150115T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000539@events.thp.uni-koeln.de
DESCRIPTION:Artur Swiech\n\nSingularities of the Free Probabilistic R-tran
sform\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Abhishek Roy
DTSTART;VALUE=DATE-TIME:20150212T101500
DTEND;VALUE=DATE-TIME:20150212T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000590@events.thp.uni-koeln.de
DESCRIPTION:Abhishek Roy\, University of Cologne\n\nAnyon condensation and
spin chains\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nDefining physics at imaginary time: ref
lection positivity for certain Riemannian manifolds\nC.C. Anderson
DTSTART;VALUE=DATE-TIME:20150122T100000
DTEND;VALUE=DATE-TIME:20150122T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000540@events.thp.uni-koeln.de
DESCRIPTION:C.C. Anderson\n\nDefining physics at imaginary time: reflectio
n positivity for certain Riemannian manifolds\n\n\n\nContact Person: Thoma
s Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Alexander Alldridge
DTSTART;VALUE=DATE-TIME:20150129T100000
DTEND;VALUE=DATE-TIME:20150129T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000541@events.thp.uni-koeln.de
DESCRIPTION:Alexander Alldridge\n\nSupergroup actions\, slices\, and radia
l parts\n\nA theorem of Helgason states that if an action of a Lie group o
n a manifold admits a slice\, then any differential operator admits a `rad
ial’ component on the slice. For actions of Lie supergroups\, this is no
longer true in general\, as the naive slice condition is too weak. We int
roduce a strong notion of slice that allows for the generalisation of Helg
ason’s theorem\, using the concept of `orbits through generalised points
’. \n\nWe study in particular the isotropy group action for a Riemannian
symmetric superspace. In this setting\, the strong slice condition holds
if and only if the supermanifold is of `even type’ (i.e. the slice in th
e naive sense is an ordinary manifold). \n\nTo remedy this situation\, we
consider a weak notion of slices. We prove in general that at least any di
fferential operator locally invariant under the transporter supergroup of
the weak slice admits a radial part on the quotient of the weak slice by t
he transporter supergroup. This quotient is (mildly) singular in general.
For the example of Riemannian symmetric superspaces\, the transporter supe
rgroup action factors through the Weyl group\, which is a reductive Lie gr
oup of positive dimension in the cases not of odd type. \n\nWe illustrate
our findings by examples. \n\nThis work is joint with J. Hilgert and T. Wu
rzbacher\, and with K. Coulembier\, respectively.\n\nContact Person: Thoma
s Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nAn introduction into noncommutative geo
metry\nVarious references
DTSTART;VALUE=DATE-TIME:20150219T101500
DTEND;VALUE=DATE-TIME:20150219T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000591@events.thp.uni-koeln.de
DESCRIPTION:Various references\n\nAn introduction into noncommutative geom
etry\n\nWe discuss extracts of the two papers "A short introduction to non
commutative geometry" by Peter Bongaarts and "Spectral triples: examples a
nd index theory" by Alan Carey\, John Phillips and Adam Rennie. Please get
in contact with Thomas Quella in order to find out the precise content of
the seminar. Modus operandi: The dice will determine who will lead the di
scussion\, so every seminar participant is kindly asked to prepare the pap
ers in advance.\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nThe Non-Commutative Geometry of the Qua
ntum Hall Effect\nBellissard\, van Elst\, Schulz-Baldes
DTSTART;VALUE=DATE-TIME:20150205T100000
DTEND;VALUE=DATE-TIME:20150205T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000542@events.thp.uni-koeln.de
DESCRIPTION:Bellissard\, van Elst\, Schulz-Baldes\n\nThe Non-Commutative G
eometry of the Quantum Hall Effect\n\nWe discuss the paper "The Non-Commut
ative Geometry of the Quantum Hall Effect" by Bellissard\, van Elst\, Schu
lz-Baldes. Modus operandi: The dice will determine who will lead the discu
ssion\, so every seminar participant is kindly asked to prepare the paper
in advance.\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Johannes Reuther
DTSTART;VALUE=DATE-TIME:20141114T140000
DTEND;VALUE=DATE-TIME:20141114T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000543@events.thp.uni-koeln.de
DESCRIPTION:Johannes Reuther\, FU Berlin\n\nA functional renormalization-g
roup approach for frustrated quantum spin-systems\n\nWe apply the function
al renormalization group (FRG) method to describe\nground state properties
of frustrated spin-1/2 systems on two-dimensional\nlattices. In order to
be able to use this technique we rewrite the spin\noperators in terms of p
seudo fermions. The resulting fermionic model is\nthen treated via FRG\, w
hich manages to sum up diagrammatic contributions\nin different interactio
n channels in infinite order. Calculating the\nmagnetic spin susceptibilit
y we determine the ground state phase diagrams\nof various frustrated spin
systems. Thereby\, we discuss models such as the\nJ1-J2 Heisenberg model
on the square lattice and the Kagome Heisenberg\nmodel. A specific focus w
ill be on the iridate compound Li_2IrO_3\, where\nexperiments suggest a ma
gnetically ordered ground state of incommensurate\nspiral type. Applying o
ur FRG technique to an extended Heisenberg-Kitaev\nmodel we are able to de
velop a microscopic scenario for the exchange\ninteractions in this compou
nd\, explaining the experimental findings.\n\n\nContact Person: Simon Treb
st
LOCATION:Seminar Room 03 - ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Igor Shavrin
DTSTART;VALUE=DATE-TIME:20140923T100000
DTEND;VALUE=DATE-TIME:20140923T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000544@events.thp.uni-koeln.de
DESCRIPTION:Igor Shavrin\, Aalto University\n\nApplications of photonic cr
ystal fiber in high-resolution interferometry\n\nIn this talk I will prese
nt my research in supercontinuum light generation in photonic crystal fibe
rs (PCF) and describe two applications of these fibers in high resolution
interferometry. In one application PCF is utilized in a light source for h
igh resolution stroboscopic white-light interferometry\, the technique use
d for characterization of surface acoustic vibrations. Another application
uses hollow-core PCF as a waveguide and gas cell for simultaneous measure
ment of the complex refractive index in gaseous analytes. \n\nContact Pers
on: Klas Lindfors
LOCATION:Institute of Chemistry\, PC302
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Charles Reichhardt
DTSTART;VALUE=DATE-TIME:20140922T140000
DTEND;VALUE=DATE-TIME:20140922T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000545@events.thp.uni-koeln.de
DESCRIPTION:Charles Reichhardt\, Los Alamos\n\nSkyrmion Lattices in Random
and Ordered Potential Landscapes\n\nSince the initial discovery of skyrmi
on lattices in chiral magnets [1]\, there has been a tremendous growth in
this field as an increasing number of compounds are found to have extended
regions of stable skyrmion lattices [2] even close to room temperature [3
]. These systems have significant promise for applications due to their s
ize scale and the low currents or drives needed to move the skyrmions [4].
Another interesting aspect of skyrmions is that the equations of motion
have significant non-dissipative terms or a Magnus effect which makes them
unique in terms of collective driven dynamics as compared to other system
s such as vortex lattices in type-II superconductors\, sliding charge dens
ity waves\, and frictional systems. We examine the driven dynamics of sky
rmions interacting with random and periodic substrate potentials using bot
h continuum based modelling and particle based simulations. In clean syste
ms we examine the range in which skyrmion motion can be explored as a func
tion of the magnetic field and current and show that there can be a curren
t-induced creation or destruction of skyrmions. In systems with random pi
nning we find that there is a finite depinning threshold and that the Hall
angle shows a strong dependence on the disorder strength. We also show th
at features in the transport curves correlate with different types of skyr
mion flow regimes including a skyrmion glass depining/skyrmion plastic flo
w region as well as a transition to a dynamically reordered skyrmion cryst
al at higher drives. We find that increasing the Magnus term produces a lo
w depinning threshold which is due to a combination of skyrmions forming c
omplex orbits within the pinning sites and skyrmion-skyrmion scattering e
ffects. If the skyrmions are moving over a periodic substrate\, with incr
easing drive the Hall angle changes in quantized steps which correspond to
periodic trajectories of the skyrmion that lock to symmetry directions of
the substrate potential.\n\n[1] S. Muhlbauer et al Science 323 915 (2009)
.\n[2] X. Z. Yu et al. Nature 465\, 901–904 (2010). \n[3] X.Z. Yu et al
Nature Materials\, 10\, 106 (2011).\n[4] A. Fert\, V. Cros\, and J. Sampa
io Nature Nanotechnology 8\, 152 (2013).\n\n\nContact Person: Markus Garst
LOCATION:Seminar Room of the Institute of Physics II (R201)
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Thomas Lang
DTSTART;VALUE=DATE-TIME:20141212T140000
DTEND;VALUE=DATE-TIME:20141212T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000548@events.thp.uni-koeln.de
DESCRIPTION:Thomas Lang\, Boston University\n\nDimensionless ratios for SU
(N) symmetric Hubbard models and their critical points\n\nUsing unbiased q
uantum Monte Carlo simulations we investigate the quantum phase transition
s in SU(N) Hubbard models on square and honeycomb lattices. We construct a
nd measure dimensionless fermionic correlation and order parameter ratios\
, which provide precise and independent estimates for the couplings at whi
ch a mass gap opens in the single particle spectrum and at which the order
sets in. Furthermore these correlation ratios prove to be highly sensitiv
e to weak order and render the need of pinning fields unnecessary. In par
ticular\, we study the nature and location of the phase transition between
the semi-metal and Mott insulating antiferromagnetic state in the SU(2) H
ubbard model on the honeycomb as well as the potentially deconfined Neel t
o valence bond solid phase transition in the SU(6) Hubbard model on the sq
uare lattice.\n\n\nContact Person: Simon Trebst
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | U. Gerland
DTSTART;VALUE=DATE-TIME:20141107T163000
DTEND;VALUE=DATE-TIME:20141107T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000549@events.thp.uni-koeln.de
DESCRIPTION:U. Gerland\, TU München \n\nSpatially orchestrated enzyme kin
etics in multi-enzyme complexes\n\nTo efficiently catalyze multi-step bioc
hemical reaction pathways\, cells have\noptimized the synergistic action o
f a multitude of enzymes. They not only\ncontrol the concentrations and ac
tivities of enzymes\, but often also\ncoordinate enzymes from the same bio
chemical reaction pathway by arranging\nthem in self-assembled multi-enzym
e complexes. Such complexes are the basis\nof `channeling' mechanisms\, wh
ere intermediate products in multi-step \nreactions are effectively passed
from one enzyme to the next. These\nsame principles can be applied in art
ificial nano-scale systems\, \nwith the ultimate goal to control and optim
ize biochemical reactions \nat will\, e.g. for the production of medical s
ubstances or renewable \nenergy sources. While enzymatic activity has been
studied for over \na century\, quantitative experiments were limited to t
he bulk level \nuntil the recent advent of single-molecule enzymology tech
niques\, \nwhich permit the quantitative characterization of the stochasti
c \nreaction dynamics of enzymes. Single-molecule experiments with \nenzym
es have also spurred the theoretical analysis of stochastic \nenzyme dynam
ics\, but the theoretical description and analysis of \nenzyme complexes i
s only beginning to develop. I will describe \nsome recent progress in thi
s direction.\n\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | C. Kiefer
DTSTART;VALUE=DATE-TIME:20141114T163000
DTEND;VALUE=DATE-TIME:20141114T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000550@events.thp.uni-koeln.de
DESCRIPTION:C. Kiefer\, Institut für Theoretische Physik\, Universität z
u Köln\n\nObservations of gravitons from the early Universe?\n\nModern th
eories of cosmology assume that the Universe underwent\na period of expone
ntial expansion ("inflation") at an early stage.\nInflation does not only
solve some of the conceptual problems of\nearlier cosmological models\, bu
t also allows a causal explanation of\nstructure formation. Moreover\, it
necessarily predicts the creation\nof gravitons\, the spin-2 particles ass
ociated with the quantized\ngravitational field. In March 2014\, the south
-pole experiment\nBicep2 announced the observational confirmation of such\
nprimordial gravitons.\nIf true\, this would constitute a major step towar
ds an understanding\nof quantum gravity and the origin of our Universe.\nI
n my talk\, I shall summarize the physics that is needed to understand\nth
is result\, review the observations\, and give an outlook on future\ndevel
opments. \n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | P. Strack
DTSTART;VALUE=DATE-TIME:20141205T163000
DTEND;VALUE=DATE-TIME:20141205T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000551@events.thp.uni-koeln.de
DESCRIPTION:P. Strack\, Institut für Theoretische Physik\, Universität z
u Köln\n\nInteracting and emergent photons in quantum optics and condense
d matter\n\nRecent experimental developments in quantum optics have opened
\nup possibilities to create strongly correlated states of matter with si
zable \nelectromagnetic or photonic components. Enabled by strong atom-pho
ton \ncoupling on the single-quantum level\, for example in cavity QED and
with \nRydberg atoms\, it is now possible to study the statistical\, and
generically \nfar-from-equilibrium\, physics of photons in new regimes far
beyond \nwhat is know from the laser theory developed in the 1970's. Here
\, I will \nsurvey our first attempts to classify such phases of photonic
matter into \nuniversality classes including glasses\, superradiant Fermi
gases\, and \nattractive quantum liquids.\nIn the second part\, I will con
sider electronic materials in which \nfrustration and interactions are so
strong that\, collective excitations \nmade out of electronic spins behave
as emergent photons\, and compute \nnew observable signatures thereof.\nF
urther information: http://www.thp.uni-koeln.de/~strack/
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Byungnam Kahng
DTSTART;VALUE=DATE-TIME:20150109T163000
DTEND;VALUE=DATE-TIME:20150109T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000552@events.thp.uni-koeln.de
DESCRIPTION:Byungnam Kahng\, Seoul National University \n\nDiscontinuous p
ercolation transitions in cluster merging processes\n\nRecently interest o
f discontinuous percolation transitions (DPT) has been boosted in complex\
nsystems\, because the DPT can be found in many real-world systems such as
epidemic\nspreading and cascading failures of inter-dependent infra-struc
ture. Nevertheless\,\nmany fundamental questions remained unsolved yet. On
e of them was to invent the model\nexhibiting the DPT in cluster merging p
rocesses and to understand diverse properties arising\nin such models. In
my talk\, I will present recent theoretical research progress of the DPT i
n\nthe cluster merging processes\, which includes models\, properties of D
PTs\, and future works.
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | M. Fleischhauer
DTSTART;VALUE=DATE-TIME:20150123T163000
DTEND;VALUE=DATE-TIME:20150123T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000553@events.thp.uni-koeln.de
DESCRIPTION:M. Fleischhauer\, Kaiserslautern\n\nMany-body physics in open
systems: Rydberg gases and Rydberg polaritons\n\nQuantum optical realizati
ons of many-body systems must often be considered\nas open systems and thu
s offer a way to study quantum correlations and\nphase transitions in a no
n-equilibrium steady-state. The competition between interactions and fluct
uations inherent to an open system will be discussed for the experimentall
y relevant examples of optically driven Rydberg gases and Rydberg polarito
ns. The steady-state phase transition to crystalline order in a lattice ga
ses will be discussed as well as the dynamics of its build-up.\nIn the sec
ond part photons coupled to Rydberg atoms under conditions of electromagne
tically induced transparency will be considered. The coupling results in s
trongly interacting polaritons\, which behave like hard-sphere objects wit
h non-local interaction giving rise to a non-local nonlinear optics.\n
LOCATION:seminar room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Christopher Mudry
DTSTART;VALUE=DATE-TIME:20150116T163000
DTEND;VALUE=DATE-TIME:20150116T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000554@events.thp.uni-koeln.de
DESCRIPTION:Christopher Mudry\, Paul-Scherrer Institut\n\nAnderson localiz
ation and the topology of classifying spaces\n\nWe deduce the generic phas
e diagrams encoding the distinct\nlocalized and delocalized phases of noni
nteracting fermionic quasiparticle\nfor any symmetry class from the tenfol
d way in one\, two\, and three dimensions.\nTo this end\, we start from a
massive Dirac Hamiltonian perturbed by\na generic disorder for any dimensi
on of space and for any one of the ten\nsymmetry classes from the tenfold
way. The physics of Anderson localization\nis then encoded by a two-dimens
ional phase diagram that we deduce from\nthe topology of the space of norm
alized Dirac masses.
LOCATION:seminar room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Mihailo Cubrovic
DTSTART;VALUE=DATE-TIME:20141029T100000
DTEND;VALUE=DATE-TIME:20141029T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000555@events.thp.uni-koeln.de
DESCRIPTION:Mihailo Cubrovic\n\nt.b.a.\n\n
LOCATION:Seminar room of the Institute for Theoretical Physics
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Johannes Waizner
DTSTART;VALUE=DATE-TIME:20141008T100000
DTEND;VALUE=DATE-TIME:20141008T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000556@events.thp.uni-koeln.de
DESCRIPTION:Johannes Waizner\n\nHelimagnons and Skyrmimagnons\n\n
LOCATION:Conference room of the Institute for Theoretical Physics
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Ralf Bulla
DTSTART;VALUE=DATE-TIME:20150107T100000
DTEND;VALUE=DATE-TIME:20150107T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000557@events.thp.uni-koeln.de
DESCRIPTION:Ralf Bulla\n\nOn anharmonic impurities\, entanglement\, and mu
lti-impurity Anderson models\n\n
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Benjamin Mille
DTSTART;VALUE=DATE-TIME:20150114T100000
DTEND;VALUE=DATE-TIME:20150114T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000558@events.thp.uni-koeln.de
DESCRIPTION:Benjamin Mille\n\nt.b.a.\n\n
LOCATION:Seminar room 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Markus Garst
DTSTART;VALUE=DATE-TIME:20141015T100000
DTEND;VALUE=DATE-TIME:20141015T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000559@events.thp.uni-koeln.de
DESCRIPTION:Markus Garst\n\nInfluence of crystalline anisotropies on the m
agnetic order in MnSi\n\n
LOCATION:Seminar Room of the Institute for Theoretical Physics
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Michael Becker
DTSTART;VALUE=DATE-TIME:20141126T100000
DTEND;VALUE=DATE-TIME:20141126T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000560@events.thp.uni-koeln.de
DESCRIPTION:Michael Becker\n\nPhD Defense\n\n
LOCATION:Seminar Room of the Institute for Theoretical Physics
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Moritz Ernst
DTSTART;VALUE=DATE-TIME:20141203T100000
DTEND;VALUE=DATE-TIME:20141203T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000561@events.thp.uni-koeln.de
DESCRIPTION:Moritz Ernst\n\nPhD Defense\n\n
LOCATION:Seminar Room of the Institute for Theoretical Physics
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Sarah Schroeter
DTSTART;VALUE=DATE-TIME:20150204T100000
DTEND;VALUE=DATE-TIME:20150204T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000562@events.thp.uni-koeln.de
DESCRIPTION:Sarah Schroeter\n\nt.b.a.\n\n
LOCATION:Conference Room of the Institute for Theoretical Physics
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | John Chalker
DTSTART;VALUE=DATE-TIME:20141204T160000
DTEND;VALUE=DATE-TIME:20141204T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000563@events.thp.uni-koeln.de
DESCRIPTION:John Chalker\, Oxford University\n\nClassical loop models and
quantum phase transitions\n\nI will give an overview of recent work on the
physics of lattice models of\nclose-packed loops. The models have two pha
ses -- one in which all loops\nare finite\, and another in which some loop
s are extended -- and the\ninterest is in universal features of these phas
es and the transitions \nbetween them. The models describe a number of pro
blems in classical \nstatistical physics -- where\, for example\, the loop
s may be vortex\nlines in a three-dimensional random field -- and also man
y-body quantum\nsystems -- where the loops are world-lines of particles.\n
\n\nContact Person: Alexander Altland
LOCATION:TP Seminarraum
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Pablo Serna Martinez
DTSTART;VALUE=DATE-TIME:20141031T140000
DTEND;VALUE=DATE-TIME:20141031T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000564@events.thp.uni-koeln.de
DESCRIPTION:Pablo Serna Martinez\, Universidad de Murcia\n\nDeconfined qua
ntum criticality in a 3D classical loop model\n\nLoops arises as long leng
th description for many quantum problems\, in particular for SU(n) magnets
. An interesting scenario in this kind of problems is the so-called deconf
ined criticality\, a transition between Néel and valence bond solid phase
s in 2D quantum magnets\, where numerical studies support a continuous pha
se transition but also display strong violations of finite size scaling th
at are not yet understood. This scenario is also believed to describe the
phase transition for classical magnets where hedgehogs are suppressed. Thr
ee dimensional completely-packed loop models were shown to describe the sa
me features as quantum magnets in 2D and the phase transition between a N
éel state and a valence bond liquid. By modifying these loop models we ca
n drive them to a phase transition with the same features: a magnetic orde
red phase where there are long loops and a paramagnetic phase where a latt
ice symmetry is broken. In common with the direct studies of quantum Hamil
tonians\, we find strong violations of scaling for the SU(2) case. We desc
ribe accurately these violations and reach larger sizes than previous stud
ies\, making use of a wide range of observables. However\, we do not find
any conventional signs of a first order transition.\n\n\nContact Person: S
imon Trebst
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Ionela Vrejoiu
DTSTART;VALUE=DATE-TIME:20141119T143000
DTEND;VALUE=DATE-TIME:20141119T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000567@events.thp.uni-koeln.de
DESCRIPTION:Ionela Vrejoiu\, MPI for Solid State Research\, Stuttgart\n\nC
hallenges and driving forces for interfacing functional perovskite oxides
\n\nThe large spectrum of perovskite oxides provides virtually unlimited p
ossibilities to design and fabricate interfaces with functional properties
. The ability to produce clean and sharp interfaces between oxide material
s in a controlled manner provides appealing possibilities to generate nove
l electronic phases. Crucial steps in achieving high quality epitaxial oxi
de heterostructures have been the use of pulsed-laser deposition and molec
ular-beam epitaxy for the growth of multicomponent oxides\, the ability to
terminate oxide substrates at well-defined ionic planes\, and the develop
ment of high pressure reflection high-energy electron diffraction to monit
or the deposition of individual atomic layers. In consequence now epitaxia
l perovskite heterostructures can be fabricated with atomic-layer precisio
n. In my presentati
on I will show examples of physical properties of epitaxial oxide heterost
ructures I have fabricated by pulsed-laser deposition. The emphasis will b
e on justifying the choice of the perovskite oxides that were interfaced (
ferromagnetic manganites and ruthenates and ferroelectrics) and on the rol
e of the interfaces\, and their quality\, in establishing the physical pro
perties of these particular heterostructures. \n\nContact Person: Markus G
rüninger
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Kavita Jain
DTSTART;VALUE=DATE-TIME:20141112T170000
DTEND;VALUE=DATE-TIME:20141112T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000568@events.thp.uni-koeln.de
DESCRIPTION:Kavita Jain\, Jawaharlal Nehru Centre\, Bangalore\n\nAdaptati
on and distribution of beneficial fitness effects\n\nAlthough adaptation i
s common\, the detailed mechanism by which the adaptive process occurs is
poorly\nunderstood. I will describe our recent results on the properties o
f adaptive walk performed by a maladapted asexual population in which bene
ficial mutations fix sequentially until a local fitness peak\nis reached.
We find a simple relationship between the trends in the fitness gain durin
g successive steps\nof the adaptive walk and the extreme value domain of t
he distribution of beneficial fitness effects (DBFE). This result may be u
seful in the experimental determination of DBFE using adaptation dynamics.
\n\nContact Person: Joachim Krug
LOCATION:Institute for Genetics\, Seminar Room 0.46
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Henry Legg
DTSTART;VALUE=DATE-TIME:20150123T140000
DTEND;VALUE=DATE-TIME:20150123T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000569@events.thp.uni-koeln.de
DESCRIPTION:Henry Legg\, University of St Andrews\n\nApplications of magne
tohydrodynamics to condensed matter - A Ward identity for magnetic helicit
y\n\n\n\nContact Person: Achim Rosch
LOCATION:Seminar Room 03 - ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Stefan Meier
DTSTART;VALUE=DATE-TIME:20150121T100000
DTEND;VALUE=DATE-TIME:20150121T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000570@events.thp.uni-koeln.de
DESCRIPTION:Stefan Meier\n\nFunctional renormalization group approach to p
hases of broken symmetries and multiband models\n\nFunctional renormalizat
ion group (fRG) methods relate theories at different energy scales via an
exact flow equation for a functional of the fields. In this talk\, I will
focus on a one-particle irreducible\, purely fermionic formulation and\, i
n particular\, on its application to phases of broken symmetries and multi
band Hubbard models. First\, I will report on a recent fRG study on antife
rromagnetic ordering in a simple two-pocket model\, including a possible e
xtension to coexistence phases of antiferromagnetism and superconductivity
. The second part will be devoted to multiband systems. Particularities of
the point-group behavior of multiband Hubbard models are discussed and fR
G results are presented for a generic three-band model for the cuprate sup
erconductors. Finally\, an outlook on a potentially highly parallelizable
fRG algorithm is given\, which should be suitable for calculations with a
larger number of bands.
LOCATION:Seminar room 03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | D. Schuricht
DTSTART;VALUE=DATE-TIME:20150130T163000
DTEND;VALUE=DATE-TIME:20150130T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000571@events.thp.uni-koeln.de
DESCRIPTION:D. Schuricht\, Utrecht\n\nTime evolution and relaxation in str
ongly correlated quantum systems\n\nRecent experiments on the dynamics of
ultra-cold atomic gases have opened up completely new ways to study far-fr
om-equilibrium quantum states. These intriguing prospects triggered tremen
dous experimental and theoretical developments and have led to an extremel
y active research field. In particular\, strongly correlated quantum syste
ms have been at the forefront of theoretical research since they show non-
trivial many-body effects. I will give a brief overview over these develop
ments with an emphasis on the dynamics of one-dimensional systems\, where
the dynamics may be restricted by the existence of non-trivial integrals o
f motion linking it to the field of integrable systems. I will then presen
t results on the universality of the time evolution in both massive and ma
ssless systems and discuss the effects of finite quench times.
LOCATION:seminar room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Philipp Strack
DTSTART;VALUE=DATE-TIME:20141205T120000
DTEND;VALUE=DATE-TIME:20141205T124500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000576@events.thp.uni-koeln.de
DESCRIPTION:Philipp Strack\, Institut für Theoretische Physik\, Universit
ät zu Köln\n\nStrongly correlated systems at the interface of quantum op
tics and condensed matter\n\nThis talk is one of a series of presentations
of research groups organized by the Bonn-Cologne Graduate School of Physi
cs and Astronomy. The aim is to provide insights into the research done at
physics institutes in Cologne. Interested students (Bachelor\, Master\, a
nd PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Ivan Bihuega
DTSTART;VALUE=DATE-TIME:20141210T143000
DTEND;VALUE=DATE-TIME:20141210T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000573@events.thp.uni-koeln.de
DESCRIPTION:Ivan Bihuega\, Universidad Autonoma de Madrid\n\nVisualizing a
nd manipulating graphene physics at the atomic scale\n\nIn 2004 graphene c
eased being a theoretical chimera to become the object of desire of the sc
ientific community. In just few years\, extraordinary properties have bein
g demonstrated and many others are emerging as a result of the tremendous
experimental and theoretical efforts devoted to this material. In this tal
k I will show how we use a scanning tunneling microscope to explore and ma
nipulate graphene physics at an atomic level. I will mainly concentrate in
two topics:\n-The investigation\, at the atomic scale\, of the impact tha
t point defects like vacancies or atomic H have in the structural\, electr
onic and magnetic properties of graphene layers grown on different substra
tes\, where the pure bidimensionality of graphene gives to these atomic de
fects a critical role.\n-The study of the coupling of graphene with its lo
cal environment and how this affects to graphene’s quasiparticle dispers
ion\, pseudospin\, van Hove singularities...\, which is absolutely critica
l to be able to integrate it in tomorrow's electronic devices. \n\n\nConta
ct Person: Thomas Michely
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Wolf Wuester
DTSTART;VALUE=DATE-TIME:20141205T140000
DTEND;VALUE=DATE-TIME:20141205T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000574@events.thp.uni-koeln.de
DESCRIPTION:Wolf Wuester\, ETH Zuerich\n\nCavity quantum electrodynamics w
ith many-body states of a two-dimensional electron gas\n\nLight-matter int
eraction has played a central role in understanding as well as engineering
new states of matter. Reversible coupling of excitons and photons enabled
groundbreaking results in condensation and superfluidity of nonequilibriu
m quasiparticles with a photonic component. We investigated such cavity-po
laritons in the presence of a high-mobility two-dimensional electron gas\,
exhibiting strongly correlated phases. When the cavity was on resonance w
ith the Fermi level\, we observed previously unknown many-body physics ass
ociated with a dynamical hole-scattering potential. In finite magnetic fie
lds\, polaritons show distinct signatures of integer and fractional quantu
m Hall ground states. Our results lay the groundwork for probing nonequili
brium dynamics of quantum Hall states and exploiting the electron density
dependence of polariton splitting so as to obtain ultrastrong optical nonl
inearities.\n\nContact Person: Philipp Strack
LOCATION:Seminar Room 03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Andreas Zilges
DTSTART;VALUE=DATE-TIME:20141128T120000
DTEND;VALUE=DATE-TIME:20141128T124500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000575@events.thp.uni-koeln.de
DESCRIPTION:Andreas Zilges\, Institut für Kernphysik\, Universität zu K
öln\n\nFrom Giants\, Pygmies and Cauldrons in the Cosmos: Nuclear Structu
re and Nuclear Astrophysics\n\nThis talk is one of a series of presentatio
ns of research groups organized by the Bonn-Cologne Graduate School of Phy
sics and Astronomy. The aim is to provide insights into the research done
at physics institutes in Cologne. Interested students (Bachelor\, Master\,
and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Lucas Labadie
DTSTART;VALUE=DATE-TIME:20141212T120000
DTEND;VALUE=DATE-TIME:20141212T124500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000577@events.thp.uni-koeln.de
DESCRIPTION:Lucas Labadie\, I. Physikalisches Institut\, Universität zu K
öln\n\nHigh-angular resolution in astrophysics: a microscope for the Univ
erse \n\nThis talk is one of a series of presentations of research groups
organized by the Bonn-Cologne Graduate School of Physics and Astronomy. Th
e aim is to provide insights into the research done at physics institutes
in Cologne. Interested students (Bachelor\, Master\, and PhD) are most wel
come.\n
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Jakub Otwinowski
DTSTART;VALUE=DATE-TIME:20141125T120000
DTEND;VALUE=DATE-TIME:20141125T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000578@events.thp.uni-koeln.de
DESCRIPTION:Jakub Otwinowski\, University of Pennsylvania\n\nEpistatic and
non epistatic models\, and how to tell the difference\n\n\n\nContact Pers
on: Joachim Krug
LOCATION:ITP conference room
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Georgii Bazykin
DTSTART;VALUE=DATE-TIME:20141203T170000
DTEND;VALUE=DATE-TIME:20141203T175500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000579@events.thp.uni-koeln.de
DESCRIPTION:Georgii Bazykin\, IKharkevitch Institute Moscow \n\nThe role o
f epistasis in evolution of influenza A\n\n
LOCATION:Institute for Genetics\, Zülpicher Str. 47a\, Seminar Room 0.46\
, Ground Floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Mara Villa
DTSTART;VALUE=DATE-TIME:20141203T180000
DTEND;VALUE=DATE-TIME:20141203T185500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000580@events.thp.uni-koeln.de
DESCRIPTION:Mara Villa\, University of Cologne\n\nDetection of reassortmen
t in the evolution of influenza virus\n\n
LOCATION:Institute for Genetics\, Zülpicher Str. 47a\, Seminar Room 0.46\
, Ground Floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | William Harvey & Richard Reeve
DTSTART;VALUE=DATE-TIME:20141204T090000
DTEND;VALUE=DATE-TIME:20141204T095500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000581@events.thp.uni-koeln.de
DESCRIPTION:William Harvey & Richard Reeve\, Glasgow University\n\nIdentif
ying genetic determinants of antigenic differences among RNA viruses\n\n
LOCATION:Institute for Theoretical Physics (New Building)\, Zülpicher Str
. 77a\, Seminar Room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Simone Pompei
DTSTART;VALUE=DATE-TIME:20141204T100000
DTEND;VALUE=DATE-TIME:20141204T105500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000582@events.thp.uni-koeln.de
DESCRIPTION:Simone Pompei\, University of Cologne\n\nAnalysis of epistasis
in the haemagglutinin protein of human influenza\n\n
LOCATION:Institute for Theoretical Physics (New Building)\, Zülpicher Str
. 77a\, Seminar Room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Marta Luksza
DTSTART;VALUE=DATE-TIME:20141104T104500
DTEND;VALUE=DATE-TIME:20141104T114000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000583@events.thp.uni-koeln.de
DESCRIPTION:Marta Luksza\, IAS Princeton\n\nEpidemiological and evolutiona
ry analysis of the 2014 Ebola virus outbreak\n\n
LOCATION:Epidemiological and evolutionary analysis of the 2014 Ebola virus
outbreak
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Marta Luksza
DTSTART;VALUE=DATE-TIME:20141204T104500
DTEND;VALUE=DATE-TIME:20141204T114000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000584@events.thp.uni-koeln.de
DESCRIPTION:Marta Luksza\, IAS Princeton\n\nEpidemiological and evolutiona
ry analysis of the 2014 Ebola virus outbreak\n\n
LOCATION:Institute for Theoretical Physics (New Building)\, Zülpicher Str
. 77a\, Seminar Room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Alexander Grüneis
DTSTART;VALUE=DATE-TIME:20150109T120000
DTEND;VALUE=DATE-TIME:20150109T124500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000585@events.thp.uni-koeln.de
DESCRIPTION:Alexander Grüneis\, II. Physikalisches Institut\, Universitä
t zu Köln\n\nSpectroscopy of low-dimensional quantum materials\n\nThis ta
lk is one of a series of presentations of research groups organized by the
Bonn-Cologne Graduate School of Physics and Astronomy. The aim is to prov
ide insights into the research done at physics institutes in Cologne. Inte
rested students (Bachelor\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Thomas Lorenz
DTSTART;VALUE=DATE-TIME:20150116T120000
DTEND;VALUE=DATE-TIME:20150116T124500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000586@events.thp.uni-koeln.de
DESCRIPTION:Thomas Lorenz\, II. Physikalisches Institut\, Universität zu
Köln\n\nQuantum spin systems: crystal growth\, thermodynamics and transpo
rt properties\n\nThis talk is one of a series of presentations of research
groups organized by the Bonn-Cologne Graduate School of Physics and Astro
nomy. The aim is to provide insights into the research done at physics ins
titutes in Cologne. Interested students (Bachelor\, Master\, and PhD) are
most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Su-Chan Park
DTSTART;VALUE=DATE-TIME:20150206T163000
DTEND;VALUE=DATE-TIME:20150206T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000587@events.thp.uni-koeln.de
DESCRIPTION:Su-Chan Park\, Catholic University of Korea \n\nWell-understoo
d and ill-understood universality classes of absorbing state phase transit
ions\n\nIn this talk\, various universality classes found in absorbing pha
se transitions will be reviewed. Starting from the contact process\, the d
irected percolation (DP) universality class and a possible classification
scheme known as the DP conjecture will be discussed. The DP conjecture sta
tes that a model system without nontrivial symmetry and/or conservation la
ws and with a single order parameter field should belong to the DP class.
Other universality classes have been found by breaking some of the requis
ites of the DP conjecture\, which will be briefly discussed. Particular fo
cus of this talk will be on a controversy around the universality class t
o which the pair contact process with diffusion (PCPD) should belong. Two
conflicting viewpoints and their supporting arguments will be reviewed.
Endeavors to settle down this\ncontroversy will be discussed.\n
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | David Luitz
DTSTART;VALUE=DATE-TIME:20150703T130000
DTEND;VALUE=DATE-TIME:20150703T143000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000654@events.thp.uni-koeln.de
DESCRIPTION:David Luitz\, Toulouse\n\nMany body localization in the random
field Heisenberg chain\n\n In this talk\, I will give an introduction to
the phenomenon of many body localization and its differences from single p
article Anderson\nlocalization. Then\, I discuss our recent exact diagonal
ization results of the many body localization (MBL) transition in the rand
om field Heisenberg chain and present in particular the energy vs\ndisorde
r strength phase diagram that was obtained from various estimators. The ph
ase boundary is strongly energy dependent\, thus providing evidence for an
extensive mobility edge. At low disorder strength\, eigentstates are ergo
dic and can be described by GOE statistics\, while in the strong field pha
se\, they are localized and show Poisson statistics. In the MBL phase\, th
e eigenstate\nthermalization hypothesis is no longer fulfilled.\n\nIf time
permits\, I will provide an outlook on our current work\, where we\nlook
at the exact time evolution of initial product states.\n\nReference:\nLuit
z\, D. J.\, Laflorencie\, N. & Alet\, F.\nMany-body localization edge in t
he random-field Heisenberg chain.\nPhys. Rev. B 91\, 081103 (2015).\n\nCon
tact Person: Simon Trebst
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Lei Wang
DTSTART;VALUE=DATE-TIME:20150424T140000
DTEND;VALUE=DATE-TIME:20150424T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000655@events.thp.uni-koeln.de
DESCRIPTION:Lei Wang\, ETH Zurich\n\nRecent Surprises in the Simulation of
Quantum Phase Transitions\n\nI will talk about two recent surprises in th
e quantum Monte Carlo (QMC) simulation of quantum phase transitions. \n\nS
urprise one is the solution of a thirty years old sign problem by Huffman
and Chandrasekharan. It enables us to study the fermionic quantum critical
point of spinless Dirac fermions using unbiased continuous-time QMC simul
ations. Compatible results are also obtained from infinite projected entan
gled-pair states calculations. I will compare the numerical results with p
redictions of the Gross-Neveu theory and discuss their physical implicatio
ns. \n\nSurprise two is a generic\, efficient and elegant approach to comp
ute fidelity susceptibility of correlated fermions\, bosons\, and quantum
spin systems in modern QMC methods. It can be used to detect quantum phase
transitions without any prior knowledge of the local order parameter. Usi
ng it I will shed light on the hypothetical spin-liquid phase in the Hubba
rd model on honeycomb lattice. \n\n\nContact Person: Simon Trebst
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nSpectral triples: examples and index th
eory\nAlan Carey\, John Phillips and Adam Rennie
DTSTART;VALUE=DATE-TIME:20150226T101500
DTEND;VALUE=DATE-TIME:20150226T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000592@events.thp.uni-koeln.de
DESCRIPTION:Alan Carey\, John Phillips and Adam Rennie\n\nSpectral triples
: examples and index theory\n\nWe discuss an extract of the paper "Spectra
l triples: examples and index theory" by Alan Carey\, John Phillips and Ad
am Rennie. Please get in contact with Thomas Quella in order to find out t
he precise content of the seminar. Modus operandi: The dice will determine
who will lead the discussion\, so every seminar participant is kindly ask
ed to prepare the papers in advance.\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Physik I
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Jochen Peschutter
DTSTART;VALUE=DATE-TIME:20150305T101500
DTEND;VALUE=DATE-TIME:20150305T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000593@events.thp.uni-koeln.de
DESCRIPTION:Jochen Peschutter\, University of Cologne\n\nQuantum spin Hami
ltonians from gl(M+N|M) WZW models and their ground state wave functions\n
\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Physik II
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Semyon Klevtsov
DTSTART;VALUE=DATE-TIME:20150312T101500
DTEND;VALUE=DATE-TIME:20150312T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000594@events.thp.uni-koeln.de
DESCRIPTION:Semyon Klevtsov\n\nQuantum Hall effect on Riemann surfaces: ef
fective action and kinetic coefficients\n\n\n\nContact Person: Thomas Quel
la
LOCATION:Seminarraum Physik II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Jean-Sebastien Bernier
DTSTART;VALUE=DATE-TIME:20150923T100000
DTEND;VALUE=DATE-TIME:20150923T110000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000707@events.thp.uni-koeln.de
DESCRIPTION:Jean-Sebastien Bernier\, University of Bonn\n\nGeneration and
propagation of correlations in non-equilibrium quantum many-body systems\n
\n\n\nContact Person: Simon Trebst
LOCATION:ETP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Eric Lutz
DTSTART;VALUE=DATE-TIME:20150612T163000
DTEND;VALUE=DATE-TIME:20150612T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000644@events.thp.uni-koeln.de
DESCRIPTION:Eric Lutz\, University of Erlangen-Nürnberg\n\nThe physics of
information: from Maxwell's demon to Landauer\n\nWe will discuss the inti
mate connection existing between information theory and thermodynamics fol
lowing its historical development. We will focus on two complementary aspe
cts: 1) the gain of information which we will illustrate with Maxwell's fa
mous demon and 2) the erasure of information summarized by Landauer's prin
ciple. We will further present a number of recent single-particle experime
nts that have for the first time realized the above gedanken experiments i
n the lab.\n\n\nContact Person: Johannes Berg
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Stephanie Matern
DTSTART;VALUE=DATE-TIME:20150408T100000
DTEND;VALUE=DATE-TIME:20150408T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000663@events.thp.uni-koeln.de
DESCRIPTION:Stephanie Matern\n\nMagnetism of a spin-orbit entangled j=1/2
Mott insulator on the fcc lattice\n\n
LOCATION:Seminar Room 0.01\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Dan I. Andersson
DTSTART;VALUE=DATE-TIME:20150408T170000
DTEND;VALUE=DATE-TIME:20150408T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000665@events.thp.uni-koeln.de
DESCRIPTION:Dan I. Andersson\, Uppsala University\n\nEvolution of antibiot
ic resistance at very low levels of antibiotic\n\nAntibiotic use results i
n generation of antibiotic concentration gradients and bacteria are often
exposed to non-lethal (sub-MIC) drug concentrations. Recent evidence sugge
sts that sub-MIC antibiotic exposure has an important role in the evolutio
n resistance by (i) directly selecting for resistance and (ii) generating
genetic and phenotypic variability that increases rates of resistance evol
ution. Importantly\, resistant mutants that appear in response to weak sel
ection pressures are more problematic than those selected under lethal ant
ibiotic concentrations due to the enrichment of mutators and high fitness
mutants. Together these findings suggest that sub-MIC exposure may acceler
ate the emergence and spread of antibiotic-resistant bacteria among humans
and animals.\n\nContact Person: Christa Stitz
LOCATION:Institute for Genetics\, Zülpicher Str. 47a\, New Seminar Room 0
.46\, ground floor
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Emilio Torres
DTSTART;VALUE=DATE-TIME:20150326T101500
DTEND;VALUE=DATE-TIME:20150326T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000596@events.thp.uni-koeln.de
DESCRIPTION:Emilio Torres\, University of Cologne\n\nStochastic Quantizati
on for Numerical Applications\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Roland Wiesendanger
DTSTART;VALUE=DATE-TIME:20150414T164500
DTEND;VALUE=DATE-TIME:20150414T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000641@events.thp.uni-koeln.de
DESCRIPTION:Roland Wiesendanger\, Universität Hamburg\n\nUltradichte magn
etische Datenspeicher und energieeffiziente Spin-Logik-Bauelemente auf a
tomarer Skala: Neueste Beiträge aus der Grundlagenforschung\n\nMagnetis
che Datenspeicher und Logikelemente auf atomarer Skala: was\nheute noch Vi
sion ist\, könnte eines Tages Wirklichkeit werden. Neue Methoden der atom
ar auflösenden Mikroskopie erlauben den direkten Zugang\nzu magnetischen
Strukturen und dynamischen Prozessen auf atomarer\nSkala. Dabei werden nic
ht nur neue magnetische Zustände entdeckt\, sondern auch die fundamentale
n magnetischen Wechselwirkungen zwischen\neinzelnen magnetischen Atomen er
forscht. Mit Hilfe der gezielten Manipulation einzelner magnetischer Atome
und Nanostrukturen auf Oberflächen lassen sich bereits heute funktionale
Bauelemente maßschneidern. Dies könnte die Informations- und Kommunikat
ionstechnologie in gleicher Weise revolutionieren\, wie wir dies in den ve
rgangenen dreißig Jahren erlebt haben.\n\n\n
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nAspects of Renormalization\nA. Zee
DTSTART;VALUE=DATE-TIME:20150402T101500
DTEND;VALUE=DATE-TIME:20150402T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000597@events.thp.uni-koeln.de
DESCRIPTION:A. Zee\n\nAspects of Renormalization\n\nWe discuss extracts fr
om Zee's book "Quantum Field Theory in a Nutshell". Modus operandi: The di
ce will determine who will lead the discussion\, so every seminar particip
ant is kindly asked to prepare the paper in advance.\n\nContact Person: Th
omas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Poulami Ganguly
DTSTART;VALUE=DATE-TIME:20150408T101500
DTEND;VALUE=DATE-TIME:20150408T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000598@events.thp.uni-koeln.de
DESCRIPTION:Poulami Ganguly\, University of Cologne\n\nTopological Boundar
y Modes and Solitons in Isostatic Lattices\n\n\n\nContact Person: Thomas Q
uella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Charles Guggenheim
DTSTART;VALUE=DATE-TIME:20150422T101500
DTEND;VALUE=DATE-TIME:20150422T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000600@events.thp.uni-koeln.de
DESCRIPTION:Charles Guggenheim\, University of Cologne\n\nAnomalous topolo
gical pumps in the Josephson effect\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nSymmetric functions and random partitio
ns\nA. Okounkov
DTSTART;VALUE=DATE-TIME:20150429T101500
DTEND;VALUE=DATE-TIME:20150429T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000601@events.thp.uni-koeln.de
DESCRIPTION:A. Okounkov\n\nSymmetric functions and random partitions\n\nWe
discuss the paper "Symmetric functions and random partitions" by A. Okoun
kov. Modus operandi: The dice will determine who will lead the discussion\
, so every seminar participant is kindly asked to prepare the paper in adv
ance.\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Jan Gelhausen
DTSTART;VALUE=DATE-TIME:20150429T100000
DTEND;VALUE=DATE-TIME:20150429T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000662@events.thp.uni-koeln.de
DESCRIPTION:Jan Gelhausen\n\nOpen Quantum Magnets with interacting Rydberg
Atoms in a Cavity\n\n
LOCATION:Seminar Room 0.01\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Emilio Torres
DTSTART;VALUE=DATE-TIME:20150506T101500
DTEND;VALUE=DATE-TIME:20150506T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000602@events.thp.uni-koeln.de
DESCRIPTION:Emilio Torres\, University of Cologne\n\nNon-Commutative Geome
try for Disordered Topological Insulators\n\n\n\nContact Person: Thomas Qu
ella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Holger Gies
DTSTART;VALUE=DATE-TIME:20150710T163000
DTEND;VALUE=DATE-TIME:20150710T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000683@events.thp.uni-koeln.de
DESCRIPTION:Holger Gies\, Jena\n\nPhysics of the quantum vacuum\n\nModern
physics describes matter and their interactions on the fundamental level a
s quantum fields. Already their ground state - the quantum vacuum - exhibi
ts properties analogous to complex media: fluctuations of quantum fields c
an induce nonlocal and nonlinear phenomena.\nThis talk gives an overview o
n present experiments using strong fields for probing the quantum vacuum.
Illustrative theory methods will be discussed that help to understand quan
tum fluctuations and quantum vacua intuitively. Recent ideas will be highl
ighted that aim at searches for "New Physics" with strong fields.\n\nConta
ct Person: Philipp Strack
LOCATION:seminar room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nThe non-commutative geometry of the com
plex classes of topological insulators\nEmil Prodan
DTSTART;VALUE=DATE-TIME:20150520T101500
DTEND;VALUE=DATE-TIME:20150520T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000604@events.thp.uni-koeln.de
DESCRIPTION:Emil Prodan\n\nThe non-commutative geometry of the complex cla
sses of topological insulators\n\nWe discuss the paper "The non-commutativ
e geometry of the complex classes of topological insulators" by Emil Proda
n. Modus operandi: The dice will determine who will lead the discussion\,
so every seminar participant is kindly asked to prepare the paper in advan
ce.\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Michael Ehrig
DTSTART;VALUE=DATE-TIME:20150527T101500
DTEND;VALUE=DATE-TIME:20150527T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000605@events.thp.uni-koeln.de
DESCRIPTION:Michael Ehrig\, Universität zu Köln\n\nGraded Brauer algebra
s\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nThe Free Will Theorem\nJohn Conway\, Si
mon Kochen
DTSTART;VALUE=DATE-TIME:20150603T101500
DTEND;VALUE=DATE-TIME:20150603T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000606@events.thp.uni-koeln.de
DESCRIPTION:John Conway\, Simon Kochen\n\nThe Free Will Theorem\n\nWe disc
uss the paper "The Free Will Theorem" by John Conway and Simon Kochen. Mod
us operandi: The dice will determine who will lead the discussion\, so eve
ry seminar participant is kindly asked to prepare the paper in advance.\n\
nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Emilio Torres
DTSTART;VALUE=DATE-TIME:20150610T101500
DTEND;VALUE=DATE-TIME:20150610T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000607@events.thp.uni-koeln.de
DESCRIPTION:Emilio Torres\n\nNon-Commutative Geometry for Disordered Topol
ogical Insulators\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nThe Noncommutative Geometry of the Quan
tum Hall Effect\nBellissard\, van Elst\, Schulz-Baldes
DTSTART;VALUE=DATE-TIME:20150617T101500
DTEND;VALUE=DATE-TIME:20150617T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000608@events.thp.uni-koeln.de
DESCRIPTION:Bellissard\, van Elst\, Schulz-Baldes\n\nThe Noncommutative Ge
ometry of the Quantum Hall Effect\n\nWe discuss chapter 4 of the paper "Th
e Noncommutative Geometry of the Quantum Hall Effect" by Bellissard\, van
Elst\, and Schulz-Baldes. Modus operandi: The dice will determine who will
lead the discussion\, so every seminar participant is kindly asked to pre
pare the paper in advance.\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Josua Groeger
DTSTART;VALUE=DATE-TIME:20150624T101500
DTEND;VALUE=DATE-TIME:20150624T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000609@events.thp.uni-koeln.de
DESCRIPTION:Josua Groeger\, University of Cologne\n\nThe two-fold way of s
uper holonomy\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Xenophon Zotos
DTSTART;VALUE=DATE-TIME:20150624T143000
DTEND;VALUE=DATE-TIME:20150624T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000700@events.thp.uni-koeln.de
DESCRIPTION:Xenophon Zotos\, University of Crete\n\nMagnetothermal transpo
rt in 1D quantum magnets\n\nI’ll present recent exact results on the fin
ite temperature and magnetic field transport in the one dimensional spin-1
/2 Heisenberg model obtained by the Bethe ansatz (BA) method.\nFurthermore
\, I’ll discuss the thermodynamics\, thermal transport and ESR of the sp
in S=1 easy-plane quasi-one dimensional quantum magnet NiCl2-4SC(NH2)2 (DT
N) \nas well as induced magnetisation by light.\n\nContact Person: Thomas
Lorenz
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nUndecidability of the Spectral Gap\nCub
itt\, Perez-Garcia and Wolf
DTSTART;VALUE=DATE-TIME:20150701T101500
DTEND;VALUE=DATE-TIME:20150701T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000610@events.thp.uni-koeln.de
DESCRIPTION:Cubitt\, Perez-Garcia and Wolf\n\nUndecidability of the Spectr
al Gap\n\nWe discuss the paper "Undecidability of the Spectral Gap" by Cub
itt\, Perez-Garcia and Wolf. Modus operandi: The dice will determine who w
ill lead the discussion\, so every seminar participant is kindly asked to
prepare the paper in advance.\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Martin Zirnbauer
DTSTART;VALUE=DATE-TIME:20150708T101500
DTEND;VALUE=DATE-TIME:20150708T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000611@events.thp.uni-koeln.de
DESCRIPTION:Martin Zirnbauer\n\nMore on the IQHE plateau transition\n\n\n\
nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Patrick Neven
DTSTART;VALUE=DATE-TIME:20150619T140000
DTEND;VALUE=DATE-TIME:20150619T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000699@events.thp.uni-koeln.de
DESCRIPTION:Patrick Neven\n\nPhD defense\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nT-Duality of Topological Insulators\nV.
Mathai and G.C. Thiang
DTSTART;VALUE=DATE-TIME:20150715T101500
DTEND;VALUE=DATE-TIME:20150715T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000612@events.thp.uni-koeln.de
DESCRIPTION:V. Mathai and G.C. Thiang\n\nT-Duality of Topological Insulato
rs\n\nWe discuss the paper "T-Duality of Topological Insulators" by V. Mat
hai and G.C. Thiang. Modus operandi: The dice will determine who will lead
the discussion\, so every seminar participant is kindly asked to prepare
the paper in advance.\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Tim Eschmann
DTSTART;VALUE=DATE-TIME:20150128T100000
DTEND;VALUE=DATE-TIME:20150128T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000613@events.thp.uni-koeln.de
DESCRIPTION:Tim Eschmann\n\nBachelor Colloquium\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Arkady V. Krasheninnikov
DTSTART;VALUE=DATE-TIME:20150113T140000
DTEND;VALUE=DATE-TIME:20150113T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000614@events.thp.uni-koeln.de
DESCRIPTION:Arkady V. Krasheninnikov\, Aalto University\, Finland \n\nLect
ure on 2D Transition-Metal Dichalcogenides: Doping\, Alloying and Electron
ic Structure Engineering \n\nFollowing isolation of a single sheet of grap
hene\, many other 2D systems were manufactured. Among them\, single transi
tion metal dichalcogenides (TMD) sheets have received a particular attenti
on\, as these materials exhibit intriguing electronic\, optical and mechan
ical properties which can be controlled by varying material composition. M
oreover\, the properties can further be tuned by introduction of defects a
nd impurities. \nIn this lecture\, after a brief introduction to the struc
ture and properties of TMDs\, I will present the results of our ﬁrst-pri
nciples theoretical studies of the morphology\, electronic and optical pro
perties of 2D TMDs obtained in collaboration with several experimental gro
ups. I will further discuss how defects and impurities can be used to tune
the characteristics of 2D TMDs. I will also touch upon the stability and
electronic characteristics of mixed TMDs\, such as MoS2xSe2(1−x)\, which
can be referred to as 2D random alloys. We demonstrated that 2D mixed ter
nary MoS2/MoSe2/MoTe2 compounds are thermodynamically stable at room tempe
rature\, and that the gap in such systems is direct and can continuously b
e tuned\, as confirmed now by the experiments carried out by several group
s. \n\n\nContact Person: Thomas Michely
LOCATION:Seminar room 03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Zala Lenarcic
DTSTART;VALUE=DATE-TIME:20150116T140000
DTEND;VALUE=DATE-TIME:20150116T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000615@events.thp.uni-koeln.de
DESCRIPTION:Zala Lenarcic\n\nNonequilibrium properties of Mott insulators\
n\n\n\nContact Person: Achim Rosch
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Maria Hermanns
DTSTART;VALUE=DATE-TIME:20150116T124500
DTEND;VALUE=DATE-TIME:20150116T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000616@events.thp.uni-koeln.de
DESCRIPTION:Maria Hermanns\, Institut für Theoretische Physik\, Universit
ät zu Köln\n\nTopological order in strongly correlated quantum systems\
n\nThis talk is one of a series of presentations of research groups organi
zed by the Bonn-Cologne Graduate School of Physics and Astronomy. The aim
is to provide insights into the research done at physics institutes in Col
ogne. Interested students (Bachelor\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Stefanie Walch
DTSTART;VALUE=DATE-TIME:20150130T120000
DTEND;VALUE=DATE-TIME:20150130T124500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000617@events.thp.uni-koeln.de
DESCRIPTION:Stefanie Walch\, I. Physikalisches Institut\, Universität zu
Köln\n\nAstrophysics with computer simulations\n\nThis talk is one of a s
eries of presentations of research groups organized by the Bonn-Cologne Gr
aduate School of Physics and Astronomy. The aim is to provide insights int
o the research done at physics institutes in Cologne. Interested students
(Bachelor\, Master\, and PhD) are most welcome.
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Christian Schüßler-Langheine
DTSTART;VALUE=DATE-TIME:20150218T143000
DTEND;VALUE=DATE-TIME:20150218T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000618@events.thp.uni-koeln.de
DESCRIPTION:Christian Schüßler-Langheine\, Helmholtz Zentrum Berlin\n\nT
owards functionality - dynamics studies of complex materials\n\nFunctional
ity in materials bases not only on the possibility to affect their propert
ies with external stimuli\, but also on the time and length scales such sw
itching occurs on. Time-resolved experimental techniques explore switching
behavior directly and furthermore provide access to coupling mechanisms b
etween different electronic and structural degrees of freedom. In the fiel
d of magnetic dynamics\, the laser-induced suppression of helical spin ord
er in heavy lanthanide metals reveals a new and very efficient angular-mom
entum transfer channel. For the antiferromagnetic semiconductor EuTe we st
udied the interplay between magnetic and structural dynamics. For the phot
on-pulse-induced Verwey transition in magnetite\, we could further narrow
down the time scale on which orbital order decays as well as gain further
insight into the character of the low-temperature phase. \n\nContact Perso
n: Thomas Koethe
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Satoru Nakatsuji
DTSTART;VALUE=DATE-TIME:20150206T140000
DTEND;VALUE=DATE-TIME:20150206T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000619@events.thp.uni-koeln.de
DESCRIPTION:Satoru Nakatsuji\, ISSP Tokyo\n\nEmergent quantum excitations
in spin ice through coupling with electrons\n\nOne of the highlights in th
e study of geometrically frustrated magnets is the emergence of nontrivial
excitations in spin liquid states\, in particular through the interplay b
etween different degrees of freedom\, e.g. between spins and mobile electr
ons.\nSuch interesting phenomena have been found in Pr$_2$Ir$_2$O$_7$\, a
metallic spin ice with two electronic sectors. One is Pr based spin ice\,
where strong quantum effects are expected for ferromagnetic exchange coupl
ing and many similarities are found to the quantum spin ice candidate Pr$_
2$Zr$_2$O$_7$. Another sector is the 5$d$ conduction electrons for which n
ovel topological phases have been predicted based on the semimetallic half
-filled $J_{¥rm eff} = 1/2$ band due to strong spin-orbit coupling. We wi
ll discuss our observations of chiral spin liquid and quantum criticality
in Pr$_2$Ir$_2$O$_7$ and topological effects due to semimetallic electroni
c structure. \n\n\nContact Person: Simon Trebst
LOCATION:Seminarraum Theorie (Neubau)
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Stephan Mandt
DTSTART;VALUE=DATE-TIME:20150211T100000
DTEND;VALUE=DATE-TIME:20150211T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000620@events.thp.uni-koeln.de
DESCRIPTION:Stephan Mandt\, Columbia University\n\nLarge scale probabilist
ic modeling and machine learning\n\nModern data analysis requires computat
ions on massive data. For example\, consider the problem of\nautomatically
classifying articles in a huge digital archive containing millions of ent
ries\, or recommending\nitems to millions of users based on their purchase
history. Bayesian probabilistic modeling allows us to\nmake assumptions a
bout hidden structure in the data that is not directly observable. In Baye
sian inference\,\nwe fit a probability distribution that reveals this stru
cture.\n\nBayesian inference has been inspired by theoretical physics over
many years\, a prominent example\nbeing Markov Chain Monte Carlo algorith
ms.\nIn a more recent approach called variational inference\, Bayesian inf
erence is mapped to an optimization problem. Here\, we fit a parametrized\
n'mean field' distribution by optimizing over variational parameters in a
way to maximize the statistical evidence of the data.\nThis method scales
up to massive data sets when using stochastic optimization\, termed stocha
stic\nvariational inference (SVI).\n\nSVI uses easy-to-compute noisy gradi
ents by subsampling from the large underlying data set.\nIt suffers from t
wo major problems: noisy gradients and non-convexity. We introduce a schem
e\nthat reduces the noise by averaging over parts of the past gradients.\n
This introduces a bias\, and we discuss the tradeoff between variance and
bias. To enable convergence to better local optima\,\nwe introduce determi
nistic annealing for SVI. We introduce a temperature parameter that determ
inistically\ndeforms the objective\, and then reduce this parameter over t
he course of the optimization. We test both\nmethods on Latent Dirichlet A
llocation\, a topic model\, applied to three large text corpora.\n\n\nCont
act Person: Achim Rosch
LOCATION:Seminar room 0.01\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:DIS | Chau Nguyen
DTSTART;VALUE=DATE-TIME:20150116T140000
DTEND;VALUE=DATE-TIME:20150116T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000624@events.thp.uni-koeln.de
DESCRIPTION:Chau Nguyen\n\nMaximum entropy models in the analysis of genom
e-wide data in cancer research\n\nWe show that various models in statistic
al modelling can be derived from the maximum entropy principle. As a parti
cular example\, we discuss the Ising model in the context of the inverse I
sing problem. Applications of maximum entropy models in disentangling dire
ct interaction from indirect correlation in cancer data will be introduced
. Another application of maximum entropy models in semi-supervised cancer
classification will also be discussed.
LOCATION:Seminarraum 3 ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Claudia Bank
DTSTART;VALUE=DATE-TIME:20150107T170000
DTEND;VALUE=DATE-TIME:20150107T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000621@events.thp.uni-koeln.de
DESCRIPTION:Claudia Bank\, EPFL Lausanne\n\nIntragenic epistasis and shift
ing fitness landscapes\n\nOne of the most controversial questions in evolu
tionary biology is the role of\nadaptation in molecular evolution. After d
ecades of debate between\nselectionists and neutralists\, new high-through
put methods are beginning to\nilluminate the full distribution of fitness
effects (DFE) of new mutations. Here\,\nwe shed light on the adaptive pote
ntial in Saccharomyces cerevisiae by\npresenting systematic high-through
put fitness measurements for hundreds of\nengineered mutations in a region
of the heat-shock protein Hsp90. We obtain\ndata sets that allow for the
evaluation of fitness consequences of the same\nmutations in different env
ironments\, and on different genetic backgrounds.\nWe demonstrate that the
change in the DFE upon environmental challenges is\nlargely consistent wi
th expectations derived from Fisher’s geometric model.\nFurthermore\, we
observe intragenic epistasis to be ubiquitous\, which\nsuggests a concave
shape of the underlying local fitness landscape.\n
LOCATION:Institute for Genetics\, Seminar Room 0.46
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Julien Berestycki
DTSTART;VALUE=DATE-TIME:20150112T160000
DTEND;VALUE=DATE-TIME:20150112T183000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000622@events.thp.uni-koeln.de
DESCRIPTION:Julien Berestycki\, Oxford University\n\nAccessibility percola
tion on the hypercube\n\n
LOCATION:Biocenter\, ground floor lecture hall
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Yukitoshi Motome
DTSTART;VALUE=DATE-TIME:20150520T143000
DTEND;VALUE=DATE-TIME:20150520T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000623@events.thp.uni-koeln.de
DESCRIPTION:Yukitoshi Motome\, University of Tokyo\n\nThermodynamics of qu
antum spin liquids\n\nThe quantum spin liquid is an exotic quantum state o
f matter in magnets\, where conventional symmetry breaking is prevented do
wn to the lowest temperature by strong quantum fluctuations. It has attrac
ted interest from not only condensed matter physics but also quantum infor
mation\, owing to the anticipated topological properties. In order to clar
ify the nature of the enigmatic state and explore its realization\, we inv
estigate thermodynamic properties of the Kitaev model and its variants\, i
n which the exact solutions prove the quantum spin liquids in the ground s
tate. We will discuss the surprisingly rich behaviors of quantum spin liqu
ids revealed by our numerical simulations\, including (i) thermal fraction
alization of quantum spins into Majorana fermions\, (ii) ``liquid-gas" tra
nsition by proliferation of loops of excited fluxes\, and (iii) phase diag
ram of ``magnetic three states of matter".\n\n\nContact Person: Simon Treb
st
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Shivaji Sondhi
DTSTART;VALUE=DATE-TIME:20150619T163000
DTEND;VALUE=DATE-TIME:20150619T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000626@events.thp.uni-koeln.de
DESCRIPTION:Shivaji Sondhi\, Princeton\n\nMany Body Localization\n\nFamous
ly\, Anderson showed in 1958 that non-interacting quantum mechanical elect
rons placed in a\nrandom potential could fail to exhibit diffusion. In 200
5 Basko\, Aleiner and Altshuler put the long\nconjectured extension of the
Anderson localization to the interacting setting\, termed Many Body\nLoca
lization\, on a much firmer footing setting off a rapidly growing volume o
f work on this\nphenomenon. I will describe the broad outlines of this wor
k and discuss how it has both enriched our\nunderstanding of the foundatio
n of quantum statistical mechanics and led to the remarkable\nnotion of no
n-equilibrium quantum phase structure that lies outside the former.\n\nCon
tact Person: Simon Trebst
LOCATION:seminar room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Alexander Grüneis
DTSTART;VALUE=DATE-TIME:20150707T164500
DTEND;VALUE=DATE-TIME:20150707T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000630@events.thp.uni-koeln.de
DESCRIPTION:Alexander Grüneis\, University of Cologne\n\nQuasiparticle dy
namics and optical properties of 2D materials\n\nThe goal of my group‘s
research is to prepare and chemically functionalize\nlayered materials and
then to characterize them in-situ using a novel\ncombination of photoelec
tron and optical spectroscopies. This approach\nprovides a solution to the
intense research efforts in trying to engineer\,\nprobe and unravel many-
body physics and the superconducting coupling\nmechanism in layered solids
. Regarding the materials under investigation\,\nI will show results from
the growing family of 2D materials such as\ngraphene\, hexagonal boron nit
ride\, transition metal dichalcogenides and\nphosphorene. Chemical functio
nalization using dopants allows for an unprecedented\ncontrol over their p
hysical properties. The proposed material\nsystems provide a new arena to
explore diverse condensed matter\nphenomena such as electron correlation\,
electron-phonon coupling and\nsuperconductivity.\n\nContact Person: Lucas
Labadie
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Tomaz Prosen
DTSTART;VALUE=DATE-TIME:20150515T163000
DTEND;VALUE=DATE-TIME:20150515T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000631@events.thp.uni-koeln.de
DESCRIPTION:Tomaz Prosen\, University of Ljubljana\n\nExact solutions of b
oundary-driven quantum master equations and new conservation laws\n\nThe a
nisotropic Heisenberg chain of spins 1/2 is one of the key paradigms of st
rongly\ncorrelated electrons in one dimension. While equilibrium propertie
s of the model\nare relatively well understood\, even very basic questions
about its non-equilibrium\nproperties were still open until very recently
. A prominent example is the question\nwhether the model exhibits ballisti
c spin transport at finite temperatures or not?\nI will outline the progre
ss on this topic which has been triggered by the discovery\nof exact solut
ion of quantum master equation of the boundary driven Heisenberg\nchain. T
he steady-state solution of non-equilibrium master equation leads\nto nove
l quasi-local conservation laws\, which in turn lead to a derivation\nof r
igorous strict lower bounds on ballistic transport coefficients. I will al
so\nexplain how such an approach of `non-equilibrium integrability' works
for some other\nstrongly interacting quantum chains\, for instance\, for t
he Hubbard model or Lai-\nSutherland model of spins 1.\n\nContact Person:
Vladislav Popkov
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Theodore L. Einstein
DTSTART;VALUE=DATE-TIME:20150206T100000
DTEND;VALUE=DATE-TIME:20150206T110000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000632@events.thp.uni-koeln.de
DESCRIPTION:Theodore L. Einstein\, University of Maryland at College Park\
n\nGeneralized Wigner Surmise in the Nanoworld and the Real World: Applica
tions to Stepped Surfaces\, Submonolayer Islands\, Metro Stations\, and La
ndkreise/Arrondissements\n\n On misoriented ("vicinal") surfaces\, the ter
race-width (spacing between adjacent steps) distribution can be related to
the spacing distribution of repelling spinless fermions in one dimension\
, and thence to generalizations of the Wigner surmise (GWS) from random-ma
trix theory. The GWS expression also emerges as the steady-state solution
of a Fokker-Planck description of step evolution. Subsequently we applied
this approach to the areas of proximity cells (capture zones) of islands a
nd quantum dots on surfaces\; going beyond mean-field is necessary to get
the correct relation between the characteristic GWS exponent and the criti
cal nucleus size. A fragmentation model offers further insights. I compare
analyses of island-size distributions and of scaling of island density vs
. flux. I discuss several computer simulations and various experimental ex
amples. In particular\, for 6P on mica we need a novel quantitative rate e
quation treatment of "hot precursors". Applications to social phenomena in
clude the distribution of Metro stations in Paris and the areal distributi
on of secondary administrative units (e.g.\, Landkreise and arrondissement
s).\n\nContact Person: Joachim Krug
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Christopher Max
DTSTART;VALUE=DATE-TIME:20150130T140000
DTEND;VALUE=DATE-TIME:20150130T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000633@events.thp.uni-koeln.de
DESCRIPTION:Christopher Max\, University of Cologne\n\nQuantum Criticality
of Crystals\n\n\n\nContact Person: Achim Rosch
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Friedrich Hehl
DTSTART;VALUE=DATE-TIME:20150424T163000
DTEND;VALUE=DATE-TIME:20150424T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000634@events.thp.uni-koeln.de
DESCRIPTION:Friedrich Hehl\, Institute for Theoretical Physics\, Cologne\n
\nOn the metamorphoses of Maxwell's equations of electrodynamics since 186
5: spotlights on the history of classical electrodynamics\n\nStarting wit
h Maxwell's equations for the electromagnetic field\n(1865)\, we first poi
nt out how Maxwell brought his system of equations\ninto quaternionic form
. Subsequently\, we recognize that what we call\nMaxwell's equations nowad
ays is a creation of Heaviside and Hertz. Then\nwe study the impact of spe
cial and of general relativity on Maxwell's\nequations. In particular we f
ollow up the metric-free and topological\nversion of Maxwell's equations v
ia exterior differential forms and\nperiod integrals and discuss some appl
ications. Alternative\nformulations via spinors\, Clifford algebras\, chai
ns and\ncochains... are shortly mentioned.
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Eugene Demler
DTSTART;VALUE=DATE-TIME:20150211T143000
DTEND;VALUE=DATE-TIME:20150211T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000635@events.thp.uni-koeln.de
DESCRIPTION:Eugene Demler\, Harvard University\n\nEmergent slow dynamics i
n quantum many-body systems\n\nI will discuss several cases where far out
of equilibrium dynamics of \nmany-body systems gives rise to emergent quas
istationary states\, that \ncan be loosely termed as prethermalized. Examp
les include dynamics of \nspin models with either short or long range inte
ractions\, quench \ndynamics of Fermi systems starting from a non-interact
ing state\, systems \nwith strong disorder\, and systems close to integrab
ility\, such as low \ndimensional condensates. This suggests that emergent
slow dynamics is a \nuniversal phenomenon of quantum systems. I will revi
ew possible \nrealizations of these scenarios in experiments with ultracol
d atoms.\n\n\nContact Person: Achim Rosch
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Ofer Biham
DTSTART;VALUE=DATE-TIME:20150218T170000
DTEND;VALUE=DATE-TIME:20150218T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000636@events.thp.uni-koeln.de
DESCRIPTION:Ofer Biham\, Hebrew University of Jerusalem\n\nCompetition-ind
uced interactions between distant miRNAs and targets in post-transcription
al regulatory networks\n\nmiRNAs play a fundamental role in post-transcrip
tional regulation. Due to the stoichiometric nature of the miRNA-mRNA inte
raction\, the regulation is bi-directional\, namely in addition to\nthe ef
fect of the miRNA regulators on their targets\, the transcripts affect the
activity of their miRNA regulators. This implies that there should be cro
ss-talk between mRNAs that share\na miRNA regulator as well as between miR
NAs that share common targets\, which is mediated by the shared regulators
and targets\, respectively. We have analyzed a recently published\,\nexpe
rimentally-determined human miRNA-mRNA interactome and found that it is a
dense\, intertwined network\, suggesting that the effect of an expression
change in a single mRNA or miRNA\ncould propagate along paths in the netwo
rk\, affecting non-adjacent regulators and targets. Through computational
modeling we determined the parameters governing the magnitude of this\npro
pagation and support the model by analysis of experimental perturbation da
ta. Our results provide a new view of post-transcriptional regulatory netw
orks\, expanding the concept of\nceRNAs (competing endogenous RNAs)\, impl
ying significant cross-talk within the network with far-reaching consequen
ces for perturbation effects.\n\nContact Person: Joachim Krug
LOCATION:Institute for Genetics\, Seminar Room 0.46
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Alexei Starobinsky
DTSTART;VALUE=DATE-TIME:20150130T100000
DTEND;VALUE=DATE-TIME:20150130T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000637@events.thp.uni-koeln.de
DESCRIPTION:Alexei Starobinsky\, Landau Institute\n\nStatus of inflation w
ith the most recent observational data and future perspectives\n\nPresent
knowledge about physical properties of an inflationary stage in the early
Universe (curvature\, its rate of change\, inflaton mass\, etc.) which fol
lows from the most recent observational data including the Planck 2014 one
s is reviewed and possibilities to find out anything new about it are disc
ussed. In particular\, features in the CMB temperature anisotropy power sp
ectrum in the multipole range l=20-40 are of interest in this respect and
may point to some new physics during inflation.
LOCATION:Konferenzraum 1
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Igor Burban
DTSTART;VALUE=DATE-TIME:20150204T163000
DTEND;VALUE=DATE-TIME:20150204T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000638@events.thp.uni-koeln.de
DESCRIPTION:Igor Burban\, Universität zu Köln\n\nÖffentliche Antrittsvo
rlesung: Die Yang-Baxter-Gleichung: Algebra\, Geometrie und mathematische
Physik\n\nIn den letzten 30 Jahren kam es zu einer besonders aktiven Wechs
elwirkung zwischen der Mathematik und der theoretischen Physik. Dank diese
r Interaktion sind neue mathematische Gebiete entstanden\, die ihrerseits
neue Methoden für verschiedene Bereiche der theoretischen Physik liefern.
\n\nDie Theorie der Yang-Baxter-Gleichung ist ein Beispiel von solchen Geb
ieten. Lösungen dieser Gleichung besitzen eine reiche und tiefe mathemati
sche Struktur und haben zahlreiche Anwendungen in der Physik. Im Vortrag w
ird ein Überblick über klassische Ergebnisse und neue Entwicklungen in d
er Theorie der Yang-Baxter-Gleichung gegeben.\n\nContact Person: Igor Burb
an
LOCATION:Großer Hörsaal des Mathematischen Instituts
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dmitry Fedosov
DTSTART;VALUE=DATE-TIME:20150410T163000
DTEND;VALUE=DATE-TIME:20150410T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000639@events.thp.uni-koeln.de
DESCRIPTION:Dmitry Fedosov\, Institute for Complex Systems\, FZ Jülich\n\
nMultiscale modeling of blood flow: From single cells to intricate multi-c
ell interactions\n\nBlood flow plays an important role in many physiologic
al processes and pathologies in the organism. To understand these processe
s\, detailed investigation of blood flow is\nrequired under realistic cond
itions including cell deformability\, hydrodynamic interactions\, and comp
lex geometries. We employ the smoothed dissipative particle dynamics metho
d\, a\nmesoscopic hydrodynamic simulation technique\, to model blood as a
suspension of deformable cells represented by a viscoelastic spring-networ
k which incorporates appropriate mechanical\nand rheological cell-membrane
properties. Blood flow in idealized micro-channel geometries will be inve
stigated. We will discuss the physical mechanisms which govern migration o
f micro-\nand nano-carriers toward the walls in micro-vessels. Moreover\,
we will present the flow behavior of blood cells in a microfluidic device
which offers great opportunities for cell\nsorting. We will illustrate the
use of complex flow geometries to separate cells of different sizes and t
he application of realistic blood flow simulations to optimize the device\
nperformance.\n\nContact Person: Joachim Krug
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Jens Elgeti
DTSTART;VALUE=DATE-TIME:20150417T163000
DTEND;VALUE=DATE-TIME:20150417T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000640@events.thp.uni-koeln.de
DESCRIPTION:Jens Elgeti\, Institute for Complex Systems\, FZ Jülich\n\nSi
mulating growing tissues\n\nGrowth of solid tumors or metastasis requiers\
, besides massive biomedical changes\, also a spatial remodeling of the ti
ssue. This remodeling\, often including displacements of healthy tissue ar
ound\, requires mechanical work to be done. These mechanics of growth has
attracted a lot of attention in recent years\, but still remains poorly un
derstood. We use particle based simulations to study mechanical properties
and effects in growing and motile tissues. These simulations have been he
lpful in understanding\, interpreting and designing experiments. I will p
resent an overview of the simulation thechnique\, and how it contributed t
o recent develobments in three dimensional tissue growth and collective ce
ll migration. In a recent series of simulations and close experimental col
laborations we found important interfacial and surface effects that lead t
o novel phenomena. For example\, the tissue divides favorably at a free su
rface\, even without any nutrient effects. This leads to the possibility a
nd stability of a negative homeostatic pressure. In turn\, a negative home
ostatic pressure leads to naturally to finite steady states and tensile st
ates.\n\nContact Person: Joachim Krug
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | James D. Bjorken
DTSTART;VALUE=DATE-TIME:20150519T164500
DTEND;VALUE=DATE-TIME:20150519T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000688@events.thp.uni-koeln.de
DESCRIPTION:James D. Bjorken\, Stanford University\n\nQuantum chromodynami
cs at the Large Hadron Collider\n\nHow turbulence arises in simple shear f
lows\, such as pipes and channels has been an open question for over a cen
tury. In these flows turbulence is found despite the linear stability of t
he laminar flow and transition is caused by finite amplitude perturbations
. Despite numerous experimental and theoretical studies it has not been po
ssible to determine a well defined critical point nor to clarify the natur
e of the transition. It will be shown for the examples of pipe and Couette
flow that the onset\nof sustained turbulence is a nonequilibrium phase tr
ansition. The critical point is determined by resolving the extremely long
time scales of the underlying growth and decay processes. By \ndetailed n
umerical simulations and experimental measurements close to the transition
point we also determine the critical exponents and show that this transit
ion falls into the directed percolation universality class.
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Björn Hof
DTSTART;VALUE=DATE-TIME:20150428T164500
DTEND;VALUE=DATE-TIME:20150428T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000647@events.thp.uni-koeln.de
DESCRIPTION:Björn Hof\, IST Austria\n\nThe onset of turbulence\n\nHow tur
bulence arises in simple shear flows\, such as pipes and channels has\nbee
n an open question for over a century. In these flows turbulence is found\
ndespite the linear stability of the laminar flow and transition is caused
by\nfinite amplitude perturbations. Despite numerous experimental and\nth
eoretical studies it has not been possible to determine a well defined\ncr
itical point nor to clarify the nature of the transition. It will be shown
\nfor the examples of pipe and Couette flow that the onset of sustained\nt
urbulence is a nonequilibrium phase transition. The critical point is\ndet
ermined by resolving the extremely long time scales of the underlying\ngro
wth and decay processes. By detailed numerical simulations and\nexperiment
al measurements close to the transition point we also determine\nthe criti
cal exponents and show that this transition falls into the directed\nperco
lation universality class.\n\nContact Person: Joachim Krug
LOCATION:Hörsaal III der Physikalischen Institute
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Benjamin Heil
DTSTART;VALUE=DATE-TIME:20150422T093000
DTEND;VALUE=DATE-TIME:20150422T101500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000664@events.thp.uni-koeln.de
DESCRIPTION:Benjamin Heil\n\nBachelor colloquium\n\n
LOCATION:Seminar Room 0.01\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Matthias Batzill
DTSTART;VALUE=DATE-TIME:20150506T143000
DTEND;VALUE=DATE-TIME:20150506T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000646@events.thp.uni-koeln.de
DESCRIPTION:Matthias Batzill\, University of South Florida\, Tampa\, USA\n
\nGraphene interfaces: metals\, dielectrics\, and van der Waals materials\
n\n\n\nContact Person: Thomas Michely
LOCATION:Seminar Room\, Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Pieter Rein ten Wolde
DTSTART;VALUE=DATE-TIME:20151030T163000
DTEND;VALUE=DATE-TIME:20151030T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000648@events.thp.uni-koeln.de
DESCRIPTION:Pieter Rein ten Wolde\, AMOLF Amsterdam\n\nFundamental limits
to chemical sensing\n\nCells can measure chemical concentrations with extr
aordinary precision. This raises the question what is the fundamental limi
t to the accuracy of chemical concentration\nmeasurements. In this talk\,
I will show that the sensing accuracy of passive signaling systems is limi
ted by the number of receptors\; a downstream processing network can never
increase\nthe sensing precision beyond this limit. Non-equilibrium system
s can beat this limit. However\, this requires receptors and their integra
tion time\, downstream molecules\, and energy. Each\nresource imposes a fu
ndamental sensing limit\, which means that the sensing precision is bounde
d by the limiting resource and cannot be enhanced by increasing another re
source. This\nresult yields a new design principle\, namely that of optima
l resource allocation in cellular sensing. It states that in an optimally
designed sensing system\, each resource is equally\nlimiting\, so that no
resource is wasted. We find that the chemotaxis network of E. coli obeys t
his principle\, indicating a selective pressure for the efficient design o
f cellular sensing\nsystems.\n\n\nContact Person: Johannes Berg
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Alexander Uhlig
DTSTART;VALUE=DATE-TIME:20150310T110000
DTEND;VALUE=DATE-TIME:20150310T120000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000649@events.thp.uni-koeln.de
DESCRIPTION:Alexander Uhlig\, Universität Leipzig\n\nLong-memory processe
s and market innovations: An empirical analysis based on Island ECN tradin
g data\n\n\n\nContact Person: Joachim Krug
LOCATION:Seminar Room TP 0.02
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Jens Bardason
DTSTART;VALUE=DATE-TIME:20150508T163000
DTEND;VALUE=DATE-TIME:20150508T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000650@events.thp.uni-koeln.de
DESCRIPTION:Jens Bardason\, MPI-PKS Dresden\n\nMany-body localization\, en
tanglement and natural orbitals\n\nIn this talk I will discuss how entangl
ement and the eigenstates (natural orbitals) and eigenvalues (occupations)
of the one-particle density matrix can be used to characterize the many-b
ody localization transition and phases. Many-body localization is the inte
racting version of the Anderson insulator\, and is reflected both as local
ization of particles in real space\, as well as in Fock-space. The study o
f entanglement\, both in eigenstates and its evolution after quenches\, ha
s been instrumental in advancing our understanding of many-body localized
phases. The entanglement entropy of eigenstates goes from an area law in t
he localized phase\, reflecting the real space localization of wave functi
ons\, to an volume law in the delocalized phase\, with diverging fluctuat
ions at the transition. In contrast\, a global quench within the many-bod
y localized phase gives rise to a slowly (logarithmically) increasing enta
nglement entropy. The entropy of occupations in the one-particle density m
atrix turns out to have similar properties as the entanglement entropy--ar
ea law in localized phase\, volume law in delocalized phase\, and divergin
g fluctuations at the transition--but this is reflecting the Fock space st
ructure of the eigenstates. Finally\, the inverse participation ratio of t
he natural orbitals can be used to define a one-particle localization leng
th in the localized phase.
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Matthias Vojta
DTSTART;VALUE=DATE-TIME:20150522T163000
DTEND;VALUE=DATE-TIME:20150522T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000651@events.thp.uni-koeln.de
DESCRIPTION:Matthias Vojta\, TU Dresden\n\nCoupled-dimer magnets: Systemat
ic expansions\, quantum criticality\, and disorder\n\nCoupled-dimer magnet
s have become model systems in the study of quantum phase transitions. Aft
er a brief introduction to quantum criticality in magnets\, the talk will
discuss various theoretical approaches to describe coupled-dimer magnets\,
using both field-theoretic and microscopic techniques\, and link the resu
lts to experimental observations. In particular\, a novel expansion in 1/d
will be presented where d is spatial dimensionality. In addition\, intere
sting phenomena arising from quenched disorder in coupled-dimer magnets wi
ll be highlighted\, both for dilute and dense concentration of defects.\n\
nContact Person: Alexander Altland
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Emad Aboulouz
DTSTART;VALUE=DATE-TIME:20150326T100000
DTEND;VALUE=DATE-TIME:20150326T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000653@events.thp.uni-koeln.de
DESCRIPTION:Emad Aboulouz\n\nMaster Colloquium\n\n\n\nContact Person: Achi
m Rosch
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Johannes Knolle
DTSTART;VALUE=DATE-TIME:20150508T140000
DTEND;VALUE=DATE-TIME:20150508T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000656@events.thp.uni-koeln.de
DESCRIPTION:Johannes Knolle\, Cambridge\n\nDynamics of a Quantum Spin Liqu
id\n\nTopological states of matter present a wide variety of striking new
phenomena\, most prominently is the fractionalization of electrons. Their
detection\, however\, is fundamentally complicated by the lack of any loca
l order. While there are now several instances of candidate topological sp
in liquids\, their identification remains challenging. Here\, we address o
ne of the key questions: How can a quantum spin liquid phase be diagnosed
in experiments?\nWe find that the dynamical response can serve as a valuab
le tool for diagnosing quantum spin liquids. We provide a complete and rar
ely available exact theoretical study of the dynamical structure factor an
d the inelastic Raman scattering response of a two-dimensional quantum spi
n liquid in Abelian and non-Abelian phases. We show that there are salient
signatures of the Majorana fermions and gauge fluxes emerging in Kitaev's
honeycomb model. Our analysis identifies new varieties of the venerable X
-ray edge problem and explores connections to the physics of quantum quenc
hes.\nA number of proposals suggest that some materials with strong spin-o
rbit coupling\, e.g. {Na/Li}2IrO3 or alpha-RuCl3 compounds\, realize some
of the physics of the Kitaev model. We discuss the current experimental si
tuation\, recent measurements and explore more generally the effect of bre
aking the integrability on response functions of Kitaev spin liquids. \n\n
Contact Person: Maria Hermanns
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Olga Petrova
DTSTART;VALUE=DATE-TIME:20150522T140000
DTEND;VALUE=DATE-TIME:20150522T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000657@events.thp.uni-koeln.de
DESCRIPTION:Olga Petrova\, MPI-PKS\n\nDefects and Majorana modes in the Ki
taev honeycomb model\n\nKitaev's honeycomb model [1] is a quantum spin liq
uid\, celebrated for\nboth the richness of its physical features\, and the
fact that it\nadmits an exact solution. The latter can be cast in terms o
f Majorana\nfermions living in the background of a static Z_2 gauge field.
The\ngapped phase of this model exhibits Z_2 topological order\, equivale
nt\nto that of the toric code. Its ground state is a featureless spin\nliq
uid whose nontrivial properties can be revealed by introducing\nlattice de
fects. In the talk I will show that certain kinds of lattice\ndislocations
and bond defects in this originally Abelian system carry\nunpaired Majora
na fermions [2\,3]. Each pair of such defects gives rise\nto a non-local p
hysical fermion mode\, i.e. a topologically-protected\nqubit\, made out of
two Majorana modes connected by a Z_2 gauge string.\nThe qubit's composit
ion reveals the crucial role of the emergent gauge\nfield\, neglected in m
ost treatments of the Kitaev model\, in the\nphysics of Majorana modes. I
will demonstrate how the non-local\nfermion can be created or annihilated
by winding a magnetic vortex\naround a defect.\n\n[1] A. Kitaev\, Ann. Phy
s. 321\, 2 (2006).\n[2] O. Petrova\, P. Mellado\, O. Tchernyshyov\, Phys.
Rev. B 88\, 140405 (2013).\n[3] O. Petrova\, P. Mellado\, O. Tchernyshyov\
, Phys. Rev. B 90\, 134404 (2014).\n\nContact Person: Maria Hermanns
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Peter Broecker
DTSTART;VALUE=DATE-TIME:20150506T100000
DTEND;VALUE=DATE-TIME:20150506T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000658@events.thp.uni-koeln.de
DESCRIPTION:Peter Broecker\n\nEntanglement and the sign problem\n\n
LOCATION:Seminar Room 0.01\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Ramses Sanchez
DTSTART;VALUE=DATE-TIME:20150610T100000
DTEND;VALUE=DATE-TIME:20150610T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000659@events.thp.uni-koeln.de
DESCRIPTION:Ramses Sanchez\n\nMean-field theory of the doped kagome antife
rromagnet\n\n
LOCATION:Seminar Room 0.01\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Andrey Bolotnikov
DTSTART;VALUE=DATE-TIME:20150410T140000
DTEND;VALUE=DATE-TIME:20150410T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000660@events.thp.uni-koeln.de
DESCRIPTION:Andrey Bolotnikov\, Duesseldorf\n\nScattering of electrons in
graphene: some of recent results\n\nAfter the experimental realization of
graphene by Novoselov and Geim in 2004\, for which they were awarded the N
obel Prize to in 2010\, the scattering theory of two-dimensional massless
Dirac fermions has become relevant because of its role in understanding gr
aphene's transport properties. The latter motivated Jhih-Sheng Wu and Mich
ael M. Fogler to study the problem of scattering on a circular step-like p
otential barrier\, which is assumed to be a model for a circular cluster o
f charged impurities. The aim of the talk is to make an overview of some m
ain aspects of their recent article Scattering of two-dimensional massless
Dirac electrons by a circular potential barrier [1]. In this publication
the scattering problem was treated with respect to the values of two param
eters\, X and rho\, characterizing the size and the strength of the barrie
r\, respectively. For each combination of X and rho a suitable tool was fo
und for studying the scattering problem. One of the article's conclusions
is the fact that formation of circular clusters increases the conductivity
compared to the case of randomly distributed impurities.\n\n[1] Jhih-Shen
g Wu and Michael M. Fogler\, Scattering of two-dimensional massless Dirac
electrons by a circular potential barrier\, arXiv: 1410.0272v1 1 Oct 2014.
\n\nContact Person: Maria Hermanns
LOCATION:Seminar room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Markus Kriener
DTSTART;VALUE=DATE-TIME:20150715T143000
DTEND;VALUE=DATE-TIME:20150715T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000661@events.thp.uni-koeln.de
DESCRIPTION:Markus Kriener\, Center for Emergent Matter Science\, Rieken\,
Japan\n\nCompeting Magnetic Phases in the Doped Magnetic Semiconductor Ge
Te\n\n\n\nContact Person: Thomas Lorenz
LOCATION:Seminar Room\, Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Alexander Kamenshchik
DTSTART;VALUE=DATE-TIME:20150414T120000
DTEND;VALUE=DATE-TIME:20150414T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000666@events.thp.uni-koeln.de
DESCRIPTION:Alexander Kamenshchik\, Uni Bologna/Landau Inst. Moscow\n\nSof
t singularity crossing and transformation of matter properties in general
relativity and cosmology\n\nWe investigate particular cosmological models\
, based either on tachyon fields or on perfect fluids\, for which soft fut
ure singularities arise in a natural way. Our main result is the descripti
on of a smooth crossing of the soft singularity in models with an anti-Cha
plygin gas or with a particular tachyon field in the presence of dust. Suc
h a crossing is made possible by certain transformations of matter propert
ies. Some of these cosmological evolutions involving tachyons are compatib
le with SNIa data. We compute numerically their dynamics involving a first
soft singularity crossing\, a turning point and a second soft singulatity
crossing during recollapse\, ending in a Big Crunch singularity.
LOCATION:Seminar Room R215
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Yoran Tournois
DTSTART;VALUE=DATE-TIME:20150417T140000
DTEND;VALUE=DATE-TIME:20150417T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000667@events.thp.uni-koeln.de
DESCRIPTION:Yoran Tournois\, Utrecht University\n\nThe holographic electro
n star\n\nThe Anti-deSitter/Conformal Field Theory (AdS/CFT) correspondenc
e is a duality relating strongly correlated quantum field theories to clas
sical gravity in one higher dimension. Although discovered in the context
of string theory\, it has more recently been applied to condensed matter p
hysics\, where it offers insight into strongly correlated systems at a qua
ntum critical point. \n\nIn this talk\, I will briefly introduce the AdS/C
FT correspondence and indicate the connection to condensed matter physics.
I turn to the electron star\, a model of a perfect fluid of charged fermi
ons backreating onto the geometry. I will discuss the numerical results ob
tained by solving the resulting equations of motion. Then\, I turn to a de
scription of fermions in curved spacetime\, after which I will consider th
e fermion equations of motion in the electron star background. Finally\, a
s an outlook\, I will mention several extensions of this model.\n\nContact
Person: Maria Hermanns
LOCATION:TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Roman Orus
DTSTART;VALUE=DATE-TIME:20150710T141500
DTEND;VALUE=DATE-TIME:20150710T154500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000668@events.thp.uni-koeln.de
DESCRIPTION:Roman Orus\, University of Mainz\n\nEntanglement\, tensor netw
orks\, and topological quantum order\n\nTopological order in a 2d quantum
matter can be determined by the topological contribution to the entangleme
nt Renyi entropies. However\, when close to a quantum phase transition\, i
ts calculation becomes cumbersome. In this talk I will show how topologica
l phase transitions in 2d systems can be much better assessed by multipart
ite entanglement\, as measured by the topological geometric entanglement o
f blocks. Specifically\, I will present an efficient tensor network algori
thm based on Projected Entangled Pair States (PEPS) to compute this quanti
ty for a torus partitioned into cylinders\, and then use this method to fi
nd sharp evidence of topological phase transitions in 2d systems with a st
ring-tension perturbation. When compared to tensor network methods for Ren
yi entropies\, this approach produces almost perfect accuracies close to c
riticality and\, on top\, is orders of magnitude faster. Moreover\, I will
show how the method also allows the identification of Minimally Entangled
States (MES)\, thus providing a very efficient and accurate way of extrac
ting the full topological information of a 2d quantum lattice model from t
he multipartite entanglement structure of its ground states. If time allow
s I will also present briefly other ongoing projects at our group involvin
g the use of tensor networks to study large-spin Kagome quantum antiferrom
agnets\, 1d symmetry-protected topological order\, continuous unitary tran
sformations\, and (1+1)d lattice gauge theories.\n\n\nContact Person: Joha
nnes Helmes
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Jürg Fröhlich
DTSTART;VALUE=DATE-TIME:20150626T163000
DTEND;VALUE=DATE-TIME:20150626T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000669@events.thp.uni-koeln.de
DESCRIPTION:Jürg Fröhlich\, ETH Zürich\n\nDirect and Indirect Acquisiti
on of Information in Quantum Mechanics\n\nIt is explained how\, in quantum
mechanics\, information about a physical system is acquired through direc
t (von Neumann) and indirect (Kraus) measurements/observations. In a first
part\, a new theory of direct (projective\, or von Neumann) measurements
is developed\, using methods and results from functional analysis. In a se
cond part\, the theory of indirect measurements is sketched\, and it is sh
own how various theorems from probability theory and statistics can be use
d for this purpose. Many of the general ideas are explained in the context
of a simple model system.\nTime permitting\, I will outline tentative app
lications of the main ideas presented in this talk to a theory of percepti
on.\n\n\nContact Person: Martin Zirnbauer
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Victor Jouffrey
DTSTART;VALUE=DATE-TIME:20150415T143000
DTEND;VALUE=DATE-TIME:20150415T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000670@events.thp.uni-koeln.de
DESCRIPTION:Victor Jouffrey\, University of Lyon\n\nSound absorption in No
n-Kramer Quantum Spin Ice\n\nIn this talk\, I will be presenting the conse
quence of the coupling between magnetic and vibrational degrees of freedom
in Non-Kramer Quantum Spin Ice models focusing on experimentally relevant
signatures for this specific class of quantum spin liquid. First\, I will
introduce Quantum Spin Ice physics borrowing insights from its well-studi
ed classical counterparts. In particular\, our work will build on the assu
mption that the monopole excitations present in classical Spin Ice remains
well-defined quasi-particles. Quantum fluctuations of the spins provide a
coherent mechanism for the transport of monopoles and lead to the emergen
ce of a U(1) gauge field and an associated gapless photon. I will briefly
explain how the pseudospin living on the vertex of the pyrochlore lattice
emerges from the combination of single-ion physics and crystal field symme
tries and insist on the importance of its non-Kramer nature to couple line
arly phonons. The coupling between magnetic and vibrational degrees of fre
edom will be introduce on physical grounds and its form will be inferred f
rom simple symmetry arguments. The last part of the talk will be focused o
n the consequences of this coupling on sound absorption measurements empha
sizing the major role of the gapless photon.\n\nContact Person: Maria Herm
anns
LOCATION:Seminar room\, Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Laura Koehler
DTSTART;VALUE=DATE-TIME:20150617T100000
DTEND;VALUE=DATE-TIME:20150617T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000671@events.thp.uni-koeln.de
DESCRIPTION:Laura Koehler\n\nStrongly correlated critical chiral paramagne
ts\n\n
LOCATION:Seminar Room 0.01\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Johannes Kombe
DTSTART;VALUE=DATE-TIME:20150422T101500
DTEND;VALUE=DATE-TIME:20150422T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000680@events.thp.uni-koeln.de
DESCRIPTION:Johannes Kombe\, Oxford University\n\nAnyons and Topological q
uantum computing\n\n\n\nContact Person: Achim Rosch
LOCATION:Seminar Room 0.01\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Dmitry Bagrets
DTSTART;VALUE=DATE-TIME:20150520T100000
DTEND;VALUE=DATE-TIME:20150520T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000673@events.thp.uni-koeln.de
DESCRIPTION:Dmitry Bagrets\n\nEffective field theory of the disordered Wey
l semimetal\n\n
LOCATION:Seminar Room 0.01\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Lukas Heinen
DTSTART;VALUE=DATE-TIME:20150603T100000
DTEND;VALUE=DATE-TIME:20150603T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000674@events.thp.uni-koeln.de
DESCRIPTION:Lukas Heinen\n\ntba\n\n
LOCATION:Seminar Room 0.01\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Wilfried Michel
DTSTART;VALUE=DATE-TIME:20150624T100000
DTEND;VALUE=DATE-TIME:20150624T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000676@events.thp.uni-koeln.de
DESCRIPTION:Wilfried Michel\n\nTracing Entanglement - From replicated Spin
s to Entanglement Spectra\n\n
LOCATION:Seminar Room 0.01\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Jonathan Lux
DTSTART;VALUE=DATE-TIME:20150701T100000
DTEND;VALUE=DATE-TIME:20150701T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000677@events.thp.uni-koeln.de
DESCRIPTION:Jonathan Lux\n\nFormation and thermal destruction of metallic
puddles in a fully compensated topological insulator\n\n
LOCATION:Seminar Room 0.01\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Simon Trebst
DTSTART;VALUE=DATE-TIME:20150708T100000
DTEND;VALUE=DATE-TIME:20150708T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000678@events.thp.uni-koeln.de
DESCRIPTION:Simon Trebst\n\nEntanglement monotonicity: c-theorem\, F-theor
em\, a-theorem\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Achim Rosch
DTSTART;VALUE=DATE-TIME:20150715T100000
DTEND;VALUE=DATE-TIME:20150715T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000679@events.thp.uni-koeln.de
DESCRIPTION:Achim Rosch\n\nSpin-Peierls Instability of Three-Dimensional S
pin Liquids with Majorana Fermi Surface\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Daniele Fausti
DTSTART;VALUE=DATE-TIME:20150428T130000
DTEND;VALUE=DATE-TIME:20150428T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000681@events.thp.uni-koeln.de
DESCRIPTION:Daniele Fausti\, University of Trieste and Elettra - Sincrotro
ne Trieste\, Italy\n\nWitnessing quasi-particles in a strongly correlated
electron system\n\nIn this presentation\, I will introduce the field of ti
me domain studies of correlated electron systems focusing on the interacti
on between phonons and high-energy excitation of electronic origin in cupr
ates. I will review our recent results in archetypal strongly correlated c
harge-transfer insulator (La2CuO4) revealing that photo-excitation in corr
elated materials pilots the formation of itinerant quasi-particles which a
re suddenly dressed (<100 fs) by an ultrafast reaction of the bosonic fiel
d. I will introduce our new approach to address correlated electron system
s by a full quantum state reconstruction of ultrashort light pulses. I wil
l explain Time Resolved Quantum Tomography and show how this provide a new
perspective for addressing by time domain studies the quantum state of lo
w energy boson in complex materials.\n\nReferences\nNature Comm. 5\, 5112
(2014)\nNew J. Phys. 16 043004 (2014)\n\nContact Person: Paul H. M. van Lo
osdrecht
LOCATION:Seminar Room\, Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Katharina J. Franke
DTSTART;VALUE=DATE-TIME:20151021T143000
DTEND;VALUE=DATE-TIME:20151021T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000682@events.thp.uni-koeln.de
DESCRIPTION:Katharina J. Franke\, Freie Universität Berlin\n\nMagnetic p
roperties of single molecules on surfaces probed by scanning tunneling spe
ctroscopy\n\nThe magnetic properties of single atoms are significantly aff
ected by details in the atomic- scale surrounding. One strategy to control
the spin state and magnetic anisotropy is to embed the atoms into specifi
cally designed organic ligands. Moreover\, the surface plays a pivotal rol
e in the magnetic properties when it interacts with the magnetic core. Her
e\, we utilize scanning tunneling microscopy and spectroscopy to character
ize the magnetic anisotropy and lifetimes of excited states of single para
magnetic molecules on a surface and point out possibilities to tune these.
\n\nContact Person: Dirk Hertel
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Stefan Maier
DTSTART;VALUE=DATE-TIME:20150529T140000
DTEND;VALUE=DATE-TIME:20150529T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000685@events.thp.uni-koeln.de
DESCRIPTION:Stefan Maier\, University of Cologne\n\nThe quest for the anti
ferromagnetic strange metal: ideas for the Wilsonian renormalization group
\n\nWhile the problem of calculating critical exponents was believed to be
\nessentially solved by some experts already in the 1980s\, this does not\
nhold true for metallic systems at present. In a recent study of the\nspin
-fermion model [1]\, Sur and Lee have found the first renormalization\ngro
up fixed point for a quantum-critical metal using an\nepsilon-expansion ar
ound $d=3$. The critical theory was shown to have a\nquasi-local boson and
one-dimensional electrons. However\, the nature of\npotential fixed point
s in the physical dimensionality $d=2$ and the\nvalues of critical exponen
ts are an important open problem. In this\ntalk\, I will therefore present
first attempts to tackle this problem\nwithin a Wilsonian-type renormaliz
ation group framework\, where modes\nwith decreasing momenta are integrate
d out successively.\n \n[1] Sur and Lee\, PRB 91\, 125136 (2015)
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Bernard Kippelen
DTSTART;VALUE=DATE-TIME:20150513T140000
DTEND;VALUE=DATE-TIME:20150513T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000686@events.thp.uni-koeln.de
DESCRIPTION:Bernard Kippelen\n\nOrganic electronics: the endless frontier\
n\n\n\nContact Person: Klaus Meerholz
LOCATION:Seminar room A\, Chemistry
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Prof. Dr. Rolf-Dietmar Herzberg
DTSTART;VALUE=DATE-TIME:20150512T164500
DTEND;VALUE=DATE-TIME:20150512T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000687@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Rolf-Dietmar Herzberg\, University of Liverpool\n\nA
lchemy in the 21st century: the quest to understand super heavy elements.\
n\nA chemical element is characterised by the total number of positively c
harged protons in the atomic nucleus. The interplay between the attractive
short range strong force and the repulsive long range Coulomb force leads
to a limit in the number of protons and neutrons that can be bound in a n
ucleus. Today single atoms of elements up to Z=118 have been created in th
e laboratory. [...]\n\nContact Person: Prof. Dr. Andreas Zilges - Institut
für Kernphysik
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Prof. Dr. Artie Hatzes
DTSTART;VALUE=DATE-TIME:20150609T164500
DTEND;VALUE=DATE-TIME:20150609T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000689@events.thp.uni-koeln.de
DESCRIPTION:Prof. Dr. Artie Hatzes\, Thüringer Landessternwarte Tautenbur
g\n\nFrom 51 Peg to the Kepler Space Mission – Twenty Years of Exoplanet
Research\n\nTwenty years ago the first Jupiter-mass planet was found orbi
ting a sunlike\nstar. With a 4-day orbital period 51 Peg b was the first i
ndication that\nplanetary systems could be far more diverse than what we e
xpected from\nthe properties of our own solar system. Early exoplanet disc
overies consisted\nmostly of giant planets in single systems.\nWe now know
of thousands of multi-planet systems and have detected\nplanets with the
mass of earth\, albeit with short orbital periods. The\nfield has also mov
ed into an era where exoplanets are being characterized\nin terms of their
true mass\, radius\, density\, surface temperature\,\nand atmospheric fea
tures. I will discuss the early history of exoplanet\nresearch but will fo
cus largely on two space missions CoRoT and Kepler\,\nthat have been at th
e forefront of these characterization studies. Almost\n20 years after the
discovery of 51 Peg\, a giant planet in a 4-day\norbit\, the field of extr
asolar planets continues to produce unexpected discoveries.\n\nContact Per
son: Lucas Labadie
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Rafael Chaves
DTSTART;VALUE=DATE-TIME:20150717T163000
DTEND;VALUE=DATE-TIME:20150717T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000690@events.thp.uni-koeln.de
DESCRIPTION:Rafael Chaves\, Institute for Theoretical Physics\, University
of Cologne\n\nRevisiting Quantum Nonlocality from a Causal Inference Pers
pective\n\nIt is a relatively new insight of classical statistics that emp
irical data can contain information about causation rather than mere corre
lation. Within that context\, during the past year we have developed and f
ormalized a new research program for the study of causal relations in both
the classical and quantum cases. In this presentation we will discuss two
recent developments that highlight the\nvery fruitful interplay between t
he causal inference literature and problems in quantum information\, a\nco
nnection which is increasingly appreciated among quantum physicists. We wi
ll describe a general algorithm for computing information-theoretic constr
aints on the correlations that can arise from a given causal structure\, w
here we allow for quantum systems as well as classical random variables. I
n a second part\, we will revisit nonlocality from a causal inference pers
pective and give an answer to the following question: How much do we need
to relax the causal assumptions entering in Bell's theorem to\nclassically
explain nonlocal correlations?
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Jean-Loup Puget
DTSTART;VALUE=DATE-TIME:20151020T164500
DTEND;VALUE=DATE-TIME:20151020T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000691@events.thp.uni-koeln.de
DESCRIPTION:Jean-Loup Puget\, Universite Paris-Sud\, Orsay\n\nOverview of
the 2015 Planck full mission results\n\n
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Dirk van der Marel
DTSTART;VALUE=DATE-TIME:20151103T164500
DTEND;VALUE=DATE-TIME:20151103T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000692@events.thp.uni-koeln.de
DESCRIPTION:Dirk van der Marel\, University of Geneva\n\nThe Higgs-mechani
sm: From low to high energies\n\n￼￼￼￼￼￼￼￼￼￼￼￼￼
￼￼￼￼￼￼￼￼￼￼￼￼￼￼￼￼￼￼￼￼￼￼￼￼
￼￼￼￼￼￼In 1964 the theoretical work of Higgs\, Guralnik\, Hagen
\, Kibble\, Brout\, and Englert led to the prediction that\, as a conseque
nce of the coupling bet- ween matter currents and gauge particles\, the ga
uge particles can acquire a non-zero mass. As Higgs phrased it\, „this p
henomenon is just the relati- vistic analog of the plasmon phenomenon to w
hich Anderson has drawn attention: that the scalar zero-mass excitations o
f a superconducting neu- tral Fermi gas become longitudinal plasmon modes
of finite mass when the gas is charged.“\n\nA superconducting gap has co
llective oscillations of its amplitude –equi- valent to the Higgs partic
le- and of its phase. As shown by Anderson in 1958\, the longitudinal and
transverse oscillations of the superconducting condensate coupled to the e
lectromagnetic field now acquire a finite mass\, which is seen experimenta
lly in the energy-momentum dispersion. In cer- tain superconductors two or
more condensates coexist. Weak coupling bet- ween the condensates then gi
ves rise to the so-called Leggett-exciton\, and the coupling to the electr
omagnetic field makes that two or more massive\nphoton-branches coexist. T
hese and many other phe- nomena in elementary par- ticles and condensed ma
tter are marvelous by the beau- ty and simplicity of the prin- ciples unit
ing them\, despite conditions and energy sca- les being so vastly differen
t.
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Ulf-G. Meissner
DTSTART;VALUE=DATE-TIME:20151117T164500
DTEND;VALUE=DATE-TIME:20151117T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000693@events.thp.uni-koeln.de
DESCRIPTION:Ulf-G. Meissner\, University of Bonn\n\nNuclear Physics as Pre
cision Science\n\nTheoretical Nuclear Physics has entered a new era. Using
the powerful machinery of chiral effective Lagrangians\, the forces betwe
en two\, three and four nucleons can now be calculated with unprecedented
precision and with serious uncertainties. Furthermore\, Monte Carlo method
s can be adopted to serve as a new and powerful approach to exactly solve
nuclear structure and reactions. I discuss the foundations of these new me
thods and illustrate them with a variety of intriguing examples. Variation
s of the fundamental constants of Nature can also be investigated and the
consequences for the element generation in the Big Bang and in stars are c
onsidered. This sheds new light on our anthropic view of the Universe.
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Sebastian Wolf
DTSTART;VALUE=DATE-TIME:20151201T164500
DTEND;VALUE=DATE-TIME:20151201T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000694@events.thp.uni-koeln.de
DESCRIPTION:Sebastian Wolf \, University of Kiel\n\nFrom dust to planets\n
\n￼￼￼￼￼￼￼￼￼￼Planets are expected to form in circumstel
lar disks around young stellar objects - a common by-product of the star-f
ormation process. Consequently\, these disks provide the key to evaluate a
nd to refine existing hypotheses for the various phases of the planet form
ation process. Currently\, various instruments/observatories go into opera
tion which will provide the required angular resolution and sensitivity ov
er a broad wavelength range which are ideal for investigating the potentia
l planet- forming region in circumstellar disks.\n\nI will discuss the fea
sibility to study the various stages of the planet formation process obser
vationally - from the growth of submicron-sized dust grains in young\, gas
-rich circum-stellar disks to the stage of long-term stable planetary syst
ems embedded in debris disks. In this context\, a special focus will be on
protoplanets which represent the major missing link on the way from dust
to planets.
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Peter Zoller
DTSTART;VALUE=DATE-TIME:20151215T164500
DTEND;VALUE=DATE-TIME:20151215T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000695@events.thp.uni-koeln.de
DESCRIPTION:Peter Zoller\, University of Innsbruck\n\nQuantum Simulation w
ith Cold Atoms and Ions\n\n
LOCATION:HS II
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Christian Schroer
DTSTART;VALUE=DATE-TIME:20160112T164500
DTEND;VALUE=DATE-TIME:20160112T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000696@events.thp.uni-koeln.de
DESCRIPTION:Christian Schroer\, TU Dresden\n\nMikroskopie mit kohärenter
Röntengstrahlung: Kristallographie des Nichtkristallinen\n\n
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Thomas Nattermann
DTSTART;VALUE=DATE-TIME:20160126T164500
DTEND;VALUE=DATE-TIME:20160126T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000697@events.thp.uni-koeln.de
DESCRIPTION:Thomas Nattermann\, University of Cologne\n\nNormale und anoma
le physikalische Dimensionen\n\n
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Matthias Christandl
DTSTART;VALUE=DATE-TIME:20151106T163000
DTEND;VALUE=DATE-TIME:20151106T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000698@events.thp.uni-koeln.de
DESCRIPTION:Matthias Christandl\, University of Copenhagen\n\nFrom Pauli's
Principle to Fermionic Entanglement\n\nThe Pauli exclusion principle is a
constraint on the natural occupation numbers of fermionic states. It has
been suspected for decades\, and only proved very recently\, that there is
a multitude of further constraints on these numbers\, generalizing the Pa
uli principle. Surprisingly\, these constraints are linear: they cut out a
geometric object known as a polytope. This is a beautiful mathematical re
sult\, but are there systems whose physics is governed by these constraint
s? \n\nIn order to address this question\, we studied a system of a few fe
rmions connected by springs. As we varied the spring constant\, the occupa
tion numbers moved within the polytope. The path they traced hugs very clo
se to the boundary of the polytope\, suggesting that the generalized const
raints affect the system. I will mention the implications of these finding
s for the structure of few-fermion ground states and then discuss the rela
tion between the geometry of the polytope and different types of fermionic
entanglement. \n\nContact Person: David Gross
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Alexey Taskin
DTSTART;VALUE=DATE-TIME:20150713T160000
DTEND;VALUE=DATE-TIME:20150713T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000701@events.thp.uni-koeln.de
DESCRIPTION:Alexey Taskin\, Osaka University\n\nNovel Physics in Topologic
al Insulator Thin Films\n\nTopological insulators (TIs) realize a new quan
tum state of matter where insulating bulk states coexist with metallic sur
face states due to a nontrivial Z2 topology of the bulk valence band. I wi
ll discuss two prominent examples of novel physics found in TIs for which
high-quality thin films grown by molecular beam epitaxy (MBE) are indispen
sable: I. A striking manifestation of the topological protection revealed
in a systematic evolution of the surface conductance as a function of thic
kness in a series of high-quality Bi2Se3 films. II. The observation of unu
sual anisotropic magneto-resistance (AMR) and planar Hall effect (PHE) in
bulk-insulating (Bi1-xSbx)2Te3 thin films\, for which the concentration of
Dirac-like surface carriers\, and consequently the magnitude of AMR and P
HE\, can be controlled by electrostatic gating.\n\nContact Person: Achim R
osch
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Maxim Dzero
DTSTART;VALUE=DATE-TIME:20150701T143000
DTEND;VALUE=DATE-TIME:20150701T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000702@events.thp.uni-koeln.de
DESCRIPTION:Maxim Dzero\n\nTopological insulators driven by an electron sp
in\n\nThe application of ideas developed in topology to the electronic ban
d structure led to an intriguing discovery: materials can conduct electric
ity at the surface while remaining insulating at the bulk. These materials
\, called topological insulators\, will have transformative impact on spin
tronics\, low-power transport\, and quantum computing. The search for a tr
ue topological insulator took years because even best candidates exhibited
significant bulk conductivity. Only recently\, literally in the past few
months\, several experimental groups established that samarium hexaboride\
, discovered in 1969 in Bell Labs\, is a first topological insulator in it
s bulk form. In my talk\, I review the theory which paved the way for this
discovery. I will explain how crystalline symmetry\, electron-electron in
teractions\, and orbital degeneracy contribute to protecting the topologic
al states in SmB6. In addition\, I will discuss the experimental signature
s of metallic surface states as well as the phenomena driven by interactio
ns between the chiral electrons. Finally\, I formulate the theoretical pri
nciples for discovering new topological insulators with designable propert
ies\n\nContact Person: Markus Garst
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Oleg Tretiakov
DTSTART;VALUE=DATE-TIME:20150714T100000
DTEND;VALUE=DATE-TIME:20150714T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000703@events.thp.uni-koeln.de
DESCRIPTION:Oleg Tretiakov\, Tohoku University\n\nAntiferromagnetic Skyrmi
ons\n\nManipulating small spin textures\, which can serve as bits of infor
mation\, by electric current is one of the main challenges in the field of
spintronics. Ferromagnetic skyrmions recently attracted a lot of attentio
n because they are small in size and are better than domain walls at avoid
ing pinning while moved by electric current. Meanwhile\, ferromagnetic sky
rmions still have disadvantages such as the presence of stray fields and t
ransverse dynamics\, making them harder to employ for spintronic applicati
ons. In this work\, we propose a novel topological object: the antiferroma
gnetic (AFM) skyrmion. This topological texture has no stray fields and we
show that its dynamics are faster compared to its ferromagnetic analogue.
We obtain the dependence of AFM skyrmion radius on the strength of Dzyalo
shinskii-Moriya interaction coming from relativistic spin-orbit effects an
d temperature. We find that the thermal properties\, e.g. such as the AFM
skyrmion radius and diffusion constant\, are rather different from those f
or ferromagnetic skyrmions. More importantly\, we show that due to unusual
topology the AFM skyrmions do not have a velocity component transverse to
the current and thus may be perfect candidates for spintronic application
s.\n\nContact Person: Markus Garst
LOCATION:Seminar Room 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Johanna Kleinen
DTSTART;VALUE=DATE-TIME:20150626T140000
DTEND;VALUE=DATE-TIME:20150626T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000704@events.thp.uni-koeln.de
DESCRIPTION:Johanna Kleinen\n\nOn the effect of a single magnetic impurity
at the edge of a 2-dimensional topological insulator (Master Colloquium)\
n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Andrew Mitchell
DTSTART;VALUE=DATE-TIME:20150724T140000
DTEND;VALUE=DATE-TIME:20150724T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000705@events.thp.uni-koeln.de
DESCRIPTION:Andrew Mitchell\, Utrecht University\n\nKondo blockade conduct
ance through single-molecule junctions\n\n\n\nContact Person: Ralf Bulla
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Catherine Pappas
DTSTART;VALUE=DATE-TIME:20150710T130000
DTEND;VALUE=DATE-TIME:20150710T143000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000706@events.thp.uni-koeln.de
DESCRIPTION:Catherine Pappas\, TU Delft\n\nMagnetic fluctuations in Multif
erroics seen by Neutron Spin Echo spectroscopy\n\n\nNeutron Spin Echo spec
troscopy (NSE) is extensively used for the\nstudy of a large variety of sl
ow motion phenomena (critical\nslowing down\, relaxation effects\, disorde
red dynamics\, soft\nmatter)\, which occur on a mesoscopic time scale betw
een\nmicroscopic collision times and macroscopic dynamics. NSE\napplicatio
ns in the field of magnetism benefit from the unique\ncombination of high
energy resolution with neutron polarization\nanalysis\, which allows a dir
ect and unambiguous separation of the\n(often) weak magnetic scattering fr
om all other structural\ncontributions. The technique will be introduced
and new results\nobtained in collaboration with the Cologne group on the\n
multiferroics TbMnO3 and MnWO3 will be discussed.\n\nContact Person: Marku
s Braden
LOCATION:Seminar Room\, Institute for Theoretical Physics (Main Building)
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Andrzej Jarosz
DTSTART;VALUE=DATE-TIME:20150722T101500
DTEND;VALUE=DATE-TIME:20150722T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000708@events.thp.uni-koeln.de
DESCRIPTION:Andrzej Jarosz\, University of Cologne\n\nAn invitation to equ
ivariant cohomology and localization\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Hisao Kobayashi
DTSTART;VALUE=DATE-TIME:20150910T143000
DTEND;VALUE=DATE-TIME:20150910T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000737@events.thp.uni-koeln.de
DESCRIPTION:Hisao Kobayashi\, University of Hyogo\n\nNuclear forward scatt
ering of EuFe2As2 under pressure and at low temperature\n\nAfter the disco
very of superconductivity in a quasi-two-dimensional LaFeAs(OF) [1]\, the
oxygen-free K- doped BaFe2As2 with the well-known quasi-two-dimensional Th
Cr2Si2-type (I4/mmm) structure becomes superconducting at 38 K [2]. The pa
rent compound\, AFe2As2 (A = Ca\, Eu\, Sr\, and Ba)\, undergoes a commensu
rate spin density wave (SDW) antiferromagnetic transition. This SDW transi
tion in AFe2As2 is suppressed by applied pressure\, giving rise to superco
nductivity at low temperature. Since pressure tuning of a stoichiometric c
ompound is a powerful technique for understanding phase transitions\, AFe2
As2 is promising candidate for studying the mechanism of superconductivity
in these iron arsenide compounds.\nThe 57Fe and 151Eu nuclear forward sca
ttering (NFS) experiments under high pressure at low temperatures were car
ried out using the EuFe2As2 single-crystal sample on the NE1 beamline at t
he accumulation ring of the High Energy Accelerator Research Organization
and on the BL09XU beamline at SPring-8 to investigate the correlation betw
een magnetism and superconductivity in the pressure-induced EuFe2As2 super
conductor.\nWe find a microscopic coexistence of magnetism at the Fe and E
u sublattices and bulk superconductivity under pressure and at low tempera
ture. The magnetic structure of the Fe sublattice changes to a modified an
tiferromagnetic structure in the superconducting state from the commensura
te stripe-type antiferromagnetic one in the normal conducting state below
3 GPa. This modified antiferromagnetic structure in the superconducting st
ate has never been observed in the magnetic ordered states in AFe2As2 unde
r pressure and in substituted AFe2As2. The modified antiferromagnetic stat
e with superconductivity in EuFe2As2 under pressure most likely is caused
by the change of the electronic state of the Fe atom due to the effective
As-As hybridization induced by pressure in the tetragonal symmetry of the
crystal structure [3]. Furthermore\, the order parameter of the modified a
ntiferromagnetic state does not compete with that of superconductivity in
the pressure-induced EuFe2As2 superconductor.\nReferences\n[1] Y. Kamihara
\, et al.\, J. Am. Chem. Soc. 130\, 3296 (2008). [2] M. Rotter\, et al.\,
Phys. Rev. Lett. 101\, 107006 (2008). [3] H. Kobayashi\, et al.\, J. Phys.
: Condens. Matter 25\, 022201 (2013).\n\nContact Person: Mohsen Abd-Elmegu
id
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Dimitri Pimenov
DTSTART;VALUE=DATE-TIME:20150807T140000
DTEND;VALUE=DATE-TIME:20150807T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000740@events.thp.uni-koeln.de
DESCRIPTION:Dimitri Pimenov\, LMU / TU Munich\n\nFermi-Edge polaritons wit
h finite hole mass\n\n\n\nContact Person: Achim Rosch
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nThe symplectic egg in classical and qua
ntum mechanics\nMaurice A. de Gosson
DTSTART;VALUE=DATE-TIME:20150805T101500
DTEND;VALUE=DATE-TIME:20150805T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000710@events.thp.uni-koeln.de
DESCRIPTION:Maurice A. de Gosson\n\nThe symplectic egg in classical and qu
antum mechanics\n\nWe discuss the paper "The symplectic egg in classical a
nd quantum mechanics" by Maurice A. de Gosson. Modus operandi: The dice wi
ll determine who will lead the discussion\, so every seminar participant i
s kindly asked to prepare the paper in advance.\n\nContact Person: Thomas
Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Akira Oiwa
DTSTART;VALUE=DATE-TIME:20150814T143000
DTEND;VALUE=DATE-TIME:20150814T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000738@events.thp.uni-koeln.de
DESCRIPTION:Akira Oiwa\, Osaka University\n\nCoupling between single photo
ns to single electron spins in electrically controlled quantum dots\n\nEle
ctrical controllability of gate-defined quantum dots (QDs) has brought sig
nificant developments in the coherent manipulation of electron spins and t
wo-qubit gate operation toward scalable qubits for quantum computations. M
oreover the suitability of gate-defined QDs to quantum information technol
ogies would be considerably enhanced if spin states in the gate-defined QD
s could couple to photon states coherently. Here we show that the photon p
olarization can couple to the spin degree of freedom in gate-defined GaAs
QDs.\nDouble QDs were fabricated in AlGaAs/GaAs quantum wells[1]. By synch
ronizing a pulse laser irradiation with a charge sensing measurement we pe
rformed the real-time single photoelectron spin detection in the double QD
. First we show that the resonant inter-dot tunneling can offer a robust d
etection scheme of the single photoelectrons trapped in the double QDs [2.
3]. In the two-electron regime\, the inter-dot tunneling of the photoelect
rons strongly depends on the relative spin orientation (parallel or anti-p
arallel) of the two QDs. Therefore by combining the resonant inter-dot tun
neling scheme with the Pauli spin effect\, we have realized the nondestruc
tive detection of single photoelectron spins. Finally\, we demonstrate the
angular momentum conversion from single photons to single electron spins
in the double QD from the dependence of the detected spins on the incident
photon polarization. We also discuss the future prospects of the photon-s
pin quantum interface.\nThis work was done in collaboration with T. Fujita
\, K. Morimoto\, G. Allison\, M. Larsson\, H. Kiyama\, S. Teraoka\, S. Haf
fouz\, D. G. Austing\, A. Ludwig\, A. D.Wieck and S. Tarucha.\n\n[1] G. Al
lison et al.\, Phys. Rev. B 90\, 235310 (2014).\n[2] T. Fujita et al.\, Ph
ys. Rev. Lett. 110\, 266803 (2013).\n[3] K. Morimoto et al.\, Phys. Rev. B
90\, 085306 (2014).\n\nContact Person: Yoichi Ando
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Andzrej Jarosz
DTSTART;VALUE=DATE-TIME:20150812T101500
DTEND;VALUE=DATE-TIME:20150812T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000711@events.thp.uni-koeln.de
DESCRIPTION:Andzrej Jarosz\n\nAn invitation to equivariant cohomology and
localization II - The symplectic case\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Ricardo Kennedy
DTSTART;VALUE=DATE-TIME:20150819T101500
DTEND;VALUE=DATE-TIME:20150819T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000712@events.thp.uni-koeln.de
DESCRIPTION:Ricardo Kennedy\, University of Cologne\n\nThe Z_2 Hopf superc
onductor and bulk boundary correspondence\n\n\n\nContact Person: Thomas Qu
ella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Roberto Bondesan
DTSTART;VALUE=DATE-TIME:20150826T101500
DTEND;VALUE=DATE-TIME:20150826T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000713@events.thp.uni-koeln.de
DESCRIPTION:Roberto Bondesan\n\nEffective theory of the IQH transition\n\n
\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Eric Brunet
DTSTART;VALUE=DATE-TIME:20151127T163000
DTEND;VALUE=DATE-TIME:20151127T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000774@events.thp.uni-koeln.de
DESCRIPTION:Eric Brunet\, ENS Paris\n\nUniversal vanishing corrections on
the position of fronts in the Fisher-KPP class\n\nA moving interface\, or
a front\, between a stable and an unstable medium is often described by an
equation such as the Fisher-KPP (Kolmogorov-Petrovsky-Piscounov) equation
. Such an equation appears in biology\, chemistry or theoretical physics.
Thirty years ago\, Bramson gave rigorous sharp estimates on the position o
f the front\, and\, fifteen years ago\, Ebert and van Saarloos heuristical
ly identified universal vanishing corrections. In this seminar\, I will pr
esent two new front equations which we believe to be in the same universal
ity class as the Fisher-KPP equation. For the first equation\, we can writ
e an exact relation between the initial condition and the positions of the
front at all times. For the second equation\, probabilistic methods give
very good estimates on the shape of the front at\nall times. In both cases
\, we can recover and make precise the universal vanishing corrections on
the position of the front.\n\n\n\nContact Person: Joachim Krug
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Tatyana Shestakova
DTSTART;VALUE=DATE-TIME:20151001T150000
DTEND;VALUE=DATE-TIME:20151001T163000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000775@events.thp.uni-koeln.de
DESCRIPTION:Tatyana Shestakova \, Rostow on Don\n\nQuantization methods an
d their applications to gravitational theory \n\n
LOCATION:Conferenceroom 1 (New building)
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Dorottya Szécsi
DTSTART;VALUE=DATE-TIME:20151020T120000
DTEND;VALUE=DATE-TIME:20151020T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000776@events.thp.uni-koeln.de
DESCRIPTION:Dorottya Szécsi \, Bonn\n\nMassive stars at low-metallicity\n
\n
LOCATION:Conferenceroom 1 (New building)
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | David Gross
DTSTART;VALUE=DATE-TIME:20151204T163000
DTEND;VALUE=DATE-TIME:20151204T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000777@events.thp.uni-koeln.de
DESCRIPTION:David Gross\, ITP Cologne\n\nFrom Single Pixel Cameras To Quan
tum State Tomography\n\nEvery time the release button of a digital camera
is pressed\, several megabytes of raw data are recorded. But the size of a
typical jpeg output file is only 10% of that. What a waste! Can't we desi
gn a process which records only the relevant 10% of the data to begin with
? I will give an introduction to the concepts and math of compressed sensi
ng - a theory that achieves this trick for certain signals. A variant of c
ompressed sensing aims to exploit representations of data in terms of low-
rank matrices. There has been a fruitful exchange of ideas between this th
eory and quantum physics. Methods that we had originally introduced in the
context of quantum state estimation have since found applications to task
s as diverse as face recognition\, the analysis of x-ray diffraction image
s\, and the prediction of user preferences in online shops. Specific quant
um information ideas that feature in this context including trace inequali
ties and their use to prove large deviation bounds for random matrices\, p
hase space methods\, and the notion of complex projective designs.
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Igor Burban
DTSTART;VALUE=DATE-TIME:20150916T091500
DTEND;VALUE=DATE-TIME:20150916T104500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000716@events.thp.uni-koeln.de
DESCRIPTION:Igor Burban\n\nQuantum Yang-Baxter equation and the universal
R-matrix\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Alexander Zhuk
DTSTART;VALUE=DATE-TIME:20150910T120000
DTEND;VALUE=DATE-TIME:20150910T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000749@events.thp.uni-koeln.de
DESCRIPTION:Alexander Zhuk\, Odessa\n\nProblematic aspects of Kaluza-Klein
models with Einstein internal spaces\n\nWe consider Kaluza-Klein (KK) mod
els where internal spaces are compact Einstein spaces. These spaces are st
abilized by background matter (e.g.\, monopole form-fields). We perturb th
is background by a compact matter source (e.g.\, the system of gravitating
masses) with the zero pressure in the external/our space and an arbitrary
pressure in the internal space. We show that in the case of curved Einste
in spaces\, the Einstein equations are compatible only if the matter sourc
e is smeared over the internal space and perturbed metric components do no
t depend on coordinates of extra dimensions. The latter means the absence
of KK modes corresponding to the metric fluctuations. There are two possib
ilities to satisfy the gravitational tests. First\, the gravitating source
(e.g. our Sun) should have the black string equation of state in the inte
rnal space. This result does not depend on the size of the internal space.
Second\, if the equation of state in the internal space is arbitrary (e.g
. dust like)\, then the size of the internal space should be small enough
and radion is very massive particle.
LOCATION:Conferenceroom 1 (New building)
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nThe original proof of Bertrand's Theore
m\nJ. L. F. Bertrand
DTSTART;VALUE=DATE-TIME:20150923T101500
DTEND;VALUE=DATE-TIME:20150923T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000717@events.thp.uni-koeln.de
DESCRIPTION:J. L. F. Bertrand\n\nThe original proof of Bertrand's Theorem\
n\nWe discuss the paper "A theorem relative to the motion of a point pulle
d towards a fixed centre" by J.L.F. Bertrand. The result is nowadays known
as "Bertrand's Theorem". Modus operandi: The dice will determine who will
lead the discussion\, so every seminar participant is kindly asked to pre
pare the paper in advance.\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Yuriy A. Stepanov
DTSTART;VALUE=DATE-TIME:20151208T123000
DTEND;VALUE=DATE-TIME:20151208T140000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000795@events.thp.uni-koeln.de
DESCRIPTION:Yuriy A. Stepanov\, University of Duisburg-Essen\n\nFinancial
markets as complex system: geometric data analysis and stochastic modeling
\n\nWe combine geometric data analysis and stochastic methods for data dri
ven modeling of complex systems with application to finance. We identify l
ow dimensional dominating variables and\nextract their stochastic models d
irectly from the data. We identify and analyze quasi-stable states of the
market.\n\nContact Person: Joachim Krug
LOCATION:TP conference room 0.02
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Dominik Ostermayr
DTSTART;VALUE=DATE-TIME:20151119T100000
DTEND;VALUE=DATE-TIME:20151119T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000720@events.thp.uni-koeln.de
DESCRIPTION:Dominik Ostermayr\n\nHarmonic maps from super Riemann surfaces
to projective spaces associated with super divison algebras\n\n\n\nContac
t Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nNonlocal Hidden-Variable Theories and Q
uantum Mechanics\, an Incompatibility Theorem\nA.J. Leggett
DTSTART;VALUE=DATE-TIME:20151022T100000
DTEND;VALUE=DATE-TIME:20151022T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000721@events.thp.uni-koeln.de
DESCRIPTION:A.J. Leggett\n\nNonlocal Hidden-Variable Theories and Quantum
Mechanics\, an Incompatibility Theorem\n\nWe discuss the paper "Nonlocal H
idden-Variable Theories and Quantum Mechanics\, an Incompatibility Theorem
" by A.J. Leggett. Modus operandi: The dice will determine who will lead t
he discussion\, so every seminar participant is kindly asked to prepare th
e paper in advance.\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Abhishek Roy
DTSTART;VALUE=DATE-TIME:20151029T100000
DTEND;VALUE=DATE-TIME:20151029T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000722@events.thp.uni-koeln.de
DESCRIPTION:Abhishek Roy\n\nThe AKLT Hamiltonian for SU(n) - a diagrammati
c method\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Hannah Bergner
DTSTART;VALUE=DATE-TIME:20151105T100000
DTEND;VALUE=DATE-TIME:20151105T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000723@events.thp.uni-koeln.de
DESCRIPTION:Hannah Bergner\, University of Freiburg\n\nAutomorphism groups
of compact complex supermanifolds\n\nBy a result of Bochner and Montgomer
y the automorphism group of a compact complex manifold M carries the struc
ture of a complex Lie group\, whose Lie algebra is isomorphic to the Lie a
lgebra of holomorphic vector fields on M. In this talk\, the case of a com
pact complex supermanifold M is considered. In this setting\, the Lie supe
ralgebra Vec(M) of holomorphic super vector fields on M is finite-dimensio
nal. We investigate how the automorphism group of a compact complex superm
anifold M can be defined and prove that it carries the structure of a comp
lex Lie supergroup with Lie superalgebra Vec(M). (This is joint work with
Matthias Kalus.)\n\nContact Person: Dominik Ostermayr
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nCopenhagen Quantum Mechanics\nTimothy J
. Hollowood
DTSTART;VALUE=DATE-TIME:20151112T100000
DTEND;VALUE=DATE-TIME:20151112T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000724@events.thp.uni-koeln.de
DESCRIPTION:Timothy J. Hollowood\n\nCopenhagen Quantum Mechanics\n\nWe dis
cuss the paper "Copenhagen Quantum Mechanics" by Timothy J. Hollowood. Mod
us operandi: The dice will determine who will lead the discussion\, so eve
ry seminar participant is kindly asked to prepare the paper in advance.\n\
nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Ori Alberton
DTSTART;VALUE=DATE-TIME:20151118T140000
DTEND;VALUE=DATE-TIME:20151118T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000793@events.thp.uni-koeln.de
DESCRIPTION:Ori Alberton\, Weizmann Institute\n\nFate of the one-dimension
al Ising quantum critical point strongly coupled to a gapless phonon\n\nTh
e problem of a quantum Ising degree of freedom coupled to a gapless bosoni
c mode appears naturally in many one dimensional systems\, yet surprisingl
y little is known how such a coupling affects the Ising quantum critical p
oint. We investigate the fate of the critical point in a regime\, where th
e weak coupling RG indicates a flow toward strong coupling. Using renormal
ization group analysis and numerical density matrix renormalization group
(DMRG) calculations we show that quantum fluctuations near the critical po
int cause phase separation on an emergent long scale\, and the transition
becomes first order. This suggests the existence of a tricritical point wi
th potentially exotic properties.\n\nContact Person: Sebastian Diehl
LOCATION:Seminaroom 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nOne Lecture On Topological Phases Of Ma
tter\nEdward Witten
DTSTART;VALUE=DATE-TIME:20151126T100000
DTEND;VALUE=DATE-TIME:20151126T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000727@events.thp.uni-koeln.de
DESCRIPTION:Edward Witten\n\nOne Lecture On Topological Phases Of Matter\n
\nWe discuss the first Lecture of Edward Witten's recent paper "Three Lect
ures\nOn Topological Phases Of Matter". Modus operandi: The dice will dete
rmine who will lead the discussion\, so every seminar participant is kindl
y asked to prepare the paper in advance.\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nTwo more Lectures On Topological Phases
Of Matter\nEdward Witten
DTSTART;VALUE=DATE-TIME:20151203T100000
DTEND;VALUE=DATE-TIME:20151203T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000728@events.thp.uni-koeln.de
DESCRIPTION:Edward Witten\n\nTwo more Lectures On Topological Phases Of Ma
tter\n\nWe discuss the second and the third Lecture of Edward Witten's rec
ent paper "Three Lectures\nOn Topological Phases Of Matter". Modus operand
i: The dice will determine who will lead the discussion\, so every seminar
participant is kindly asked to prepare the paper in advance.\n\nContact P
erson: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Kay Herklotz
DTSTART;VALUE=DATE-TIME:20151210T100000
DTEND;VALUE=DATE-TIME:20151210T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000729@events.thp.uni-koeln.de
DESCRIPTION:Kay Herklotz\, University of Cologne\n\nSU(N) spin chains and
their edge states\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Rochus Klesse
DTSTART;VALUE=DATE-TIME:20160114T100000
DTEND;VALUE=DATE-TIME:20160114T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000732@events.thp.uni-koeln.de
DESCRIPTION:Rochus Klesse\, University of Cologne\n\nExtremal n-fidelities
\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Fabian Heidrich-Meisner
DTSTART;VALUE=DATE-TIME:20160120T143000
DTEND;VALUE=DATE-TIME:20160120T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000804@events.thp.uni-koeln.de
DESCRIPTION:Fabian Heidrich-Meisner\, LMU Munich\n\nSpin and heat transpor
t in low-dimensional quantum magnets\n\n\n\nContact Person: Matteo Montagn
ese
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Martin Zirnbauer
DTSTART;VALUE=DATE-TIME:20160128T100000
DTEND;VALUE=DATE-TIME:20160128T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000734@events.thp.uni-koeln.de
DESCRIPTION:Martin Zirnbauer\, University of Cologne\n\nFix-point search:
How to couple a WZW model to a non-linear sigma-model\n\n\n\nContact Perso
n: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Yoichi Ando
DTSTART;VALUE=DATE-TIME:20160412T164500
DTEND;VALUE=DATE-TIME:20160412T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000818@events.thp.uni-koeln.de
DESCRIPTION:Yoichi Ando\, University of Cologne\n\nTopological Insulators
and Superconductors\n\nTopological insulators and superconductors are new
quantum states of matter that are characterized by nontrivial topological
structures of the Hilbert space. Recently\, they attract a lot of a
ttention because of the appearance of exotic quasiparticles such
as spin-helical Dirac fermions or Majorana fermions on their surface
s\, which hold promise for various novel applications. In this colloquium\
, I will introduce the basics of those materials and present some of the k
ey contributions we have made in this new frontier.\n\nContact Person: Sim
on Trebst
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Eslam Khalaf
DTSTART;VALUE=DATE-TIME:20160211T100000
DTEND;VALUE=DATE-TIME:20160211T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000735@events.thp.uni-koeln.de
DESCRIPTION:Eslam Khalaf\, MPI Stuttgart\n\nAnderson localization at the e
dge of a 2D topological insulator\n\nWe study transport via edge modes in
a disordered 2D topological insulator allowing for the presence of non-pro
tected diffusive channels in addition to the topologically protected edge
channels. This scenario can be realized at the interface between two quant
um Hall system (class A)\, in a Weyl semimetal in a magnetic field (Class
A) or at the edge of a quantum spin Hall system (class AII). The edge tran
sport is described by a one-dimensional field theory in the form of a supe
rsymmetric non-linear sigma model with a topological term. The transfer-ma
trix formalism is employed to map the problem to the problem of finding th
e eigenfunctions of the Laplace operator on a symmetric superspace with an
additional vector potential. The latter problem is solved exactly\, enabl
ing us to obtain the full counting statistics and mesoscopic conductance f
luctuations in the system. Our main finding is that disorder is much more
effective in localizing the diffusive (non-protected) channels in the pres
ence of topologically protected ones. This manifests itself as a suppressi
on of the shot noise at scales much shorter than the localization length a
nd the appearance of a gap in the distribution function of transmission ei
genvalues close to unit transmission.\n\nContact Person: Dmitry Bagrets
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Pavel Ostrovsky
DTSTART;VALUE=DATE-TIME:20160212T140000
DTEND;VALUE=DATE-TIME:20160212T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000810@events.thp.uni-koeln.de
DESCRIPTION:Pavel Ostrovsky\, MPI Stuttgart\n\nAnomalous Hall effect in we
akly disordered ferromagnets\n\nAnomalous Hall effect arises in systems wi
th both spin-orbit coupling and magnetization. Generally\, there are three
mechanisms contributing to anomalous Hall conductivity: intrinsic\, side
jump\, and skew scattering. The standard diagrammatic approach to the anom
alous Hall effect is limited to computation of ladder diagrams. We demonst
rate that this approach is insufficient. An important additional contribut
ion comes from diagrams with a single pair of intersecting disorder lines.
This contribution constitutes an inherent part of skew scattering on pair
s of closely located defects and essentially modifies previously obtained
results for anomalous Hall conductivity. We argue that this statement is g
eneral and applies to all models of anomalous Hall effect. We illustrate i
t by an explicit calculation for two-dimensional massive Dirac fermions an
d for the Rashba ferromagnet model with weak disorder. In the case of Dira
c electrons\, inclusion of the diagrams with crossed impurity lines revers
es the sign of the skew scattering term and strongly suppresses the total
Hall conductivity at high electron concentrations. In the 2D Rashba model\
, the proposed mechanism provides the only contribution to the anomalous H
all conductivity in the most relevant metallic regime.\n\n\nContact Person
: Dmitry Bagrets
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nSupergeometry in mathematics and physic
s\nMikhail Kapranov
DTSTART;VALUE=DATE-TIME:20160204T100000
DTEND;VALUE=DATE-TIME:20160204T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000736@events.thp.uni-koeln.de
DESCRIPTION:Mikhail Kapranov\n\nSupergeometry in mathematics and physics\n
\nWe discuss the paper "Supergeometry in mathematics and physics" by Mikha
il Kapranov. Modus operandi: The dice will determine who will lead the dis
cussion\, so every seminar participant is kindly asked to prepare the pape
r in advance.\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Till Kranz
DTSTART;VALUE=DATE-TIME:20150828T140000
DTEND;VALUE=DATE-TIME:20150828T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000739@events.thp.uni-koeln.de
DESCRIPTION:Till Kranz\, Oxford University\n\nBacteria and Trails on Surfa
ces\n\nSwimming of Bacteria at low Reynolds numbers is relatively well und
erstood.\nMuch less is known about bacteria crawling on surfaces. In parti
cular as\nsome species leave sticky trails that are believed to help them
coordinate.\nI will introduce a simple semi-microscopic model for the bact
eria-trail\ninteraction. Based on this model I will discuss the effects of
the\ntrail-mediated self-interaction on a single bacterium and whether or
not it\nactually allows trail-following behaviour.\n\nContact Person: Joa
chim Krug
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Hua Wu
DTSTART;VALUE=DATE-TIME:20150819T143000
DTEND;VALUE=DATE-TIME:20150819T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000741@events.thp.uni-koeln.de
DESCRIPTION:Hua Wu\, Fudan University\n\nSpin-orbit coupling in transition
-metal based materials\n\nCurrently 5d transition-metal oxides receive con
siderable attention due to their possibly significant spin-orbit coupling
(SOC). In this talk\, we will show\, using ab initio calculations\, that t
he SOC is indeed important in one-dimensional (1D) and 2D 5d transition-me
tal oxides. This is exemplified by addressing the varying magnetic moments
in Fe or Co doped Sr2IrO4 [1] and the SOC tuning magnetism in Sr3NiIrO6 [
2]. However\, the SOC turns insignificant in 3D double perovskites Ca2FeOs
O6 and Sr2NiIrO6 due to the band effect. In contrast to the high-temperatu
re ferrimagnetism in Ca2FeOsO6 [3]\, an unusual magnetic frustration appea
rs in Sr2NiIrO6 [4]. Finally\, we will discuss how to ‘engineer’ a max
imum magnetic\nanisotropy in Co\, Ru\, and Os adatoms on MgO (001) surface
[5].\n\n[1] X. D. Ou & H. Wu\, PRB 89\, 035138 (2014).\n[2] X. D. Ou & H.
Wu\, Sci. Rep. 4\, 4609 (2014).\n[3] H. B. Wang et al.\, PRB 90\, 054406
(2014).\n[4] X. D. Ou et al.\, Sci. Rep. 4\, 7542 (2014).\n[5] X. D. Ou et
al.\, submitted (2015).\n\n\nContact Person: Markus Braden
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Marko Kralj
DTSTART;VALUE=DATE-TIME:20150826T143000
DTEND;VALUE=DATE-TIME:20150826T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000742@events.thp.uni-koeln.de
DESCRIPTION:Marko Kralj\, Institute of Physics - Zagreb\n\nComplex structu
res based on epitaxial graphene\n\nWhile epitaxial growth secures a source
of high-quality graphene for large-scale applications\, it also provides
ample possibilities to study and tune the properties of graphene in terms
of its structure\, electronic bands or electron correlations. In particula
r\, the choice of the substrate and growing conditions can be considered a
s a tool to form more complex structures based on epitaxial graphene.\nIn
this talk I will first present low energy electron microscopy characteriza
tion of graphene on Ir(111) and discuss the "intrinsic" stress-relaxation
features\, wrinkles\, which are a result of graphene growth process on man
y substrates. It will be shown how the specific substrate interaction lead
s to a macroscopic quasi-hexagonal network of wrinkles. Also\, the frustra
tion within the network is identified as a governing force for the formati
on of complex wrinkle profiles with multiple lobes. Furthermore\, the use
of vicinal substrates for the growth of epitaxial graphene will be explore
d as a route for the uniaxial engineering of graphene. Based on scanning t
unneling microscopy and angle-resolved photoemission spectroscopy experime
ntal results as well as van der Waals-density functional theory calculatio
ns\, we propose a general mechanism for the observed vicinal substrate res
tructuring induced by graphene. Moreover\, by comparing graphene grown on
flat and vicinal Ir substrates\, we observe locally variable doping\, the
Dirac cone anisotropy\, and a pronounced localization of states at step ed
ges. In particular\, the anisotropy is associated to a nanoscale potential
modulation induced by the uniaxial pattern\, and the pronounced states to
an enhanced chemical binding and charge transfer. We will also show by at
omic force microscopy and Raman spectroscopy that upon the transfer of suc
h epitaxial graphene to a flat substrate\, the uniaxial strain imposed by
the growth process on a vicinal substrate is macroscopically preserved.\n\
nContact Person: Carsten Busse
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Johannes Reuther
DTSTART;VALUE=DATE-TIME:20150824T140000
DTEND;VALUE=DATE-TIME:20150824T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000743@events.thp.uni-koeln.de
DESCRIPTION:Johannes Reuther\, FU Berlin\n\nClassification of spin liquids
on the square lattice with strong spin-orbit coupling\n\nThe investigatio
n of spin liquids is a fascinating field in condensed\nmatter physics that
is increasingly motivated by experiments. Exhaustive\nclassifications of
spin liquids have been carried out in several systems\,\nparticularly when
full SU(2) spin-rotation symmetry is present. Systematic\nstudies that ex
plore strongly spin-orbit-coupled magnetic compounds (for\nwhich there are
many experimental examples) are\, however\, relatively\nscarce. We report
on a classification of Z_2 spin liquids on the square\nlattice when SU(2)
spin symmetry is maximally lifted. Using projective\nsymmetry group metho
ds\, we find that\, surprisingly\, the lifting of spin\nsymmetry yields va
stly more spin liquid states compared to SU(2)-invariant\nsystems. A gener
ic feature of the SU(2)-broken case is that the spinons\nnaturally undergo
p+ip pairing\; consequently\, many of these Z_2 spin\nliquids feature a t
opologically nontrivial spinon band structure\nsupporting gapless Majorana
edge states. These boundary modes are often\nprotected by a combination o
f time reversal and lattice symmetries and\nhence resemble recently propos
ed topological crystalline superconductors.\n\nContact Person: Simon Trebs
t
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Alessandro Fasse
DTSTART;VALUE=DATE-TIME:20150825T120000
DTEND;VALUE=DATE-TIME:20150825T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000744@events.thp.uni-koeln.de
DESCRIPTION:Alessandro Fasse\, University of Cologne\n\nAn Introduction to
symplectic geometry I - Basics\n\n
LOCATION:SR-THP
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Alessandro Fasse
DTSTART;VALUE=DATE-TIME:20150901T120000
DTEND;VALUE=DATE-TIME:20150901T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000745@events.thp.uni-koeln.de
DESCRIPTION:Alessandro Fasse\, University of Cologne\n\nAn Introduction to
symplectic geometry II - Applications in physics\n\nIn the first talk we
have seen that Symplectic Geometrie is a generalization of Hamilton mechan
ics and gives us a way to describe and see the phase space in geometrical
terms. In this continuation we will talk about several applications of mat
hematical theorems to physics\, e.g. Gromov's theorem from 1985 and the pr
oblem of geometric quantization.
LOCATION:SR-THP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Dirk Honecker
DTSTART;VALUE=DATE-TIME:20150930T143000
DTEND;VALUE=DATE-TIME:20150930T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000746@events.thp.uni-koeln.de
DESCRIPTION:Dirk Honecker\, Institut Laue-Langevin\, Grenoble \n\nMagnetic
small-angle neutron scattering of bulk ferromagnets\n\n\n\nContact Person
: Sabrina Disch
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | David Mikhail
DTSTART;VALUE=DATE-TIME:20150831T100000
DTEND;VALUE=DATE-TIME:20150831T110000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000747@events.thp.uni-koeln.de
DESCRIPTION:David Mikhail\n\nEinfluss des Tunnelns durch das Vakuum auf Me
ssungen der lokalen Zustandsdichte in Graphen in Anwesenheit einer Stoerst
elle.\n\n\n\nContact Person: Achim Rosch
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Erik Aurell
DTSTART;VALUE=DATE-TIME:20160115T163000
DTEND;VALUE=DATE-TIME:20160115T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000748@events.thp.uni-koeln.de
DESCRIPTION:Erik Aurell\, KTH Stockholm\n\nMinimal absent words in genome
sequences\n\nAbsent words are sub-sequences of letters that cannot be foun
d in a given text. Minimal absent words (MAWs) are absent words all of the
sub-sequences of which can be found in the text.\nIt has been observed fo
r some time that the length distribution of MAWs in genome sequences have
a curious two-mode structure with on the one hand many long fairly short M
AWs ("the\nbulk") and on the other hand some very long MAWs ("the tail").
I will show that the first feature arises from statistical sampling of sub
-sequences from a random genome while the second\ncan be explained by a si
mple probabilistic model of genome evolution. Tail MAWs also seem to carry
biological information as will be discussed in the talk. We were led to t
he study of\nMAWs from a biotechnological problem of optimal tag design fo
r (tagged) RNA-sequencing. I will therefore also describe some of the resu
lts obtained by this method to distinguish primary\nfrom processed RNA in
the human pathogen Enterococcus faecalis\, including the discovery of many
new non-coding genes in this organism.\n\nContact Person: Michael Lässig
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Sandipan Sengupta
DTSTART;VALUE=DATE-TIME:20150929T120000
DTEND;VALUE=DATE-TIME:20150929T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000750@events.thp.uni-koeln.de
DESCRIPTION:Sandipan Sengupta\, University of Pune\n\nTorsional instantons
effects in quantum gravity and phenomenological implications\n\nWe show t
hat in the first order gravity theory coupled to axions\, there exist new
kind of instanton configurations (solutions of Euclidean equations of moti
on) whose instanton number can be interpreted as the torsional Nieh-Yan to
pological index. These torsional pseudoparticles turn out to be the Giddin
gs-Strominger wormholes. Importantly\, these instantons are shown to induc
e tunneling between degenerate topological vacua in gravity theory\, leadi
ng to a rich vacuum structure exactly similar to the famous theta vacuum o
f gauge theories. This nonperturbative quantum vacuum is characterised by
a topological vacuum angle\, which can be identified with the Barbero-Immi
rzi parameter. We conclude with a discussion on how this nonperturbative v
acuum structure in quantum gravity\, hitherto unnoticed\, could have impor
tant implications in the context of cosmology and various parity violating
phenomena in particle physics. In particular\, based on this framework\,
we propose a possible solution to the cosmological constant
LOCATION:Conferenceroom 1 (New building)
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Bela Bauer
DTSTART;VALUE=DATE-TIME:20150925T140000
DTEND;VALUE=DATE-TIME:20150925T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000751@events.thp.uni-koeln.de
DESCRIPTION:Bela Bauer\, Microsoft Station Q\n\nTopological Crystalline Bo
se Insulators in Two Dimensions\n\n\n\nContact Person: Simon Trebst
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Philipp Weiss
DTSTART;VALUE=DATE-TIME:20150924T140000
DTEND;VALUE=DATE-TIME:20150924T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000752@events.thp.uni-koeln.de
DESCRIPTION:Philipp Weiss\, Karlsruhe Institute for Technology\n\nInterfer
ence of quantum critical excitations and soft diffusive modes in a disorde
red antiferromagnetic metal\n\n\n\nContact Person: Achim Rosch
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Ian Affleck
DTSTART;VALUE=DATE-TIME:20150923T143000
DTEND;VALUE=DATE-TIME:20150923T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000753@events.thp.uni-koeln.de
DESCRIPTION:Ian Affleck\, University of Vancouver\n\nOrbital Kondo Effect
in Fractional Quantum Hall Systems\n\n\n\nContact Person: Achim Rosch
LOCATION:Seminar room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Elizabeth Winstanley
DTSTART;VALUE=DATE-TIME:20151027T120000
DTEND;VALUE=DATE-TIME:20151027T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000754@events.thp.uni-koeln.de
DESCRIPTION:Elizabeth Winstanley\, University of Sheffield\n\nRotating qua
ntum states \n\nIn the canonical quantization of fields on curved space-ti
me\, the definition\nof the vacuum state is of fundamental importance. We
consider the definition\nof vacuum states for scalar and fermion fields on
rotating Minkowski and\nanti-de Sitter space-times. The construction of
the vacuum state for a\nfermion field is much less constrained than for a
scalar field. We explore\nthe consequences of this freedom for the definit
ion of rotating thermal\nstates.
LOCATION:Conferenceroom 1 (New building)
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Alexander Drewitz
DTSTART;VALUE=DATE-TIME:20151023T163000
DTEND;VALUE=DATE-TIME:20151023T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000755@events.thp.uni-koeln.de
DESCRIPTION:Alexander Drewitz\, Mathematisches Institut Köln\n\nThe maxim
al particle of branching random walk in random environment\n\nOne-dimensio
nal branching Brownian motion has been the subject of intensive research\,
in particular during the last decade. We consider the discrete space vers
ion of branching random walk and investigate the setting of a spatially ra
ndom branching environment\; in particular we are interested in the positi
on of the maximal particle. Via the Feynman-Kac formula this is connected
to fluctuations of the solutions to the parabolic Anderson model (i.e.\, t
he heat equation with a random potential) as well as to a randomized versi
on of the Fisher-KPP equation. The Fisher-KPP equation is a fundamental re
action-diffusion partial differential equation which had originally been i
ntroduced in order to model the spread of an advantageous alelle in a popu
lation of a one-dimensional habitat.
LOCATION:seminar room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Oliver Bürschaper
DTSTART;VALUE=DATE-TIME:20150916T111500
DTEND;VALUE=DATE-TIME:20150916T124500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000756@events.thp.uni-koeln.de
DESCRIPTION:Oliver Bürschaper\n\nProtected gates for topological quantum
field theories\n\nWe give restrictions on the locality-preserving unitary
automorphisms U\, which are protected gates\, for topologically ordered sy
stems. For arbitrary anyon models\, we show that such unitaries only gener
ate a finite group\, and hence do not provide universality. For abelian an
yon models\, we find that the logical action of U is contained in a proper
subgroup of the generalized Clifford group. In the case D(Z2)\, which des
cribes Kitaev's toric code\, this represents a tightening of statement pre
viously obtained within the stabilizer framework (PRL 110:170503). For non
-abelian models\, we find that such automorphisms are very limited: for ex
ample\, there is no non-trivial gate for Fibonacci anyons. For Ising anyon
s\, protected gates are elements of the Pauli group. These results are der
ived by relating such automorphisms to symmetries of the underlying anyon
model: protected gates realize automorphisms of the Verlinde algebra. We a
dditionally use the compatibility with basis changes to characterize the l
ogical action. \n\nContact Person: David Gross
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Jamir Marino
DTSTART;VALUE=DATE-TIME:20151009T140000
DTEND;VALUE=DATE-TIME:20151009T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000757@events.thp.uni-koeln.de
DESCRIPTION:Jamir Marino\, TU Dresden\n\nDriven Markovian Quantum Critical
ity\n\nWe identify a new universality class in one-dimensional driven open
quantum systems with a dark state. Salient features are the persistence o
f both the microscopic non-equilibrium conditions as well as the quantum c
oherence of dynamics close to criticality. This provides a non-equilibrium
analogue of quantum criticality\, and is sharply distinct from more gener
ic driven systems\, where both effective thermalization as well as asympto
tic decoherence ensue\, paralleling classical dynamical criticality. We qu
antify universality by computing the full set of independent critical expo
nents within a functional renormalization group approach.\n\n\n\nContact P
erson: Philipp Strack
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Marijan Beg
DTSTART;VALUE=DATE-TIME:20151023T140000
DTEND;VALUE=DATE-TIME:20151023T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000758@events.thp.uni-koeln.de
DESCRIPTION:Marijan Beg\, University of Southampton\n\nGround state search
\, hysteretic behaviour\, reversal mechanism\, and normal modes of skyrmio
nic textures in confined helimagnetic nanostructures\n\nMagnetic skyrmions
have the potential to provide solutions for low-power\, high-density data
storage and processing. One of the major challenges in developing skyrmio
n-based devices is the skyrmions' magnetic stability in confined helimagne
tic nanostructures. Through a systematic study of equilibrium states\, usi
ng a full three-dimensional micromagnetic model including demagnetisation
effects\, we demonstrate that skyrmionic textures are the lowest energy st
ates in helimagnetic thin film nanostructures at zero external magnetic fi
eld and in absence of magnetocrystalline anisotropy. We also report the re
gions of metastability for non-ground state equilibrium configurations. We
show that bistable skyrmionic textures undergo hysteretic behaviour betwe
en two energetically equivalent skyrmionic states with different core orie
ntation\, even in absence of both magnetocrystalline and demagnetisation-b
ased shape anisotropies\, suggesting the existence of novel Dzyaloshinskii
-Moriya-based shape anisotropy. We also show that the skyrmionic texture c
ore reversal dynamics is facilitated by the Bloch point occurrence and pro
pagation. Finally\, we report the resonance frequencies and corresponding
normal modes of all identified equilibrium states as well as how the reson
ance frequencies change depending on both the external magnetic bias field
and disk sample diameter.\n\nContact Person: Markus Garst
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Lukas Heinen
DTSTART;VALUE=DATE-TIME:20151021T100000
DTEND;VALUE=DATE-TIME:20151021T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000759@events.thp.uni-koeln.de
DESCRIPTION:Lukas Heinen\n\nDipolar Interactions in Thin Films of Chiral M
agnets\n\n
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Jan Gelhausen
DTSTART;VALUE=DATE-TIME:20151028T100000
DTEND;VALUE=DATE-TIME:20151028T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000760@events.thp.uni-koeln.de
DESCRIPTION:Jan Gelhausen\n\nMany-body localization\n\n
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Robert Bamler
DTSTART;VALUE=DATE-TIME:20151104T100000
DTEND;VALUE=DATE-TIME:20151104T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000761@events.thp.uni-koeln.de
DESCRIPTION:Robert Bamler\n\nTheory for forces on smooth magnetic textures
\n\n
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Kevin O'Brien
DTSTART;VALUE=DATE-TIME:20151111T100000
DTEND;VALUE=DATE-TIME:20151111T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000762@events.thp.uni-koeln.de
DESCRIPTION:Kevin O'Brien\n\nWeyl Spin Liquids\n\n
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Max Genske
DTSTART;VALUE=DATE-TIME:20151118T100000
DTEND;VALUE=DATE-TIME:20151118T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000763@events.thp.uni-koeln.de
DESCRIPTION:Max Genske\n\nThe Floquet-Boltzmann equation\n\n
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Laura Koehler
DTSTART;VALUE=DATE-TIME:20151125T100000
DTEND;VALUE=DATE-TIME:20151125T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000764@events.thp.uni-koeln.de
DESCRIPTION:Laura Koehler\n\nStrongly correlated critical chiral paramagne
ts\n\n
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Rubens Carvalho
DTSTART;VALUE=DATE-TIME:20151202T100000
DTEND;VALUE=DATE-TIME:20151202T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000765@events.thp.uni-koeln.de
DESCRIPTION:Rubens Carvalho\n\nEffects of band-filling and disorder in the
Falicov-Kimball model\n\n
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Finn Lasse Buessen
DTSTART;VALUE=DATE-TIME:20151209T100000
DTEND;VALUE=DATE-TIME:20151209T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000766@events.thp.uni-koeln.de
DESCRIPTION:Finn Lasse Buessen\n\nIntroduction to the Pseudo-Fermion Funct
ional Renormalization Group\n\n
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | David Mesterhazy & Florian Hebenstreit
DTSTART;VALUE=DATE-TIME:20151218T100000
DTEND;VALUE=DATE-TIME:20151218T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000803@events.thp.uni-koeln.de
DESCRIPTION:David Mesterhazy & Florian Hebenstreit\, Universitity of Bern
\n\nDissipative dynamics of Bose-Einstein condensation and entanglement ge
neration\n\nWe elaborate on a proposal for the state preparation of quantu
m many-body systems by engineered dissipation. Specifically\, we discuss t
he purely dissipative dynamics of a large system of s = 1/2 quantum spins
or\, equivalently\, hard-core bosons on a regular lattice. In the first pa
rt of the talk\, we introduce the underlying quantum master equation (Lind
blad equation) and exemplify how it can be used to determine the equations
of motion for correlation functions. In the second part of the talk\, we
resolve the real-time dynamics of the dissipative process. This allows us
to identify different characteristic time scales for the dynamics for whic
h we determine their finite-size scaling. We introduce the concept of cumu
lative entanglement distribution to quantify multi-particle entanglement a
nd show that the considered protocol serves as an efficient method to prep
are a macroscopically entangled Bose-Einstein condensate.\n\nContact Perso
n: Sebastian Diehl
LOCATION:Seminar Room 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Christopher Bartel
DTSTART;VALUE=DATE-TIME:20160113T100000
DTEND;VALUE=DATE-TIME:20160113T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000769@events.thp.uni-koeln.de
DESCRIPTION:Christopher Bartel\n\nModeling Newton's Cradle\n\n
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Johannes Waizner
DTSTART;VALUE=DATE-TIME:20160127T100000
DTEND;VALUE=DATE-TIME:20160127T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000770@events.thp.uni-koeln.de
DESCRIPTION:Johannes Waizner\n\nChiral magnetic resonances\, linear dichro
ism\, and spin-wave excitations in skyrmion crystals\n\n
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Johannes Helmes
DTSTART;VALUE=DATE-TIME:20160203T100000
DTEND;VALUE=DATE-TIME:20160203T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000771@events.thp.uni-koeln.de
DESCRIPTION:Johannes Helmes\n\nBoson fermion duality in corner entanglemen
t entropies of free field theories\n\n
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Yoran Tournois
DTSTART;VALUE=DATE-TIME:20160210T100000
DTEND;VALUE=DATE-TIME:20160210T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000772@events.thp.uni-koeln.de
DESCRIPTION:Yoran Tournois\n\nProperties of non-abelian excitations in the
fractional quantum Hall effect\n\n
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Stephanie Matern
DTSTART;VALUE=DATE-TIME:20151211T140000
DTEND;VALUE=DATE-TIME:20151211T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000773@events.thp.uni-koeln.de
DESCRIPTION:Stephanie Matern\n\nUnconventional magnetism in spin-orbit ent
angled Mott insulators (Master Colloquium)\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | S. Santhosh Kumar
DTSTART;VALUE=DATE-TIME:20151030T120000
DTEND;VALUE=DATE-TIME:20151030T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000783@events.thp.uni-koeln.de
DESCRIPTION:S. Santhosh Kumar \, IISER\, Trivandrum\n\nUnderstanding Hawki
ng temperature from quantum entanglement\n\nOne of the strong connection b
etween the quantum information\ntheory and the black hole physics is based
on the conjecture of interpreting\nentanglement entropy as the black hole
entropy\, which passed various\nnumerical tests. In the present talk\, we
add yet another strong supportive\nevidence to this conjecture\, that is
we numerically show that the\ntemperature of entanglement is same as the H
awking temperature of black hole\nfor massless free scalar fields. Also we
show the validity of the first law\nof black hole mechanics using entangl
ement entropy and temperature.
LOCATION:0.03 (Neubau)
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Arijeet Pal
DTSTART;VALUE=DATE-TIME:20151218T140000
DTEND;VALUE=DATE-TIME:20151218T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000779@events.thp.uni-koeln.de
DESCRIPTION:Arijeet Pal\, University of Oxford\n\nFinite temperature mobil
ity edge in many-body localized systems\n\nThe ergodic hypothesis for an i
solated quantum system has been a subject of intense investigation in rece
nt years. Under what conditions does a quantum system thermalize in the ab
sence of a heat bath? It has been argued that in the presence of strong di
sorder\, a system loses its ability to equilibrate itself even at infinite
temperature\, a phenomena now known as many-body localization (MBL). I wi
ll review the basic notions of this new phase of matter characterized by i
ts dynamics. Due to the violation of equilibrium statistical physics in th
is phase\, MBL protects topological and symmetry-breaking orders in situat
ions where they are destroyed at thermal equilibrium.\n\nIn this talk I wi
ll discuss the phase transition between MBL and ergodic phases tuned by en
ergy density\, leading to a finite temperature mobility edge. As concrete
examples I will focus on the one-dimensional random-field Heisenberg and t
he infinite-dimensional quantum random energy models. The latter has been
a useful mean-field model for analyzing the thermodynamic spin-glass trans
ition. Its tractability allows the comparison between analytical and numer
ical study of a finite temperature mobility edge.\n\nContact Person: Phili
pp Strack
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Michael Scherer
DTSTART;VALUE=DATE-TIME:20151120T140000
DTEND;VALUE=DATE-TIME:20151120T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000780@events.thp.uni-koeln.de
DESCRIPTION:Michael Scherer\, University of Heidelberg\n\nCompetition of d
ensity waves and quantum multicritical behavior in Dirac materials\n\nI di
scuss the competition of spin- and charge-density waves and their quantum
multicritical behavior for the semimetal-insulator transitions of low-dime
nsional Dirac fermions. Employing the effective Gross-Neveu-Yukawa theory
with two order parameters as a model for graphene and a growing number of
other two-dimensional Dirac materials allows us to describe the physics ne
ar the multicritical point at which the semimetallic and the two ordered p
hases meet. With the functional renormalization group approach\, we reveal
a complex structure of fixed points. Their the stability properties decis
ively depend on the number of Dirac fermions Nf. We give estimates for the
critical exponents and observe crucial quantitative corrections as compar
ed to a previous first-order epsilon expansion. For small Nf\, the univers
al behavior near the multicritical point is determined by the chiral Heise
nberg universality class supplemented by a decoupled\, purely bosonic\, Is
ing sector. At large Nf\, a novel fixed point with nontrivial couplings be
tween all sectors becomes stable. At intermediate Nf\, including the graph
ene case (Nf=2) no stable and physically admissible fixed point exists. We
therefore suggest that Graphene's phase diagram in the vicinity of the in
tersection between the semimetal\, antiferromagnetic and staggered density
phases is governed by a triple point exhibiting first-order transitions.\
n\nContact Person: Philipp Strack
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Tapio Ala-Nissilä
DTSTART;VALUE=DATE-TIME:20160212T163000
DTEND;VALUE=DATE-TIME:20160212T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000781@events.thp.uni-koeln.de
DESCRIPTION:Tapio Ala-Nissilä\, Aalto University\, Helsinki\n\nDemon’s
Work in the Classical and Quantum Worlds\n\nStochastic thermodynamics offe
rs a powerful formalism to study\nfluctuating thermodynamic variables\, su
ch as (free) energy\, entropy\,\nheat\, and work in small systems driven b
eyond the linear response\nregime. Small electronic devices\, such as sing
le-electron boxes and\nquantum dots have been recently shown to provide we
ll-controlled\nbenchmarks for stochastic thermodynamics. In particular\, i
t is\npossible to realize the ubiquitous concepts of a Szilard engine and\
na Maxwell’s demon in such systems. While stochastic\nthermodynamics giv
es a complete theoretical picture for devices such\nas the Maxwell’s dem
on at classical level\, attempts to generalize the\nconcept of work (and o
ther thermodynamic quantities) to open\nquantum systems have met with some
difficulties. The main problem\nin quantum mechanics is that there is no
unique work operator\, since\nfor irreversible processes work depends both
on the state of the\nsystem as well as the path taken.\n\nIn this talk I
will discuss the analysis of devices such as the\nMaxwell’s demon based
on stochastic thermodynamics at the classical\nlevel. I will then describe
some recent progress in defining work\nand its moments for quantum system
s within the two-measurement\nprotocol (TMP) approach\, which for isolated
systems coincides with the\nclassical definition of work in the appropria
te limit. In particular\, I will\nshow that using the TMP within the Linbl
ad master equation formalism\nyields explicit results for driven\, open qu
antum systems.\n\nContact Person: Joachim Krug
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Torsten Karzig
DTSTART;VALUE=DATE-TIME:20151030T140000
DTEND;VALUE=DATE-TIME:20151030T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000782@events.thp.uni-koeln.de
DESCRIPTION:Torsten Karzig\, Microsoft Station Q\n\nSteps towards robust q
uantum computation with Majorana bound states\n\nBraiding of Majorana zero
modes provides a promising platform for quantum information processing. S
trictly speaking\, however\, the scheme relies on infinite braiding times
as it utilizes the adiabatic limit. I will discuss how to minimize nonadia
batic errors for finite braiding times by finding an optimal protocol for
the Majorana movement or adding so-called counter-diabatic terms to the Ha
miltonian.\n\nIn the second part of the talk I will present a scheme to su
bstantially increase the robustness of a Majorana pi/8 phase gate\, which
is a missing ingredient when implementing universal quantum computation us
ing Majorana bound states.\n\nContact Person: Maria Hermanns
LOCATION:0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Gunter M. Schütz
DTSTART;VALUE=DATE-TIME:20160415T163000
DTEND;VALUE=DATE-TIME:20160415T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000784@events.thp.uni-koeln.de
DESCRIPTION:Gunter M. Schütz\, Forschungszentrum Jülich\n\nThe Fibonacci
family of dynamical universality classes\n\nWe use the universal nonlinea
r fluctuating hydrodynamics\napproach to study anomalous one-dimensional t
ransport far from\nthermal equilibrium in terms of the dynamical structure
function.\nGenerically for more than one conservation law mode coupling t
heory\nis shown to predict a discrete family of dynamical universality\ncl
asses with dynamical exponents which are consecutive ratios of\nneighborin
g Fibonacci numbers\, starting with z = 2 (corresponding\nto a diffusive m
ode) or z = 3/2 (Kardar-Parisi-Zhang (KPZ) mode).\nIf neither a diffusive
nor a KPZ mode are present\, all Fibonacci\nmodes have as dynamical expone
nt the golden mean z=(1+\\sqrt5)/2.\nThe scaling functions of the Fibonacc
i modes are asymmetric Levy\ndistributions which are completely fixed by t
he macroscopic\nstationary properties\, viz. the current-density relation
and the\ncompressibility matrix of the system. The theoretical predictions
\nare confirmed by Monte-Carlo simulations of a three-lane asymmetric\nsim
ple exclusion process.\n\n\nContact Person: Joachim Krug
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Yoshio Kuramoto
DTSTART;VALUE=DATE-TIME:20151026T161500
DTEND;VALUE=DATE-TIME:20151026T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000785@events.thp.uni-koeln.de
DESCRIPTION:Yoshio Kuramoto\, Institute of Materials Structure Science KE
K\, Tsukuba\, Japan\n\nOrthogonality and exciton correlations leading to K
ondo-like effect\n\nIn certain Sm systems with mixed valence such as SmOs4
Sb12 and\nSmT2Al20 with T=Ti\, V\, Cr\, Ta\, etc\, the resistivity and spe
cific heat\nshow behaviors reminiscent of the Kondo effect. However\, the
\nbehaviors are almost independent of applied magnetic field. We\nascribe
the Kondo-like behavior to charge correlations. Acccoding to\nour model\
, the effective hybridization of Sm 4f-electrons is reduced\nby the orthog
onality effect with the Coulomb interaction U between 4f\nand conduction e
lectrons. The Coulomb interaction also acts to\nenhance the hybridization
via the exciton-like correlation. The\northogonality effect becomes domin
ant as U and/or the number of\nconduction channels increases\, and eventua
lly makes the effective\nhybridization vanish. We combine the continuous-
time Monte Carlo\ncalculation and the analytic theory to derive the dynami
cs in the wide\ntemperature range.\n\nContact Person: Achim Rosch
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Peter Zoller
DTSTART;VALUE=DATE-TIME:20151214T160000
DTEND;VALUE=DATE-TIME:20151214T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000786@events.thp.uni-koeln.de
DESCRIPTION:Peter Zoller\, University of Innsbruck\n\nDriven Dissipative O
pen Many-Body Systems in Quantum Optics \n\n\n\nContact Person: Achim Rosc
h
LOCATION:HS II
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Sebastian Diehl
DTSTART;VALUE=DATE-TIME:20160108T163000
DTEND;VALUE=DATE-TIME:20160108T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000787@events.thp.uni-koeln.de
DESCRIPTION:Sebastian Diehl\, ITP Cologne\n\nUniversal Quantum Dynamics in
Driven Open Many-Body Systems\, and Localized Majorana-like Modes in Inte
racting Fermion Systems\n\nThe talk is divided into two parts.\nIn part on
e\, we discuss universal aspects of quantum dynamics present in driven ope
n many-particle systems. Oftentimes\, driven systems show full decoherence
at large wavelength\, but we present two situations which do not follow t
his generic pattern. The first concerns the critical dynamics in a driven
open system with a dark state realizable in microcavity arrays\, and the o
ther one an ensemble of Rydberg atoms\, in which coherent quantum dynamics
leads to a variant of a non-equilibrium absorbing state transition withou
t direct classical counterpart.\nIn part two\, we discuss\, in a number co
nserving framework\, an exactly solvable model of interacting fermions sup
porting non-local zero-energy Majorana-like edge excitations. The construc
tion draws intuition from an approach of targeted dissipative cooling into
topologically non-trivial states. The model has an exactly solvable line\
, on varying the density of fermions\, described by a topologically non-tr
ivial ground state wave-function. We characterize its thermodynamic and to
pological properties. Knowledge of the ground state wavefunction allows us
to construct analytically number conserving braiding operators\, which ar
e exponentially localized at the edges.
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Igor Mekhov
DTSTART;VALUE=DATE-TIME:20160115T140000
DTEND;VALUE=DATE-TIME:20160115T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000788@events.thp.uni-koeln.de
DESCRIPTION:Igor Mekhov\, Oxford University\n\nUsing quantized light in ul
tracold atom problems\n\nAlthough light is the main tool in quantum gas ph
ysics\, its quantumness is often neglected. We show that elevating light t
o a quantum variable leads to a plethora of novel many-body phenomena\, un
obtainable in classical optical setups. \n First\, we prove that the quan
tum backaction of a weak global measurement can efficiently compete with s
tandard short-range processes in a strongly correlated system (ultracold b
osons or fermions in an optical lattice)\, leading to novel phenomena. We
demonstrate generation of the multimode generalizations of Schroedinger ca
t and NOON states\, nonlocal quantum Zeno dynamics\, and non-Hermitian pro
cesses without the need of postselection. For fermions\, we show the measu
rement-induced antiferromagnetic states\, as well as the protection and br
eak-up of strongly interacting fermion pairs. The backaction results in th
e generation of genuinely multipartite entangled modes of matter waves\, w
hich show non-Gaussian properties beyond quantum optical analogues. \n Se
cond\, trapping quantum gases inside a high-Q cavity\, creates a paradigm
of quantum optical lattices. We demonstrate the emergence of novel many-bo
dy phases: delocalized dimers\, trimers\, etc. of matter waves\, even beyo
nd the density orders such as density waves and supersolids. We show that
cavity QED of strongly correlated systems can efficiently simulate systems
with short- and long-range interactions\, while still profiting from the
collective enhancement of the light-matter interaction.\n\nContact Person:
Philipp Strack
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Tobias Fritz
DTSTART;VALUE=DATE-TIME:20151111T100000
DTEND;VALUE=DATE-TIME:20151111T110000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000789@events.thp.uni-koeln.de
DESCRIPTION:Tobias Fritz\, MIS Leipzig\n\nThe mathematical structure of re
source theories\n\nResources and the problem of their efficient use form a
n\nessential part of engineering and sometimes even of everyday life. I\nw
ill introduce a mathematical toolbox for dealing with problems of this\nfo
rm\, and sketch some applications to information theory and graph\ntheory.
Given enough time and interest\, I can explain the difficulties\nthat one
faces when trying to extend this framework to approximate\nresource conve
rsions\, as they are commonly considered in information theory.\n\nContact
Person: David Gross
LOCATION:TP Neubau 1.04
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Frank Meyer zu Heringdorf
DTSTART;VALUE=DATE-TIME:20151209T143000
DTEND;VALUE=DATE-TIME:20151209T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000791@events.thp.uni-koeln.de
DESCRIPTION:Frank Meyer zu Heringdorf\, University of Duisburg-Essen\n\nPl
asmoemission: Emission of Electrons in a strong Plasmonic Field\n\n\n\nCo
ntact Person: Thomas Michely
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Giulio Monaco
DTSTART;VALUE=DATE-TIME:20151116T150000
DTEND;VALUE=DATE-TIME:20151116T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000792@events.thp.uni-koeln.de
DESCRIPTION:Giulio Monaco\, University of Trento\n\nInelastic X-ray scatte
ring experiments to probe electronic excitations\n\nInelastic X-ray scatte
ring at third generation synchrotron sources is a technique gaining an inc
reasing interest from a growing community of users. Referring to the capab
ilities of beamline ID20 at the ESRF\, I will recall the main fields of ac
tivity for IXS to probe electronic excitations in condensed matter\, focus
ing in particular on resonant inelastic X-ray scattering experiments at th
e Ir L3 edge.\n\nContact Person: Paul van Loosdrecht
LOCATION:Conference Room II\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Su-Chan Park
DTSTART;VALUE=DATE-TIME:20160225T140000
DTEND;VALUE=DATE-TIME:20160225T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000817@events.thp.uni-koeln.de
DESCRIPTION:Su-Chan Park\, Catholic University of Korea\n\nRigorous Thermo
dynamics and the Entropy Principle\n\n\n\nContact Person: Joachim Krug
LOCATION:TP conference room 0.01
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Alessandro Fasse
DTSTART;VALUE=DATE-TIME:20151208T120000
DTEND;VALUE=DATE-TIME:20151208T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000800@events.thp.uni-koeln.de
DESCRIPTION:Alessandro Fasse\, University of Cologne\n\nNaked Singularitie
s in the canonical quantized LTB-Model\n\nThe final state of a spherically
symmetric star always admits a singularity at its center if only gravitat
ional effects are considered. This singularity is covered by an event hori
zon in most cases. However\, the existence of singularities in final theor
y of Quantum Gravity is so far unclear. For some initial conditions to the
matter distribution it is possible that the formed singularity might be t
emporary visible. This case is called a naked singularity and is of centra
l interest in this thesis. Their existence implies the breakdown of Genera
l Relativity itself\, since it manifests that future is unpredictable from
initial data alone. Anything could form in the central singularity due to
the presence of an infinitely large energy density. It was shown that ini
tial conditions leading to naked singularities are physically meaningful a
nd cannot be neglected. The following question arises: Are singularities a
n artifact of General Relativity itself and can be resolved by taking quan
tum mechanical effects into account? Here we show\, that for a specific mo
del containing a naked singularity\, we obtain an everywhere vanishing wav
e function. This result can be interpreted as the avoidance of the classic
ally allowed naked singularity. Furthermore\, our toy model shows certain
similarities to the Friedmann-Lemaitre-Robertson-Walker metric (FLRW metri
c). We show that a specific perturbation around this solution is also quan
tum mechanically forbidden. Our results demonstrate that canonical quantiz
ation is at least in our case capable of contributing to the ongoing debat
e on singularity avoidance. However\, we consider only one case of a naked
singularity and a result the general case of (naked) singularities still
remains unclear.
LOCATION:Conferenceroom 1 (New building)
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Marc Schulz
DTSTART;VALUE=DATE-TIME:20160108T140000
DTEND;VALUE=DATE-TIME:20160108T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000796@events.thp.uni-koeln.de
DESCRIPTION:Marc Schulz\, University of Minnesota\n\nFrustrated topologica
l symmetry breaking: geometrical frustration and anyon condensation\n\n\n\
nContact Person: Johannes Helmes
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Vincent Cros
DTSTART;VALUE=DATE-TIME:20151221T160000
DTEND;VALUE=DATE-TIME:20151221T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000797@events.thp.uni-koeln.de
DESCRIPTION:Vincent Cros\, Universite Paris-Sud\n\nSub-100 nm skyrmions at
room temperature: From magnetic thin films to asymmetric magnetic multila
yers\n\n\n\nContact Person: Jan Mueller
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Manuel Zohlen
DTSTART;VALUE=DATE-TIME:20151210T084500
DTEND;VALUE=DATE-TIME:20151210T093000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000798@events.thp.uni-koeln.de
DESCRIPTION:Manuel Zohlen\n\nVortex crystallization in a bilayer Heisenber
g-Kitaev model\n\n\n\nContact Person: Simon Trebst
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Wilfried Michel
DTSTART;VALUE=DATE-TIME:20151211T150000
DTEND;VALUE=DATE-TIME:20151211T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000799@events.thp.uni-koeln.de
DESCRIPTION:Wilfried Michel\n\nFinite-Temperature Sensitivity of Entanglem
ent Spectra and Their Numerical Reconstruction from Renyi Entropies (Maste
r Colloquium)\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Christoph Droesser
DTSTART;VALUE=DATE-TIME:20160510T164500
DTEND;VALUE=DATE-TIME:20160510T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000801@events.thp.uni-koeln.de
DESCRIPTION:Christoph Droesser\, Die Zeit\n\nSechs Argumente\, warum Sie a
lle musikalisch sind\n\nViele Menschen halten sich für unmusikalisch. Sie
mögen ihre Stimme nicht \nund singen nicht mit\, wenn in Gesellschaft Li
eder angestimmt werden. Aber \nneue Erkenntnisse der Hirnforschung zeigen\
, dass bis auf eine kleine Minderheit praktisch jeder Mensch musikalische
Fähigkeiten besitzt. Wir kommen mit einem fest verdrahteten musikalischen
Sinn auf die Welt. Der Vortrag zeigt anhand von überzeugenden Tonbe
ispielen\, wie viel Musikalität \nin jedem Menschen steckt\, auch wen
n er nie ein virtuoser Musiker werden wird.\n\nContact Person: Simon Trebs
t
LOCATION:HS I
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Michael Brockmann
DTSTART;VALUE=DATE-TIME:20160226T140000
DTEND;VALUE=DATE-TIME:20160226T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000802@events.thp.uni-koeln.de
DESCRIPTION:Michael Brockmann\, MPI PKS Dresden\n\nEquilibration in the sp
in-1/2 Heisenberg chain after an interaction quench\n\n\n\nContact Person:
Achim Rosch
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Benjamin Mille
DTSTART;VALUE=DATE-TIME:20160105T130000
DTEND;VALUE=DATE-TIME:20160105T140000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000806@events.thp.uni-koeln.de
DESCRIPTION:Benjamin Mille\n\nReal-space properties of two-impurity Anders
on models (Master defense)\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Markus Grassl
DTSTART;VALUE=DATE-TIME:20160128T120000
DTEND;VALUE=DATE-TIME:20160128T131500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000807@events.thp.uni-koeln.de
DESCRIPTION:Markus Grassl\, University Erlangen-Nuernberg\n\nEntanglement
Polytopes of Some Five Qubit States\n\nThe local spectra of quantum states
in SLOCC classes of n qubit states\ngive rise to polytopes in n-dimension
al real space. While for more than\nthree qubits there are infinitely SLOC
C classes\, there are always\nfinitely many so-called entanglement polytop
es. The entanglement\npolytopes can be computed from a generating set of a
ll covariants with\nrespect to the group of local transformations. Further
more\, a duality\nbetween entanglement polytopes and algebraic varieties y
ields a\ndescription of different types of entanglement. In the talk\, we
will\nillustrate this approach and present results for entanglement polyto
pes\nfor some five qubit states.\n\nContact Person: David Gross
LOCATION:Seminar Room 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Pascale Ehrenfreund
DTSTART;VALUE=DATE-TIME:20160524T164500
DTEND;VALUE=DATE-TIME:20160524T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000808@events.thp.uni-koeln.de
DESCRIPTION: Pascale Ehrenfreund\, DLR\n\nCosmic carbon chemistry and the
signatures of life in our solar system\n\nAstronomical observations have
shown that carbonaceous matter is ubiquitous in our own as well as distant
galaxies and a significant number of molecules that are used in contempor
ary biochemistry on Earth are found in interstellar and circumstellar regi
ons as well as solar system environments. Understanding the evolution o
f organic molecules and their voyage from molecular clouds to the ear
ly solar system and Earth provides important constraints on the emergence
of life on Earth and possibly elsewhere. The spectacular touch-down of the
Philae lander on the comet 67/P allowed the \nfirst measurements of organ
ic molecules on a cometary surface. These results contribute new insights
into impact delivered material that may have provided significant raw mate
rial for the origin of life. In-depth understanding of the organic reserv
oir in different space environments as well as data on the stability of or
ganic and prebiotic material in solar system environments are vital to ass
ess the sources of prebiotic material available to the young planets and t
he search for life in our solar system. This lecture will review the evolu
tion of organic matter in space including recent observations\, space expe
riments and laboratory research and discuss the science and technology pre
paration necessary for robotic and human exploration efforts investigatin
g habitability and biosignatures in our solar system.\n\nContact Person: S
imon Trebst
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Holger Sierks
DTSTART;VALUE=DATE-TIME:20160705T164500
DTEND;VALUE=DATE-TIME:20160705T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000809@events.thp.uni-koeln.de
DESCRIPTION:Holger Sierks \, Max Planck Institute for Solar System Researc
h\n\nNucleus and activity of Comet 67P through the eyes of the ROSETTA/OS
IRIS cameras\n\nComets with their coma and tail are a spectacular
sight on the night sky\; \nthey are important objects to understand
the origin of our solar system. Comets are pristine and thus carry informa
tion on how they initially formed 4.5 billion years ago. 67P/Churyumov-Ger
asimenko is the first comet studied in detail with a spacecraft in its vic
inity for more than two years along its orbit around the sun. The Rosetta
mission of the European Space Agency arrived on August 6\, 2014\, at the
target comet 67P. Onboard the Rosetta spacecraft\, the two scientific cam
eras\, the OSIRIS narrow- and the wide-angle camera\, are observing the co
metary nucleus\, its activity\, as well as the dust and gas environment. T
he presentation will give an overview on what OSIRIS observed. The scient
ific results reveal a nucleus with two lobes and varied morphology. Activ
e regions are located at steep cliffs and collapsed pits which form
collimated gas jets. Dust is accelerated by the gas\, forming bright jet f
ilaments and the large scale\, diffuse coma of the comet.\n\nContact Perso
n: Simon Trebst
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Claus Schneider
DTSTART;VALUE=DATE-TIME:20160518T143000
DTEND;VALUE=DATE-TIME:20160518T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000873@events.thp.uni-koeln.de
DESCRIPTION:Claus Schneider\, FZ Juelich\n\nJuSPARC - Probing the solid st
ate at ultrafast timescales\n\nProcesses involving electrons and spins oft
en take place on sub-picosecond timescales. This is particularly true for
electronic phase transitions\, ultrafast demagnetization\, or local redox
processes during resistive switching. The rapid development in femtosecond
laser sources enables new experimental avenues which open the access to t
he electronic\, spin\, and lattice response on such ultrashort timescales.
With JuSPARC we plan to establish a unique experimental environment to ex
plore ultrafast processes in condensed matter by means of spectroscopy\, m
icroscopy and scattering techniques.\n\nContact Person: Paul van Loosdrech
t
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Spiros Sotiriadis
DTSTART;VALUE=DATE-TIME:20160125T123000
DTEND;VALUE=DATE-TIME:20160125T134500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000812@events.thp.uni-koeln.de
DESCRIPTION:Spiros Sotiriadis\, University of Pisa\n\nEquilibration and me
mory preservation after a quantum quench\n\nResearch in out-of-equilibrium
quantum physics has recently revealed relaxation towards a non-thermal st
atistical ensemble (Generalised Gibbs Ensemble or shortly GGE) that retain
s more memory of the initial state than the conventional thermal ensemble.
The information content of this ensemble remains however a riddle. By ana
lytically studying the time evolution after abrupt changes (quantum quench
es) in extended one-dimensional quantum systems\, we demonstrate relaxatio
n according to the GGE in various different settings and specify the infor
mation that survives in the stationary state. In the case of evolution und
er a gapless non-interacting Hamiltonian on the other hand\, we observe th
e failure of the GGE and find evidence of a novel type of equilibration ch
aracterised by the preservation of non-Gaussian correlations of the initia
l state. We propose an experimental check of our predictions based on curr
ent experimental techniques.\n\nContact Person: Sebastian Diehl
LOCATION:Seminarroom 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Tobias Grass
DTSTART;VALUE=DATE-TIME:20160127T140000
DTEND;VALUE=DATE-TIME:20160127T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000813@events.thp.uni-koeln.de
DESCRIPTION:Tobias Grass\, Institut de Ciencies Fotoniques\, Barcelona\n\n
Make ions count: solving computational problems via quantum simulation\n\n
Trapped ions provide flexible emulators of spin Hamiltonians. In this talk
\, I will motivate to use ions for an implementation of a Mattis-type spin
glass model. Finding the ground state of this model is equivalent to the
optimization process in the number partitioning problem - a potentially NP
-hard computational task. A transverse magnetic field introduces quantum e
ffects\, and opens the door to quantum annealing. A numerical study of the
system dynamics demonstrates the feasibility of this approach.\n\nContact
Person: Sebastian Diehl
LOCATION:Seminaroom 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Lukas Janssen
DTSTART;VALUE=DATE-TIME:20160518T110000
DTEND;VALUE=DATE-TIME:20160518T123000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000871@events.thp.uni-koeln.de
DESCRIPTION:Lukas Janssen\, TU Dresden\n\nSpontaneous breaking of Lorentz
symmetry in QED3\n\nThe phase diagram of quantum electrodynamics in three
space-time dimensions as a function of fermion flavor number N exhibits tw
o well-known phases: at large N > Nc1 the system is in a conformal gapless
state\, while for small N < Nc2 the fermions are expected to develop a dy
namical mass due to spontaneous chiral symmetry breaking. Using epsilon ex
pansion near the lower critical dimension of two\, in combination with the
recent results on the generalization of the F theorem to continuous dimen
sion\, we show that Nc1 > Nc2. There is therefore an intermediate range of
values of N at which a third phase is stabilized. We demonstrate that thi
s phase is characterized by spontaneous breaking of Lorentz symmetry\, in
which a composite vector boson field acquires a vacuum expectation value w
ith the fermions and the photon remaining massless.\n\nContact Person: Die
trich Roscher
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Dr. Martin Kliesch
DTSTART;VALUE=DATE-TIME:20160510T120000
DTEND;VALUE=DATE-TIME:20160510T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000872@events.thp.uni-koeln.de
DESCRIPTION:Dr. Martin Kliesch\, FU Berlin\n\nLocality of temperature\n\nT
his work is concerned with thermal quantum states of Hamiltonians on\nspin
and fermionic lattice systems with short range interactions. We\nprovide
results leading to a local definition of temperature\, thereby\nextending
the notion of "intensivity of temperature'' to interacting\nquantum models
. More precisely\, we derive a perturbation formula for\nthermal states. T
he influence of the perturbation is exactly given in\nterms of a generaliz
ed covariance. For this covariance we prove\nexponential clustering of cor
relations above a universal critical\ntemperature\, which upper bounds phy
sical critical temperatures such as\nthe Curie temperature. As a corollary
\, we obtain that above a the\ncritical temperature\, thermal states are s
table against distant\nHamiltonian perturbations. Moreover\, our results i
mply that above the\ncritical temperature local expectation values can be
approximated with a\ncomputational cost independent of the system size.\n\
nContact Person: David Gross
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Reinhard Meinel
DTSTART;VALUE=DATE-TIME:20160610T163000
DTEND;VALUE=DATE-TIME:20160610T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000814@events.thp.uni-koeln.de
DESCRIPTION:Reinhard Meinel\, Friedrich-Schiller-Universität Jena\n\nCons
tructive proof of the no-hair theorem\n\nAccording to the no-hair theorem\
, the Kerr-Newman black hole\nsolution represents the most general asympto
tically flat\, stationary\n(electro-) vacuum black hole solution in genera
l relativity. The talk\nshows how this solution can indeed be constructed
as the unique solution\nto the corresponding boundary value problem of the
axially symmetric\nEinstein-Maxwell equations in a straightforward manner
.\n\nContact Person: Claus Kiefer
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | José L. Casadiego Bastidas
DTSTART;VALUE=DATE-TIME:20160212T120000
DTEND;VALUE=DATE-TIME:20160212T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000815@events.thp.uni-koeln.de
DESCRIPTION:José L. Casadiego Bastidas\, Max Planck Institute\, Goettinge
n\n\nNetwork Dynamics as an Inverse Problem: Reconstruction from Time Seri
es\n\nHow single units interact in a complex network fundamentally underli
es its collective dynamics. Yet\, identifying the physical structure of in
teractions from recorded time series still poses a great challenge. Up-to-
date methods either require (i) a detailed prior knowledge of the units' d
ynamical features\, (ii) to externally drive the network or (iii) the netw
ork dynamics to be at stable states\, such as fixed points or limit cycles
. Here we develop a theory to reveal physical interactions of networks tha
t relies on recorded time series only. By decomposing the dynamics of sing
le units in terms of network interactions of different orders (pairs\, tri
plets\, quadruplets\,...)\, we pose network reconstruction as an error min
imization problem. We propose a greedy algorithm to solve such minimizatio
n problems. Our approach is principally model independent\, ensuring its g
enerality and applicability in different fields and making it particularly
suitable when structural connections are desired\, dynamical features are
unknown and perturbing the network is infeasible. Thus\, our approach may
serve as a key stepping stone for the expanding field of model-independen
t network reconstruction.\n\nContact Person: David Gross
LOCATION:Seminarroom I Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Thomas Kahle
DTSTART;VALUE=DATE-TIME:20160212T140000
DTEND;VALUE=DATE-TIME:20160212T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000816@events.thp.uni-koeln.de
DESCRIPTION:Thomas Kahle\, OvGU Magdeburg\n\nSuccess stories and challenge
s between algebra and statistics\n\nThe field of algebraic statistics is c
oncerned with the\ninterplay of techniques from commutative algebra\, comb
inatorics\,\n(real) algebraic geometry\, and related fields with problems\
narising in data analysis. Since its inception in the late 1990s\,\nit ha
s brought forward both new results in statistics as well as\nchallenging r
esearch directions in pure mathematics. We survey\nsome of these developm
ents.\n\nContact Person: David Gross
LOCATION:Seminarroom 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | David Gross
DTSTART;VALUE=DATE-TIME:20160419T164500
DTEND;VALUE=DATE-TIME:20160419T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000819@events.thp.uni-koeln.de
DESCRIPTION:David Gross\, University of Cologne\n\nCompressed Sensing: Vo
n Bildverarbeitung zur Quantenzustandstomographie\n\nDie Übertragung von
Bildern und Videos im Internet ist nur möglich\, da solche Datensätze ho
chgradig komprimierbar sind. Bei der Aufnahme der Daten wurde diese Eigens
chaft jedoch bisher nicht benutzt: Eine Digitalkamera z.B. tastet das Bild
Pixel für Pixel ab und reduziert es erst danach auf seine wesentlichen K
omponenten. Seit etwa zehn Jahren zeigt die viel beachtete Theorie des com
pressed sensing\, dass dem nicht so sein muss. In vielen Situationen kann
man Datensätze fehlerfrei aus einer Menge von Messungen rekonstruieren\,
deren Anzahl lediglich proportional zur komprimierten Größe der Daten is
t. Physiker waren von Anfang an an der Entwicklung der Theorie beteilig
t. Ich werde eine Reihe von Anwendungen vorstellen\, die auf mathematisch
en Methoden aus der Quantenmechanik \naufbauen. Die Beispiele umfassen Auf
gaben der Bildverarbeitung\, der Mobilkommunikation\, aber auch der experi
mentellen Rekonstruktion quantenmechanischer Dichtematrizen. Alle bekannt
en Beweismethoden beruhen auf randomisierten Konstruktionen\, bei denen
die Messungen zumindest teilweise zufällig gewählt werden müssen. Ein
Schwerpunkt des Vortrags wird die Rolle des Zufalls und Ansätze zur Deran
domisierung sein. \n\nContact Person: Simon Trebst
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Christian Schroer
DTSTART;VALUE=DATE-TIME:20160607T164500
DTEND;VALUE=DATE-TIME:20160607T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000820@events.thp.uni-koeln.de
DESCRIPTION:Christian Schroer\, DESY\n\nMikroskopie mit kohärenter Röntg
enstrahlung: Kristallographie des Nichtkristallinen \n\nDer Hauptvorteil d
er Mikroskopie mit Röntgenstrahlung ist die Möglichkeit\, auch das Inner
e von Objekten zerstörungsfrei abbilden zu können. Aber obwohl die Wel
lenlänge von Röntgenstrahlung im Bereich atomarer Abstände liegt\, g
elingt es heute nicht\, Atome aufzulösen. Das liegt vor allem an den heu
tigen Röntgenoptiken\, die aufgrund der schwachen Wechselwirkung von Rön
tgenstrahlung mit Materie eine stark beschränkte numerische Apertur hab
en\, und so ihr Auflösungsvermögen begrenzt wird. Ein Ausweg ist der Ve
rzicht auf eine abbildende Röntgenoptik und die Beleuchtung der Probe
mit kohärenter Röntgenstrahlung. Das von der Probe gestreute Licht wird
von einem Flächendetektor aufgezeichnet. Dabei geht die Information über
die Phase der gestreuten elektromagnetischen Welle verloren. Diese kan
n mit Hilfe numerischer Methoden und zusätzlichen Informationen reko
nstruiert werden\, so dass sich ein Bild der Probe errechnen lässt. Dabe
i sind heute \nhöchste Auflösungen im Bereich von ca. 5 nm möglich. In
diesem Vortrag wird ein Überblick über \ndie Bildgebung mit kohärent
er Röntgenstrahlung an modernen Synchrotronstrahlungsquellen und dem R
öntgen-Freie-Elektronen-Laser gegeben. \n\nContact Person: Simon Trebst
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Norbert Pietralla
DTSTART;VALUE=DATE-TIME:20160621T164500
DTEND;VALUE=DATE-TIME:20160621T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000821@events.thp.uni-koeln.de
DESCRIPTION:Norbert Pietralla\, TU Darmstadt\n\nNuclei in the Sky – Nove
l Large-Scale Experiments on Natural Nucleosynthesis et al.\n\nThe world
we live in is made of 81 stable chemical elements and another dozen of rad
ioactive species all coming in different abundances. How were these elemen
ts synthesized in nature? What are the cosmic sites for their formation? D
espite considerable progress in our understanding\, the sites \nfor
the nucleosynthesis of heavy elements are still unclear. Neutron
-star mergers are the strongest candidates. Yet\, scientists are l
acking quantitative information on properties of neutron-rich nucle
i for deeper insight. New research infrastructures for addressing the
open questions are under construction or have even started operation. At D
armstadt the international Facility for Antiproton and Ion Research (FAIR)
is under construction\, with considerable arsenal of novel instrument
s being already partly ready for use. We will motivate some exp
erimental routes\, give an overview of the FAIR project\, in particul
ar with respect to its pillar on \nNuclear Structure\, Nuclear Astr
ophysics and Reactions (NU STAR)\, and address recent scientific su
ccesses and progress. \n\nContact Person: Simon Trebst
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Loic Henriet
DTSTART;VALUE=DATE-TIME:20160209T100000
DTEND;VALUE=DATE-TIME:20160209T110000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000822@events.thp.uni-koeln.de
DESCRIPTION:Loic Henriet\, Ecole Polytechnique\, France\n\nNon-equilibrium
phenomena in light-matter systems\n\nRecent experimental developments off
er platforms to investigate the interaction between light and matter at th
e quantum level\, encouraging the buildup of theoretical tools to describe
their dynamics. The great control over the system parameters also permits
to tune many-body Hamiltonians\, opening the way to explore novel quantum
phases. In this talk\, I will first introduce a nano-engine device compos
ed of a quantum dot coupled to external environments\, and show that vacuu
m symmetry breaking generates a rectified current flowing through the devi
ce. I will then present a stochastic approach which aims at computing the
out-of-equilibrium dynamics of spin-boson models. This approach permits to
explore the strong coupling regime of the Rabi model\, which is the simpl
est model of interaction between light and matter\, and to investigate the
quantum phase transition in the ohmic spinboson model\, which describes a
two-level system interacting with a dissipative environment. I will also
present an hybrid setup comprising a double quantum dot coupled to a micro
wave cavity\, which was realized recently. This system produces a highly e
ntangled state of light and matter in relation to Kondo physics. \n\nConta
ct Person: Sebastian Diehl
LOCATION:Seminarroom 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Dirk Witthaut
DTSTART;VALUE=DATE-TIME:20160209T150000
DTEND;VALUE=DATE-TIME:20160209T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000823@events.thp.uni-koeln.de
DESCRIPTION:Dirk Witthaut\, Institut für Energie- und Klimaforschung\, FZ
Jülich\n\nPrediction\, detection and spreading of failures in supply net
works\n\nThe robust supply with electric power is fundamental for economy\
, industry\nand our daily life. In periods of high loads the breakdown of
a single\ntransmission line can cause a global cascade of failures implyin
g\nlarge-scale outages with potentially catastrophic consequences. Such pe
riods\nof high loads are expected to become more likely in the future\, as
electric\npower from renewable sources is often generated far away from t
he consumers.\nIn this talk I will discuss the stability of power grids to
transmission\nline failures from a network science perspective\, addressi
ng the following\nquestions: Which links are indispensable for network ope
ration? How does a\nfailure spread\, i.e. which parts of a network are aff
ected by the initial\nfailure? How can we efficiently detect those failure
s with few measurements?\n\nContact Person: Joachim Krug
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Erwin Frey
DTSTART;VALUE=DATE-TIME:20160513T163000
DTEND;VALUE=DATE-TIME:20160513T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000824@events.thp.uni-koeln.de
DESCRIPTION:Erwin Frey\, LMU München\n\nEvolutionary Games\n\nMicrobial l
aboratory communities have become model systems for studying the complex
interplay between nonlinear dynamics of evolutionary selection forces\,
stochastic fluctuations arising\nfrom the probabilistic nature of intera
ctions\, and spatial organization. Major research goals are to identify a
nd understand mechanisms that ensures viability of microbial colonies by
\nallowing for species diversity\, cooperative behavior and other kinds o
f social behavior. A synthesis of evolutionary game theory\, nonlinear d
ynamics\, and the theory of stochastic\nprocesses provides the conceptual
framework for a deeper understanding of these ecological systems. In thi
s talk\, we will give an introduction into the modern formulation of the
se\ntheories and illustrate their effectiveness focusing on selected exa
mples of microbial systems. We also discuss current challenges and future
perspectives in quantifying\nbacterial population dynamics\, and how th
is might have an impact on research in non-equilibrium physics.\n\nContac
t Person: Joachim Krug
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Masaki Oshikawa
DTSTART;VALUE=DATE-TIME:20160226T163000
DTEND;VALUE=DATE-TIME:20160226T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000825@events.thp.uni-koeln.de
DESCRIPTION:Masaki Oshikawa\, ISSP Tokyo\n\nSymmetry Protection of Quantum
Phases\n\nClassification of quantum phases is one of the central problems
in\nstatistical mechanics and condensed matter physics. Traditionally\,\n
it had been associated to spontaneous symmetry breakings.\nHowever\, a ric
h variety of quantum phases without any spontaneous\nsymmetry breaking hav
e been found and dubbed as topological\nphases. Symmetries can still play
an important role even when there\nis no spontaneous symmetry breaking\, a
s some quantum phases\nare distinct only in the presence of certain symmet
ries. I will review\nthe concept of "symmetry-protected topological phases
" and then\ndiscuss our recent attempts in generalizing the notion of symm
etry\nprotection of quantum phases.\n\nContact Person: Simon Trebst
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Jan Manousakis
DTSTART;VALUE=DATE-TIME:20160318T140000
DTEND;VALUE=DATE-TIME:20160318T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000826@events.thp.uni-koeln.de
DESCRIPTION:Jan Manousakis\n\nField theory of statistical toplogical insul
ators with chiral symmetry (Master defense)\n\n
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Carsten Bauer
DTSTART;VALUE=DATE-TIME:20160316T100000
DTEND;VALUE=DATE-TIME:20160316T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000829@events.thp.uni-koeln.de
DESCRIPTION:Carsten Bauer\, ITP Frankfurt\n\nQuasi-Particle Velocity Renor
malization in Graphene\n\n\n\nContact Person: Simon Trebst
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Baruch Meerson
DTSTART;VALUE=DATE-TIME:20160617T163000
DTEND;VALUE=DATE-TIME:20160617T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000830@events.thp.uni-koeln.de
DESCRIPTION:Baruch Meerson\, Hebrew University of Jerusalem\n\nWeak-noise
theory and large deviations of surface height in the Kardar-Parisi-Zhang e
quation\n\nThe Kardar-Parisi-Zhang (KPZ) equation describes an important u
niversality class of nonequilibrium\nstochastic models\, including stochas
tic interface growth. There has been much recent\ninterest in the one-poin
t probability distribution P(H\, t) of height H of the evolving interface
at\ntime t. I will show how one can use the weak-noise theory (also known
as the optimal fluctuation\nmethod\, the macroscopic fluctuation theory\,
or simply WKB) to evaluate P(H\, t) for different initial\nconditions. At
small t and H\, P(H\,t) is Gaussian\, but its tails are non-Gaussian and h
ighly asymmetric.\nIn a proper moving frame\, one of the tails agrees at a
ll times with the asymptotics of the Tracy-Widom distribution (for the fla
t and curved interface)\, and of the Baik-Rains distribution (for the stat
ionary interface)\, previously observed at long times. The other tail disp
lays a behavior that differs from the known long-time asymptotics. We argu
e that this tail should be also observable at long times once |H| is very
large. The case of stationary interface is especially interesting. Here at
short times the large deviation function of the height exhibits a singula
rity at a critical value of |H|.\n\nContact Person: Joachim Krug
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Roderich Moessner
DTSTART;VALUE=DATE-TIME:20160408T140000
DTEND;VALUE=DATE-TIME:20160408T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000828@events.thp.uni-koeln.de
DESCRIPTION:Roderich Moessner\, MPI for Physics of Complex Systems\, Dresd
en\n\nThermodynamics and order beyond equilibrium - the physics of periodi
cally driven quantum systems\n\nThe field of thermodynamics is one of the
crown jewels of classical\nphysics. Extending its ideas and concepts to th
e non-equilibrium setting\nis a challenging topic of perennial interest. H
ere\, we study perhaps the\nsimplest non-equilibrium class of quantum prob
lems\, namely Floquet\nsystems\, i.e. systems whose Hamiltonians depend on
time periodically\, \nH(t+T) = H(t). For these\, there is no energy conse
rvation\, and hence not\neven a natural definition of temperature. We find
that it is nonetheless\npossible to identify three fundamentally distinct
thermodynamic ensembles.\nWe also ask if there exists a sharp notion of a
phase in such driven\,\ninteracting quantum systems. Disorder turns out t
o play a crucial role\,\nenabling the existence of states which are straig
htforward analogues of\nequilibrium states with broken symmetries and topo
logical order\, while\nothers - genuinely new to the Floquet problem - are
characterized by a\ncombination of order and non-trivial periodic dynamic
s.\n\nContact Person: Martin Zirnbauer
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Michael Walter
DTSTART;VALUE=DATE-TIME:20160304T140000
DTEND;VALUE=DATE-TIME:20160304T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000831@events.thp.uni-koeln.de
DESCRIPTION:Michael Walter\, Stanford University\n\nRandom tensor networks
and holographic duality\n\nTensor networks provide a natural framework fo
r studying\nbulk-to-boundary or holographic correspondences. In this talk\
, we will\nexplore the holographic properties of random tensor networks wi
th\nlarge bond dimensions. We find that they realize many of the\ninterest
ing structural features of the AdS/CFT correspondence in\nquantum gravity:
Entanglement entropies of boundary subsystem\ncorrespond to minimal domai
n walls in the bulk\, and the physics in the\ndomain is encoded faithfully
in the boundary subsystem. Increasing the\nentanglement in the bulk ultim
ately creates the analog of a black\nhole\, with an associated Hawking-Pag
e phase transition. All this can\nbe understood by mapping the statistical
properties of random tensors\nto the partition function of classical ferr
omagnetic Ising models.\nFrom the perspective of quantum information theor
y\, random tensor\nnetworks implement quantum error-correcting codes with
interesting\nlocality properties\, and their emergence can be understood a
s an\nassisted form of entanglement distillation.
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Ferdinand Brennecke
DTSTART;VALUE=DATE-TIME:20160415T140000
DTEND;VALUE=DATE-TIME:20160415T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000832@events.thp.uni-koeln.de
DESCRIPTION:Ferdinand Brennecke\, University of Bonn\n\nEquation of state
of the 2d Hubbard model\n\nQuantum gases of interacting fermionic atoms in
optical lattices promise to shed new light on the low-temperature phases
of Hubbard-type models\, such as Mott-insulating and spin-ordered phases o
r possible d-wave superconductivity. We experimentally realize the two-dim
ensional Hubbard model by loading a quantum degenerate two-component Fermi
gas of 40K atoms into an anisotropic optical lattice geometry. Using high
-resolution absorption imaging combined with radio-frequency spectroscopy
we are able to resolve the in-situ distribution of singly and doubly occup
ied lattice sites within a single two-dimensional layer.\n\nIn this talk\,
I will report on the in-situ observation of the fermionic Mott insulator
and a measurement of the equation of state of the repulsive Hubbard model
in two dimensions which constitutes a benchmark for state-of-the-art theor
etical approaches.\n\nContact Person: Philipp Strack
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Michael Walter
DTSTART;VALUE=DATE-TIME:20160303T130000
DTEND;VALUE=DATE-TIME:20160303T140000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000833@events.thp.uni-koeln.de
DESCRIPTION:Michael Walter\, Stanford University\n\nKronecker coefficients
\, moment polytopes\, and computational complexity\n\nThe Kronecker coeffi
cients are among the most fascinating objects in\nclassical representation
theory. While many of their fundamental\nproperties remain mysterious\, t
he past decade has brought some\nsignificant advances\, in part through ne
w and surprising connections\nto quantum physics and computational complex
ity theory. In this talk\,\nI will give an introduction to this subject an
d its motivations\, and\ndiscuss some recent results.\n\nSpecifically\, I
will explain that the problem of deciding positivity\nof Kronecker coeffic
ients is NP-hard in general\, while their\nasymptotic non-vanishing\, as e
ncoded by certain moment polytopes\, can\nbe decided in NP and coNP (arXiv
:1410.8144\, 1507.02955\, 1511.03675).\nThis is in marked contrast to cele
brated results on the\nLittlewood-Richardson coefficients and the Horn ine
qualities\, and it\nsuggests that representation theory can be strictly ea
sier in the\nasymptotic regime. Lastly\, and somewhat counter-intuitively\
, our\nhardness result can be turned into an efficient algorithm for study
ing\nthe failure of the saturation property for Kronecker coefficients\,\n
which is at present only poorly understood.
LOCATION:Seminarroom 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nObservation of Gravitational Waves from
a Binary Black Hole Merger\nB. P. Abbott et al.
DTSTART;VALUE=DATE-TIME:20160218T100000
DTEND;VALUE=DATE-TIME:20160218T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000834@events.thp.uni-koeln.de
DESCRIPTION:B. P. Abbott et al.\n\nObservation of Gravitational Waves fr
om a Binary Black Hole Merger\n\nWe discuss the recent paper "Observation
of Gravitational Waves from a Binary Black Hole Merger" by B. P. Abbott
et al. Modus operandi: The dice will determine who will lead the discussio
n\, so every seminar participant is kindly asked to prepare the paper in a
dvance.\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Josua Groeger
DTSTART;VALUE=DATE-TIME:20160225T100000
DTEND;VALUE=DATE-TIME:20160225T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000835@events.thp.uni-koeln.de
DESCRIPTION:Josua Groeger\, University of Cologne\n\nCalabi-Yau Conditions
and Batalin-Vilkovisky Structures on Supermanifolds\n\n\n\nContact Person
: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nEquivalence of topological insulators a
nd superconductors\nE. Cobanera and G. Ortiz
DTSTART;VALUE=DATE-TIME:20160303T100000
DTEND;VALUE=DATE-TIME:20160303T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000836@events.thp.uni-koeln.de
DESCRIPTION:E. Cobanera and G. Ortiz\n\nEquivalence of topological insulat
ors and superconductors\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Christopher Max
DTSTART;VALUE=DATE-TIME:20160310T101500
DTEND;VALUE=DATE-TIME:20160310T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000837@events.thp.uni-koeln.de
DESCRIPTION:Christopher Max \, University of Cologne\n\nFourier Analysis o
n the Supersphere\n\n\n\nContact Person: Thomas Quella
LOCATION:Seminarraum Theoretische Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Boye Buyens
DTSTART;VALUE=DATE-TIME:20160307T140000
DTEND;VALUE=DATE-TIME:20160307T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000838@events.thp.uni-koeln.de
DESCRIPTION:Boye Buyens\, Ghent University\n\nGauge field theories: the Ha
miltonian picture\n\nMotivated by the entanglement properties of low-energ
y states of local Hamiltonians I introduce matrix product states (MPS) as
a variational ansatz for the study of one dimensional quantum many-body sy
stems. Then I apply the MPS formalism to study 1+1 dimensional QED\, also
know as the massive Schwinger model. I explain how MPS are used to compute
an approximation of the ground state and discuss its entanglement propert
ies. Next\, MPS are used to study non-equilibrium dynamics by a quench in
the form of a uniform background electric field. When the electric backgro
und field is small\, the results are explained by investigating the low-en
ergy spectrum of the Hamiltonian. For larger values of the quench we obser
ve thermalisation. Finally\, I discuss how the MPS framework is generalise
d to higher dimensions and can be used to simulate real-time evolution.\n\
nContact Person: Sebastian Diehl
LOCATION:Seminarroom 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Christian Majenz
DTSTART;VALUE=DATE-TIME:20160315T150000
DTEND;VALUE=DATE-TIME:20160315T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000839@events.thp.uni-koeln.de
DESCRIPTION:Christian Majenz\, University of Copenhagen\n\nDecoupling and
quantum source coding\n\nThe decoupling technique has proven a useful tool
in quantum\ninformation theory\, with proofs of results as different as c
hannel\ncoding theorems and thermodynamical work extraction relying on it.
I\nwill show how decoupling is used in quantum source coding problems suc
h\nas state merging and state redistribution and discuss the one shot case
.\n\nContact Person: David Gross
LOCATION:Seminarroom 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Anne Nielsen
DTSTART;VALUE=DATE-TIME:20160603T140000
DTEND;VALUE=DATE-TIME:20160603T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000840@events.thp.uni-koeln.de
DESCRIPTION:Anne Nielsen\, MPI-PKS Dresden\n\nFractional quantum Hall phys
ics in lattice systems\n\nThe fractional quantum Hall effect\, which can b
e realized in certain\ntwo-dimensional systems at low temperature and high
magnetic field\, leads\nto many interesting properties\, such as the poss
ibility to have anyonic\nquasiparticles that are neither bosons nor fermio
ns. There is currently\nmuch interest in investigating the possibilities f
or having fractional\nquantum Hall physics in lattice systems\, both becau
se it may lead to new\nways to realize the effect\, and because the lattic
e gives rise to new\nfeatures and opportunities. Here\, we propose a quite
general approach\nbased on conformal field theory to obtain lattice fract
ional quantum Hall\nmodels. The models have analytical ground states\, and
we use Monte Carlo\nsimulations to compute\, e.g.\, topological entanglem
ent entropies and shape\nand statistics of anyons. We also discuss how one
can interpolate between\nlattice and continuum fractional quantum Hall mo
dels and propose a scheme\nto implement a related model in ultracold atoms
in optical lattices.
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Ruslan Temirov
DTSTART;VALUE=DATE-TIME:20160601T143000
DTEND;VALUE=DATE-TIME:20160601T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000842@events.thp.uni-koeln.de
DESCRIPTION:Ruslan Temirov\, FZ Juelich\n\nManipulation and control of mol
ecular degrees of freedom with a scanning probe microscope\n\n\n\nContact
Person: Thomas Michely
LOCATION:Seminar room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Alexander Ako Khajetoorians
DTSTART;VALUE=DATE-TIME:20160615T143000
DTEND;VALUE=DATE-TIME:20160615T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000843@events.thp.uni-koeln.de
DESCRIPTION:Alexander Ako Khajetoorians\, Radboud University\n\nSpin sensi
ng and magnetic design at the single atom level\n\n\n\nContact Person: Tho
mas Michely
LOCATION:Seminar room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Alessio Chiocchetta
DTSTART;VALUE=DATE-TIME:20160324T160000
DTEND;VALUE=DATE-TIME:20160324T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000844@events.thp.uni-koeln.de
DESCRIPTION:Alessio Chiocchetta\, SISSA\, Trieste\n\nShort-time universali
ty in isolated quantum systems after a quench\n\nThe non-equilibrium dynam
ics of an isolated quantum system after a sudden quench to a dynamical cri
tical point is expected to be characterized by scaling and universal expon
ents due to the absence of time scales. We explore these features for a qu
ench of the parameters of a Hamiltonian with O(N) symmetry\, starting from
the ground state of the disordered phase. In the limit of large N\, the e
xponents and scaling forms of the relevant two-time correlation functions
can be calculated exactly. For generic N\, we use a perturbative renormali
zation-group approach to compute such exponent\, to leading order in a dim
ensional expansion.\n\nContact Person: Sebastian Diehl
LOCATION:Seminarroom 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Claus Kiefer
DTSTART;VALUE=DATE-TIME:20160426T164500
DTEND;VALUE=DATE-TIME:20160426T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000845@events.thp.uni-koeln.de
DESCRIPTION:Claus Kiefer\, Institut für Theoretische Physik\, Universitä
t zu Köln\n\nGravitationswellen\n\n\n\nContact Person: Simon Trebst
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | David Dung
DTSTART;VALUE=DATE-TIME:20160323T100000
DTEND;VALUE=DATE-TIME:20160323T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000846@events.thp.uni-koeln.de
DESCRIPTION:David Dung\, University of Bonn\n\nCoupled Photon Bose-Einstei
n Condensates in Variable Potentials\n\n
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Reinhard Werner
DTSTART;VALUE=DATE-TIME:20160603T163000
DTEND;VALUE=DATE-TIME:20160603T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000847@events.thp.uni-koeln.de
DESCRIPTION:Reinhard Werner\, Leibniz-Universität\, Hannover\n\nMeasureme
nt uncertainty relations\n\n\nThe textbook uncertainty relation due to Ken
nard\, Weyl and Robertson is a "preparation uncertainty relation"\, which
constrains how sharply the position and momentum distributions of a fixed
state can be concentrated. It has nothing to say about error -disturbance
tradeoffs for setups like Heisenberg's gamma-ray microscope from 1927. For
mulated by Heisenberg only as a heuristic principle\, this tradeoff links
the accuracy of an approximate position measurement to the possibility to
retrieve the momentum after the measurement. We generalize this problem to
a simpler one\, namely the quality of optimal joint measurements of pos
ition and momentum. It is then only required that a device provides a posi
tion value and a momentum value in each shot\, like the microscope and th
e momentum retrieval in the error/disturbance case. We will show quantita
tively that the distribution of the position outputs must in general diffe
r from that of an ideal position measurement\, and similarly for momentum\
, where the respective deviations satisfy a relation looking formally like
the textbook preparation uncertainty relation.\n\nOur setup is conceptual
ly straightforward and covers arbitrary pairs or tuples of observables. It
turns out that the equality of the preparation and measurement uncertaint
y bounds is due to the high symmetry of canonical pairs of observables lin
ked via Fourier transform. For generic pairs of observables the measuremen
t uncertainty is larger than the preparation uncertainty.\n\nContact Perso
n: David Gross
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Regina Dittmann
DTSTART;VALUE=DATE-TIME:20160413T143000
DTEND;VALUE=DATE-TIME:20160413T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000848@events.thp.uni-koeln.de
DESCRIPTION:Regina Dittmann\, Forschungszentrum Juelich\n\nUncovering nano
scale changes in the electronic structure during the operation of complex
oxide memristive devices\n\nOxide-based memristive devices\, which exhibit
two or more resistive states under electrical biasing\, are promising can
didates for future non-volatile memories as well as for active elements fo
r neuromorphic computing. It has become widely accepted that memristive sw
itching in oxides is in most cases connected with a voltage-driven oxygen
vacancy movement and a resulting metal-to-insulator transition. However\,
the current knowledge of the microscopic details is very limited so far. O
ne of the obstacles for its further elucidation has been that the net chan
ges of the atomic and electronic structure during memristive switching are
very small and occur primarily at the electrode interface or within nanos
cale filaments. \nBy employing different approaches of X-ray based spectro
microscopy\, we could prove the formation of an oxygen vacancy enriched fi
lament in epitaxial SrTiO3 thin film devices\, which occurs preferentially
at preformed positions such as extended defects. For high current operati
on\, electric biasing goes along with the formation of SrO at the electrod
e interface which has a significant impact on the stabilization of the res
istance states of the devices. \nIn operando studies of SrTiO3 devices wit
h photoelectron-transparent graphene electrodes enabled us to detect rever
sible changes of the O K-edge spectra within spatially confined regions of
the devices. Based on these results\, we obtain for the first time a quan
titative estimate of the amount of oxygen vacancies shifted during the swi
tching process.\n
LOCATION:Seminar room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Bernard Kippelen
DTSTART;VALUE=DATE-TIME:20160525T143000
DTEND;VALUE=DATE-TIME:20160525T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000869@events.thp.uni-koeln.de
DESCRIPTION:Bernard Kippelen\, Georgia Institute of Technology\n\nOrganic
Electronics: Finding Simplicity in Complexity\n\nConjugated organic molecu
les and polymers enable the demonstration of flexible semiconductor device
s that can be processed at low temperature onto different substrates with
variable form factors. Over the past decades\, device performance has impr
oved greatly as a large number of new compounds were synthesized and teste
d in various device geometries. While molecular-level models have been suc
cessful in providing a rational design of molecules and polymers for highe
r performance\, models to predict the morphology of thin films and consequ
ently macroscopic physical properties\, such as charge mobility\, remain e
lusive. The lack of such models has resulted in a trial and error approach
and limits our ability to predict ultimate performance. Furthermore\, org
anic solids exhibit photophysical properties that are unique and different
from those of conventional inorganic semiconductors. The question then ar
ises whether semiconductor equations developed for inorganic semiconductor
devices can be applied to describe the physical properties of organic ele
ctronic devices. In this talk\, we will highlight some fundamental differe
nces in the physical properties between organic and inorganic semiconducto
rs\, but show that general models such as the Shockley diode equation can
be applied to organic photodiodes and solar cells. In particular\, we will
emphasize the importance to understand and mitigate parasitic effects suc
h as shunt resistance effects in these devices as they often overshadow th
e intrinsic physical properties and can lead to different interpretations
of results.\n\nContact Person: Klaus Meerholz
LOCATION:Seminar Room\, Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Tilman Disselkamp
DTSTART;VALUE=DATE-TIME:20160615T100000
DTEND;VALUE=DATE-TIME:20160615T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000864@events.thp.uni-koeln.de
DESCRIPTION:Tilman Disselkamp\n\nSpin textures in spin-orbit entangled Mot
t insulators\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Jamir Marino
DTSTART;VALUE=DATE-TIME:20160622T100000
DTEND;VALUE=DATE-TIME:20160622T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000860@events.thp.uni-koeln.de
DESCRIPTION:Jamir Marino\n\nNon-equilibrium quantum criticality: from isol
ated systems to driven-dissipative platforms\n\n
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | David Lindner + Lukas Gross
DTSTART;VALUE=DATE-TIME:20160420T100000
DTEND;VALUE=DATE-TIME:20160420T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000851@events.thp.uni-koeln.de
DESCRIPTION:David Lindner + Lukas Gross\n\nBachelor Colloquium\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Florian Lange
DTSTART;VALUE=DATE-TIME:20160427T100000
DTEND;VALUE=DATE-TIME:20160427T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000852@events.thp.uni-koeln.de
DESCRIPTION:Florian Lange\n\nWeakly driven many-particle quantum systems\n
\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Mukul Laad
DTSTART;VALUE=DATE-TIME:20160628T160000
DTEND;VALUE=DATE-TIME:20160628T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000878@events.thp.uni-koeln.de
DESCRIPTION:Mukul Laad\, University of Chennai\n\nA First-Principles Corre
lated Approach to the Normal State of Layered Strontium Ruthenate\n\n Unco
nventional Superconductivity (USC) in layered Sr$_{2}$RuO$_{4}$\nis of lon
g-standing interest because it is long thought to be a\nsuperconducting an
alogue of $^{3}He$. However\, resurgence of recent\ndata points toward a
much more involved pairing symmetry\, where the\ninterplay between multi-b
and character\, sizable multi-band\nelectronic correlations and strong spi
n-orbit coupling conspires to\nselect an apparently rather unusual\, hithe
rto unknown\, USC pair\nsymmetry. This mandates detailed revisiting of th
e normal state\nand\, in particular\, of the $T$-dependent incoherence-coh
erence\ncrossover. Here\, using a modern first-principles correlated view
\,\nwe study this issue in the real structure of Sr$_{2}$RuO$_{4}$ in\ndet
ail and present a unified and quantitative description of a range\nof unus
ual physical responses in the normal state across the\ncrossover. Armed w
ith these strengths\, we propose that a new and\nimportant element\, that
of dominant (quasi-one-dimensional $xz\,yz$)\ninterband charge fluctuation
s in a ``Hund'' metal\, may be a primary\npair glue for USC in this system
. We will emphasize internal\nconsistency of our proposed scenario vis-a-
vis a wide range of\nconstraints imposed by extant data.\n\nContact Person
: Simon Trebst
LOCATION:Seminar Room Kernphysik
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Max Gerlach
DTSTART;VALUE=DATE-TIME:20160511T100000
DTEND;VALUE=DATE-TIME:20160511T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000854@events.thp.uni-koeln.de
DESCRIPTION:Max Gerlach\n\nCompeting orders in a nearly antiferromagnetic
metal\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Zala Lenarcic
DTSTART;VALUE=DATE-TIME:20160720T100000
DTEND;VALUE=DATE-TIME:20160720T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000855@events.thp.uni-koeln.de
DESCRIPTION:Zala Lenarcic\n\nReviving the integrability\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Sarah Schroeter
DTSTART;VALUE=DATE-TIME:20160601T100000
DTEND;VALUE=DATE-TIME:20160601T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000856@events.thp.uni-koeln.de
DESCRIPTION:Sarah Schroeter\n\nSkyrmion Caloritronics\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Jan Attig
DTSTART;VALUE=DATE-TIME:20160608T100000
DTEND;VALUE=DATE-TIME:20160608T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000857@events.thp.uni-koeln.de
DESCRIPTION:Jan Attig\n\nSpiral Spin Liquids\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Dietrich Roscher
DTSTART;VALUE=DATE-TIME:20160413T100000
DTEND;VALUE=DATE-TIME:20160413T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000862@events.thp.uni-koeln.de
DESCRIPTION:Dietrich Roscher\n\nInhomogeneous Phases of Fermionic Systems\
n\n
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Henry Legg
DTSTART;VALUE=DATE-TIME:20160629T100000
DTEND;VALUE=DATE-TIME:20160629T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000861@events.thp.uni-koeln.de
DESCRIPTION:Henry Legg\n\nAnisotropic magnetoresistance from the surface o
f disordered topological insulators\n\n
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Leonhard Grill
DTSTART;VALUE=DATE-TIME:20161005T143000
DTEND;VALUE=DATE-TIME:20161005T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000877@events.thp.uni-koeln.de
DESCRIPTION:Leonhard Grill\, University of Graz\n\nAssembly and characteri
zation of single functional molecules on surfaces\n\nFunctional molecules
on surfaces and their assembly into pre-defined architectures are key chal
lenges in nanotechnology and of interest in various fields from molecular
electronics over novel materials to molecular machines. Various examples o
f functional molecules\, studied by scanning tunneling microscopy (STM) un
der ultrahigh vacuum conditions\, will be discussed. Specifically designed
molecular building blocks are connected to two-dimensional networks or on
e-dimensional chains\, which can act as molecular wires. On the other hand
\, chemical processes within individual molecular can be controlled via th
eir environment. This was observed for molecular switches\, where the atom
ic-scale surroundings cause drastic changes in their switching probability
. It could be shown that the rate of an intramolecular hydrogen transfer r
eaction can be tuned up and down by single atoms in the vicinity of the mo
lecule. Single atoms were also found to modify the appearance of adsorbed
molecules in STM images during their diffusion underneath the molecules. A
combination of the two approaches will be discussed\, potentially leading
to heterogeneous molecular nanostructures that contain functional molecul
es.\n\nContact Person: Alexander Grueneis
LOCATION:Seminar room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Elio Koenig
DTSTART;VALUE=DATE-TIME:20160624T140000
DTEND;VALUE=DATE-TIME:20160624T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000863@events.thp.uni-koeln.de
DESCRIPTION:Elio Koenig\, University of Wisconsin\, Madison\n\nAnomalous H
all effect in topological insulators and superconductors\n\nIn the first p
art of the talk\, the recent advance in the theory of the anomalous Hall e
ffect is reviewed. Remarkably\, it was shown that diagrams with crossed im
purity lines yield an anomalous Hall conductivity that is independent of i
mpurity concentration\, and thus is of the same order as other known extri
nsic side jump and skew scattering terms. Based on a semiclassical interpr
etation\, we explain that such diagrams represent diffractive skew scatter
ing contributions originating from rare two-impurity complexes. \n\nNext\,
results for the anomalous Hall conductivity sigma_xy of the surface state
s in cubic topological Kondo insulators are presented. We consider a gener
ic model for the surface states with three Dirac cones on the (001) surfac
e: The Fermi velocity\, the Fermi momentum and the Zeeman energy in differ
ent Dirac pockets may be unequal. The microscopic impurity potential media
tes mixed intra and interband extrinsic scattering processes. We discuss v
arious special cases of our results and the experimental relevance of our
study in the context of the recent hysteretic magnetotransport data in SmB
6 samples.\n\nThe last part of the talk is devoted to our recent study of
the temperature dependent anomalous ac Hall conductance sigma_xy(omega\, T
) for a 2D chiral p-wave superconductor [3]. This quantity determines the
polar Kerr effect\, as it was observed in Sr2RuO4. We concentrate on a sin
gle band model with generic\, isotropic dispersion relation subjected to r
are\, weak impurities treated in the Born approximation. Again\, the empha
sis is on diffractive skew scattering from quantum impurity complexes. It
is explicitly shown\, that this effect contributes to leading order in imp
urity concentration and is thus comparable to earlier results within the s
ame model.\n\n\n\nContact Person: Dmitry Bagrets
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Stefan Wolff
DTSTART;VALUE=DATE-TIME:20160706T100000
DTEND;VALUE=DATE-TIME:20160706T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000865@events.thp.uni-koeln.de
DESCRIPTION:Stefan Wolff\, Uni Bonn\n\nDissipative time evolution of a chi
ral state after a quantum quench\n\n\n\nContact Person: Jan Gelhausen
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Finn Lasse Buessen
DTSTART;VALUE=DATE-TIME:20160429T140000
DTEND;VALUE=DATE-TIME:20160429T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000867@events.thp.uni-koeln.de
DESCRIPTION:Finn Lasse Buessen\, University of Cologne\n\nFunctional Renor
malization Group Studies of Spin-Orbit Entangled j=1/2 Mott Insulators (Ma
ster's Colloquium)\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Thomas Quella
DTSTART;VALUE=DATE-TIME:20160414T120000
DTEND;VALUE=DATE-TIME:20160414T140000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000868@events.thp.uni-koeln.de
DESCRIPTION:Thomas Quella\, THP\, University of Cologne\n\nSymmetry protec
tion of multicritical phase transitions\n\n
LOCATION:Seminar room THP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Hendrik Bluhm
DTSTART;VALUE=DATE-TIME:20160511T143000
DTEND;VALUE=DATE-TIME:20160511T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000870@events.thp.uni-koeln.de
DESCRIPTION:Hendrik Bluhm\, RWTH Aachen\n\nSpin qubits in GaAs quantum dot
s - an experimental perspective on the central spin problem and quantum co
ntrol\n\n\n\nContact Person: Achim Rosch
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Tomaz Prosen
DTSTART;VALUE=DATE-TIME:20160513T140000
DTEND;VALUE=DATE-TIME:20160513T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000874@events.thp.uni-koeln.de
DESCRIPTION:Tomaz Prosen\, University of Ljubljana\n\nIntegrability of a d
eterministic cellular automaton driven by stochastic boundaries\n\nWe prop
ose an interacting many-body space-time-discrete Markov chain model\, whic
h is composed of an integrable deterministic and reversible cellular autom
aton (the rule 54 of [Bobenko et al\, CMP 158\, 127 (1993)]) on a finite o
ne-dimensional lattice\, and local stochastic Markov chains at the two lat
tice boundaries which provide chemical baths for absorbing or emitting the
solitons. Ergodicity and mixing of this many-body Markov chain is proven
for generic values of bath parameters\, implying existence of a unique non
-equilibrium steady state. The latter is constructed exactly and explicitl
y in terms of a particularly simple form of matrix product ansatz which is
termed a patch ansatz. This gives rise to an explicit computation of obse
rvables and k-point correlations in the steady state as well as the constr
uction of a nontrivial set of local conservation laws. Feasibility of an e
xact solution for the full spectrum and eigenvectors (decay modes) of the
Markov matrix is suggested as well. We conjecture that such ideas can pave
the road towards a theory of integrability of boundary driven classical d
eterministic lattice systems.\n\nContact Person: Zala Lenarcic
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Steven Mathey
DTSTART;VALUE=DATE-TIME:20160504T143000
DTEND;VALUE=DATE-TIME:20160504T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000875@events.thp.uni-koeln.de
DESCRIPTION:Steven Mathey\, University of Grenoble\n\nNon-Equilibrium inte
rface dynamics with correlated noise: Emergent symmetries and non-universa
l observables\n\nThe Kardar-Parisi-Zhang (KPZ) equation provides one of th
e simplest non trivial examples of a Non-Equilibrium Steady State. Its uni
versal features capture a very wide range of physical phenomena ranging fr
om varied types of interfaces to turbulent hydrodynamic flows or thermodyn
amics of polymers in noisy environments. Enormous progress has been made i
n the last 10 years thanks to an exact derivation of the statistics of the
KPZ dynamics in the case of one-dimensional systems driven by a stochasti
c white noise. The cases of higher dimensions and/or\ncorrelated noise rem
ain however unsolved. \n\nIn this presentation I discuss the physics of a
one-dimensional interface that is subjected to a noise with smooth spatio-
temporal correlations. This problem was previously studied numerically as
well as with the Replica Trick in a Gaussian variational approach.It was f
ound that the small scale features depend on the details of the microscopi
c noise while (up to the overall amplitude factors) the exact solution wit
h white noise governs the large scales. In the present work\, Functional R
enormalisation Group (FRG) methods are employed in order to resolve the no
n-perturbative features of KPZ dynamics. The FRG makes it possible to foll
ow the renormalisation group flow from its initial conditions all the way
down to its fixed point\, that is from microscopic dynamics to the large d
istance properties. I show that the exact solution emerges on large scales
independently of the details of the\nnoise correlations. Moreover the sma
ll scale features (and their dependence on the particular choice of the no
ise correlations) are resolved and compared to direct numerical simulation
s.\n\nContact Person: Sebastian Diehl
LOCATION:Seminar room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Dieter Vollhardt
DTSTART;VALUE=DATE-TIME:20160701T163000
DTEND;VALUE=DATE-TIME:20160701T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000876@events.thp.uni-koeln.de
DESCRIPTION:Dieter Vollhardt\, University of Augsburg\n\nSuperfluid Helium
-3: Universal Concepts for Condensed Matter and the Big Bang\n\nSince thei
r discovery in 1971 the superfluid phases of Helium-3 have\nproved to be t
he ideal testing ground for many fundamental concepts of\nmodern physics.
Phenomena such as anisotropic Cooper pairing\, p-wave states\,\nchirality\
, macroscopic quantum coherence\, spontaneous breaking of high\nsymmetries
\, and exotic topological defects are not only an important\nenrichment of
the physics of condensed matter\, but also provide important\nlinks to pa
rticle physics\, defect formation in the early universe and\, most\nrecent
ly\, quantum turbulence. I will present an introduction into the\nphysics
of superfluid Helium-3 and describe the progress made in this\nfascinating
field of basic research.\n\nContact Person: Philipp Strack
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Yin-Chen He
DTSTART;VALUE=DATE-TIME:20160610T140000
DTEND;VALUE=DATE-TIME:20160610T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000879@events.thp.uni-koeln.de
DESCRIPTION:Yin-Chen He\, MPI-PKS Dresden\n\nSpin liquids on kagome lattic
e and symmetry protected topological phase\n\nIn my talk I will introduce
the spin liquid phases that occur in kagome antiferromagnets\, and discuss
their physical origin that are closely related with the newly discovered
symmetry protected topological phase (SPT). I will first present our numer
ical (DMRG) study on the kagome XXZ spin model that exhibits two distinct
spin liquid phases\, namely the chiral spin liquid and the kagome spin liq
uid (the groundstate of the nearest neighbor kagome Heisenberg model). Bot
h phases extend from the extreme easy-axis limit\, through SU(2) symmetric
point\, to the pure easy-plane limit. The two phases are separated by a c
ontinuous phase transition. Motivated by these numerical results\, I will
then focus on the easy-axis kagome spin system\, and reformulate it as a l
attice gauge model. Such formulation enables us to achieve a controlled th
eoretical description for the spin liquid phases. We then show that the ch
iral spin liquid is indeed a gauged U(1) SPT phase. On the other hand\, we
also propose that the kagome spin liquid is a critical spin liquid phase\
, which can be considered as a gauged deconfined critical point between a
SPT and a superfluid phase. \n\n\nContact Person: Simon Trebst
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nMany body localization and thermalizati
on in quantum statistical mechanics\nRahul Nandkishore and David A. Huse
DTSTART;VALUE=DATE-TIME:20160512T101500
DTEND;VALUE=DATE-TIME:20160512T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000880@events.thp.uni-koeln.de
DESCRIPTION:Rahul Nandkishore and David A. Huse\n\nMany body localization
and thermalization in quantum statistical mechanics\n\nPaper by Rahul Nand
kishore and David A. Huse. \n\nContact Person: Alexander Alldridge
LOCATION:Meeting room\, extension building\, 1.04
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nIntegrability and combinatorics: Select
ed topics\nPaul Zinn-Justin
DTSTART;VALUE=DATE-TIME:20160428T120000
DTEND;VALUE=DATE-TIME:20160428T140000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000881@events.thp.uni-koeln.de
DESCRIPTION:Paul Zinn-Justin\n\nIntegrability and combinatorics: Selected
topics\n\nPaper by Paul Zinn-Justin.\n\nContact Person: Alexander Alldridg
e
LOCATION:THP seminar room
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Martin Zirnbauer
DTSTART;VALUE=DATE-TIME:20160421T120000
DTEND;VALUE=DATE-TIME:20160421T140000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000882@events.thp.uni-koeln.de
DESCRIPTION:Martin Zirnbauer\, THP\, University of Cologne\n\nSigma models
coupled to WZW models\n\n\n\nContact Person: Alexander Alldridge
LOCATION:THP seminar room
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Artur Swiech
DTSTART;VALUE=DATE-TIME:20160324T104500
DTEND;VALUE=DATE-TIME:20160324T121500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000883@events.thp.uni-koeln.de
DESCRIPTION:Artur Swiech\, THP\, University of Cologne\n\nQuaternionic R t
ransform and non-Hermitian random matrices\n\n\n\nContact Person: Alexande
r Alldridge
LOCATION:THP seminar room
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Thomas Quella
DTSTART;VALUE=DATE-TIME:20160414T120000
DTEND;VALUE=DATE-TIME:20160414T140000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000884@events.thp.uni-koeln.de
DESCRIPTION:Thomas Quella\, THP\, University of Cologne\n\nSymmetry protec
tion of multicritical phase transitions\n\n\n\nContact Person: Alexander A
lldridge
LOCATION:THP seminar room
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nQuantropy\nJ.C. Baez and B.S. Pollard
DTSTART;VALUE=DATE-TIME:20160317T101500
DTEND;VALUE=DATE-TIME:20160317T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000885@events.thp.uni-koeln.de
DESCRIPTION:J.C. Baez and B.S. Pollard\n\nQuantropy\n\nJournal reference:
Entropy 17 (2015)\, 772-789.\n\nContact Person: Alexander Alldridge
LOCATION:THP seminar room
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Zhong-Chao Wei
DTSTART;VALUE=DATE-TIME:20160518T093000
DTEND;VALUE=DATE-TIME:20160518T103000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000886@events.thp.uni-koeln.de
DESCRIPTION:Zhong-Chao Wei\, Chinese Academy of Sciences\, Beijing\n\nMajo
rana Reflection Positivity With Applications In Strongly Correlated System
s\n\nIn this talk we discuss the method of Majorana reflection positivity\
nand its applications in the study of strongly correlated systems.\n\nThe
first application concerns the ground state degeneracy of\ninteracting spi
nless fermions. Based on Majorana reflection\npositivity\, we prove rigour
ously that the ground state of this model\nis either unique or doubly dege
nerate if the lattice size N is even\,\nand is always doubly degenerate if
N is odd. This proof holds in all\ndimensions with arbitrary lattice stru
ctures.\n\nThe second application is about the sign problem in quantum Mon
te\nCarlo simulations. We examine this problem with a new perspective\nbas
ed on the Majorana reflection positivity. Two sufficient\nconditions are p
roven for the absence of the fermion sign problem. Our\nproof provides a u
nified description for nearly all the interacting\nlattice fermion models
that are previously known to be free of the\nsign problem. It also allows
us to identify a number of new\nsign-problem-free interacting fermion mode
ls.\n\nContact Person: Alexander Alldridge
LOCATION:SR 0.03 (new building)
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Jonathan Lux
DTSTART;VALUE=DATE-TIME:20160524T120000
DTEND;VALUE=DATE-TIME:20160524T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000887@events.thp.uni-koeln.de
DESCRIPTION:Jonathan Lux\n\nFluctuations in and out of equilibrium: Therma
lization\, quantum measurements and Coulomb disorder\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Walter Hofstetter
DTSTART;VALUE=DATE-TIME:20161125T163000
DTEND;VALUE=DATE-TIME:20161125T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000888@events.thp.uni-koeln.de
DESCRIPTION:Walter Hofstetter\, Johann Wolfgang Goethe-Universität Frankf
urt\n\nInteracting topological states of ultracold lattice gases\n\nThe l
ast years have witnessed dramatic progress in experimental control and the
oretical modeling of quantum simulations based on ultracold atoms. Major r
ecent developments include synthetic gauge fields for neutral atoms\, whic
h allow the simulation of topologically nontrivial phases of matter with s
trong interactions. I will discuss two examples: \n\nWe consider a spinfu
l and time-reversal invariant version of the Hofstadter-Harper problem\, w
hich has been realized in ultracold atoms\, with an additional staggered p
otential and spin-orbit coupling. Without interactions\, the system exhibi
ts various phases such as topological and normal insulator\, metal and sem
i-metal phases with two or even more Dirac cones. Using real-space dynamic
al mean-field theory (DMFT)\, we investigate the stability of the Quantum
Spin Hall state in the presence of strong interactions. To test the bulk-b
oundary correspondence between edge mode parity and bulk Chern index of th
e interacting system\, we calculate an effective topological Hamiltonian b
ased on the local self-energy of DMFT. \n\nWe furthermore investigate the
Haldane honeycomb lattice tight-binding model\, for bosons with additiona
l local Hubbard interactions. We analyze the ground state phase diagram at
filling one\, and uncover three distinct phases: a uniform superfluid (SF
)\, a chiral superfluid (CSF) and a plaquette Mott insulator with local cu
rrent loops (PMI). \n\nContact Person: Sebastian Diehl
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Marcello Dalmonte
DTSTART;VALUE=DATE-TIME:20160630T110000
DTEND;VALUE=DATE-TIME:20160630T123000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000890@events.thp.uni-koeln.de
DESCRIPTION:Marcello Dalmonte\, University of Innsbruck\n\nEffects of clus
tering in soft-shoulder Hubbard models: from supersymmetric critical point
s to unconventional quantum liquid.\n\nIn this seminar\, I will discuss ho
w complementing the Bose-Hubbard model with soft-shoulder interactions all
ows for the stabilization of exotic state of matters which\, in one- and t
wo-dimensions\, break the typical Luttinger and Landau liquid paradigms. I
n the first part talk\, I will present discuss the basic classical statist
ical mechanics ingredients of such potentials\, which support cluster solu
tions with extensive ground state degeneracy. Using a combination of field
theoretical and numerical approaches\, the phase diagram of the model wil
l be presented. In particular\, I will focus on the existence of a Cluster
Luttinger liquid phase\, which cannot be captured using conventional ‘c
oarse graining’ schemes of Abelian bosonization\, and show how this phas
e is separated by a conventional Luttinger liquid via a phase transition w
ith emergent conformal supersymmetry. In the second part of the talk\, I w
ill discuss the fate of such states and transitions in two-dimensions usin
g numerical simulations. In this context\, strong soft-shoulder interactio
ns lead to a dramatic change of the ‘Bose surface’\, and stabilize a p
hase with no broken symmetry but still displaying quasi-long-range coheren
ce\, of Bose-metal type. The mechanism for the stabilization of such exoti
c liquids is clusterization\, which defines a low-energy manifold displayi
ng extensive ground state degeneracy and\, and the same time\, suppress su
perfluid order. Finally\, I will present some considerations on the experi
mental realization of both one- and two-dimensional cases using laser-dres
sed Rydberg atoms. \n\nContact Person: Jamir Marino
LOCATION:Seminar room 0.01\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Qimiao Si
DTSTART;VALUE=DATE-TIME:20160629T143000
DTEND;VALUE=DATE-TIME:20160629T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000891@events.thp.uni-koeln.de
DESCRIPTION:Qimiao Si\, Rice University\n\nFrustrated Magnetism and Superc
onductivity in Iron Pnictides and Chalcogenides\n\n
LOCATION:Seminar room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Alexander Glaetzle
DTSTART;VALUE=DATE-TIME:20160617T140000
DTEND;VALUE=DATE-TIME:20160617T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000892@events.thp.uni-koeln.de
DESCRIPTION:Alexander Glaetzle\, University of Innsbruck\n\nDesigning Quan
tum Spin Models with Laser-Dressed Rydberg Atoms\n\nIn my talk I will star
t with a review of our recent work on realizing a broad class of lattice s
pin-1/2 models with cold alkali atoms stored in optical or magnetic trap a
rrays. In particular\, we exploit the strong angular dependence of van der
Waals interactions between high angular momentum Rydberg states. Together
with the possibility of designing step-like potentials we can implement A
belian gauge theories in a series of geometries\, which could be demonstra
ted within state of the art experiments. The resulting energy scales of in
teractions compare well with typical temperatures and decoherence time-sca
les\, making the exploration of exotic forms of quantum magnetism\, includ
ing emergent gauge theories\, compass models and quantum spin ice models\,
accessible within state-of-the-art experiments.
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Laura Classen
DTSTART;VALUE=DATE-TIME:20160722T140000
DTEND;VALUE=DATE-TIME:20160722T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000893@events.thp.uni-koeln.de
DESCRIPTION:Laura Classen\, University of Heidelberg\n\nInterplay between
magnetism\, superconductivity\, and orbital order in 5-pocket model for ir
on-based superconductors\n\nWe report the results of the full parquet reno
rmalization group (pRG) analysis of the 5-pocket model for Fe-based super
conductors (three hole pockets and two electron pockets). We depart from t
he low-energy orbital model and use as input the fact that excitations nea
r all five pockets are made out of xz\, yz\, and xy d-orbitals. We argue\
, based on symmetry that there are 40 different coupling constants which d
escribe the interactions between low-energy fermions and flow under pRG.
The pRG analysis reveals four stable fixed trajectories. They can be group
ed into two classes\, where the 5-pocket model effectively reduces either
to a 3-pocket or a 4-pocket one. We argue that in both cases superconducti
vity wins over SDW if all five Fermi energies are small and pRG runs over
a wide energy range. The resulting superconducting symmetry is !\n of s+-
fo\n r\nm for both effective models\, but the magnitude of the gap differ
s between the hole pockets at (0\,0) and (pi\,pi) in the 1Fe zone. SDW mag
netism is of stripe type in the 3-pocket and of checkerboard type in the 4
-pocket case. Additionally a spontaneous orbital order develops before su
perconductivity that splits the band degeneracy at high-symmetry points.
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nQuantum integrable systems\nJasper Stok
man
DTSTART;VALUE=DATE-TIME:20160602T101500
DTEND;VALUE=DATE-TIME:20160602T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000894@events.thp.uni-koeln.de
DESCRIPTION:Jasper Stokman\n\nQuantum integrable systems\n\n\n\nContact Pe
rson: Alexander Alldridge
LOCATION:New building\, 1.04
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Juliane Weber
DTSTART;VALUE=DATE-TIME:20160628T123000
DTEND;VALUE=DATE-TIME:20160628T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000895@events.thp.uni-koeln.de
DESCRIPTION:Juliane Weber\, Institute of Energy and Climate Research\, FZ
Jülich\n\nStatistical features of wind determining the storage need in a
fully renewable energy system\n\n\n\nContact Person: Joachim Krug
LOCATION:TP conference room 0.02
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Grace Lu
DTSTART;VALUE=DATE-TIME:20160614T140000
DTEND;VALUE=DATE-TIME:20160614T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000896@events.thp.uni-koeln.de
DESCRIPTION:Grace Lu\, USC Los Angeles\n\nSemiconductor and Magnetic Nanow
ires\n\n\n\nContact Person: Achim Rosch
LOCATION:HS II\, Institute of Physics
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Markus Mueller
DTSTART;VALUE=DATE-TIME:20160712T140000
DTEND;VALUE=DATE-TIME:20160712T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000897@events.thp.uni-koeln.de
DESCRIPTION:Markus Mueller\, Paul-Scherrer Institut\n\nOn many-body mobili
ty edges in interacting systems\n\nIn recent years\, many-body localizatio
n and the prediction of a metal-insulator transition at finite temperature
has attracted a lot of attention as a way to maintain permanent off-equil
ibrium conditions in a thermodynamic\, but closed quantum many-body system
. Such transitions\, driven by energy density (or ”temperature”)\, req
uire the presence of a many-body mobility edge in energy\, that separates
localized from ergodic states. I argue that for short range interactions t
his scenario is beyond the control of perturbation theory and seems incons
istent due to inclusions of the ergodic phase in the supposedly localized
phase. Those inclusions are mobile and induce global delocalization. These
considerations modify the phase diagrams for interacting systems both wit
h and without quenched disorder. \n\nContact Person: Philipp Strack
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Michael Spira
DTSTART;VALUE=DATE-TIME:20160715T163000
DTEND;VALUE=DATE-TIME:20160715T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000898@events.thp.uni-koeln.de
DESCRIPTION:Michael Spira\, Paul Scherrer Institute\n\nHiggs Physics @ LHC
\n\nThe recent discovery of the Higgs boson at the LHC marked the completi
on of the theoretical description of strong\, weak and electromagnetic int
eractions among the known elementary particles and builds up the basis of
the Standard Model (SM) of particle physics. This talk will provide an int
roduction into the physics of Higgs bosons and their quantitative tests at
the LHC. This includes the decay and production profile of the SM Higgs b
oson and will also make remarks about extensions of the SM and their Higgs
bosons.\n\n\n\nContact Person: Alexander Altland
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Lorenz Mayer
DTSTART;VALUE=DATE-TIME:20160609T100000
DTEND;VALUE=DATE-TIME:20160609T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000899@events.thp.uni-koeln.de
DESCRIPTION:Lorenz Mayer\, BCGS\, University of Bonn\n\nExample of a topol
ogical insulator of class AIII in three dimensions\n\n\n\nContact Person:
Alexander Alldridge
LOCATION:Theory building\, 1.04
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | David Dean
DTSTART;VALUE=DATE-TIME:20161021T163000
DTEND;VALUE=DATE-TIME:20161021T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000900@events.thp.uni-koeln.de
DESCRIPTION:David Dean\, University of Bordeaux\n\nStochastic Density Func
tional Theory for Electrolytes Out of Equilibrium\n\nThe dynamics of inter
acting Brownian particles can be described by a stochastic \nequation for
the density field. I will show how the linearised version of this \nequa
tion can be used to recover\, very simply\, certain of Onsager's results
\non electrolyte conductivity. In addition I will show how it can analyse
the \nout of equilibrium thermal Casimir effect between parallel plates c
ontaining \nBrownian charges\, in particular the case where the plates ar
e held at different temperatures\nand when an electric field drives a curr
ent in one of the plates.\n\n\nContact Person: Joachim Krug
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nGeometric models of matter\nM.F. Atiyah
\, N.S. Manton\, and B.F. Schroers
DTSTART;VALUE=DATE-TIME:20160616T101500
DTEND;VALUE=DATE-TIME:20160616T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000901@events.thp.uni-koeln.de
DESCRIPTION:M.F. Atiyah\, N.S. Manton\, and B.F. Schroers\n\nGeometric mod
els of matter\n\n\nInspired by soliton models\, we propose a description o
f static particles in terms of Riemannian 4-manifolds with self-dual Weyl
tensor. For electrically charged particles\, the 4-manifolds are non-compa
ct and asymptotically fibred by circles over physical 3-space. This is aki
n to the Kaluza–Klein description of electromagnetism\, except that we e
xchange the roles of magnetic and electric fields\, and only assume the bu
ndle structure asymptotically\, away from the core of the particle in ques
tion. We identify the Chern class of the circle bundle at infinity with mi
nus the electric charge and\, at least provisionally\, the signature of th
e 4-manifold with the baryon number. Electrically neutral particles are de
scribed by compact 4-manifolds. We illustrate our approach by studying the
Taub–Newman\, Unti\, Tamburino (Taub–NUT) manifold as a model for the
electron\, the Atiyah–Hitchin manifold as a model for the proton\, CP2
with the Fubini– Study metric as a model for the neutron and S4 with its
standard metric as a model for the neutrino.\n\nContact Person: Alexander
Alldridge
LOCATION:Meeting room\, theory building\, 1.04
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Margherita Disertori
DTSTART;VALUE=DATE-TIME:20160721T101500
DTEND;VALUE=DATE-TIME:20160721T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000902@events.thp.uni-koeln.de
DESCRIPTION:Margherita Disertori\, Hausdorff Centre for Mathematics\, Bonn
\n\nHistory dependent stochastic processes and nonlinear sigma models\n\nE
dge reinforced random walk (ERRW) and vertex reinforced jump processes\n(V
RJP) are history dependent stochastic processes\, where the particle\ntend
s to come back more often on sites it has already visited in the past.\nFo
r a particular scheme of reinforcement these processes are random walks\ni
n a random environment whose mixing measure can be related to a nonlinear\
nsigma model introduced in the context of random matrix models for quantum
\ndiffusion. This relation allows to prove\, in particular\, transience fo
r\nweak reinforcement of both processes\, in d larger or equal to 3. I wil
l\ngive a review of the problem and some recent results.\n\nContact Person
: Martin Zirnbauer
LOCATION:Seminar room\, theory building
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Michael Ziese
DTSTART;VALUE=DATE-TIME:20160713T110000
DTEND;VALUE=DATE-TIME:20160713T123000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000903@events.thp.uni-koeln.de
DESCRIPTION:Michael Ziese\, Leipzig University\n\nMagnetic and Magnetotran
sport Properties of Superlattices with Ultrathin SrRuO3 Layers\n\nHeterost
ructures with ultrathin layers are an exciting playground for materials sc
ience\, since quantum confinement and interfacial properties often lead to
new functionalities. In this talk a survey is given of the magnetic and m
agnetotransport properties of SrRuO3/manganite superlattices and trilayers
. The itinerant ferromagnet SrRuO3 has a comparatively high conductivity a
nd large magnetocrystalline anisotropy and can be grown in excellent quali
ty in these all-perovskite heterostructures. The properties of the superla
ttices are rather complex showing a transition from orthorhombic to tetrag
onal crystalline symmetry of the SrRuO3 layers coupled with large changes
in the magnetocrystalline and magnetoresistance anisotropy. Embedding of L
a0.7Ba0.3MnO3 within SrRuO3 layers leads to the stabilization of ferromagn
etism above 150 K in single unit cell thick manganite layers. This appears
to be related to an interfacial anomalous Hall effect observed in the sup
erlattices.\n\nContact Person: Ionela Verjoiu
LOCATION:Seminar Room 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Martin Zirnbauer
DTSTART;VALUE=DATE-TIME:20160623T101500
DTEND;VALUE=DATE-TIME:20160623T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000904@events.thp.uni-koeln.de
DESCRIPTION:Martin Zirnbauer\, ITP UoC\n\nFrom the Chalker-Coddington mode
l to the conformal field theory of the IQHE plateau transition\n\n\n\nCont
act Person: Alexander Alldridge
LOCATION:Theory building
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Christian Faber and Matthias Pukrop
DTSTART;VALUE=DATE-TIME:20160715T140000
DTEND;VALUE=DATE-TIME:20160715T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000905@events.thp.uni-koeln.de
DESCRIPTION:Christian Faber and Matthias Pukrop\n\nBachelor colloquia\n\n\
n\nContact Person: Achim Rosch
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Cedric Beny
DTSTART;VALUE=DATE-TIME:20160706T160000
DTEND;VALUE=DATE-TIME:20160706T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000906@events.thp.uni-koeln.de
DESCRIPTION:Cedric Beny\, Hannover\n\nTensor networks and AdS/CFT \n\nI w
ill introduce some basic facts about the AdS/CFT correspondance which may
be relevant to tensor network models. The group of isometries of Anti de S
itter space is also the group of Lorentzian conformal maps on its "boundar
y at infinity". Similarly\, the isometries of Hyperbolic space or de Sitte
r space form the Euclidean conformal group. Thinking of path integrals as
continuous tensor networks\, one can see how the ground state of a quantum
field theory in AdS space may be thought of as that of a conformal field
theory on its boundary\, whose correlators are represented by tree tensor
networks. TTNs also arise when computing correlators in MERA\, which can b
e thought of as a discretisation of de Sitter space. Is there a formal rel
ationship between these two pictures?\n\nContact Person: David Gross
LOCATION:Seminar room 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Halil Cakir
DTSTART;VALUE=DATE-TIME:20160708T140000
DTEND;VALUE=DATE-TIME:20160708T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000907@events.thp.uni-koeln.de
DESCRIPTION:Halil Cakir\, University of Heidelberg\n\nDynamics of the Tran
sverse Field Ising Chain after a Sudden Quench\n\nDue to experimental adva
nces in the preparation and control of \nultra-cold atomic gases\, there i
s a widespread interest in the behaviour \nof quantum systems out of equil
ibrium. A common way to probe quantum \nsystems for non-equilibrium phenom
ena is given by sudden quenches. I \nwill present results concerning the d
ynamics of the longitudinal spin \ncorrelation function after a sudden que
nch in the Transverse Field Ising \nChain. A distinguishing feature of thi
s model is that it exhibits a \nquantum critical point separating a ferrom
agnetic from a paramagnetic \nphase. Furthermore\, the system can be expre
ssed as a fermionic harmonic \noscillator\, which allows us to determine t
he longitudinal correlation \nfunction after a sudden quench exactly by us
ing Wick's theorem. In \nparticular\, I will concentrate on the behaviour
of the longitudinal \ncorrelation function for quenches from an initially
large external field \nto the vicinity of the quantum critical point withi
n the paramagnetic \nphase. We conjectured a formula for the asymptotic be
haviour in this \ncase and compared it to numerical calculations of the co
rrelator. Based \non this conjectured formula\, we found that the decay of
the correlation \nfunction is characterized by two correlation lengths an
d that the \ncorrelation function attains its stationary values already at
short \ndistances.\n\n\nContact Person: Simon Trebst
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Darshan Joshi
DTSTART;VALUE=DATE-TIME:20160630T120000
DTEND;VALUE=DATE-TIME:20160630T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000908@events.thp.uni-koeln.de
DESCRIPTION:Darshan Joshi\, TU Dresden\n\nCoupled-dimer magnets: From Heis
enberg to Kitaev\n\n\n\nContact Person: Achim Rosch
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Wulf Wulfhekel
DTSTART;VALUE=DATE-TIME:20160921T143000
DTEND;VALUE=DATE-TIME:20160921T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000909@events.thp.uni-koeln.de
DESCRIPTION:Wulf Wulfhekel\, KIT\n\nMolecular systems for spintronics and
mechatronics\n\n\n\nContact Person: Thomas Michely
LOCATION:Seminar room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Max Gerlach
DTSTART;VALUE=DATE-TIME:20170120T140000
DTEND;VALUE=DATE-TIME:20170120T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000990@events.thp.uni-koeln.de
DESCRIPTION:Max Gerlach\n\nQuantum Monte Carlo studies of a metallic spin-
density wave transition\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nTwo Lectures On The Jones Polynomial An
d Khovanov Homology\nEdward Witten
DTSTART;VALUE=DATE-TIME:20160630T101500
DTEND;VALUE=DATE-TIME:20160630T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000911@events.thp.uni-koeln.de
DESCRIPTION:Edward Witten\n\nTwo Lectures On The Jones Polynomial And Khov
anov Homology\n\n\n\nContact Person: Alexander Alldridge
LOCATION:Theory building\, 1.04 or 2.04
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Sebastian Loth
DTSTART;VALUE=DATE-TIME:20161102T143000
DTEND;VALUE=DATE-TIME:20161102T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000912@events.thp.uni-koeln.de
DESCRIPTION:Sebastian Loth\, MPI\n\nHarnessing quantum effects in atom-siz
ed antiferromagnets\n\nAntiferromagnets are often used only for their resi
lience to external magnetic fields and appear ill-suited for use as active
elements in spintronic devices. But when shrunk to nanometer dimensions a
ntiferromagnets gain in functionality. We use low-temperature scanning tun
neling microscopy to create small antiferromagnets of our own design atom
by atom. At this extreme scale of individual atoms we can begin to harness
quantum mechanical effects. \nIn this way we can build antiferromagnetic
nanostructures that show two stable magnetic states with no net magnetic m
oment or structures that have a unique ground state but feature rich magne
tic dynamics of their excited states. I will introduce how inter-atomic ex
change bias gives control over the spin ground state and excitation dynami
cs of antiferromagnets and demonstrate how coupling to the dissipative env
ironment can be used to stabilize spins.\n\n\nContact Person: Thomas Miche
ly
LOCATION:Seminar room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Joanna Meinel
DTSTART;VALUE=DATE-TIME:20160707T101500
DTEND;VALUE=DATE-TIME:20160707T114500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000913@events.thp.uni-koeln.de
DESCRIPTION:Joanna Meinel\, University of Bonn\n\nThe affine nilTemperley-
Lieb algebra and combinatorics of circular particle configurations\n\nWe s
tudy the affine nilTemperley-Lieb algebra\, an algebra given by\ngenerator
s and relations. We introduce its action on combinatorially defined\nparti
cle configurations\, and using this action\, we describe explicitly\nsever
al bases and the centre of the algebra.\n\nContact Person: Alexander Alldr
idge
LOCATION:Theory building
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Robert Bamler
DTSTART;VALUE=DATE-TIME:20160711T123000
DTEND;VALUE=DATE-TIME:20160711T140000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000914@events.thp.uni-koeln.de
DESCRIPTION:Robert Bamler\n\nPhase-Space Berry Phases in Chiral Magnets: S
kyrmion Charge\, Hall Effect\, and Dynamics of Magnetic Skyrmions\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Johannes Lang
DTSTART;VALUE=DATE-TIME:20161130T100000
DTEND;VALUE=DATE-TIME:20161130T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000915@events.thp.uni-koeln.de
DESCRIPTION:Johannes Lang\, TU Munich\n\nCritical relaxation in open syste
ms without quasiparticles\n\n\n\nContact Person: Sebastian Diehl
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Emilio Torres
DTSTART;VALUE=DATE-TIME:20161012T100000
DTEND;VALUE=DATE-TIME:20161012T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000916@events.thp.uni-koeln.de
DESCRIPTION:Emilio Torres\n\nDualities\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:DIS | Fanny Groll
DTSTART;VALUE=DATE-TIME:20160711T160000
DTEND;VALUE=DATE-TIME:20160711T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000917@events.thp.uni-koeln.de
DESCRIPTION:Fanny Groll\n\nDiversity and Stability in Food Webs - Impacts
of Non-Equilibrium Dynamics\, Topology and Variation\n\n\n\nContact Perso
n: Fanny Groll
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Dario Poletti
DTSTART;VALUE=DATE-TIME:20160720T160000
DTEND;VALUE=DATE-TIME:20160720T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000918@events.thp.uni-koeln.de
DESCRIPTION:Dario Poletti\, Singapore University of Technology and Design\
n\nGeometry of system-bath coupling and gauge fields in bosonic ladders: m
anipulating currents and driving phase transitions \n\nQuantum systems in
contact with an environment display a rich physics emerging from the inte
rplay between dissipative and Hamiltonian terms. We consider a dissipative
boundary driven ladder in presence of a gauge field. The dissipation stim
ulates currents while the gauge field tends to steer the flow. We show tha
t depending on the geometry of coupling to the baths and of the strength o
f the gauge field\, non-equilibrium phase transitions emerge strongly modi
fying the currents both in magnitude and spatial distribution. \n\nContact
Person: Jamir Marino
LOCATION:Seminarroom 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Xenophon Zotos
DTSTART;VALUE=DATE-TIME:20170118T143000
DTEND;VALUE=DATE-TIME:20170118T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000998@events.thp.uni-koeln.de
DESCRIPTION:Xenophon Zotos\, University of Crete\n\nNovel view on the dyna
mics of a 1D and 2D prototype quantum many body system\n\nI will present r
ecent results\, (i) on a novel TBA approach to magneto-thermal transport i
n the Heisenberg spin 1/2 chain\, as well as an extension to far out of
equilibrium thermal transport (thermal quench) [1]\, (ii) on the high temp
erature dynamics of quantum compass models [2]. \n\n[1] X. Zotos\, arXiv:
1604.08434 \n\n[2] A. Briffa and X. Zotos\, arXiv: 1611.00637\n\n\nContact
Person: P. van Loosdrecht
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Keith Lee
DTSTART;VALUE=DATE-TIME:20160713T160000
DTEND;VALUE=DATE-TIME:20160713T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000920@events.thp.uni-koeln.de
DESCRIPTION:Keith Lee\, University of Waterloo\n\nQuantum algorithms\, qua
ntum field theory\, and computational complexity\n\n\n\nContact Person: Da
vid Gross
LOCATION:Seminar 0.02\, theory building
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Hidenori Takagi
DTSTART;VALUE=DATE-TIME:20161004T163000
DTEND;VALUE=DATE-TIME:20161004T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000921@events.thp.uni-koeln.de
DESCRIPTION:Hidenori Takagi\, MPI Stuttgart\n\nOpening Colloquium SFB 1238
\n\n\n\nContact Person: Simon Trebst
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Mohammad Faghfoor Maghrebi
DTSTART;VALUE=DATE-TIME:20160721T100000
DTEND;VALUE=DATE-TIME:20160721T110000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000926@events.thp.uni-koeln.de
DESCRIPTION:Mohammad Faghfoor Maghrebi\, University of Maryland\n\nSteady
states and dynamics in many-body driven-dissipative systems\n\nMany-body s
ystems with both coherent dynamics and dissipation constitute a rich class
of models which are nevertheless much less explored than their dissipatio
nless counterparts. The advent of numerous experimental platforms that sim
ulate such dynamics poses an immediate challenge to systematically underst
and and classify these models. In particular\, nontrivial many-body states
emerge as steady states under non-equilibrium dynamics. In this talk\, I
use a systematic approach to study nonequilibrium phases and phase transit
ions and the dynamics in such models. I show that an effective thermal beh
avior generically emerges as a result of dissipation. Finally I use this e
quivalence to make quantitative predictions about the properties of the st
eady-state its dynamical properties.\n\nContact Person: Sebastian Diehl
LOCATION:Seminarroom 0.01\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Tim Eschmann
DTSTART;VALUE=DATE-TIME:20160812T140000
DTEND;VALUE=DATE-TIME:20160812T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000927@events.thp.uni-koeln.de
DESCRIPTION:Tim Eschmann\n\nTBA\n\n
LOCATION:Seminar Room TP 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Mateus Araujo
DTSTART;VALUE=DATE-TIME:20160815T150000
DTEND;VALUE=DATE-TIME:20160815T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000933@events.thp.uni-koeln.de
DESCRIPTION:Mateus Araujo\, University of Vienna\n\nA purification postula
te for quantum mechanics with no causal order\n\nA recent framework for st
udying causal structures introduced the notion of a\nprocess: a resource s
hared between some parties that is compatible with standard\nquantum mecha
nics in each party’s laboratory\, but that does not presuppose the\nexis
tence of a global causal order between them.\nThese processes can be used
to perform several tasks that are impossible in\nstandard quantum mechanic
s: they allow for the violation of causal inequalities\,\nand provide an a
dvantage for computational and communication complexity.\nNonetheless\, no
physical process is known that allows for the violation of a\ncausal ineq
uality. There is therefore considerable interest in determining which\npro
cesses are physical and which are just mathematical artefacts of the\nfram
ework. Here we make the first step in this direction\, by proposing a\npur
ification postulate: processes are physical only if they are purifiable. W
e\nderive necessary conditions for a process to be purifiable\, and show t
hat\nseveral known processes do not satisfy them.\n\nContact Person: David
Gross
LOCATION:Seminarroom 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Rosario Fazio
DTSTART;VALUE=DATE-TIME:20161017T160000
DTEND;VALUE=DATE-TIME:20161017T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000934@events.thp.uni-koeln.de
DESCRIPTION:Rosario Fazio\, ICTP\, Trieste\n\nSteady state phase diagram o
f driven-dissipative systems\n\nThanks to the recent impressing experiment
al progresses the investigation of non- equilibrium properties of driven-d
issipative systems has entered the quantum world. Rydberg atoms in optical
lattices\, systems of trapped ions\, exciton- polariton condensates\, col
d atoms in cavities\, arrays of coupled QED cavities\, are probably the mo
st intensively investigated experimental platforms in relation to this aim
. I will discuss properties of phases and phase transitions in the steady
state of these systems.\n\nContact Person: Jamir Marino
LOCATION:Seminarroom 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Loris M. Cangemi
DTSTART;VALUE=DATE-TIME:20160824T100000
DTEND;VALUE=DATE-TIME:20160824T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000935@events.thp.uni-koeln.de
DESCRIPTION:Loris M. Cangemi\, University of Naples\n\nCharge transport in
organic semiconductors: theory and simulation\n\n\n\nContact Person: Ralf
Bulla
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Sebastian Huber
DTSTART;VALUE=DATE-TIME:20170203T163000
DTEND;VALUE=DATE-TIME:20170203T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000936@events.thp.uni-koeln.de
DESCRIPTION:Sebastian Huber\, ETH Zurich\n\nTopological Mechanical Metamat
erials\n\nThe elastic properties of materials are determined by a few mate
rial constants such as the Young’s modulus. Using super-structures one c
an effectively change these “constants”. In this way we obtain functio
nalities such as wave-guiding\, acoustic lensing or programmable failure.
I will show how topological band theory\, known from the description of el
ectrons in solids\, provides us with a powerful design-principle for such
mechanical metamaterials.\n\n\nContact Person: Simon Trebst
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:GSEM | Subrata Dev
DTSTART;VALUE=DATE-TIME:20160923T100000
DTEND;VALUE=DATE-TIME:20160923T110000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000937@events.thp.uni-koeln.de
DESCRIPTION:Subrata Dev\, S.N. Bose National Centre for Basic Sciences\, K
olkata\, India\n\nOptimal conditions of external medium and intracellular
environment for efficient chemotactic performance in E. coli\n\nWe investi
gate how the efficiency of E. coli chemotaxis depends on the external\nenv
ironment and the internal biochemical pathway of the E.coli cell. When the
cell is in a medium\nwhere the nutrient is diffusing and the form of nutr
ient profile is Gaussian\, we find that there exists an\noptimal width of
the profile for which the search time becomes minimum. In the case when th
e nutrient\ndiffusion and cell movement occurs over comparable time-scales
\, there exists an optimum value of the\nnutrient diffusivity for which th
e search time becomes minimum. The simulation results in a phenotype\nmode
l agree well with our analytical calculations in a related coarse-grained
model. In a single cell\nchemotaxis the internal biochemical pathway invol
ves noise due to the fluctuations present in the\nnumber of different mole
cules taking part in the reactions. This noise plays a very crucial role o
n the\nchemotactic performance of E. coli bacterium. We find that in the l
ong time limit the localization and\nthe uptake\, i.e. the total nutrient
intercepted along its trajectories\, becomes maximum for an optimum\nvalue
of the noise strength. We discuss a simple mechanism to explain this effe
ct.\n\nContact Person: Joachim Krug
LOCATION:TP conference room 0.01
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Thomas Nutz
DTSTART;VALUE=DATE-TIME:20160908T150000
DTEND;VALUE=DATE-TIME:20160908T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000938@events.thp.uni-koeln.de
DESCRIPTION:Thomas Nutz\, Imperial College London\n\nEfficient benchmarkin
g of photonic cluster state sources\n\n Certain single-photon sources are
capable of emitting strings of entangled photons. In particular\, photonic
cluster state sources could enable measurement-based quantum computing an
d are therefore under intense investigation. While experiments are progres
sing\, the issue of benchmarking comes to the fore.\n The challenge is
to quantify the long-range entanglement of the photonic state using only t
he few-photon correlation measurements that are feasible given limited emi
ssion/detection efficiencies. We present a lower bound on localizable enta
nglement that requires nothing but simple three-qubit correlation measurem
ents. This method therefore enables direct demonstration of computationall
y powerful multi-photon entanglement with currently available experimental
capabilities.\n\nContact Person: David Gross
LOCATION:Seminarroom 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Masatoshi Sato
DTSTART;VALUE=DATE-TIME:20160922T140000
DTEND;VALUE=DATE-TIME:20160922T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000939@events.thp.uni-koeln.de
DESCRIPTION:Masatoshi Sato\, Kyoto University\n\nNonsymmorphic Symmetry an
d New Topological Phases\n\nNonsymmorphic symmetry is crystal symmetry rea
lized as combination of a point group operation and a non-primitive lattic
e translation. Many crystals have such nonsymmorphic crystal symmetry\, bu
t it effects on topological phases just begin to be explored very recently
. It has been discovered that nonsymmorphic symmetry provides intrinsicall
y new topological phases in insulators and superconductors. For example\,
the new topological phases may be characterized by new Z2 and Z4 topologic
al indices\, hosting exotic Mobius twisted surface states. In addition\, n
onsymmorphic symmetry also provides new gapless structure in nodal superco
nductors. In this talk\, I will explain our recent results on nonsymmorphi
c topological phases.\n\nContact Person: Yoichi Ando
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Titus Neupert
DTSTART;VALUE=DATE-TIME:20161207T143000
DTEND;VALUE=DATE-TIME:20161207T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000940@events.thp.uni-koeln.de
DESCRIPTION:Titus Neupert\, University of Zurich\n\nOne-dimensional edge m
odes of three-dimensional topological insulators\n\nI will discuss two ins
tances of one-dimensional conducting edge channels that can appear on the
boundary of three-dimensional topological crystalline insulators\, one sup
ported by an experimental observation and the second one being a theoretic
al prediction. For the first part\, I will discuss channels that appear at
step edges on the surface of (Pb\,Sn)Se. These conducting channels can be
understood as arising from a Berry curvature mismatch between Dirac surfa
ce states on either side of the step edge. Experimentally\, they have been
found to be remarkably robust against defects\, magnetic fields and eleva
ted temperature. Second\, I will introduce the concept of higher-order thr
ee-dimensional topological insulators\, which have gapped surfaces\, but s
upport topologically protected gapless states on their one-dimensional phy
sical edges.\n\nContact Person: Simon Trebst
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Je-Geun Park
DTSTART;VALUE=DATE-TIME:20170517T143000
DTEND;VALUE=DATE-TIME:20170517T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001068@events.thp.uni-koeln.de
DESCRIPTION:Je-Geun Park \, Seoul National University\n\nOpportunities and
challenges of two-dimensional magnetic van der Waals materials: magnetic
graphene?\n\n\n\nContact Person: Daniel Khomskii
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Michael Kiessling
DTSTART;VALUE=DATE-TIME:20161026T143000
DTEND;VALUE=DATE-TIME:20161026T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000942@events.thp.uni-koeln.de
DESCRIPTION:Michael Kiessling\, Rutgers University\n\nOn the quantum mecha
nics of a single photon\n\nThe quantum mechanical wave equation for a sing
le photon is conspicuously missing from textbooks on quantum mechanics. Op
inions range from the claim that this notion is meaningless to suggestions
that Maxwell's\nelectromagnetic field equations supply it in disguise. Af
ter reviewing the arguments pro and con\, we will propose a Lorentz covar
iant wave equation for a photon and demonstrate that it possesses the desi
rable features. This is joint work with A. Shadi Tahvildar-Zadeh.\n\nConta
ct Person: Markus Kunze
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Samuel Bieri
DTSTART;VALUE=DATE-TIME:20161104T140000
DTEND;VALUE=DATE-TIME:20161104T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000943@events.thp.uni-koeln.de
DESCRIPTION:Samuel Bieri\, ETH Zurich / Sorbonne\n\nQuantum spin liquids i
n frustrated magnets\n\nQuantum spin liquids are fascinating phases in qua
ntum magnetism. Broad theoretical advances\, and fast progress in material
s science have significantly advanced the field in recent years.\n\nAfter
a general introduction to the subject\, I will talk about the projective s
ymmetry group approach to the problem of classification of such exotic pha
ses. In a second part\, I will present work on the theory for the kapellas
ite material\, a spin S=1/2 Heisenberg antiferromagnet on the kagome latti
ce. Finally\, I will discuss a highly intriguing phase that was recently c
haracterized in the triangular spin S=1 compound BaNiSbO.\n\nSB et al\, PR
B 93\, 094437 (2016).\nSB et al\, PRB 92\, 060407(R) (2015).\nB. Fak\, SB\
, et al\, arXiv:1610.03753 (2016).\n\n\nContact Person: Simon Trebst
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Chau Nguyen
DTSTART;VALUE=DATE-TIME:20160921T150000
DTEND;VALUE=DATE-TIME:20160921T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000944@events.thp.uni-koeln.de
DESCRIPTION:Chau Nguyen\, MPI Dresden\n\nA geometric approach to quantum s
teerability\n\nFully characterizing the steerability of a quantum state of
a bipartite\nsystem has remained an open problem since the concept of ste
erability\nwas defined. In this talk\, we discuss a geometric approach to\
nsteerability and suggest a necessary and sufficient condition for a\ntwo-
qubit state to be steerable with respect to projective measurements.\nTo t
his end\, we define the critical radius of local models and show that\na s
tate of two qubits is steerable with respect to projective\nmeasurements f
rom Alice's side if and only if her critical radius of\nlocal models is le
ss than 1. We then calculate the critical radius of\nlocal models for the
so-called T-states by proving the optimality of a\nrecently suggested loca
l hidden state model.\n\nContact Person: David Gross
LOCATION:Seminarroom 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Benedikt Sabaß
DTSTART;VALUE=DATE-TIME:20161118T163000
DTEND;VALUE=DATE-TIME:20161118T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000945@events.thp.uni-koeln.de
DESCRIPTION:Benedikt Sabaß\, FZ Jülich\n\nMicromechanics of Life: Coordi
nation of Forces by Eukaryotes and Prokaryotes\n\nCells have the ability t
o generate mechanical forces. Coordination of these forces is not only imp
ortant for multicellular life\, but also plays a role for various diseases
. We combine physical theory and traction microscopy to uncover mechanisms
of how cells feel and respond to forces. Here\, we present a synopsis of
recent findings on mechanisms of collective organization\, ranging from ba
cteria to eukaryotic tissue cells.\n
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | William G. Unruh
DTSTART;VALUE=DATE-TIME:20170120T163000
DTEND;VALUE=DATE-TIME:20170120T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000946@events.thp.uni-koeln.de
DESCRIPTION:William G. Unruh\, University of British Columbia\, Vancouver\
n\nMeasuring Black Hole radiation in the lab\n\nHawking's prediction that
black holes should radiate was one of the biggest surprizes in physics of
the late 20th century. It has dominated much of the study in the interface
between gravity and Quantum Mechanics ever since. The calculation Hawking
presented is problematic\, and thus experimental confirmation would be go
od. Unfortunately\, finding small black holes is hard. However\, there tur
n out to be analog systems\, systems with horizons which one can and is st
udying in the lab. I will present the arguments and the current experiment
al effort to see the radiation\, and the arguments that some experiments h
ave already seen it.\n\nContact Person: Claus Kiefer
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Bernd Buechner
DTSTART;VALUE=DATE-TIME:20161123T143000
DTEND;VALUE=DATE-TIME:20161123T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000947@events.thp.uni-koeln.de
DESCRIPTION:Bernd Buechner\, IFW Dresden\n\nAnisotropic Magnetism and Spin
Gap in alpha-RuCl3\n\nQuantum spin liquids are a central theme in current
condensed matter physics as they host emergent topological order and frac
tionalized excitations. An important example are interacting Kitaev spins
on a honeycomb lattice which are theoretically predicted to exhibit topolo
gical and quantum spin liquids. Identifying signatures of Kitaev physics\,
however\, is extremely challenging as real materials\, such as the iridat
es (Na\,Li)2IrO3\, inevitably entail an isotropic Heisenberg and additiona
l spin-exchange interactions\, thereby stabilizing a magnetically ordered
state. Hexagonal Ru trichloride α-RuCl3 has been recently reported to be
near the Kitaev spin-liquid phase boundary. The layered honeycomb structur
e of α-RuCl3 contains layers weakly coupled by van der Waals interaction\
, i.e. it is a correlated 2d-material offering many possibilities for “m
aterials engineering”. We have characterized the electronic and magnetic
properties of α-RuCl3 by a broad spectrum of experimental techniques. Fr
om electron spectroscopy basic parameters determining the insulating state
of α-RuCl3 are extracted. Moreover\, strongly anisotropic magnetic prope
rties as measured from magnetization\, specific heat\, thermal conductivit
y\, and NMR measurements will be presented and discussed. Both\, the beha
vior of α-RuCl3 in the paramagnetic phase as well as the properties of th
e ordered state strongly differ from that found in conventional two-dimens
ional magnets. In particular\, we find a very unusual field-temperature ph
ase diagram with evidence for a novel quantum critical point.\n\nContact P
erson: Markus Braden
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Alex Kruchkov
DTSTART;VALUE=DATE-TIME:20161014T140000
DTEND;VALUE=DATE-TIME:20161014T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000948@events.thp.uni-koeln.de
DESCRIPTION:Alex Kruchkov\, Ecole Polytechnique Federale de Lausanne\n\nQu
antum Lightsaber: condensation of light in an ultrathin tube\n\nLight can
be converted into a liquid\, a quantum liquid called Bose-Einstein condens
ate\, where it nearly stops if travels in one dimension. In this talk\, I
address a quasiequilibrium one-dimensional Bose-Einstein condensation of p
hotons trapped in a microtube\, which is possible because the light modes
have a cut-off frequency (a photon’s “mass”) and interact through di
fferent processes of absorption\, emission\, and scattering on molecules a
nd atoms. I discuss the conditions for the one-dimensional condensation of
light and the role of photon- photon interactions in the system. This the
oretical study is in the strong connection with the experiments of the Wei
tz Quantum Optics group (University of Bonn).\n\nContact Person: Achim Ros
ch
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Tusharkanti Dey
DTSTART;VALUE=DATE-TIME:20161019T143000
DTEND;VALUE=DATE-TIME:20161019T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000949@events.thp.uni-koeln.de
DESCRIPTION:Tusharkanti Dey\, University of Augsburg\n\nPossible materials
for realization of (i) Heisenberg-Kitaev physics in triangular lattice an
d (ii) excitonic magnetism\n\nPresence of a strong spin-orbit coupling (SO
C) comparable to Coulomb interaction (U) and crystal field in iridium base
d oxides give rise to novel properties. Especially the honeycomb lattice i
ridates attracted lot of attention in the context of Heisenberg-Kitaev mod
el. Extension of this model to triangular lattice has been studied theoret
ically and a rich phase diagram has been proposed [1\, 2]. Possible materi
als for the realization of Heisenberg-Kitaev model in a triangular lattice
will be discussed in this talk.\n\nMaterials with 5d4 electronic configur
ation are believed to be in a nonmagnetic ground state (J=0). An interplay
between U and SOC in these materials may lead to novel magnetism called e
xcitonic magnetism [3]. In the 2nd part of the talk\, Ba2YIrO6 with 5d4 (I
r5+) electronic configuration will be discussed in the context of excitoni
c magnetism.\nReferences:\n[1] M. Becker et al.\, Phys. Rev. B 91\, 155135
(2015)\n[2] A. Catuneanu et al.\, Phys. Rev. B 92\, 165108 (2015)\n[3] G.
Khaliullin\, Phys. Rev. Lett. 111\, 197201 (2013)\n\nContact Person: T. L
orenz
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Malte Henkel
DTSTART;VALUE=DATE-TIME:20170113T163000
DTEND;VALUE=DATE-TIME:20170113T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000966@events.thp.uni-koeln.de
DESCRIPTION:Malte Henkel\, Universite de Lorraine Nancy\n\nNew dynamical s
ymmetries in interface growth: what do we know about them and what do they
teach us ?\n\nInterface growth is a paradigmatic example of a complex sys
tem made from a large number of strongly interacting degrees of freedom\,
with dynamically created long-range correlations. Such systems can undergo
physical ageing\, that is they display (i) slow relaxational behaviour\,
(ii) breaking of time-translation-invariance and (iii) dynamical scaling.
Through simulations and simple exactly solvable models\, we investigate in
to the existence of new\, non-trivial dynamical symmetries extending dynam
ical scaling and their possible consequences.\n\nContact Person: Joachim K
rug
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Peter Broecker
DTSTART;VALUE=DATE-TIME:20161019T100000
DTEND;VALUE=DATE-TIME:20161019T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000951@events.thp.uni-koeln.de
DESCRIPTION:Peter Broecker\n\nMachine learning of quantum phases of matter
\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Michael Buchhold
DTSTART;VALUE=DATE-TIME:20161026T100000
DTEND;VALUE=DATE-TIME:20161026T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000952@events.thp.uni-koeln.de
DESCRIPTION:Michael Buchhold\n\nExploring Non-Equilibrium Phase Transition
s in Driven Rydberg Systems\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Jan Mueller
DTSTART;VALUE=DATE-TIME:20161102T100000
DTEND;VALUE=DATE-TIME:20161102T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000953@events.thp.uni-koeln.de
DESCRIPTION:Jan Mueller\n\nHelices and Skyrmions\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Henry Legg
DTSTART;VALUE=DATE-TIME:20161109T100000
DTEND;VALUE=DATE-TIME:20161109T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000954@events.thp.uni-koeln.de
DESCRIPTION:Henry Legg\n\nSpin-liquid RKKY\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Jan Gelhausen
DTSTART;VALUE=DATE-TIME:20161123T100000
DTEND;VALUE=DATE-TIME:20161123T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000955@events.thp.uni-koeln.de
DESCRIPTION:Jan Gelhausen\n\nQuantum-optical magnets with competing short-
and long-range interactions: Rydberg-dressed spin lattice in an optical c
avity\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Bjoern Trauzettel
DTSTART;VALUE=DATE-TIME:20170201T143000
DTEND;VALUE=DATE-TIME:20170201T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000994@events.thp.uni-koeln.de
DESCRIPTION:Bjoern Trauzettel\, University of Wuerzburg\n\nChiral anomaly
in real space from stable fractional charges at the edge of a quantum spin
Hall insulator\n\nThe chiral anomaly is based on a non-conserved chiral c
harge and can happen in Dirac fermion systems under the influence of exter
nal electromagnetic fields. In this case\, the spectral flow leads to a t
ransfer of right- to left-moving excitations or vice versa. The correspond
ing transfer of chiral particles happens in momentum space. We here descri
be an intriguing way to introduce the chiral anomaly into real space. Our
system consists of two quantum dots that are formed at the helical edges o
f a quantum spin Hall insulator by means of magnetic barriers. Such a setu
p gives rise to fractional charges which we show to be sharp quantum numbe
rs for large barrier strength.\nInterestingly\, it is possible to map the
system onto a quantum spin Hall ring in the presence of a flux pierced thr
ough the ring where the relative angle between the magnetization direction
s of the barriers takes the role of the flux. The chiral anomaly in this s
ystem is then directly related to the excess occupation of particles in th
e two quantum dots. This analogy allows us to predict an observable conseq
uence of the chiral anomaly in real space.\n\nContact Person: Alex Altland
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Yasir Iqbal
DTSTART;VALUE=DATE-TIME:20161209T140000
DTEND;VALUE=DATE-TIME:20161209T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000965@events.thp.uni-koeln.de
DESCRIPTION:Yasir Iqbal\, University of Wuerzburg\n\nIntertwined nematic o
rders in a frustrated ferromagnet\n\nWe investigate the quantum phases of
the frustrated spin-$\\frac{1}{2}$ $J_1$-$J_2$-$J_3$ Heisenberg model on t
he square lattice with ferromagnetic $J_1$ and antiferromagnetic $J_2$ and
$J_3$ interactions. Using the pseudo-fermion functional renormalization g
roup technique\, we find an intermediate paramagnetic phase located betwee
n classically ordered ferromagnetic\, stripy antiferromagnetic\, and incom
mensurate spiral phases. We observe that quantum fluctuations lead to sign
ificant shifts of the spiral pitch angles compared to the classical limit.
By computing the response of the system with respect to various spin rota
tion and lattice symmetry-breaking perturbations\, we identify a complex i
nterplay between different nematic spin states in the paramagnetic phase.
While retaining time-reversal invariance\, these phases either break spin-
rotation symmetry\, lattice-rotation symmetry\, or a combination of both.
We therefore propose the $J_1$-$J_2$-$J_3$ Heisenberg model on the square
lattice as a paradigmatic example where different intimately connected typ
es of nematicities emerge in the same model.\n\nContact Person: Finn Lasse
Buessen
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Tim Eschmann
DTSTART;VALUE=DATE-TIME:20161221T100000
DTEND;VALUE=DATE-TIME:20161221T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000959@events.thp.uni-koeln.de
DESCRIPTION:Tim Eschmann\n\nQuantum Monte Carlo Simulations on Kitaev Syst
ems\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Maria Hermanns
DTSTART;VALUE=DATE-TIME:20170111T100000
DTEND;VALUE=DATE-TIME:20170111T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000960@events.thp.uni-koeln.de
DESCRIPTION:Maria Hermanns\n\nNon-abelian hierarchies\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Philipp Weiss
DTSTART;VALUE=DATE-TIME:20170125T100000
DTEND;VALUE=DATE-TIME:20170125T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000961@events.thp.uni-koeln.de
DESCRIPTION:Philipp Weiss\n\nNoisy Boltzmann equations\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Jan Attig
DTSTART;VALUE=DATE-TIME:20170208T100000
DTEND;VALUE=DATE-TIME:20170208T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000962@events.thp.uni-koeln.de
DESCRIPTION:Jan Attig\n\nClassical Spin Spirals and Free Fermions\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Finn Lasse Buessen
DTSTART;VALUE=DATE-TIME:20170201T100000
DTEND;VALUE=DATE-TIME:20170201T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000964@events.thp.uni-koeln.de
DESCRIPTION:Finn Lasse Buessen\n\nSpin liquids and competing magnetic orde
rs in three-dimensional frustrated magnets\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Yuval Vinkler
DTSTART;VALUE=DATE-TIME:20170119T140000
DTEND;VALUE=DATE-TIME:20170119T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001012@events.thp.uni-koeln.de
DESCRIPTION:Yuval Vinkler\, FU Berlin\n\nTime Reversal Symmetric Topologic
al Josephson Junction with a Spin Impurity\n\n\n\nContact Person: Achim R
osch
LOCATION:Seminar Room\, Institute for Theoretical Physics (Main Building)
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Leon Schoonderwoerd
DTSTART;VALUE=DATE-TIME:20161007T140000
DTEND;VALUE=DATE-TIME:20161007T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000967@events.thp.uni-koeln.de
DESCRIPTION:Leon Schoonderwoerd\, University of Amsterdam\n\nTensor networ
k algorithms for 1D spin chains: DMRG and entanglement entropy minimizatio
n\n\nTensor networks provide a novel and powerful way to think about and p
erform calculations with many-body systems. This talk treats tensor networ
ks in the form of Matrix Product states (MPS) and Matrix Product Operators
(MPO)\, which are used for calculations on (1D) spin chains. Firstly\, De
nsity Matrix Renormalization Group (DMRG) algorithms\, concerned with find
ing the ground state and its energy. Secondly\, an approach for the minimi
zation of entanglement entropy using unitary basis transformations is give
n. The idea for this latter part is based on [1]\, but instead of a parame
ter-based approach\, an environment network-based algorithm is used. The c
ombination of the entropy minimization with DMRG is discussed. Results obt
ained using the minimization algorithm are shown\, and the method's limita
tions are discussed.\n\n[1] C. Krumnow\, L. Veis\, Ö. Legeza & J. Eisert\
, Fermionic orbital optimisation in tensor network states\, arXiv 1504.000
42v3\n\nContact Person: Simon Trebst
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Stefan Wessel
DTSTART;VALUE=DATE-TIME:20161202T140000
DTEND;VALUE=DATE-TIME:20161202T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000968@events.thp.uni-koeln.de
DESCRIPTION:Stefan Wessel\, RWTH Aachen\n\nExcitation Modes and Gap Scalin
g near Quantum Critical Dimerized Antiferromagnets\n\nResults are presente
d from large-scale quantum Monte Carlo simulations on the excitation modes
in two- \nand three-dimensional quantum antiferromagnets of coupled spin
dimers accross their quantum critical \npoints. The identification of the
amplitude (Higgs) mode from dynamical spin and singlet spectral \nfunction
s are examined and compared to scaling predictions. For the three-dimensio
nal case\, we \nidentify characteristic multiplicative logarithmic correct
ions in the exciation gap scaling atop the \nleading mean-field behavior.
These are in accord with field-theoretical predictions based on an \neffec
tive description of the quantum critical system in terms of an asymptotica
lly-free field theory. \nThe width of the Higgs mode resonance is observed
to scale linearly with the Higgs mass near \ncriticality\, indicative of
this critically well-defined excitation mode of the symmetry broken phase.
\n\n\nContact Person: Peter Broecker
LOCATION:Seminar room 0.03\, ITP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Hiroki Isobe
DTSTART;VALUE=DATE-TIME:20161013T140000
DTEND;VALUE=DATE-TIME:20161013T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000969@events.thp.uni-koeln.de
DESCRIPTION:Hiroki Isobe\, MIT\n\nInterlayer pairing symmetry of composite
fermions in quantum Hall bilayers\n\nSince the discovery of quantum Hall
effect\, two-dimensional electron system under magnetic field has provided
lots of intriguing physics topics both experimentally and theoretically\,
including integer/fractional quantized Hall conductance\, anyon statistic
s\, and non-Abelian particles. Electron-electron interactions play crucia
l roles in such quantum Hall problems. Even richer phenomena take place f
or two parallel two-dimensional sheets. Bilayer systems\, or more general
ly multicomponent systems\, have additional degrees of freedom\, and they
allow interlayer paired states at even-denominator filling fraction in eac
h layer\, which exhibits the Fermi sea of composite fermions without inter
actions. I will discuss the interlayer paired state in the presence of th
e Coulomb interaction and its pairing symmetry\, and will make a comment o
n a possible topological order of the ground state.\n\nContact Person: Yoi
chi Ando
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Achim Schwenk
DTSTART;VALUE=DATE-TIME:20161025T164500
DTEND;VALUE=DATE-TIME:20161025T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000970@events.thp.uni-koeln.de
DESCRIPTION:Achim Schwenk\, TU Darmstadt\n\nFrom nuclear forces to neutron
stars\n\n
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Tobias Bollenbach
DTSTART;VALUE=DATE-TIME:20161108T164500
DTEND;VALUE=DATE-TIME:20161108T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000971@events.thp.uni-koeln.de
DESCRIPTION:Tobias Bollenbach\, University of Cologne\n\nQuantitative appr
oaches to antibiotic resistance evolution\n\n
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Giulio Biroli
DTSTART;VALUE=DATE-TIME:20161122T164500
DTEND;VALUE=DATE-TIME:20161122T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000972@events.thp.uni-koeln.de
DESCRIPTION:Giulio Biroli\, Institut de Physique Theorique\, CEA Saclay\n\
nNon-Linear Responses\, Soft-Modes and the True Nature of Glasses\n\n
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Sebastian Diehl
DTSTART;VALUE=DATE-TIME:20161206T164500
DTEND;VALUE=DATE-TIME:20161206T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000973@events.thp.uni-koeln.de
DESCRIPTION:Sebastian Diehl\, University of Cologne\n\nDriven Open Quantum
Systems: From Micro- to Macrophysics\n\n
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Klaus Mecke und Aura Heydenreich
DTSTART;VALUE=DATE-TIME:20170124T164500
DTEND;VALUE=DATE-TIME:20170124T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000974@events.thp.uni-koeln.de
DESCRIPTION:Klaus Mecke und Aura Heydenreich\, Universität Erlangen-Nürn
berg\n\nKosmo-Poetik: Was haben Physik und Literatur sich zu erzählen?\n\
n Warum und zu welchem Ende ist es lohnenswert\, sich mit den Beziehungen
zwischen Physik und Literatur zu beschäftigen? Das soll im Vortrag anhand
von historischen Beispielen und systematischen Analysen skizziert werden.
So ist z.B. zur Zeit Johannes Keplers die Synthese wissenschaftlicher und
literarischer Schreibweisen in einem Text noch denkbar: Kepler entwirft 1
609 in seinem Somnium eine fiktive Mondreise\, die den Kampf zwischen den
miteinander konfligierenden Weltbildern inszeniert und durch allegorische\
, optische\, narrative und wissenschaftliche Schreibverfahren der neuen as
tronomischen Auffassung zur Verbreitung verhilft. Mit Kepler als Vorbild r
eflektieren auch heute literarische Texte den Beitrag der Physik zur Kultu
r des 20. und 21. Jahrhunderts\, so z.B. Thomas Lehrs Roman '42' und Raoul
Schrotts Epos 'Erste Erde'. Das Erlanger Zentrum für Literatur und Natur
wissenschaft (ELINAS) widmet sich diesem interdisziplinären Austausch dur
ch Tandemprojekte: dieses zusammen mit der Literaturwissenschaftlerin Aura
Heydenreich.
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Peter Thirolf
DTSTART;VALUE=DATE-TIME:20170131T164500
DTEND;VALUE=DATE-TIME:20170131T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000975@events.thp.uni-koeln.de
DESCRIPTION:Peter Thirolf\, Ludwig-Maximilians-Universitaet Muenchen\n\nDi
rect Detection of the Elusive 229Thorium Isomer: Milestone Towards a Nucle
ar Clock\n\n
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Andreas Burkert
DTSTART;VALUE=DATE-TIME:20170110T164500
DTEND;VALUE=DATE-TIME:20170110T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000976@events.thp.uni-koeln.de
DESCRIPTION:Andreas Burkert\, Ludwig-Maximilians-Universitaet Muenchen\n\n
The origin and dynamics of high-redshift disk galaxies\n\n
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Daniel Loss
DTSTART;VALUE=DATE-TIME:20161111T163000
DTEND;VALUE=DATE-TIME:20161111T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000977@events.thp.uni-koeln.de
DESCRIPTION:Daniel Loss\, University of Basel\n\nFrom Majorana Fermions to
Parafermions in Nanowires and Atomic Chains\n\nI will present recent prog
ress on Majorana fermions and other exotic excitations with non-Abelian br
aid statistics that can emerge in condensed matter systems. These excitati
ons have attracted wide attention recently\, also because of their potenti
al applications in topological quantum computing. Majorana fermion zero-mo
des and their generalizations\, parafermions\, can emerge in nanowires and
atomic chains in the presence of spin orbit interaction or spatially peri
odic magnetic fields\, in RKKY systems forming intrinsic spin helices\, in
topological insulators\, and typically in the presence of superconductivi
ty. I will discuss some candidate materials such as semiconducting Rashba
nanowires and atomic magnetic chains and show some recent experimental pro
gress. Finally\, I plan to discuss parafermions\, which\, in contrast to M
ajorana fermions\, can emerge only in the presence of strong electron-elec
tron interactions and have a more powerful braid statistics that enables e
ntanglement and in particular exact CNOT gates by braiding alone (without
the need of any measurements).\n\n\nContact Person: Alexander Altland
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Karin Everschor
DTSTART;VALUE=DATE-TIME:20161216T140000
DTEND;VALUE=DATE-TIME:20161216T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000978@events.thp.uni-koeln.de
DESCRIPTION:Karin Everschor\, University of Mainz\n\nProduction of magneti
c textures via spin currents\n\nA major challenge in next-generation magne
tic storage technologies is the efficient and controllable creation and ma
nipulation of magnetic textures.\n\nWe predict a way to create magnetic do
main walls and skyrmions by means of a homogeneous DC current without the
need of specialized setups and without requiring any standard “twisting
” interactions like Dzyaloshinskii-Moriya or dipole-dipole interactions.
This is possible by exploiting a dynamical instability arising by the int
erplay of current-induced spin-transfer torque and locally engineered anis
otropies.\n\nThe magnetic textures can be created efficiently\, controllab
ly and periodically with a period that can be tuned by the applied current
strength. We propose specific experimental setups to observe the periodic
formation of domain walls and skyrmions.\n\n\n\nContact Person: Achim Ros
ch
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Zeljka Stojanac
DTSTART;VALUE=DATE-TIME:20161012T110000
DTEND;VALUE=DATE-TIME:20161012T123000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000979@events.thp.uni-koeln.de
DESCRIPTION:Zeljka Stojanac\, Universität Bonn\n\nLow-rank tensor recover
y via Iterative Hard Thresholding algorithm\n\nLow-rank tensor recovery i
s an interesting subject from both \ntheoretical and application point of
view. On one side\, it is a \nnatural extension of the sparse vector and l
ow-rank matrix recovery \nproblem. On the other side\, estimating a low-ra
nk tensor has \napplications in many different areas such as machine learn
ing\, video \ncompression\, and seismic data interpolation. In this talk\,
an \niterative approach to low rank tensor recovery is introduced. This \
napproach is a generalization of the iterative hard thresholding \nalgorit
hm for sparse vector and low-rank matrix recovery to tensor \nscenario (te
nsor IHT or TIHT algorithm). Here\, we consider the tensor \ntrain decompo
sition (or TT-decomposition)\, also called the matrix \nproduct states (or
MPS). The a!\n nalysis\nof the algorithm is based on a \nversion of the r
estricted isometry property (tensor RIP or TRIP). We \nshow that subgaussi
an measurement ensembles satisfy TRIP with high \nprobability under an alm
ost optimal condition on the number of \nmeasurements. Additionally\, we s
how that partial Fourier maps combined \nwith random sign flips of the ten
sor entries satisfy TRIP with high \nprobability. Under the assumption tha
t the linear operator satisfies \nTRIP and under an additional assumption
on the thresholding operator\, \nwe provide a linear convergence result fo
r the TIHT algorithm. Similar \nresults also hold for HOSVD (Tucker) and H
ierarchical Tucker \ndecomposition (HT-decomposition). Finally\, we illust
rate the \nperformance of iterative hard thresholding algorithm for tensor
\nrecovery via numerical experiments where we consider recovery from \nGa
ussian measurement ensembles and Fourier measurements for third \norder te
nsors.
LOCATION:Seminarroom 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:BCGS | Udo Seifert
DTSTART;VALUE=DATE-TIME:20161028T163000
DTEND;VALUE=DATE-TIME:20161028T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000980@events.thp.uni-koeln.de
DESCRIPTION:Udo Seifert\, University of Stuttgart\n\nStochastic thermodyna
mics: From principles to the cost of precision\n\nFor the macroscopic worl
d\, classical thermodynamics formulates the laws governing the transformat
ion of various forms of energy into each other. Stochastic thermodynamics
extends these concepts to micro- and nano-systems embedded or coupled to a
heat bath where fluctuations play a dominant role. Examples are colloidal
particles in time-dependent laser traps\, single biomolecules manipulated
by optical tweezers or AFM tips\, and transport through quantum dots. For
these systems\, exact non-equilibrium relations like the Jarzynski relati
on\, fluctuation theorems and\, most recently\, a thermodynamic uncertaint
y relation have been discovered. I will introduce the main principles\, sh
ow a few experimental applications\, and discuss the universal trade-off b
etween the thermodynamic cost and the precision of any biomolecular\, or\,
more generally\, of any isothermal non-equilibrium process.\n\nContact Pe
rson: Johannes Berg
LOCATION:Lecture Hall II
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Charles Marcus
DTSTART;VALUE=DATE-TIME:20130508T143000
DTEND;VALUE=DATE-TIME:20130508T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000984@events.thp.uni-koeln.de
DESCRIPTION:Charles Marcus\, Center for Quantum Devices\, University of Co
penhagen\n\nHas Majorana returned\, and why we should care\n\n\n\nContact
Person: Achim Rosch
LOCATION:Lecture Hall 3
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Steve Zelditch
DTSTART;VALUE=DATE-TIME:20161123T160000
DTEND;VALUE=DATE-TIME:20161123T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000983@events.thp.uni-koeln.de
DESCRIPTION:Steve Zelditch\, Northwestern University\n\nHow to fill a doma
in with quantum states in quantum Hall problems\n\nLet D be a domain in so
me surface M. In fact\, M could have any dimension. We would like to const
ruct global quantum states on M which are localized in D and completely fi
ll up D without much spillover outside D. We answer the question by making
the quantum states eigenstates of a certain Hamiltonian defined so that D
is the energy set H < E. The projection onto the corresponding eigenspace
s defines a partial Bergman kernel and when normalized properly\, it tends
to 1 on D and zero outside D as Planck's constant tends to zero. There is
a universal transition from 0 to 1.\n\nContact Person: George Marinescu
LOCATION:Lecture Hall VIII\, Main Building
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Wei Zhong-Chao
DTSTART;VALUE=DATE-TIME:20161026T120000
DTEND;VALUE=DATE-TIME:20161026T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000985@events.thp.uni-koeln.de
DESCRIPTION:Wei Zhong-Chao\, ITP\, Cologne\n\nSearch for a unified princip
le for sign-problem-free quantum Monte Carlo\n\nThis group seminar talk is
based on a part of the\nspeaker's PhD thesis on applications of reflectio
n positivity in\nstrongly correlated lattice models. Some mathematical st
ructures behind\nsign-problem-free quantum Monte Carlo simulations has bee
n proposed by different research groups in the past a few years. The speak
er is trying to unify all these theories with his limited mathematical kno
wledge.\nComments and suggestions are welcome.\n\nContact Person: Alexande
r Alldridge
LOCATION:seminar room K0.01\, theory annex
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Johannes Berg
DTSTART;VALUE=DATE-TIME:20161216T163000
DTEND;VALUE=DATE-TIME:20161216T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000986@events.thp.uni-koeln.de
DESCRIPTION:Johannes Berg\, University of Cologne\, Institute for Theoreti
cal Physics\n\nStatistical physics of the inverse Ising problem\n\nThe inv
erse Ising problem seeks to reconstruct the parameters of an Ising Hamilto
nian on the basis of spin configurations sampled from the Boltzmann measur
e. The last decade has witnessed many applications of the inverse Ising pr
oblem driven by the advent of large-scale data in different scientific dis
ciplines\, especially biology. In this talk I will give an introduction t
o the inverse Ising problem\, discussing its applications as well as diffe
rent approaches from statistical physics. A particular focus is on the lin
k between approaches to the inverse Ising problem based on the optimisatio
n of some `objective function' and the statistical physics of disordered s
ystems. This allows to characterise the performance of an arbitrary object
ive function and to calculate the objective function which optimally recon
structs the model parameters.\n
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Michael Knap
DTSTART;VALUE=DATE-TIME:20170301T143000
DTEND;VALUE=DATE-TIME:20170301T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000987@events.thp.uni-koeln.de
DESCRIPTION:Michael Knap\, TU Munich\n\nNonequilibrium dynamics in diffusi
ve many-body systems: from scrambling to heating\n\nIn this talk\, we will
discuss our recent results on scrambling of quantum information and therm
alization in the one-dimensional Bose-Hubbard model. Numerically exact res
ults are presented for the out-of-time (OTO) as well as time ordered corre
lation functions using matrix product operator techniques. I will also giv
e a short account on how to measure such OTO correlators in quantum gas mi
croscopes. If time permits\, we will also discuss pre-thermalization and h
eating dynamics in the periodically driven Bose-Hubbard model and a relate
d O(N) field theory. Relevant references include:\n[1] Scrambling and ther
malization in a diffusive quantum many-body system. A. Bohrdt\, et al. [ar
Xiv:1612.02434]\n[2] Floquet prethermalization and regimes of heating in a
periodically driven\, interacting quantum system. S. Weidinger\, et al. [
arXiv:1609.09089]\n[3] Prethermal Floquet steady-states and instabilities
in the periodically-driven\, weakly-interacting Bose-Hubbard model. M. Buk
ov et al. Phys. Rev. Lett. 115\, 205301 (2015) [arXiv:1507.01946]\n\nConta
ct Person: Jamir Marino
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:TR183 | Sid Parameswaran
DTSTART;VALUE=DATE-TIME:20170301T100000
DTEND;VALUE=DATE-TIME:20170301T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000989@events.thp.uni-koeln.de
DESCRIPTION:Sid Parameswaran\, UC Irvine\n\nSymmetry\, Topology\, and Resp
onse in Semimetals\n\nI will examine the role of topological ideas in unde
rstanding semimetals\, gapless phases whose Fermi surfaces may be shrunk t
o isolated point nodes. First\, I will review the theory of ‘Weyl semime
tals’ that arise from accidental degeneracies in 3D crystals\, and explo
re the consequences of the resulting band topology. I will show that the
interplay of crystal symmetry and topology can aid in identifying “filli
ng-enforced” semimetals\, including in strongly correlated systems such
as heavy fermion materials. I will also sketch how the topological underp
innings of these gapless phases may be probed experimentally via transport
and spectroscopy\, and through numerical simulations of their descendant
gapped phases.\n\nReferences: Nat. Phys. 9\, 299 (2013)\; PRX 4\, 031035 (
2014) \; PRX 5\, 041046 (2015)\; PRB 94\, 125122 (2016)\; arXiv:1508.01546
\, 1609.04023.\n\nContact Person: Simon Trebst
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Klaus Richter
DTSTART;VALUE=DATE-TIME:20170127T163000
DTEND;VALUE=DATE-TIME:20170127T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000991@events.thp.uni-koeln.de
DESCRIPTION:Klaus Richter\, University of Regensburg\n\nSemiclassical Path
s to Many-Body Interference\n\nConcepts based on multi-particle interferen
ce have been proven very fruitful for better understanding\nvarious differ
ent many-body phenomena\, including quantum dynamics of cold atoms\, "many
-body localization"\,\ncorrelated transport through molecules\, or scatter
ing in photonic networks. We will consider such phenomena\nusing semiclass
ical techniques based on interfering Feynman paths.\nA major objective of
such approaches to an interacting many-body system is to combine\ninformat
ion of its two complementary classical limits\, namely a classical system
of particles\nand/or a classical field theory\, into a unified framework\,
providing a picture of many-body interference\nbased on coherent sums ove
r classical solutions.\nFollowing this direction we will illustrate recent
progress in the semiclassical analysis of many-body\ninterference using a
prime example of integrable quantum field theory\, the Lieb-Liniger model
\, describing\ninteracting bosons on a ring. We show that\, in the limit o
f high excitations\, its spectrum can be\nunderstood by means of suitable
generalizations of the so-called Weyl expansion for the smooth part\, and
a\ntrace formula for the oscillatory part\, revealing a spectral shell str
ucture in terms of many-body periodic\norbits.\nWe will then show how for
large particle number the complementary classical limit of the Lieb-Linige
r model\,\ngiven by a nonlinear Schroedinger equation\, admits as well an
analysis as an integrable classical system\,\nnow near its ground state. T
his enables the description of a sequence of quantum phase transitions ari
sing\nfor increasing (attractive) interaction\, along with an understandin
g of numerical results for the spreading\nof information around criticalli
ty.\nIn the opposite case of non-integrable systems\, applications of many
particle interference comprise\ncoherent backscattering and echo phenomen
a in Fock space. \n\nContact Person: Alexander Altland
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Matthias Punk
DTSTART;VALUE=DATE-TIME:20170125T143000
DTEND;VALUE=DATE-TIME:20170125T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000992@events.thp.uni-koeln.de
DESCRIPTION:Matthias Punk\, LMU Munich\n\nQuantum critical points in metal
s: non-Fermi liquids and their field theoretical description\n\nMetals are
found frequently in nature and their properties are usually very well des
cribed within Landau’s Fermi liquid theory. Various strongly correlated
materials exhibit strange metallic phases which do not fit into the Fermi-
liquid framework\, however. The theoretical description of such non-Fermi
liquids remains one of the main unsolved problems in condensed matter phys
ics. In this talk I will give an introduction to the problem and show how
interesting strongly coupled field theories arise in the low energy descri
ption of such states\, which are still poorly understood. I will focus on
the paradigmatic problem of a metal coupled to fluctuations of a critical
Ising order parameter and discuss unexpected scaling properties at finite
temperature.\n\n\nContact Person: Simon Trebst
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Junichi Iwasaki
DTSTART;VALUE=DATE-TIME:20161125T140000
DTEND;VALUE=DATE-TIME:20161125T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000993@events.thp.uni-koeln.de
DESCRIPTION:Junichi Iwasaki\, University of Tokyo\n\nDeformation of Skyrmi
on Crystal under Strain and under Driving Current\n\nManipulation of spin
textures has been attracting a broad interest\nfrom the viewpoints of both
fundamental physics and applications over\ndecades. In particular\, the c
ontrol magnetic skyrmions is one of the\nhottest topics. In the first part
of my talk\, I will talk about the\nstatic deformation of skyrmion crysta
ls under uniaxial strain revealed\nby the Lorentz TEM observation. This ex
perimental result is analyzed\nby the model with an anisotropic Dzyaloshin
skii-Moriya interaction\,\nwhich shows a good agreement with the experimen
t. In the next part\, I\nwill discuss the dynamical deformation of skyrmio
n crystals under a\ndriving current and the corresponding suppression of t
he Bragg peak\nintensities\, which we expect to be measured by neutron sca
ttering\nexperiments.\n\nContact Person: Achim Rosch
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Mikhail Katsnelson
DTSTART;VALUE=DATE-TIME:20161208T160000
DTEND;VALUE=DATE-TIME:20161208T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000995@events.thp.uni-koeln.de
DESCRIPTION:Mikhail Katsnelson\, University of Nijmegen\n\nGauge fields an
d strain engineering in graphene\n\n\nIt is demonstrated now both experime
ntally and theoretically that graphene is usually not flat but covered by
ripples resulting from both intrinsic flexural instability of two-dimensio
nal membranes and roughness of substrate. Thus charge carriers are not jus
t Dirac fermions but Dirac fermions moving in a curved space. The effect o
f the corrugations on the electron spectrum can be described in terms of g
auge (pseudo-magnetic) fields which result\, in particular\, in formation
of pseudo-Landau levels predicted theoretically and found experimentally .
These gauge fields can be used for "strain engineering"\, including tunab
le gap opening\, quantum pumping [and creation of valley-polarized current
. Ripples can induce puddles\, that is\, charge inhomogeneities. The scatt
ering by the ripples is also one of the limiting factors restricting the c
harge carrier mobility in graphene.\n\n\nContact Person: George Marinescu
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:Journal Club/Dice Seminar\nThe limits of Matrix Product State mode
ls\nMiguel Navascues\, Tamas Vertesi
DTSTART;VALUE=DATE-TIME:20161207T120000
DTEND;VALUE=DATE-TIME:20161207T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000996@events.thp.uni-koeln.de
DESCRIPTION:Miguel Navascues\, Tamas Vertesi\n\nThe limits of Matrix Produ
ct State models\n\nhttps://arxiv.org/abs/1509.04507\n\nContact Person: Ale
xander Alldridge
LOCATION:seminar room K0.01\, theory annex
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Johannes Helmes
DTSTART;VALUE=DATE-TIME:20161202T090000
DTEND;VALUE=DATE-TIME:20161202T110000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000997@events.thp.uni-koeln.de
DESCRIPTION:Johannes Helmes\n\nAn entanglement perspective on phase transi
tions\, conventional and topological order (PhD Defense)\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TR183 | Markus Heinrich
DTSTART;VALUE=DATE-TIME:20161220T100000
DTEND;VALUE=DATE-TIME:20161220T110000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000000999@events.thp.uni-koeln.de
DESCRIPTION:Markus Heinrich\, Friedrich-Schiller-Universität Jena\n\nSurf
ace states in holographic Weyl semimetals\n\nWeyl semimetals (WSMs) are a
class of gapless topological materials\nwhich have gained a lot of interes
t in the last few years. In these\nstates of matter\, low-energy excitatio
ns behave as chiral massless\nparticles\, i.e. Weyl fermions. Besides exhi
biting anomalous transport\neffects\, the most prominent feature of these
crystals are topologically\nprotected surface states\, the so-called Fermi
arcs. Their emergence can\nbe tied to an effective axial magnetic field a
rising at a surface due to\nlattice deformations and inducing a surface cu
rrent by the chiral\nmagnetic effect. Using a holographic model\, I comput
ed these currents in\nthe strong coupling limit. The results show that the
bulk-boundary\ncorrespondence in WSMs is in some sense independent of int
eractions\ndemonstrating the universality of anomaly-related effects. In t
he end\, I\nwill discuss the limits of this universality.\nSee also arXiv:
1612.00836.\n\nContact Person: Simon Trebst
LOCATION:Seminarroom 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Max Hering
DTSTART;VALUE=DATE-TIME:20170202T123000
DTEND;VALUE=DATE-TIME:20170202T133000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001000@events.thp.uni-koeln.de
DESCRIPTION:Max Hering\, FU Berlin\n\nFunctional-renormalization-group ana
lysis of Dzyaloshinsky-Moriya and Heisenberg spin interactions on the kago
me lattice\n\nWe investigate the effects of Dzyaloshinsky-Moriya (DM) inte
ractions on\nthe frustrated J_1-J_2 kagome-Heisenberg model using the pseu
do-fermion\nfunctional-renormalization-group (PFFRG) technique. In order t
o treat the\noff-diagonal nature of DM interactions\, we develop an extend
ed PFFRG\nscheme. We benchmark this approach in parameter regimes that hav
e\npreviously been studied with other methods and find good agreement of t
he\nmagnetic phase diagram. Particularly\, finite DM interactions are foun
d to\nstabilize all types of non-collinear magnetic orders of the J_1-J_2\
nHeisenberg model (q=0\, √3x√3\, and cuboc orders) and shrink the exte
nts of\nmagnetically disordered phases. We discuss our results in the ligh
t of the\nmineral herbertsmithite which has been experimentally predicted
to host a\nquantum spin liquid at low temperatures. Our PFFRG data indicat
es that\nthis material lies in close proximity to a quantum critical point
. In\nparts of the experimentally relevant parameter regime for herbertsmi
thite\,\nthe spin-correlation profile is found to be in good qualitative a
greement\nwith recent inelastic-neutron-scattering data.\n\n\nContact Pers
on: Simon Trebst
LOCATION:Seminar Room (I. Physik/Astrophysics)
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Laura Baez
DTSTART;VALUE=DATE-TIME:20170315T100000
DTEND;VALUE=DATE-TIME:20170315T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001001@events.thp.uni-koeln.de
DESCRIPTION:Laura Baez\, FU Berlin\n\nNumerical treatment of spin systems
with unrestricted spin length S: A functional renormalization group study\
n\n\n\nContact Person: Simon Trebst
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Fernando Pastawski
DTSTART;VALUE=DATE-TIME:20170123T130000
DTEND;VALUE=DATE-TIME:20170123T140000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001004@events.thp.uni-koeln.de
DESCRIPTION:Fernando Pastawski\, FU Berlin\n\nHolographic quantum error co
rrecting codes: geometry as a structure of information\n\n\n\nContact Pers
on: Achim Rosch
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Christine Muschik
DTSTART;VALUE=DATE-TIME:20170123T160000
DTEND;VALUE=DATE-TIME:20170123T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001005@events.thp.uni-koeln.de
DESCRIPTION:Christine Muschik\, University of Innsbruck\n\nReal-time dynam
ics of lattice gauge theories with a few-qubit quantum computer\n\nGauge t
heories are fundamental to our understanding of interactions between the e
lementary constituents of matter as mediated by gauge bosons. However\, co
mputing the real-time dynamics in gauge theories is a notorious challenge
for classical computational methods. In the spirit of Feynman's vision of
a quantum simulator\, this has recently stimulated theoretical effort to d
evise schemes for simulating such theories on engineered quantum-mechanica
l devices\, with the difficulty that gauge invariance and the associated l
ocal conservation laws (Gauss laws) need to be implemented. Here we report
the first experimental demonstration of a digital quantum simulation of a
lattice gauge theory\, by realising 1+1-dimensional quantum electrodynami
cs (Schwinger model) on a few-qubit trapped-ion quantum computer. We are i
nterested in the real-time evolution of the Schwinger mechanism\, describi
ng the instability of the bare vacuum due to quantum fluctuations\, which
manifests itself in the spontaneous creation of electron-positron pairs. T
o make efficient use of our quantum resources\, we map the original proble
m to a spin model by eliminating the gauge fields in favour of exotic long
-range interactions\, which have a direct and efficient implementation on
an ion trap architecture. We explore the Schwinger mechanism of particle-a
ntiparticle generation by monitoring the mass production and the vacuum pe
rsistence amplitude. Moreover\, we track the real-time evolution of entang
lement in the system\, which illustrates how particle creation and entangl
ement generation are directly related. Our work represents a first step to
wards quantum simulating high-energy theories with atomic physics experime
nts\, the long-term vision being the extension to real-time quantum simula
tions of non-Abelian lattice gauge theories. \n\n[1] E. A. Martinez*\, C.
A. Muschik*\, P. Schindler\, D. Nigg\, A. Erhard\, M. Heyl\, P. Hauke\, M.
Dalmonte\, T. Monz\, P. Zoller\, and R. Blatt\, Nature 534\, 516-519 (201
6).\n\nContact Person: Achim Rosch
LOCATION:Seminar room\, Theoretical Physics
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Shunji Matsuura
DTSTART;VALUE=DATE-TIME:20170207T160000
DTEND;VALUE=DATE-TIME:20170207T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001006@events.thp.uni-koeln.de
DESCRIPTION:Shunji Matsuura\, Niels Bohr Institute\n\nCharged entanglement
entropy in SPT and SET phases\n\nIt has been known that the topological e
ntanglement entropy is a useful\norder parameter to detect topologically o
rdered phases.\nWhen global symmetries are imposed\, new types of topologi
cal phases emerge.\nThey are called symmetry protected topological (SPT) p
hases for short range entangled states\nand symmetry enriched topological
(SET) phases for long range entangled states.\nSince the entanglement ent
ropy is insensitive to global symmetries\,\nthe topological entanglement e
ntropy is no longer a good order parameter to distinguish\nSPT and SET pha
ses.\nIn this talk I introduce a new entanglement quantity\, a charged ent
anglement entropy\,\nby grand canonically generalising the entanglement en
tropy.\nThis charged entanglement entropy is sensitive to global symmetrie
s\,\nand it shows a new universal term\, in addition to the topological en
tanglement entropy\,\nwhich can be used to distinguish SPT and SET phases.
\n\nContact Person: Achim Rosch
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Nicola Wurz
DTSTART;VALUE=DATE-TIME:20170317T140000
DTEND;VALUE=DATE-TIME:20170317T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001007@events.thp.uni-koeln.de
DESCRIPTION:Nicola Wurz\, University of Bonn\n\nImprinting Spin Spirals i
nto an Ultracold Fermi Gas\n\n\n\nContact Person: Achim Rosch
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Michael Kastoryano
DTSTART;VALUE=DATE-TIME:20170127T140000
DTEND;VALUE=DATE-TIME:20170127T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001008@events.thp.uni-koeln.de
DESCRIPTION:Michael Kastoryano\, Niels Bohr International Academy\n\nNew t
ools from Quantum Information Theory for the analysis of Many body systems
\n\n In a celebrated recent result\, Fawzi and Renner [CMP 340 (2015)] sho
wed that for a given quantum state\, and a tripatition ABC of a quantum sy
stem\, the conditional mutual information I(A:C|B) is small if and only if
there exists a map which approximately recovers the erasure of subsystem
C\, without acting on system A. Such states are called Markov states\, and
the maps are called local recovery maps. \nI will consider applications o
f this important new result to the analysis of many-body systems. In parti
cular\, I will show that if the thermal (Gibbs) state of a local Hamiltoni
an is Markov\, and satisfies some physically reasonable assumption on the
long range correlations\, then (i) expectation values of local observables
can be evaluated efficiently\, and (ii) the Gibbs state can be sampled (p
repared) efficiently on a quantum computer. \nUsing similar methods\, I wi
ll argue that ground states of certain local gapped Hamiltonians can be pr
epared in sub-linear time (on a quantum computer) if and only if the topol
ogical entanglement entropy is zero. \nFurthermore\, a slight strengthenin
g of these methods provide checkable conditions for the parent Hamiltonian
of a PEPS to be gapped\, as long as the Li-Haldane type conjecture holds.
I'll finally comment on further applications of local recovery maps\, inc
luding approximate error correcting codes and toy models for the AdS/CFT c
orrespondence\, and argue that these tools from quantum information theory
will play an important role in analysis of many body systems. \n\nContact
Person: Achim Rosch
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Terenz Feng
DTSTART;VALUE=DATE-TIME:20170210T140000
DTEND;VALUE=DATE-TIME:20170210T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001009@events.thp.uni-koeln.de
DESCRIPTION:Terenz Feng\n\nMoving Majorana States in 1d p-wave Superconduc
tors\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Yasuhiro Tada
DTSTART;VALUE=DATE-TIME:20170113T140000
DTEND;VALUE=DATE-TIME:20170113T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001010@events.thp.uni-koeln.de
DESCRIPTION:Yasuhiro Tada\, ISSP\, Tokyo University\n\nCooper pairing in g
auged fermion models for superconductivity\n\n\n\nContact Person: Achim Ro
sch
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Johannes Waizner
DTSTART;VALUE=DATE-TIME:20170116T103000
DTEND;VALUE=DATE-TIME:20170116T120000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001011@events.thp.uni-koeln.de
DESCRIPTION:Johannes Waizner\n\nSpin wave excitations in magnetic helices
and skyrmion lattices\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Marco Schiro
DTSTART;VALUE=DATE-TIME:20170419T143000
DTEND;VALUE=DATE-TIME:20170419T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001013@events.thp.uni-koeln.de
DESCRIPTION:Marco Schiro\n\nQuantum Many Body Physics with Strongly Intera
cting Matter and Light \n\nDevelopments in quantum optics and quantum engi
neering have brought forth the possibility of studying emergent collective
phenomena in hybrid quantum light-matter systems. \nThese platforms\, whi
ch are intrinsically driven and dissipative\, allow to probe fundamental m
any body physics in uncharted territories. \nIn this talk I will discuss t
he steady state properties of paradigmatic lattice models of photons coupl
ed to qubits\, highlighting those aspects of the physics which are genuine
nonequilibrium features \nand cannot be understood even qualitatively fro
m an effective equilibrium. I will then discuss the role of non-Markovian
bath correlations on a prototypical light-matter phase transition\, \nthe
Dicke superradiance of N qubits coupled to a cavity\, and show that ohmic/
subohmic environemnts can induce a dissipative phase transition surving ev
en at finite N\, \nsmoothly connected to the well studied Caldeira-Leggett
/spin-boson one. Finally\, I will present our ongoing effort to develop a
new approach to driven-dissipative lattice models\, \nbased on non-equilib
rium dynamical mean field theory.\n\nContact Person: Jamir Marino
LOCATION:Seminar room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:SPS | Reik Donner
DTSTART;VALUE=DATE-TIME:20170221T140000
DTEND;VALUE=DATE-TIME:20170221T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001014@events.thp.uni-koeln.de
DESCRIPTION:Reik Donner\, Potsdam Institute for Climate Impact Research\n\
nFunctional network analysis: Using complex network theory to characterize
multivariate or spatially distributed time series\n\nAs a by-product of t
he rising interest in the structural and dynamical characterization of net
works in various scientific disciplines\, complex network based methods ha
ve recently found wide use as an\nexploratory tool of data analysis across
fields. In particular\, functional networks encoding essential statistica
l interrelationships among multivariate time series have proven to be a ve
rsatile tool in\nclimate sciences\, neurophysiology and various other area
s. In my talk\, I will focus on some recent applications of functional net
work analysis in the field of climatology to highlight the potentials as w
ell\nas ongoing challenges of such "climate network" approaches. As one pa
rticular example\, I will demonstrate how the El Nino Southern Oscillation
\, the most prominent mode of tropical climate variability\, is reflected
in the global correlation structure of surface air temperatures. I will th
en present a straightforward methodological extension utilizing the idea o
f coupled networks and their appropriate structural quantification\, and d
emonstrate the application of this idea to studying ocean-atmosphere inter
dependences in the Northern latitude extratropics during boreal winter.\n\
n\nContact Person: Joachim Krug
LOCATION:Seminarraum Theoretische Physik (Altbau)
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Marco Moretti
DTSTART;VALUE=DATE-TIME:20170524T143000
DTEND;VALUE=DATE-TIME:20170524T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001015@events.thp.uni-koeln.de
DESCRIPTION:Marco Moretti\, ESRF\, Grenoble\n\nMagnetic and orbital excita
tions studied by x-rays\n\n\n\nContact Person: M. Grüninger
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:SPS | Adrian Odenweller
DTSTART;VALUE=DATE-TIME:20170221T120000
DTEND;VALUE=DATE-TIME:20170221T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001016@events.thp.uni-koeln.de
DESCRIPTION:Adrian Odenweller\, University of Cologne\n\nCoupled complex n
etwork analysis of extreme precipitation in the Asian monsoon region\n\n\n
\nContact Person: Joachim Krug
LOCATION:Seminarraum Theoretische Physik (Altbau)
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Pantelis Bamboulis
DTSTART;VALUE=DATE-TIME:20170308T143000
DTEND;VALUE=DATE-TIME:20170308T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001017@events.thp.uni-koeln.de
DESCRIPTION:Pantelis Bamboulis \, Uni Twente\, NL\n\nStructure and Dynamic
s of 2D Material Confined Water\n\n\n\nContact Person: T. Michely
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Juergen Braun
DTSTART;VALUE=DATE-TIME:20170222T143000
DTEND;VALUE=DATE-TIME:20170222T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001018@events.thp.uni-koeln.de
DESCRIPTION:Juergen Braun \, LMU München\n\nCorrelation\, temperature and
dynamical aspects: recent developments in the one-step description of ang
le-resolved photoemission\n\n\n\nContact Person: P. van Loosdrecht
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Vladislav Kataev
DTSTART;VALUE=DATE-TIME:20170329T143000
DTEND;VALUE=DATE-TIME:20170329T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001019@events.thp.uni-koeln.de
DESCRIPTION:Vladislav Kataev\, IFW Dresden\n\nSpin-orbit coupling effects
in complex iridium oxides as seen by high-field ESR spectroscopy\n\nCompl
ex iridium oxides have attracted recently a lot of attention due to an int
imate entanglement of spin and orbital degrees of freedom which may give r
ise to a novel spin-orbital Mott insulating behavior and exotic quantum sp
in liquid phases. Electron spin resonance (ESR) spectroscopy is known to b
e an instructive tool for studying the spin-orbit coupling (SOC) effects a
s it can directly access the relevant parameters sensitive to SOC\, such a
s the g-factor tensor\, magnetic anisotropy gaps and spin dynamics. In thi
s talk\, two of our recent results on multi-frequency sub-THz ESR spectros
copy on iridium oxides in strong magnetic fields will be discussed:\n(1) s
urprising inversion of the orbital states in the prototypical spin-orbital
Mott insulator Sr2IrO4 with Ir4+ (5d5\, J = 1/2) due to the long-range cr
ystal field effects\;\n\n(2) evidence that the unexpected magnetism in the
“non-magnetic” Ir5+ (5d4\, J = 0) double perovskite Ba2YIrO6 may not
be due to the “failed dominance of SOC” as proposed in recent literatu
re.\n\n\nContact Person: T. Lorenz
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Daniele Fausti
DTSTART;VALUE=DATE-TIME:20170412T143000
DTEND;VALUE=DATE-TIME:20170412T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001022@events.thp.uni-koeln.de
DESCRIPTION:Daniele Fausti\, University Triest Elettra\n\nOptical control
and quasiparticle witnessing in strongly correlated electron systems\n\n\n
\nContact Person: Paul van Loosdrecht
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Karen Michaeli
DTSTART;VALUE=DATE-TIME:20170621T143000
DTEND;VALUE=DATE-TIME:20170621T154500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001023@events.thp.uni-koeln.de
DESCRIPTION:Karen Michaeli\, Weizmann Institute of Science\n\nSuperconduct
ivity in the Presence of Spin-Orbit Coupling — Old Dog\, New Tricks\n\nT
he coupling between the spin of an electron and its momentum is recognized
to generate a variety of new phases in condensed matter systems. For exam
ple\, it has been recently demonstrated that spin-orbit coupling can chang
e the nature of a trivial insulator to endow it with topological propertie
s. Or\, in symmetry broken states\, spin-orbit coupling permits exotic low
energy excitations such as skyrmions in helimagnets. The interplay betwee
n superconductivity and spin-orbit effects gives rise to additional surpri
sing features\, which I will discuss in my talk. For instance\, it stabili
zes a condensate of Cooper pairs with finite momentum (a variant of the Fu
lde-Ferrel-Larkin-Ovchinikov state) up to high magnetic fields. Even more
surprisingly\, in the presence of spin-orbit coupling the transition tempe
rature into the superconducting state may increase under application of a
Zeeman magnetic field. Furthermore\, such superconductors can exhibit pe
rsistent currents without magnetic fields in doubly connected geometries.\
n\nContact Person: Simon Trebst
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | David Mross
DTSTART;VALUE=DATE-TIME:20170623T163000
DTEND;VALUE=DATE-TIME:20170623T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001024@events.thp.uni-koeln.de
DESCRIPTION:David Mross\, Weizmann Institute of Science\n\nThe power of vo
rtices – dual perspectives on exotic quantum phases\n\nThe analysis of t
opological excitations in interacting many-body systems often provides imp
ortant insights into quantum phases and phase transitions. Seminal example
s are the (thermal) BKT transition as well as the (quantum) superfluid-Mot
t insulator transition\, which are naturally described in terms of vortice
s. More recently\, such a ‘dual’ formulation has proven extremely illu
minating in the study of exotic phases of matter that host fractional exci
tations\, e.g.\, in topological phases and quantum magnets. In my talk\, I
will review the dual description of conventional phases of matter and exp
lain how exotic\, fractionalized phases are captured within this approach.
I will then generalize these dualities to fermionic systems\, and discuss
the implications for the half-filled Landau level and strongly interactin
g surfaces of topological insulators. Finally\, I will describe how two-di
mensional Dirac fermions (and their symmetries) can be mapped onto interac
ting bosons.\n\nContact Person: Simon Trebst
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Eran Sela
DTSTART;VALUE=DATE-TIME:20170628T143000
DTEND;VALUE=DATE-TIME:20170628T154500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001025@events.thp.uni-koeln.de
DESCRIPTION:Eran Sela\, Tel Aviv University\n\nMajorana States in the Coul
omb Blockade Regime – Signatures and Applications\n\nIn this talk I will
discuss recent experimental and theoretical advances combining one dimens
ional topological nanowires into small mesoscopic islands\, pushing Majora
na physics into the Coulomb blockade regime\, and creating new quantum pha
ses governed by correlations. I will elucidate that transport through such
islands gives access to a rather unstudied type of quantum impurity physi
cs\, where the electrons in the leads combine with the Majorana fermions i
n the island to yield effective bosonic charge carriers. This gives rise t
o novel non-equilibrium transport behavior. Pushing these islands using a
gate volatge into charge degeneracy points presents very interesting regim
es allowing to probe strongly correlated Majorana fermions at short time s
cales and at high energy scales. In addition\, creating arrays of such is
lands may form a highly convenient platform for topological quantum comput
ing schemes based on the surface code. Here\, electron transport can be us
ed for quantum measurements and manipulation of the stored information in
the Majorana qubits.\n\nContact Person: Simon Trebst
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Ciaran Hickey
DTSTART;VALUE=DATE-TIME:20170302T100000
DTEND;VALUE=DATE-TIME:20170302T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001027@events.thp.uni-koeln.de
DESCRIPTION:Ciaran Hickey\, University of Toronto\n\nChiral Magnetic and T
opological Order in Mott Insulators\n\nExperimentalists have recently been
able to engineer non-trivial topological band structures using ultracold
atoms in optical lattices. Motivated by ongoing experimental efforts to tu
ne interactions\, we explore the interplay between strong correlations and
topology in these systems. \n\nFocusing on the Haldane-Hubbard honeycomb
model as an example\, we show that its strongly interacting Mott limit exh
ibits various chiral magnetic orders\, including a wide regime of triple-Q
tetrahedral order. Incorporating an additional third-neighbour hopping fr
ustrates and ultimately melts the tetrahedral magnetic order. From analysi
ng low energy spectra\, many-body Chern numbers\, entanglement spectra\, a
nd modular matrices\, we identify the molten state as a chiral spin liquid
with gapped semion excitations. Our numerical results suggest that this f
rustration induced melting may be realised as an exotic continuous quantum
phase transition. \n\nFinally\, we discuss recent results which point tow
ard a common mechanism of realising chiral spin liquids in Mott insulators
through the continuous melting of non-coplanar magnetic "parent" states.\
n\n\nContact Person: Simon Trebst
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Andreas Winter
DTSTART;VALUE=DATE-TIME:20170630T163000
DTEND;VALUE=DATE-TIME:20170630T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001028@events.thp.uni-koeln.de
DESCRIPTION:Andreas Winter\, Universitat Autònoma de Barcelona\n\nGrand c
anonical Gibbs state for systems with non-commuting charges\n\nThe grand c
anonical ensemble lies at the core of quantum and classical \nstatistica
l mechanics. A small system thermalizes to this ensemble while\nexchanging
heat and particles with a bath. A quantum system may exchange \nquantiti
es represented by operators that fail to commute. Whether such \na
system thermalizes and what form the thermal state has are questions
\nabout truly quantum thermodynamics. Here we investigate this the
rmal \nstate from three perspectives. First\, we introduce an app
roximate\nmicrocanonical ensemble. If this ensemble characterizes the syst
em-\nand-bath composite\, tracing out the bath yields the system's thermal
\nstate. This state is expected to be the equilibrium point\, we argue\,
\nof typical dynamics. Finally\, we define a resource-theory model for\n
thermodynamic exchanges of noncommuting observables. Complete passivity\n
-- the inability to extract work from equilibrium states --
\, implies \nthe thermal state's form\, too. Our work opens new a
venues into \nequilibrium in the presence of quantum noncommutation.
\n[Based on arXiv:1512.01189] \n\n\n\nContact Person: David Gross
LOCATION:SR 0.03 TP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Roger Melko
DTSTART;VALUE=DATE-TIME:20170426T143000
DTEND;VALUE=DATE-TIME:20170426T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001029@events.thp.uni-koeln.de
DESCRIPTION:Roger Melko\, University of Waterloo\, Perimeter Institute\n\n
Quantum machine learning\n\n\n\nContact Person: Simon Trebst
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Jeroen van den Brink
DTSTART;VALUE=DATE-TIME:20170503T143000
DTEND;VALUE=DATE-TIME:20170503T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001030@events.thp.uni-koeln.de
DESCRIPTION:Jeroen van den Brink\, IFW Dresden\n\nJosephson Currents Induc
ed by the Witten Effect\n\n\n\nContact Person: M. Grüninger
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Dmitry Novoselov
DTSTART;VALUE=DATE-TIME:20170315T143000
DTEND;VALUE=DATE-TIME:20170315T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001031@events.thp.uni-koeln.de
DESCRIPTION:Dmitry Novoselov\n\nCorrelation effects and phonon modes softe
ning with doping in Ba1-xKxBiO3\n\n\n\nContact Person: D. Khomskii
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Xiao Lin
DTSTART;VALUE=DATE-TIME:20170510T143000
DTEND;VALUE=DATE-TIME:20170510T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001032@events.thp.uni-koeln.de
DESCRIPTION:Xiao Lin\, University of Cologne\n\nUnconventional superconduc
tivity and strange metallicity in SrTiO3\n\n\n\nContact Person: Joachim He
mberger
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Masahiko G. Yamada
DTSTART;VALUE=DATE-TIME:20170316T100000
DTEND;VALUE=DATE-TIME:20170316T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001035@events.thp.uni-koeln.de
DESCRIPTION:Masahiko G. Yamada\n\nDesigning Kitaev spin liquids in metal-o
rganic frameworks\n\n\n\nContact Person: Maria Hermanns
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Jan Attig
DTSTART;VALUE=DATE-TIME:20170331T140000
DTEND;VALUE=DATE-TIME:20170331T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001036@events.thp.uni-koeln.de
DESCRIPTION:Jan Attig\, University of Cologne\n\nClassical Spin Spirals in
Frustrated Magnets from Free-Fermion Band Topology\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Markus Kriener
DTSTART;VALUE=DATE-TIME:20170726T140000
DTEND;VALUE=DATE-TIME:20170726T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001034@events.thp.uni-koeln.de
DESCRIPTION:Markus Kriener\, RIKEN Center for Emergent Matter Science\, Ja
pan\n\nDoping into the polar semiconductor GeTe: From nanoscale magnetic p
hase separation to superconductivity\n\n\n\nContact Person: Thomas Lorenz
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Hanno Schmiedt
DTSTART;VALUE=DATE-TIME:20170512T163000
DTEND;VALUE=DATE-TIME:20170512T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001038@events.thp.uni-koeln.de
DESCRIPTION:Hanno Schmiedt\, University of Cologne\n\nSymmetry and dynamic
s in floppy molecules: A new five-dimensional super-rotor model and its co
nsequences\n\nExtremely floppy molecules are indescribable by the common i
deas of molecular physics. Their ground state wave functions are highly de
localized and the concept of molecular structure breaks down. Recently\, w
e established a fundamentally new 'super-rotor' model\, which is based on
a five-dimensional rotational symmetry. The respective states are describe
d by the irreducible representations of SO(5) and the Hamiltonian is propo
rtional to the respective Casimir operator. The prototypical example of fl
oppy molecules is protonated methane\, which was measured only recently in
the Cologne lab. With our simple model\, we are - for the first time - ab
le to predict energy levels which actually compare very favourably to the
experimental values. In addition\, the exchange symmetry of the protons ca
n be\ndetermined by using an isomorphism of the permutation group to a sub
group of SO(5). In this talk\, we discuss the basic concepts of this new a
pproach and ask some of the most urgent questions for\nfurther development
s.\n\nContact Person: Alexander Altland
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Nadine Hauptmann
DTSTART;VALUE=DATE-TIME:20170531T143000
DTEND;VALUE=DATE-TIME:20170531T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001039@events.thp.uni-koeln.de
DESCRIPTION:Nadine Hauptmann\, Universität Nijmegen\n\n2D materials and n
ano-scale skyrmions investigated by spin-resolved scanning probe microscop
ies\n\n\n\nContact Person: T. Michely
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Urs Staub
DTSTART;VALUE=DATE-TIME:20170614T143000
DTEND;VALUE=DATE-TIME:20170614T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001041@events.thp.uni-koeln.de
DESCRIPTION:Urs Staub\, Paul Scherrer Institute\n\nUltrafast manipulation
of magnetic\, electronic and crystal structure\n\nThe understanding of ele
ctronic and structural phase transitions is of basic importance in condens
ed matter physics. In this presentation\, I will concentrate on phase tran
sitions that can be triggered externally by electronic excitations and add
ress the how we can excite particle modes of lattice excitation\, and expl
ore how these are related to the electronic and magnetic properties and th
e corresponding phase transitions. The goal is to understand how and how f
ast we can trigger electronic transitions and how they might couple to str
uctural motions of the atomic lattice. [1-3] These can be done using pump-
probe schemes\, with x-rays as a probe down to ultrafast time scales\, as
created by an x-ray free electron laser. \nThe presented examples will inc
lude the charge and orbital order phase transition in half doped manganite
s [1\,3] and multiferroic TbMnO3. I will also present very briefly newest
results on the octahedral rotation transitions in simple perovskite SrTiO3
and EuTiO3\, which shows opposite behaviour when triggering this phase tr
ansition. \n\n\nReferences\n[1] P. Beaud et al. Nature Materials 13\, 923
(2014) \n[2] Kubacka et al. Science 343\, 1333 (2014)\n[3] V. Esposito et
al. Phys. Rev. Lett. (in press) (2017).\n\n\nContact Person: Markus Braden
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Gavin J. Sherlock
DTSTART;VALUE=DATE-TIME:20170419T170000
DTEND;VALUE=DATE-TIME:20170419T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001042@events.thp.uni-koeln.de
DESCRIPTION:Gavin J. Sherlock\, Stanford University\n\nPopulation Dynamics
\, Beneficial Mutations and Evolutionary Trade-offs in Yeast\n\nWe have de
veloped a lineage tracking system\, based on random DNA barcodes\, that al
lows us to follow the emergence of adaptive lineages within an evolving po
pulation to characterize the dynamics of the evolutionary process. We can
further use the lineage tags to identify and isolate specific lineages for
whole genome sequencing\, and fitness remeasurement\, such that we can ch
aracterize the molecular basis of adaptation\, and the costs incurred by s
uch mutations in other experimental conditions. These data allow us to det
ermine where within the growth cycle adaptive lineages gain their fitness
benefits.
LOCATION:Conference Room 2
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Richard Neher
DTSTART;VALUE=DATE-TIME:20170503T170000
DTEND;VALUE=DATE-TIME:20170503T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001043@events.thp.uni-koeln.de
DESCRIPTION:Richard Neher\, Universität Basel\n\nWithin-host evolution of
HIV\n\nRNA viruses rapidly evade host immune responses by changing target
ed proteins. We used deep sequencing of HIV populations from many consecut
ive samples to track virus evolution and quantify competing tendencies of
immune escape and rapid replication. Accurate measurements of minor varian
t frequencies allowed us to estimate the landscape of fitness cost at almo
st all positions of the HIV genome. In addition to HIV RNA from plasma sam
ples during untreated HIV infection\, we sequenced latently integrated HIV
genomes after many years of therapy. By comparing these sequences to pre-
treatment samples\, we quantify establishment\, turn-over\, and maintenan
ce of the latent HIV-1 reservoir.
LOCATION:Conference Room 2\,
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Akos Kovacs
DTSTART;VALUE=DATE-TIME:20170510T170000
DTEND;VALUE=DATE-TIME:20170510T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001044@events.thp.uni-koeln.de
DESCRIPTION:Akos Kovacs\, Friedrich Schiller Universität\, Jena\n\nDivisi
on of labor and evolution of autonomy in bacterial biofilms\n\n\nBiofilms
are structurally complex bacterial communities\, where the cells are enclo
sed in an extracellular matrix that mediates the attachment of cells to ea
ch other or to surfaces. While the biofilm matrix benefits the population\
, i.e. protection\, attachment to a substratum or surface spreading\, its
production is costly for the individuals. Mutant strains of the Gram-posit
ive bacterium\, Bacillus subtilis lacking matrix production have a higher
fitness under well mixed planktonic conditions. Matrix producers have an a
dvantage when cultivated in spatially structured environment initiated at
low cell densities\, i.e. in colony biofilms [1]. Contrariwise\, biofilms
on an air- medium interface\, the so called pellicles are governed by diff
erent ecological processes. Colonization of the air-liquid interface requi
res aerotaxis driven motility [2]. Moreover\, non-producers are excluded f
rom the pellicles formed by wild-type cooperators\, however\, their abunda
nce could change over time after prophage awakening [3]. Here\, I will pre
sent the long term evolutionary dynamics of biofilms formed through geneti
c division of labor. Despite a short term success\, genetic division of la
bor in biofilm formation collapses and slows down the evolution of autonom
y of the winning partner. Differences in dependency levels and availabilit
y of public goods exchanged by the cooperating partners influence cooperat
ion collapse revealing a barrier against evolution of intraspecific cooper
ation in microbes.\n[1] van Gestel et al 2014 ISME Journal [2] Hölscher e
t al 2015 J Mol Biol\n[3] Martin et al 2017 Nat Commun
LOCATION:Conference Room 2\,
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB680 | Rosalind Allen
DTSTART;VALUE=DATE-TIME:20170511T110000
DTEND;VALUE=DATE-TIME:20170511T120000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001045@events.thp.uni-koeln.de
DESCRIPTION:Rosalind Allen\, University of Edinburgh\n\nGrowth-dependent a
ction of cell-wall targeting antibiotics\n\n\nMany clinically relevant ant
ibiotics target bacterial cell wall synthesis. Although it is known which
antibiotics bind which cell wall synthesis enzymes\, how this leads to bac
terial growth inhibition and killing is unclear. We have measured growth c
urves for Escherichia coli bacteria in the presence of various cell-wall t
argeting antibiotics\, on a variety of growth media. We see clear effects
of growth rate on the antibiotic efficacy. I will discuss these results an
d present a preliminary mathematical model which seeks to explain them.
LOCATION: Conference Room 2
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Karsten Flensberg
DTSTART;VALUE=DATE-TIME:20170712T143000
DTEND;VALUE=DATE-TIME:20170712T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001046@events.thp.uni-koeln.de
DESCRIPTION:Karsten Flensberg\, Niels-Bohr-Institute\, Copenhagen\n\nMajor
ana wires: towards non-local quantum states\n\n\n\nContact Person: Altland
/ Trebst
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:SPS | Parongama Sen
DTSTART;VALUE=DATE-TIME:20170523T120000
DTEND;VALUE=DATE-TIME:20170523T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001047@events.thp.uni-koeln.de
DESCRIPTION:Parongama Sen\, University of Calcutta\n\nAn empirical analysi
s of the Ebola outbreak using an Euclidean network model\n\nModelling the
spread of epidemics on complex networks has led to a number of interesting
results in the recent past. Starting with a brief overview\, we discuss
the characteristic features of the Susceptible-Infected-Removed (SIR) mod
el considered on a network embedded in Euclidean space with random long r
ange interactions chosen following a certain prescription. \nNumerical si
mulations suggest a simple form of the cumulative density of infected agen
ts at time t\, \nR(t)\, depending on the network parameters and the infec
tion probability q.\nThe epidemic dynamics shows the effect of the phase t
ransition occurring in the network. \nThe data for the Ebola outbreak that
occurred in 2014-2016 in three countries of West Africa are analysed with
in a common framework using this \nmodel. The predicted form of R(t) is
seen to fit well with the data. We also show that in the Euclidean model\,
appropriate choices of the parameters reproduce the data for the three co
untries with considerable accuracy. These choices are correlated with popu
lation density\, control schemes and other factors. Comparing the real dat
a and the results from the model one can also estimate the size of the act
ual population susceptible to the disease.\n\n\nContact Person: Joachim Kr
ug
LOCATION:TP conference room 0.02
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Peter Prelovsek
DTSTART;VALUE=DATE-TIME:20170403T140000
DTEND;VALUE=DATE-TIME:20170403T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001048@events.thp.uni-koeln.de
DESCRIPTION:Peter Prelovsek\n\nMany-body localization - search for an idea
l nonequilibrium system\n\nMany-body localization (MBL) is the quantum phe
nomenon involving the interplay of disorder and particle interaction\, ch
aracterized by the nonergodic behaviour of physical observables. It is int
ensively investigated theoretically within disordered many-body models and
experimentally in optical lattices of cold atoms. Within a one-dimensiona
l random-field spin system dynamical density correlations can be used as
an indicator for the MBL phase and are closely related to the dynamical sp
in conductivity and d.c. transport. \nAn analytical approach indicates th
at one dimension might still be singular with the subdiffusion in the ergo
dic phase. On the other hand\, an analogous simulation of the Hubbard chai
n shows that a disordered potential does not induce full MBL\, but only c
harge localisation.\n\n\nContact Person: Zala Lenarcic
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SPS | Malte Schröder
DTSTART;VALUE=DATE-TIME:20170411T140000
DTEND;VALUE=DATE-TIME:20170411T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001049@events.thp.uni-koeln.de
DESCRIPTION:Malte Schröder\, Max Planck Institute for Dynamics and Self-O
rganization Göttingen\n\nNetwork formation by individual decisions: Mappi
ng global optimization to local percolation\n\nThe emergence of global str
uctures in networks is at the core of our increasingly connected world\, r
anging from international trade to the spreading of innovations in social
networks. Many of these networks are constructed by individual decisions o
ptimizing connectivity under various constraints\, for example people choo
sing their friends in geographically constrained social networks. Yet\, ho
w and under which conditions these local decisions create global structure
s is hardly understood.\n\nWe study a general optimization problem modelin
g the emergence of global interactions in networks in the presence of loca
l feedback and transaction costs over long distances. Related problems ari
se for economic decisions in trade networks\, for biological interactions
in the context of cooperation and in social networks for the adoption of i
nnovations. We map a wide range of these global optimization problems to a
local percolation model where connectivity increases when the transaction
costs in the network decrease. We explain how this transition is affected
by the network structure and the local feedback effects: While the transi
tion is discontinuous in compact networks and for strong enough feedback e
ffects\, the transition is slow in networks with a large diameter and smal
l feedback effects.\n\n\nContact Person: Dirk Witthaut
LOCATION:Institute for theoretical Physics (New Building)\, Room 0.01
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Dirk Sander
DTSTART;VALUE=DATE-TIME:20171025T143000
DTEND;VALUE=DATE-TIME:20171025T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001050@events.thp.uni-koeln.de
DESCRIPTION:Dirk Sander\, Max-Planck-Institut für Mikrostrukturphysik\, H
alle\n\nNew insights into nanomagnetism and superconductivity by low-tempe
rature scanning tunneling microscopy\n\nSpin-polarized scanning tunneling
microscopy at low temperature (8 K) and in high magnetic fields (6 T) is a
powerful technique to investigate magnetic properties of individual nanos
cale objects ranging in size form single atoms to several thousand atoms.
I focus on the magnetization reversal and the spin-dependent electronic pr
operties of bilayer Co\, Fe-decorated Co and Fe islands on Cu(111). We fin
d a novel noncollinear\, helical magnetic order in the Fe islands\, which
is identified by a magnetic stripe contrast with a period of 1.28 nm. The
high spatial resolution of the scanning tunneling spectroscopy reveals th
e significance of structural and electronic relaxation for the magnetic an
isotropy and the spin-dependent transport properties of single islands. In
an outlook I present first results from our new STM\, which operates at 0
.3 K in a vector magnetic field\, on superconductivity of Pb monolayers an
d on the proximity effect.\n\nContact Person: T. Michely
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Maximilian Genske
DTSTART;VALUE=DATE-TIME:20170707T140000
DTEND;VALUE=DATE-TIME:20170707T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001051@events.thp.uni-koeln.de
DESCRIPTION:Maximilian Genske\n\nPhD Defense\n\n
LOCATION:Seminar Room 0.03 ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Sergej Moroz
DTSTART;VALUE=DATE-TIME:20170405T143000
DTEND;VALUE=DATE-TIME:20170405T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001052@events.thp.uni-koeln.de
DESCRIPTION:Sergej Moroz\n\nTopological order\, symmetry\, and Hall respon
se of two-dimensional spin-singlet superconductors\n\n\n\nContact Person:
Sebastian Diehl
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Kamran Behnia
DTSTART;VALUE=DATE-TIME:20170516T143000
DTEND;VALUE=DATE-TIME:20170516T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001081@events.thp.uni-koeln.de
DESCRIPTION:Kamran Behnia\, ESPCI ParisTech\n\nBerry Curvature and entropy
flow in Mn3Sn\, a non-collinear magnet metal with Weyl nodes\n\n\n\nConta
ct Person: Joachim Hemberger
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Tommaso Calarco
DTSTART;VALUE=DATE-TIME:20170602T163000
DTEND;VALUE=DATE-TIME:20170602T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001072@events.thp.uni-koeln.de
DESCRIPTION:Tommaso Calarco\, Ulm University\n\nQuantum technologies and q
uantum control\n\nThe control of quantum states is essential both for fund
amental investigations and for technological applications of quantum physi
cs. In quantum few-body systems\, decoherence arising from interaction wit
h the environment hinders the realization of desired processes. In quantum
many-body systems\, complexity of their dynamics further makes state prep
aration via external manipulation highly non-trivial. An effective strateg
y to counter these effects is offered by quantum optimal control theory\,
exploiting quantum coherence to dynamically reach a desired goal with high
accuracy even under limitations on resources such as time\, bandwidth\, a
nd precision. In this talk I will (i) introduce the quantum optimal contro
l method we developed to this aim\, the CRAB (Chopped Random Basis) algori
thm\, (ii) present experimental results obtained via its application to va
rious physical systems\, from quantum logical operations in solid-state qu
antum optics to quantum criticality in ultra-cold atoms\, (iii) use these
examples to illustrate the quantum speed limit\, i.e. the maximum speed ac
hievable for a given quantum transformation\, and (iv) propose a way to ch
aracterise the latter in an information-theoretical fashion by the bandwid
th of the optimized control pulses. \n\nContact Person: Achim Rosch
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Dennis Wawrzik
DTSTART;VALUE=DATE-TIME:20170503T100000
DTEND;VALUE=DATE-TIME:20170503T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001056@events.thp.uni-koeln.de
DESCRIPTION:Dennis Wawrzik\n\nTopological semimetals and insulators in thr
ee-dimensional honeycomb materials\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Vatsal Dwivedi
DTSTART;VALUE=DATE-TIME:20170510T100000
DTEND;VALUE=DATE-TIME:20170510T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001057@events.thp.uni-koeln.de
DESCRIPTION:Vatsal Dwivedi\n\nTopological phases\, Riemann surfaces and ge
neralized transfer matrices\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Michael Scherer
DTSTART;VALUE=DATE-TIME:20170524T100000
DTEND;VALUE=DATE-TIME:20170524T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001059@events.thp.uni-koeln.de
DESCRIPTION:Michael Scherer\n\nInteractions and phase transitions in two-d
imensional Dirac materials and fermion-induced quantum criticality\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Yoran Tournois
DTSTART;VALUE=DATE-TIME:20170531T100000
DTEND;VALUE=DATE-TIME:20170531T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001060@events.thp.uni-koeln.de
DESCRIPTION:Yoran Tournois\n\nMatrix product states and the fractional qua
ntum Hall effect\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Dietrich Roscher
DTSTART;VALUE=DATE-TIME:20170517T100000
DTEND;VALUE=DATE-TIME:20170517T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001061@events.thp.uni-koeln.de
DESCRIPTION:Dietrich Roscher\n\nSpin Liquids and FRG Diagrammatics\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Tim Eschmann
DTSTART;VALUE=DATE-TIME:20170621T100000
DTEND;VALUE=DATE-TIME:20170621T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001062@events.thp.uni-koeln.de
DESCRIPTION:Tim Eschmann\n\nThermodynamics of 3D Kitaev Spin Liquids\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Carsten Bauer
DTSTART;VALUE=DATE-TIME:20170628T100000
DTEND;VALUE=DATE-TIME:20170628T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001063@events.thp.uni-koeln.de
DESCRIPTION:Carsten Bauer\n\nQuantum critical metals and machine learning\
n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Bernhard Ihrig
DTSTART;VALUE=DATE-TIME:20170705T100000
DTEND;VALUE=DATE-TIME:20170705T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001064@events.thp.uni-koeln.de
DESCRIPTION:Bernhard Ihrig \, University of Heidelberg\n\nChiral critical
behavior of Dirac materials: Gross-Neveu-Yukawa model at three loops\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Lukas Heinen
DTSTART;VALUE=DATE-TIME:20170719T100000
DTEND;VALUE=DATE-TIME:20170719T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001066@events.thp.uni-koeln.de
DESCRIPTION:Lukas Heinen\n\nRotating Skyrmion Lattices\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Igor Mazin
DTSTART;VALUE=DATE-TIME:20170522T153000
DTEND;VALUE=DATE-TIME:20170522T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001070@events.thp.uni-koeln.de
DESCRIPTION:Igor Mazin\n\nMolecular orbitals vs relativistic orbitals in t
2g honeycomb lattics: SrRu206 as compared to Na2Ir03\, RuC13\, and Li2Ru03
\n\n\n\nContact Person: Daniel Khomskii
LOCATION:SR alte Theorie
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Igor Herbut
DTSTART;VALUE=DATE-TIME:20170502T130000
DTEND;VALUE=DATE-TIME:20170502T140000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001071@events.thp.uni-koeln.de
DESCRIPTION:Igor Herbut\, Simon Fraser University\, Canada\n\nNon-fermi li
quids\, fixed point collisions\, and tensorial order in grey tin and in so
me popular field theories\n\nAbrikosov proposed in 1974 that a 3D electron
ic system with its fermi level at the point of quadratic band crossing\, a
s in the (spin-orbit coupled) gray tin or mercury telluride\, should repre
sent the simplest non-fermi liquids\, due to the common long-range Coulomb
interaction between the particles. I will review this idea and discuss ho
w a non-fermi liquid ground state may be unstable to ordering via the mech
anism of "fixed-point collision". This mechanism\, with its concomitant hi
erarchy of scales\, may also be identified as the culprit behind the notor
ious dynamical chiral symmetry breaking in the three dimensional electrody
namics\, known as the effective theory of several strongly interacting con
densed matter systems and as a favorite toy model of particle theorists. S
ome further applications of the nematic order parameters\, possibly releva
nt to gray tin or iridates\, in the current search for higher-dimensio
nal interacting field theories will also be mentioned. \n\nContact Person
: Michael Scherer
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Mikael Fremling
DTSTART;VALUE=DATE-TIME:20170616T140000
DTEND;VALUE=DATE-TIME:20170616T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001073@events.thp.uni-koeln.de
DESCRIPTION:Mikael Fremling\, University of Maynooth\n\nComposite Fermion
Fermi liquid and the half-filled Landau level\n\n\n\nContact Person: Maria
Hermanns
LOCATION:0.03 ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Julius Janusonis
DTSTART;VALUE=DATE-TIME:20170425T140000
DTEND;VALUE=DATE-TIME:20170425T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001074@events.thp.uni-koeln.de
DESCRIPTION:Julius Janusonis\n\nMagnetoelastic excitations in ferromagneti
c films\n\n\n\nContact Person: Paul van Loosdrecht
LOCATION:conference room old Theory
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Andrei Bernevig
DTSTART;VALUE=DATE-TIME:20170714T163000
DTEND;VALUE=DATE-TIME:20170714T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001076@events.thp.uni-koeln.de
DESCRIPTION:Andrei Bernevig\, Princeton University\n\nHow to find topologi
cal states of matter\n\nThe previous 11 years have seen several breakthrou
ghs in our understanding of topological states of matter. New Insulators a
nd semimetals\, exhibiting new properties imposed by a variety of symmetr
ies (the most well known of which is time reversal) have been theoreticall
y predicted and experimentally discovered. These materials are described b
y topological indices\, a set of "serial numbers" that characterize the st
ate of matter. \n\nIn this talk\, I will review the progress made in these
years with a focus on the prediction of new topological indices and on ma
terial discovery. I will then show a surprising link between chemistry bon
ding and topological states of matter which leads to the prediction of man
y new classes of materials as topological. \n\nContact Person: Simon Trebs
t
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Andrei Bernevig
DTSTART;VALUE=DATE-TIME:20170714T163000
DTEND;VALUE=DATE-TIME:20170714T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001077@events.thp.uni-koeln.de
DESCRIPTION:Andrei Bernevig\, Princeton University\n\nHow to find topologi
cal states of matter\n\nThe previous 11 years have seen several breakthrou
ghs in our understanding of topological states of matter. New Insulators a
nd semimetals\, exhibiting new properties imposed by a variety of symmetr
ies (the most well known of which is time reversal) have been theoreticall
y predicted and experimentally discovered. These materials are described b
y topological indices\, a set of "serial numbers" that characterize the st
ate of matter. \n\nIn this talk\, I will review the progress made in these
years with a focus on the prediction of new topological indices and on ma
terial discovery. I will then show a surprising link between chemistry bon
ding and topological states of matter which leads to the prediction of man
y new classes of materials as topological. \n\nContact Person: Simon Trebs
t
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Edgar Roldan
DTSTART;VALUE=DATE-TIME:20170526T163000
DTEND;VALUE=DATE-TIME:20170526T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001078@events.thp.uni-koeln.de
DESCRIPTION:Edgar Roldan\, MPI-PKS Dresden\n\nMartingale theory for nonequ
ilibrium thermodynamics\n\nThe laws of thermodynamics can be extended to m
esoscopic systems for which energy changes are on the order of the thermal
energy are relevant. Therefore\, thermodynamic observables associated wit
h mesoscopic degrees of freedom are stochastic. A key example of such ther
modynamic observable is the stochastic entropy production in nonequilibriu
m processes. Little is known beyond fluctuation theorems about universal s
tatistics of entropy-production fluctuations. Using Martingale theory we h
ave discovered novel universal statistics of stochastic entropy production
in nonequilibrium steady states such as: (i) The distribution of the nega
tive record (which we call infimum) of entropy production (ii) the passage
probabilities of entropy production\; (iii) the stopping-time fluctuation
s of entropy production. Our work is based on the finding that in a nonequ
ilibrium steady state\, the exponential of minus the entropy production is
a martingale process. A martingale is a process representing a fair game
with no net gain or loss and its connection to thermodynamics has not been
fully explored yet. Notably\, our results have interesting implications f
or stochastic processes that can be discussed in colloidal systems and act
ive molecular processes. For example\, we make predictions for the distrib
ution of the maximum backtrack depth of RNA polymerases during transcripti
on.\n\nContact Person: Joachim Krug
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Muhittin Mungan
DTSTART;VALUE=DATE-TIME:20170519T163000
DTEND;VALUE=DATE-TIME:20170519T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001079@events.thp.uni-koeln.de
DESCRIPTION:Muhittin Mungan\, Bogazici University and Bonn University\n\nD
epinning as a Coagulation Process\n\nWe consider a one-dimensional model t
hat describes the depinning of an\nelastic chain of particles in a strongl
y pinning\, phase-disordered periodic\nenvironment under a slowly increasi
ng driving force. The evolution towards\ndepinning occurs by the triggerin
g of avalanches in regions of activity\nwhich are at first isolated\, but
later grow and merge. For large system\nsizes the dynamically critical beh
avior is dominated by the coagulation of\nthese active regions. Our analys
is and numerical simulations show that the\nevolution of the sizes of acti
ve regions is well described by a Smoluchowski\ncoagulation equation\, all
owing us to predict correlation lengths and\navalanche sizes in terms of c
ertain moments of the size distribution. Time\npermitting\, we will also b
riefly present work in progress on the thermal\nbehaviour of the model.\n\
n\nContact Person: Joachim Krug
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Prof. Martin Zirnbauer
DTSTART;VALUE=DATE-TIME:20170504T100000
DTEND;VALUE=DATE-TIME:20170504T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001080@events.thp.uni-koeln.de
DESCRIPTION:Prof. Martin Zirnbauer\, Institute for Theoretical Physics\, U
niversity of Cologne\n\n Coset CFT construction for plateau transitions\n\
n\n\nContact Person: Alexander Alldridge
LOCATION:seminar room\, theoretical physics (215)
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Christoph Berke
DTSTART;VALUE=DATE-TIME:20170522T100000
DTEND;VALUE=DATE-TIME:20170522T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001082@events.thp.uni-koeln.de
DESCRIPTION:Christoph Berke\, TU Dresden\n\nWeyl semimetal on the pyrochlo
re lattice\n\nThe study of topological phases of matter is among the most
active research fields in modern solid state physics. Over the last couple
of years\, there has been growing interest in the topological classificat
ion of gapless systems. One example of a gapless system\, with defining to
pological properties\, is the Weyl semimetal (TWS). In Weyl semimetals\, c
onduction and valence bands touch at isolated points in the Brillouin zone
. These Weyl points are topologically pro- tected and can only disappear i
f they annihilate pairwise. The Weyl semimetal hosts non-trivial surface s
tates\, which take the form of open Fermi arcs\, connect- ing the projecti
ons of two Weyl points to the Brillouin zone of the surface. Due to the ro
bustness of this phase\, Weyl semimetals are of interest for applications
in quantum computers or electronic devices. In this work\, we consider a m
odel for the iridium electrons in pyrochlore iridates. For this material c
lass\, a Weyl- semimetal phase has been predicted. We calculate the phase
diagram and find a rich variety of phases\, the TWS\, a strong topological
insulator\, a type-II Weyl semimetal and various kinds of magnetic order.
For the TWS\, we study the un- conventional surface states for various ge
ometries. For lower electron densities\, we find a plethora of new magneti
c configurations. We then turn our attention towards possible instabilitie
s in Weyl semimetals. We study the stability of the Weyl semimetal phase a
gainst the formation of charge density waves. In the back- folded Brilloui
n zone\, Weyl points that were originally far apart can be mapped close to
each other and annihilate if that reduces the free energy. However we did
not find a charge density wave. We therefore study the behavior of Weyl p
oints under the influence of a charge density wave. We find mechanisms\, t
hat could possibly avoid the formation of such a charge configuration. For
example\, one-dimensional Fermi lines emerge.\n\nContact Person: Simon Tr
ebst
LOCATION:Seminarraum E0.02
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Marcel Zimmer
DTSTART;VALUE=DATE-TIME:20170518T100000
DTEND;VALUE=DATE-TIME:20170518T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001083@events.thp.uni-koeln.de
DESCRIPTION:Marcel Zimmer\, University of Cologne\n\n A Noncommutative Geo
metry Approach for Disordered Topological Crystalline Insulators\n\n\n\nCo
ntact Person: Alexander Alldridge
LOCATION:seminar room\, theoretical physics (215)
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Chris Hooley
DTSTART;VALUE=DATE-TIME:20170714T140000
DTEND;VALUE=DATE-TIME:20170714T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001084@events.thp.uni-koeln.de
DESCRIPTION:Chris Hooley\, University of St. Andrews\n\nFeynman path integ
rals over matrix product states: insights into unconventional phase transi
tions\n\nAn interesting topic in the theory of quantum phase transitions i
s that of the transition between a classically ordered state\, such as a N
éel state\, and a quantum ordered state\, such as a valence bond crystal.
On the classically ordered side of the transition\, we have a well devel
oped understanding based on the spontaneous breaking of a continuous symme
try and the occurrence of associated Goldstone modes (spin waves). On the
quantum ordered side\, things are rather less clear. Even the descriptio
n of the quantum ordered state itself is not straightforward\, since it is
not a saddle-point of the usual spin-coherent-state path integral.\n \nIn
this talk\, I shall present an approach designed to address this problem
by constructing the path integral over matrix product states rather than s
pin coherent states. This allows both classically ordered states (which a
re matrix product states of bond dimension 1) and quantum ordered states (
which are matrix product states of higher bond dimension) to be captured o
n an equal footing. I shall use this approach to show that\, for at least
one example of such a transition\, a Landau-Ginzburg-Wilson-type descript
ion can be given\, where the ‘order parameter’ is a field representing
the nearest-neighbour entanglement of the spins.\n \nThe talk is designed
to be entirely self-contained: in particular\, no prior knowledge of matr
ix product states or quantum ordered phases is assumed. The work about wh
ich I shall speak was undertaken in collaboration with Andrew Green (Unive
rsity College London)\, Jonathan Keeling (St Andrews)\, and Steve Simon (O
xford)\, under the auspices of the TOPNES programme. Most of the details
can be found at https://arxiv.org/abs/1607.01778.
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Nikolai Kiselev
DTSTART;VALUE=DATE-TIME:20170602T140000
DTEND;VALUE=DATE-TIME:20170602T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001085@events.thp.uni-koeln.de
DESCRIPTION:Nikolai Kiselev\, Peter Gruenberg Institut and Institute for A
dvanced Simulation\n\n3D magnetic textures in chiral magnets\n\n\n\nContac
t Person: Jan Mueller
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SPS | Sebastian Pitikaris
DTSTART;VALUE=DATE-TIME:20170530T120000
DTEND;VALUE=DATE-TIME:20170530T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001086@events.thp.uni-koeln.de
DESCRIPTION:Sebastian Pitikaris\, DLR\n\nLocal Mechanical Properties of Gr
anular Media\n\nGranular materials consist of macroscopic\, athermal packi
ngs of particles which\nonly interact via dissipative contact forces. The
systems can adopt different\nstates of aggregation depending on the exter
nal driving conditions.\nThe viscosity dependence of a granular fluid will
be probed\nby an active microrheology setup. We demonstrate access to thr
ee viscosity\nregimes depending on the shear rate. In a static granular sy
stem we measure\nthe contact forces on grain scale and evaluate the local
mechanical heterogeneities\nin an amorphous and crystalline packing.\n\nCo
ntact Person: Andreas Schadschneider
LOCATION:Conference room TP 0.02
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Tomáš Bzdušek
DTSTART;VALUE=DATE-TIME:20170721T140000
DTEND;VALUE=DATE-TIME:20170721T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001087@events.thp.uni-koeln.de
DESCRIPTION:Tomáš Bzdušek\, ETH Zürich\n\nBringing order to the zoo of
band structure nodes\n\n\n\nContact Person: Maria Hermanns
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Udai Raj Singh
DTSTART;VALUE=DATE-TIME:20170721T150000
DTEND;VALUE=DATE-TIME:20170721T163000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001088@events.thp.uni-koeln.de
DESCRIPTION:Udai Raj Singh\, Institute for Nanostructure and Solid State P
hysics\, University of Hamburg\n\nSpectroscopic-Imaging and Spin-Polarized
STM Studies of Superconductivity\, Nematicity and Magnetism in 11-Iron Ch
alcogenide Superconductors\n\n\n\nContact Person: T. Michely
LOCATION:Seminar room THP 'Altbau'
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Paolo Giubellino
DTSTART;VALUE=DATE-TIME:20171017T164500
DTEND;VALUE=DATE-TIME:20171017T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001089@events.thp.uni-koeln.de
DESCRIPTION:Paolo Giubellino\, FAIR Darmstadt\n\nFAIR - The Universe in th
e Laboratory\n\n\n\nContact Person: Andreas Zilges
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Eva Grebel
DTSTART;VALUE=DATE-TIME:20171107T164500
DTEND;VALUE=DATE-TIME:20171107T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001090@events.thp.uni-koeln.de
DESCRIPTION:Eva Grebel\, Heidelberg\n\nDwarf Galaxies - Fossils of Galaxy
Evolution\n\n\n\nContact Person: Stephanie Walch
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Johan Elf
DTSTART;VALUE=DATE-TIME:20180123T150000
DTEND;VALUE=DATE-TIME:20180123T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001091@events.thp.uni-koeln.de
DESCRIPTION:Johan Elf\, Lund University\n\nKinetics of dCas9 target search
in Escherichia coli\n\n\n\nContact Person: Tobias Bollenbach
LOCATION:HS I
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Satya Majumdar
DTSTART;VALUE=DATE-TIME:20171205T164500
DTEND;VALUE=DATE-TIME:20171205T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001092@events.thp.uni-koeln.de
DESCRIPTION:Satya Majumdar\, Paris-Sud\n\nKPZ story\n\nThe celebrated KPZ
equation (Kardar\, Parisi\, Zhang\, 1986) is an important milestone in sta
tistical physics\, originally introduced to describe the late time dynamic
s in two dimensional growth models. Over the last 30 years\, the KPZ story
has evolved in various interesting directions\, making links on \nthe way
to different areas of physics and mathematics. This includes in particula
r the link to the famous Tracy-Widom distribution in random matrix theory.
The story of KPZ is a very successful one\, involving \ntheoretical physi
cs\, mathematics and experiments--a fertile playground for interdisciplina
ry science. In this talk\, I will review the evolution of the KPZ story\,
pointing out the important landmarks as I go along. At the very end\, I wi
ll discuss some recent developments establishing a nice link between the K
PZ height fluctuations and the edge physics in cold atom systems.\n\nConta
ct Person: Joachim Krug
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Christof Wetterich
DTSTART;VALUE=DATE-TIME:20171219T164500
DTEND;VALUE=DATE-TIME:20171219T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001093@events.thp.uni-koeln.de
DESCRIPTION:Christof Wetterich\, Heidelberg\n\nQuantum Gravity\, Dark Ener
gy\, and the Origin of the Universe\n\n\n\nContact Person: Sebastian Diehl
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Rupert Huber
DTSTART;VALUE=DATE-TIME:20180109T164500
DTEND;VALUE=DATE-TIME:20180109T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001094@events.thp.uni-koeln.de
DESCRIPTION:Rupert Huber\, Regensburg\n\nFaster than a cycle of light\n\n\
n\nContact Person: Paul van Loosdrecht
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Zi Yang Meng
DTSTART;VALUE=DATE-TIME:20171110T163000
DTEND;VALUE=DATE-TIME:20171110T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001122@events.thp.uni-koeln.de
DESCRIPTION:Zi Yang Meng\, Institute of Physics\, Chinese Academy of Scien
ces\n\nItinerant quantum criticality\, self-learning Monte Carlo\, duality
and all that\n\nBased on the recent conceptual and technical developments
of quantum Monte Carlo simulations in correlated electron systems\, I wil
l present and discuss fresh results of itinerant quantum\ncritical points\
, i.e.\, the critical phenomena arising from the strong coupling between F
ermi surface and bosonic fluctuations\, which are made possible by the sel
f-learning Monte Carlo scheme. After\nwhich\, I will also discuss the late
ly proposed duality relations between interaction-driven topological phase
transitions and deconfined quantum critical points\, which is verified vi
a unbiased\nlarge-scale quantum Monte Carlo simulations.\n\n\nContact Pers
on: Simon Trebst
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Masahito Hayashi
DTSTART;VALUE=DATE-TIME:20170623T140000
DTEND;VALUE=DATE-TIME:20170623T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001096@events.thp.uni-koeln.de
DESCRIPTION:Masahito Hayashi\, Nagoya University\n\nVerification of Measur
ement-Based Quantum Computation\n\nQuantum computation offers a novel way
of processing information and promises solution\nof some classically intra
ctable problems. However\, if the component of the quantum computor has\ns
ome errors\, it does not output a correct computation outcome. Since the q
uantum computor is composed\nof several components\, the unexpected correl
ation causes unexpected error that cannot be corrected\nby error correctio
n. To resolve this problem\, we need to verify the quantum computor. If a
problem is\nin NP\, we can verify the correctness of a solution\, but a pr
oblem that we want to solve with a quantum\ncomputer is not necessarily in
NP. We need to verify quantum computer. Usually a quantum computer is\nco
mposed of a combination of so many quantum circuits. It is not easy to pre
dict the outcome of the\ncombination of so many quantum circuits. That is\
, since we do not know the computation outcome\,\nwe cannot verify the com
putation outcome by itself. To resolve this problem\, we employ\nmeasureme
nt-based quantum computation (MBQC). MBQC is composed of graph state and l
ocal measurements\,\nwhich are known to us. In particular\, the computatio
n resorce is given as the quantum correlation of\nthe graph state\, which
is in a known form. Hence\, we can verify these components by using the me
thod\nof statistical hypothesis testing. In this talk\, we consider the fo
llowing three settings.\n\n(1) We perfectly trust our local measurement. S
o\, we need to verify only the graph state.\n(2) We trust local measuremen
t\, but it is noisy. The noise can be converted to noise of graph state.\n
So\, we need to verify only the noisy graph state. This protocol works wit
h noisy graph state.\n(3) We do not trust measurement as well as graph sta
te. However\, it accept only the case when\nthe measurement and the graph
state are noiseless.\n\nSetting (3) has weakest assumption\, but it works
with ideal case. Setting (2) has stronger\nassumption\, but it works with
realistic case. Further\, our verification scheme can be applied to\nthe b
lind quantum computation. This talk is based on joint works with T. Morim
ae\, K. Fujii\, M. Hajdusek\,\nY. Takeuchi. The detail is available in arX
iv:1701.05688\, arXiv:1610.05216\, arXiv:1603.02195\,\nPhys. Rev. Lett. 1
15\, 220502 (2015).\n\nContact Person: David Gross
LOCATION:Seminarroom 0.02\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Michael Klatt
DTSTART;VALUE=DATE-TIME:20180112T163000
DTEND;VALUE=DATE-TIME:20180112T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001170@events.thp.uni-koeln.de
DESCRIPTION:Michael Klatt\, Karlsruhe Institute of Technology\n\nUniversal
hidden order in amorphous cellular geometries\n\nStarting from an amorpho
us partitioning of space into cells\, we iteratively optimize the `central
ity' of the\ncells\, minimizing the so-called Quantizer energy. The energy
landscape is replete with local minima to which the system converges desp
ite the existence of lower-energy crystalline configurations. Irrespective
of the level and type of disorder in the initial configurations\, the tes
sellations converge to the same amorphous state\, as measured by the same
structure factor and energy distributions. The final disordered configurat
ions exhibit an anomalous suppression of long-wavelength density fluctuati
ons\, known as hyperuniformity. For systems related to the Quantizer probl
em\, such as selfassembled copolymeric phases\, our findings suggest the p
ossibility of stable disordered hyperuniform phases.\n\nContact Person: Ma
tthias Sperl
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Jan Carl Budich
DTSTART;VALUE=DATE-TIME:20170705T143000
DTEND;VALUE=DATE-TIME:20170705T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001108@events.thp.uni-koeln.de
DESCRIPTION:Jan Carl Budich\, University of Innsbruck\n\nTopological Quant
um Matter far from Equilibrium\n\nTopological states of quantum matter suc
h as topological insulators and superconductors have been an active field
of research in physics for many years. The recent experimental progress on
their realization with ultracold atomic gases raises natural questions ab
out the notion of topological quantum matter far from thermal equilibrium.
In this talk\, we present our theoretical findings in this context.\n\nWe
first discuss the non-equilibrium Hall response of a system initialized i
n a topologically trivial state before its Hamiltonian is ramped into a Ch
ern insulator phase\, comparing the coherent dynamics with effects of deph
asing. In the second part of the talk\, we discuss non-equilibrium proper
ties of driven systems. In particular\, we show how a perfect spin momentu
m locking\, so far only known from edge states of two-dimensional topologi
cal insulators can emerge in the stroboscopic dynamics of one-dimensional
Floquet lattice systems. Finally\, we discuss dynamically defined topologi
cal quantum numbers that have no non-equilibrium counterpart\, and report
on their very recent experimental observation.\n\nContact Person: Sebastia
n Diehl
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Nicolas Regnault
DTSTART;VALUE=DATE-TIME:20170707T163000
DTEND;VALUE=DATE-TIME:20170707T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001103@events.thp.uni-koeln.de
DESCRIPTION:Nicolas Regnault\, ENS Paris\n\nMany body localization and the
rmalization: (machine) learning from the entanglement spectrum\n\nWe numer
ically explore the many body localization transition through the lens of t
he entanglement spectrum\, i.e. the spectrum of the reduced density matrix
. The level statistics of the entanglement spectrum as obtained through nu
merical diagonalization\, unveil structures beyond that revealed by more l
imited measures such as entanglement entropy. We will also show that a sim
ple artificial neural network trained on entanglement spectra of individua
l states of a many-body quantum system can be used to determine the transi
tion between a many-body localized and a thermalizing regime.\n\nContact P
erson: Maria Hermanns
LOCATION:0.03 ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Sabrina Disch
DTSTART;VALUE=DATE-TIME:20171115T143000
DTEND;VALUE=DATE-TIME:20171115T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001104@events.thp.uni-koeln.de
DESCRIPTION:Sabrina Disch\, Department Chemie\, University of Cologne\n\nM
agnetic structure on the Nanoscale: Intraparticle Magnetization and Interp
article Interactions\n\nMagnetic nanoparticles reveal unique magnetic prop
erties and relaxation phenomena which make them relevant for data storage\
, electronic and mechanical engineering\, and biomedical applications1\,2.
Whereas the implementation of nanomagnetic properties into technological
applications is progressing rapidly\, understanding the microscopic origin
of phenomena such as magnetization enhancement or decrease\, magnetic ani
sotropy and the related magnetization distribution in individual nanoparti
cles\, and interparticle interactions leading to aggregation or even order
ed assemblies of nanoparticles is fundamentally challenging and needs inte
nsive research.\nPolarized neutrons are an excellent\, microscopic probe f
or spatial and time-resolved studies of magnetism. In this contribution\,
I will present examples of our recent studies of magnetic nanoparticles on
different scales\, ranging from atomic magnetic structures to the mesosca
le intraparticle magnetization\, and interparticle interactions in well-or
dered arrays of magnetic nanocubes.\nReferences:\n[1] S. D. Bader\, Rev. M
od. Phys. 78\, 1 (2006)\; DOI: 10.1103/RevModPhys.78.1\n[2] Q. A. Pankhurs
t et al.\, J. Phys. D: Appl. Phys. 36\, R167 (2003)\; DOI: 10.1088/0022-37
27/36/13/201\n\nContact Person: P. v. Loosdrecht
LOCATION:Seminar Room of the Institute of Physics 2
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Christian Hess
DTSTART;VALUE=DATE-TIME:20171018T143000
DTEND;VALUE=DATE-TIME:20171018T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001105@events.thp.uni-koeln.de
DESCRIPTION:Christian Hess\, IFW Dresden\n\nResonantly enhanced quasiparti
cle interference and superconductivity in LiFeAs: evidence for q~0 bosonic
modes\n\nThe identification of the electron-boson interaction is believed
to be the key for rationalizing the Cooper pairing mechanism in a superco
nductor. In strong- coupling conventional superconductors\, the fingerprin
ts of the electronic band renormalization due to the electron-boson intera
ction are found in the fine structure of tunneling spectra\, where the ide
ntification of this fine structure with the phononic density of states rep
resents one of the hallmarks of modern condensed matters physics. In many
unconventional superconductors\, the unknown nature of the pairing boson\,
absence of momentum resolution\, as well as possible inelastic tunneling
effects render the interpretation of the tunneling spectra often cumbersom
e and ambiguous. Here we exploit a so far unnoticed boson-assisted resonan
t enhancement of the impurity scattering potential and thus the quasiparti
cle interference (QPI) amplitude in order to identify the nature of a poss
ible pairing boson in the unconventional superconductor LiFeAs. In high-re
solution Fourier transform scanning tunneling spectroscopy (FT-STS) measur
ements we indeed observe a resonance-like enhancement of the QPI amplitude
in both the normal and the superconducting state\, which implies an impor
tant coupling of electronic states to corresponding bosonic states at q~0
and energy at about 8meV. We show that these bosonic states seen in the QP
I are in perfect agreement with a strong inelastic contribution on the tun
neling dI/dU spectra recorded away from impurities which renders the obser
ved small-q modes promising candidates for providing the pairing interacti
on in LiFeAs.\n\nContact Person: P. van Loosdrecht
LOCATION:Seminar Room of the Institute of Physics 2
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Roman Riwar
DTSTART;VALUE=DATE-TIME:20170627T160000
DTEND;VALUE=DATE-TIME:20170627T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001106@events.thp.uni-koeln.de
DESCRIPTION:Roman Riwar\, Institute for Theoretical Nanoelectronics\, FZ J
ülich\n\nTopological electric circuits\n\nThe prospect of intrinsically p
rotected quantum computing is driving the research on topological quantum
systems. Materials with a topologically nontrivial band structure are howe
ver difficult to manufacture experimentally. We recently showed that topol
ogical materials can be engineered by quite simple means\, when considerin
g a different space: superconducting junctions have the phase difference a
nd the number of transported charges across the junction as conjugate vari
ables. In the main part of the talk\, I will present the example of a four
-terminal junction whose energy spectrum exhibits Weyl singularities in th
e space of three independent phases\, which thus play the role of\nquasimo
menta. The nonzero Chern number can be directly probed through a transport
measurement\, namely\, through a quantised transconductance. In the final
part of the talk\, I will provide an outlook on future directions. For on
e\, electric circuits may be used to study topological phase transitions s
pecific to open systems out of equilibrium\, and secondly\, they may exhib
it a so far unexplored connection between topology and quantum thermodynam
ics.\n\nContact Person: Achim Rosch
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:DIS | Sebastian Pitikaris
DTSTART;VALUE=DATE-TIME:20170626T100000
DTEND;VALUE=DATE-TIME:20170626T110000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001107@events.thp.uni-koeln.de
DESCRIPTION:Sebastian Pitikaris \, DLR\n\nLocal Mechanical Properties of G
ranular Media \n\nGranular materials consist of macroscopic\, athermal pac
kings of particles which only interact via dissipative contact forces. The
systems can adopt different states of aggregation depending on the extern
al driving conditions. The viscosity dependence of a granular fluid will b
e probed by an active microrheology setup. We demonstrate access to three
viscosity regimes depending on the shear rate. In a static granular system
we measure the contact forces on grain scale and evaluate the local mecha
nical heterogeneities in an amorphous and crystalline packing.\n\n\nContac
t Person: Matthias Sperl
LOCATION:Conference room TP 0.02
END:VEVENT
BEGIN:VEVENT
SUMMARY:SPS | Petros Polichronidis
DTSTART;VALUE=DATE-TIME:20170620T120000
DTEND;VALUE=DATE-TIME:20170620T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001102@events.thp.uni-koeln.de
DESCRIPTION:Petros Polichronidis\, Universitaet Duisburg-Essen\n\nAnalysis
\, modelling and simulation of the traffic kinematics of parades\, using t
he Rose Monday parade in Cologne as the example\n\nGPS data from participa
ting groups in the Cologne Rose Monday parade are analyzed. The preparatio
n of the measured data requires a correction of the data by a specially ad
apted algorithm for the map-matching method. A higher average velocity is
observed for the last participant\, the carnival prince\, than for the hea
d of the parade. This prince paradox can be explained by the the constant
moving vehicle driving ahead of the parade leaving the train path. In addi
tion\, the inﬂuence of the route on the traﬃc kinematics of the parade
is examined. Some areas can be determined in which the parade shows veloc
ities below or above the average. Based on the results of the data analysi
s\, for the ﬁrst time a model can be established for parading groups as
a modiﬁed Nagel-Schreckenberg model. The characteristics observed in the
data analysis can be reproduced by this model in simulations. Furthermore
\, the train group model is expanded in a second simulation in order to ad
just the average velocity of the prince.\n\nContact Person: Andreas Schads
chneider
LOCATION:Seminarraum 0.02 (Neubau)
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Christopher Max
DTSTART;VALUE=DATE-TIME:20170629T100000
DTEND;VALUE=DATE-TIME:20170629T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001109@events.thp.uni-koeln.de
DESCRIPTION:Christopher Max\, University of Cologne\n\n A KKR-theoretical
approach to the bulk-boundary correspondence of topological insulators\n\
n\n\nContact Person: Alexander Alldridge
LOCATION:seminar room\, theoretical physics (215)
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Rafael Chaves
DTSTART;VALUE=DATE-TIME:20170629T160000
DTEND;VALUE=DATE-TIME:20170629T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001110@events.thp.uni-koeln.de
DESCRIPTION:Rafael Chaves\, Natal\n\nQuantum violations of the Instrumenta
l Inequality\n\n\n\nContact Person: David Gross
LOCATION:Seminar room\, Theory Building
END:VEVENT
BEGIN:VEVENT
SUMMARY:LGAKQZ | Christopher Max
DTSTART;VALUE=DATE-TIME:20170706T100000
DTEND;VALUE=DATE-TIME:20170706T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001111@events.thp.uni-koeln.de
DESCRIPTION:Christopher Max\, University of Cologne\n\nA KKR-theoretical a
pproach to the bulk-boundary correspondence of topological insulators and
superconductors\, part II\n\n\n\nContact Person: Alexander Alldridge
LOCATION:seminar room\, theoretical physics (215)
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Yasu Kato
DTSTART;VALUE=DATE-TIME:20170712T100000
DTEND;VALUE=DATE-TIME:20170712T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001112@events.thp.uni-koeln.de
DESCRIPTION:Yasu Kato\, University of Tokyo\n\nA Monte-Carlo study of thre
e-dimensional chiral spin liquids in anisotropic hypernonagon Kitaev model
s\n\nThe Kitaev model is an exactly-soluble quantum spin model with frustr
ation. Although the original model was defined on a honeycomb lattice\, th
e model has been extended to various tricoordinate lattices without losing
the exact solubility. We analyze two different anisotropic limits of the
Kitaev model on a three-dimensional lattice comprising nine-site elementar
y loops\, which we call the hypernonagon lattice. In both cases\, the effe
ctive Ising-type models retain the time-reversal symmetry\, suggesting tha
t the ground states are chiral spin liquids. Using Monte Carlo simulations
that respect the local and global constraints on the Ising variables repr
esenting Z2 fluxes\, we show that there is a first-order phase transition
at a finite temperature in each case\, but in a different manner.\n\nConta
ct Person: Simon Trebst
LOCATION:Seminarraum E0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Hakop Pashayan
DTSTART;VALUE=DATE-TIME:20170706T160000
DTEND;VALUE=DATE-TIME:20170706T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001113@events.thp.uni-koeln.de
DESCRIPTION:Hakop Pashayan\, University of Sydney\n\nFrom estimation of qu
antum probabilities to simulation of quantum circuits\n\n\n\nContact Perso
n: David Gross
LOCATION:Theorie Neubau
END:VEVENT
BEGIN:VEVENT
SUMMARY:SPS | Simon Lee Dettmer
DTSTART;VALUE=DATE-TIME:20171005T100000
DTEND;VALUE=DATE-TIME:20171005T120000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001123@events.thp.uni-koeln.de
DESCRIPTION:Simon Lee Dettmer\n\nStochastic inference from snapshots of th
e non-equilibrium steady state: the asymmetric Ising model and beyond (PhD
Defense)\n\n\n\nContact Person: Simon Lee Dettmer
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Joaquin E. Drut
DTSTART;VALUE=DATE-TIME:20171103T140000
DTEND;VALUE=DATE-TIME:20171103T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001115@events.thp.uni-koeln.de
DESCRIPTION:Joaquin E. Drut\, University of North Carolina\n\nSignal-to-no
ise issues in non-relativistic matter: from entanglement to thermodynamics
\n\nNon-relativistic quantum matter\, as realized in ultracold atomic gase
s\, continues to be a remarkably versatile playground for many-body physic
s. Experimentalists have exquisite control over temperature\, density\, co
upling\, and shape of the trapping potential. Additionally\, a wide range
of properties can be measured: from simple ones like equations of state to
more involved ones like the bulk viscosity and entanglement. The latter h
as received much attention due to its connection to quantum phase transiti
ons\, but it has proven extremely difficult to compute: stochastic methods
display exponential signal-to-noise issues of a very similar nature as th
ose due to the infamous sign problem affecting finite-density QCD. In this
talk\, I will present an algorithm that solves the signal-to-noise issue
for entanglement\, and I will show results for strongly interacting system
s in three spatial dimensions that are the first of their kind. I will als
o present a few recent explorations of the thermodynamics of polarized mat
ter and other cases that usually have a sign problem\, using complexified
stochastic quantization.\n\nContact Person: Zala Lenarcic
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Thomas Boemerich
DTSTART;VALUE=DATE-TIME:20170727T153000
DTEND;VALUE=DATE-TIME:20170727T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001116@events.thp.uni-koeln.de
DESCRIPTION:Thomas Boemerich\n\nBachelor's Colloquium\n\n
LOCATION:Seminar Room of the Institute for Theoretical Physics
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Marcel Gievers
DTSTART;VALUE=DATE-TIME:20170727T150000
DTEND;VALUE=DATE-TIME:20170727T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001117@events.thp.uni-koeln.de
DESCRIPTION:Marcel Gievers\n\nBachelor's Colloquium\n\n
LOCATION:Seminar Room of the Institute for Theoretical Physics
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Terenz Feng
DTSTART;VALUE=DATE-TIME:20170720T160000
DTEND;VALUE=DATE-TIME:20170720T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001118@events.thp.uni-koeln.de
DESCRIPTION:Terenz Feng\n\nMaster defense: Decoherence of Driven Majorana
Qubits\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Cornelius Krellner
DTSTART;VALUE=DATE-TIME:20171129T143000
DTEND;VALUE=DATE-TIME:20171129T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001119@events.thp.uni-koeln.de
DESCRIPTION:Cornelius Krellner\, Universität Frankfurt \n\nCorrelated mat
ter: Insights from new materials\n\nWithin the field of solid-state physic
s\, the discovery of remarkable phases and transitions is often tightly co
upled to the design\, growth and characterization of novel materials. Ther
efore\, the past several decades of work in the field of correlated electr
on physics can be described by a list of materials that have defined new s
tates of matter at extreme conditions\, e.g. low temperatures\, high magne
tic field or pressure. In most cases\, a thorough understanding of the und
erlying physical mechanisms is accessible only\, if high-quality single cr
ystals with sufficient sizes are available. \nIn this lecture\, I shall gi
ve an overview about my own contributions to this research area in recent
years focusing on three very different material classes (i) quantum critic
ality and superconductivity in heavy-fermion metals [1-3]\, (ii) crystal g
rowth of LnFeAsO iron-pnictide superconductors [4\,5]\, and (iii) spin-liq
uid phases in Cu-based frustrated spin systems [6].\n \nReferences\n[1] A
. Steppke et al.\, Science 339\, 933 (2013).\n[2] E. Schuberth et al.\, Sc
ience 351\, 6272 (2016).\n[3] H. Pfau et al.\, Phys. Rev. Lett. 119\, 1264
02 (2017). \n[4] A. Jesche et al.\, Phys. Rev. B 86\, 020501(R) (2012). \n
[5] A. Adamski et al.\, Phys. Rev. B 96\, 100503(R) (2017).\n[6] P. Puphal
et al.\, J. Mater. Chem. C 5\, 2629 (2017).\n\n\nContact Person: M. Brade
n
LOCATION:Seminar Room of the Institute of Physics 2
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Masahiko Yamada
DTSTART;VALUE=DATE-TIME:20171027T140000
DTEND;VALUE=DATE-TIME:20171027T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001121@events.thp.uni-koeln.de
DESCRIPTION:Masahiko Yamada\, ISSP\, University of Tokyo\n\nCrystalline sp
in-orbital liquids with an emergent SU(4) symmetry\n\nA promising approach
to realize quantum spin liquids is to enhance\nthe spin-space symmetry fr
om usual SU(2) to SU(N). While the SU(N)\nsymmetry with a general N is pro
posed in ultracold atoms using\nnuclear spin degrees of freedom\, its real
ization in magnetic\nmaterials is challenging. Here we propose a new mecha
nism by\nwhich the SU(4) symmetry emerges in the strong spin-orbit couplin
g\nlimit. The spin-orbit coupling in d^1 transition metal compounds\nwith
edge-sharing anion octahedra leads to strongly\nbond-dependent hopping\, w
hich is apparently not SU(4)-symmetric.\nHowever\, in the honeycomb struct
ure\, a gauge transformation maps\nthe system to an SU(4)-symmetric Hubbar
d model. In the strong\nrepulsion limit at quarter filling\, the low-energ
y effective model\nis the SU(4) Heisenberg model on the honeycomb lattice\
, which\ncannot have a trivial gapped ground state and is expected to\nhos
t a gapless spin-orbital liquid. By generalizing this model\nto other thre
e-dimensional lattices\, we also propose crystalline\nspin-orbital liquids
protected by this emergent SU(4) symmetry\nand space group symmetries.\n\
nContact Person: Simon Trebst
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Harold Zandvliet
DTSTART;VALUE=DATE-TIME:20171122T143000
DTEND;VALUE=DATE-TIME:20171122T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001124@events.thp.uni-koeln.de
DESCRIPTION:Harold Zandvliet\, University of Twente\n\n1D electron systems
studied with scanning tunneling microscopy and spectroscopy\n\nScanning t
unneling microscopy is an ideal technique to explore the structural and el
ectronic properties of low-dimensional electron system. In this talk I wil
l focus on the study of physical properties self-organizing metallic nanow
ires on semiconductor surfaces and transport through single molecules. The
metallic nanowires show unique physical properties owing to their one-dim
ensional nature. Many of these properties are intimately related to electr
on-electron interactions\, which play a much more prominent role in one di
mension than in two or three dimensions. I will present our work on Pt\, A
u and Ir atom chains on Ge(001) surfaces and provide a few examples of the
ir unique properties\, such as Peierls instability\, quantum confinement\,
suppression of the density of density states near the Fermi level and nan
owire length quantization. If time allows I will also elaborate on the tra
nsport through single molecules.\n\nContact Person: T. Michely
LOCATION:Seminar Room of the Institute of Physics 2
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Tim Wehling
DTSTART;VALUE=DATE-TIME:20171009T130000
DTEND;VALUE=DATE-TIME:20171009T140000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001125@events.thp.uni-koeln.de
DESCRIPTION:Tim Wehling\, Universität Bremen\n\nElectronic Interactions i
n Two-Dimensional Materials\n\nSince the isolation of monolayer graphene\,
the library of two dimensional (2d) materials has been continuously growi
ng. Together with recent developments in on-demand stacking of these atomi
cally thin crystals\, a whole new class of hybrid materials is coming into
reach\, which holds promises from the realization of exotic electronic qu
antum phases at elevated temperatures to novel optoelectronic applications
. Interactions between electrons are central to all these kinds of promise
s. In my talk\, I will discuss why Coulomb interactions in 2d materials ar
e very different from their 3d counterparts\, how they influence material
properties and how interactions can be manipulated in 2d materials. As exa
mple systems I will consider graphene as well as transition metal dichalco
genides like MoS2. In these systems interactions renormalize electronic qu
asiparticles through pronounced band gap shifts\, lead to the emergence of
many-particle modes such as excitons with unusually high binding energies
and can finally drive the electron system towards different kinds of inst
abilities including superconductivity and charge density wave states.\n\nC
ontact Person: T. Michely
LOCATION:Seminar room Institute of physics 2
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Kazumasa Hattori
DTSTART;VALUE=DATE-TIME:20170824T140000
DTEND;VALUE=DATE-TIME:20170824T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001127@events.thp.uni-koeln.de
DESCRIPTION:Kazumasa Hattori\, Tokyo Metropolitan University\n\nMultiorbit
al superconductors and local nodal cooper pairs\n\n\n\nContact Person: Ach
im Rosch
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Andrei Marshakov
DTSTART;VALUE=DATE-TIME:20170926T143000
DTEND;VALUE=DATE-TIME:20170926T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001128@events.thp.uni-koeln.de
DESCRIPTION:Andrei Marshakov\, Skoltech\, Moscow\n\nModern applications of
2d CFT\n\n\n\nContact Person: Semyon Klevtsov
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Marco Tulio
DTSTART;VALUE=DATE-TIME:20170906T150000
DTEND;VALUE=DATE-TIME:20170906T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001130@events.thp.uni-koeln.de
DESCRIPTION:Marco Tulio\, University of Tokyo\n\n How to invert an unitary
?\n\nIf you are given a black box unitary U\, can you build the inverse\nU
^\\dagger out of it? In this talk we are going to discuss this\nproblem\,
and more generally which transformations on unitary channels\ncan be done
according to the rules of quantum mechanics\n\n\nContact Person: David Gro
ss
LOCATION:Seminar 0.02\, theory building
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Peter Milde
DTSTART;VALUE=DATE-TIME:20171024T130000
DTEND;VALUE=DATE-TIME:20171024T140000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001131@events.thp.uni-koeln.de
DESCRIPTION:Peter Milde\, TU Dresden \n\nScanning Force Microscopy Investi
gations of Skyrmions\n\n\n\nContact Person: I. Lindfors-Vrejoiu
LOCATION:Seminar Room Kernphysik
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Lukas Janssen
DTSTART;VALUE=DATE-TIME:20171020T140000
DTEND;VALUE=DATE-TIME:20171020T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001132@events.thp.uni-koeln.de
DESCRIPTION:Lukas Janssen\n\nA fermionic gauge theory for bosonic deconfin
ed criticality\n\n\n\nContact Person: Michael Scherer
LOCATION:Seminar Room 003\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Jeison A. Fischer
DTSTART;VALUE=DATE-TIME:20170928T110000
DTEND;VALUE=DATE-TIME:20170928T120000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001133@events.thp.uni-koeln.de
DESCRIPTION:Jeison A. Fischer\, MPI Halle\n\nExchange-driven non-collinear
magnetism in nanostructures studied by spin polarized-STM\n\n\n\nContact
Person: T. Michely
LOCATION:Seminar room of the Institute of Physics 2
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Tobias Mueller
DTSTART;VALUE=DATE-TIME:20170927T100000
DTEND;VALUE=DATE-TIME:20170927T110000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001135@events.thp.uni-koeln.de
DESCRIPTION:Tobias Mueller\, University of Wuerzburg\n\nDynamical measurem
ent of the interaction strength in helical Luttinger Liquids\n\nIn one-dim
ensional Luttinger liquids the interaction strength is determined by the L
uttinger Parameter K. It proves proves difficult to be measured\, as it is
usually hidden in power-law dependencies on temperature or bias. In this
talk I will propose a setup\, which allows a dynamical measurement of this
parameter.\n\nIn this talk we will\, based on an equation of motion descr
iption of Luttinger Liquids\, discuss a setup with a capacitive gate\, whi
ch allows to probe the interactions directly. In this setup\, an expressio
n for the frequency dependence of the conductivity can be obtained\, from
which we can extract K directly and from a low frequency expansion. Furthe
rmore the influence of the precise form of the change in interactions at t
he contacts is examined using the formalism. As a perfectly suited system
to test the predictions\, we will shortly discuss helical edge states of t
opological insulators.\n\n\nContact Person: Simon Trebst
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Taner Esat
DTSTART;VALUE=DATE-TIME:20170927T143000
DTEND;VALUE=DATE-TIME:20170927T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001137@events.thp.uni-koeln.de
DESCRIPTION: Taner Esat\, Peter-Gruenberg-Institut Juelich\n\nA chemically
driven quantum phase transition in a two-molecule Kondo system\n\nMagneti
sm of molecules is in the focus of intense research\, because it could lea
d to new spin-based electronic devices. In this context\, two molecules ad
sorbed on a metal surface and carrying magnetic moments constitute an impo
rtant model system which helps to understand the fundamental properties of
molecular magnetism – in particular the interaction between their magne
tic moments. Typically the interaction of spins on a metal surface is domi
nated and tuned by the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction
– an indirect exchange interaction mediated by the conduction electrons
of the metal.\nHere we show that the non-magnetic\, chemical interaction b
etween the molecules can become the decisive effect if the spin-moment-car
rying molecular orbitals extend in space and therefore lead to the formati
on of bonding and antibonding orbitals due to wave function overlap. We de
monstrate that this splitting has a crucial influence on the magnetic prop
erties exemplified by two neighbouring metal-molecule (Au-PTCDA) complexes
\, i.e. dimers\, on the Au(111) surface. Interestingly\, in this particula
r case\, competition between the binding energy gain\, due to the chemical
interaction between the moment-carrying orbitals\, and the gain of additi
onal hybridization energy\, due to the strong entanglement between the loc
al moment and the conduction band of the substrate\, is the driving force
of a quantum phase transition (QPT) in the dimer. Small changes in the wav
e function overlap\, involving slightly different dimer configurations\, d
rive the system through a quantum critical point (QCP) from a partially Ko
ndo-screened triplet to a singlet ground state\, with one dimer configurat
ion being located extremely close to a quantum critical point.\n\n\nContac
t Person: T. Michely
LOCATION:Seminar room Institute of physics 2
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Tobias Meng
DTSTART;VALUE=DATE-TIME:20171201T140000
DTEND;VALUE=DATE-TIME:20171201T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001138@events.thp.uni-koeln.de
DESCRIPTION:Tobias Meng\, TU Dresden\n\nThe gravity of Weyl: tabletop sign
atures of the mixed axial-gravitational anomaly\n\nTopological semimetals
have recently been one of the most active topics in solid state physics\,
and provide an exceptionally fruitful meeting point for fields as diverse
as chemistry\, band structure calculations and high-energy field theory. T
his talk will discuss the observation of quantum anomalies in Weyl semimet
als. These anomalies are rooted in an incompatibility of quantum mechanics
and classical conservation laws. In particular\, I will focus on recent m
easurements demonstrating the presence of the mixed axial-gravitational an
omaly in Weyl semimetals. In contrast to earlier expectations\, which woul
d for example search for this phenomenon in the hydrodynamics of neutron s
tars\, we used a conceptually simple thermoelectric transport experiment t
o find signatures of the mixed axial-gravitational anomaly in the Weyl sem
imetal NbP.\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Svetlana Mansurova
DTSTART;VALUE=DATE-TIME:20171122T093000
DTEND;VALUE=DATE-TIME:20171122T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001139@events.thp.uni-koeln.de
DESCRIPTION:Svetlana Mansurova\, INAOE\n\nHybrid device structures based o
n amorphous silicon and organic semiconductors\n\nIn the first part of the
talk a brief overview of the research activities in area of fabrication a
nd characterization of hybrid device structures based on amorphous silicon
and organic semiconductors will be presented. The second part of the talk
will be devoted to the discussion of the dynamic grating technique based
on non-steady-state photo-EMF effect and its application for characterizat
ion of the photo-physical properties of organic\, inorganic and hybrid sem
iconductors.\n\nContact Person: Ann-Christin Schmaedicke
LOCATION:Seminar Room 147\, Institute for Physical Chemistry
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Jan Gelhausen
DTSTART;VALUE=DATE-TIME:20171011T100000
DTEND;VALUE=DATE-TIME:20171011T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001140@events.thp.uni-koeln.de
DESCRIPTION:Jan Gelhausen\n\nDissipative Dicke Model with Collective Atomi
c Decay: Bistability\, Noise-Driven Activation and Non-Thermal First Order
Superradiance Transition\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Florian Lange
DTSTART;VALUE=DATE-TIME:20171220T100000
DTEND;VALUE=DATE-TIME:20171220T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001141@events.thp.uni-koeln.de
DESCRIPTION:Florian Lange\n\nGeneralized Gibbs ensembles in open quantum s
ystems\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Falko Pientka
DTSTART;VALUE=DATE-TIME:20171013T140000
DTEND;VALUE=DATE-TIME:20171013T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001142@events.thp.uni-koeln.de
DESCRIPTION:Falko Pientka\, Harvard University\n\nTransport phenomena of n
eutral excitations in interacting 2d systems\n\nIn the first part of the t
alk\, I will propose a transport experiment of \nexcitons in 2d transition
-metal dichalcogenides. Due to their \ninteractions with unbound electrons
in the Fermi sea\, excitons are \ndressed by a cloud of particle-hole exc
itations forming Fermi polarons. \nAn in-plane electric field cannot direc
tly accelerate neutral excitons\, \nhowever\, due to the polaronic dressin
g\, the unbound electrons will drag \nthe excitons along. This phenomenon
is similar to Coulomb drag in \nbilayer semiconductors. We determine the d
rag conductivity for a low \ndensity of excitons using simple arguments as
well as a diagrammatic \ncalculation based on a self-consistent T matrix
approximation. Due to \nthe strong nonperturbative coupling\, the exciton
drag mobility is \nexpected to be of the same order as the electron mobili
ty even at zero \ntemperature.\nTime permitting\, I will discuss a novel p
robe of quantum Hall \nferromagnetism in graphene based on thermal transpo
rt in the second part \nof the talk. Strong interactions lift the high deg
eneracy of the \nzero-energy Landau level in graphene mono- and bilayers\,
giving rise to \na rich phase diagram of competing spin and valley order.
Here we show \nthat thermal transport at low temperatures can give compel
ling evidence \nfor spontaneous symmetry breaking and exhibits many other
signatures \ndistinguishing the various phases.
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Tathagata Chowdhury
DTSTART;VALUE=DATE-TIME:20171025T103000
DTEND;VALUE=DATE-TIME:20171025T120000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001143@events.thp.uni-koeln.de
DESCRIPTION:Tathagata Chowdhury\n\nLong range entanglement near a Kondo-de
struction quantum critical point\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | A. Schulz\, A. Schadschneider
DTSTART;VALUE=DATE-TIME:20171006T140000
DTEND;VALUE=DATE-TIME:20171006T183000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001144@events.thp.uni-koeln.de
DESCRIPTION:A. Schulz\, A. Schadschneider\, Universität zu Köln\n\nLehre
rfortbildung Physik/Astronomie\n\nPeter Schilke (Köln): Das unsichtbare U
niversum mit ALMA sichtbar gemacht\n\nNorbert Wex (Bonn): 50 Jahre Pulsare
\, 50 Jahre kosmische Uhren für Einstein\n\nAndreas Schulz (Köln\, Bonn)
: Die Bewohnbarkeit unseres Planeten\n\nAlexander Küpper (Köln): Erfahru
ngen mit einer inklusiven astron. Lernumgebung\n\nMartin Quast (Bonn): Wo
sind die Aliens? – Exoplaneten und ihre Bewohnbarkeit\n\nContact Person:
Andreas Schadschneider
LOCATION:Seminarraum 0.03 (Neubau)
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Yuval Vinkler
DTSTART;VALUE=DATE-TIME:20171108T100000
DTEND;VALUE=DATE-TIME:20171108T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001145@events.thp.uni-koeln.de
DESCRIPTION:Yuval Vinkler\n\ntba\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Jan Attig
DTSTART;VALUE=DATE-TIME:20171115T100000
DTEND;VALUE=DATE-TIME:20171115T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001146@events.thp.uni-koeln.de
DESCRIPTION:Jan Attig\n\nTwo-stage multipolar ordering in PrTM2Al20 Kondo
materials\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Henry Legg
DTSTART;VALUE=DATE-TIME:20171122T100000
DTEND;VALUE=DATE-TIME:20171122T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001147@events.thp.uni-koeln.de
DESCRIPTION:Henry Legg\n\nTransport in 2D and 3D Dirac materials\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Ciaran Hickey
DTSTART;VALUE=DATE-TIME:20171129T100000
DTEND;VALUE=DATE-TIME:20171129T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001148@events.thp.uni-koeln.de
DESCRIPTION:Ciaran Hickey\n\nCuprates in High Magnetic Fields: Pseudo-Answ
ers to Pseudogap Questions\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Marko Kralj
DTSTART;VALUE=DATE-TIME:20171113T140000
DTEND;VALUE=DATE-TIME:20171113T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001175@events.thp.uni-koeln.de
DESCRIPTION:Marko Kralj\, Institute of Physics\, Zagreb\n\nTransferring mi
llimeter sized atomically thin layers: atomic-scale defects and structural
modifications\n\n\n\nContact Person: Thomas Michely
LOCATION:Seminarroom New Theorie 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | John Bechhoefer
DTSTART;VALUE=DATE-TIME:20171117T163000
DTEND;VALUE=DATE-TIME:20171117T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001149@events.thp.uni-koeln.de
DESCRIPTION:John Bechhoefer\, Simon Fraser University\, Vancouver\n\nThe d
etails are in the devil: Experiments on Maxwell's demon and the role of in
formation in thermodynamics\n\nOne hundred and fifty years ago\, Maxwell's
demon was first posed as a fundamental challenge to the newly developed f
ield of statistical physics. Just two months later\, Maxwell's paper "On g
overnors" gave the first analysis of a feedback system. These two foundati
onal works reflect the fundamental and practical aspects of control. Here\
, I will present an experiment that unites the two: using feedback to crea
te `impossible' dynamics\, we make a Maxwell demon that can reach the fund
amental limits to control set by thermodynamics. We test - and then extend
- Rolf Landauer's 1961 prediction that information erasure requires at le
ast as much work as can be extracted from a system by virtue of informatio
n. These fundamental thermodynamic limits are benchmarks for evaluating th
e performance of practical information engines\, such as those active with
in cells and other complex systems.\n\nContact Person: Joachim Krug
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Federico Tonielli
DTSTART;VALUE=DATE-TIME:20171206T100000
DTEND;VALUE=DATE-TIME:20171206T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001150@events.thp.uni-koeln.de
DESCRIPTION:Federico Tonielli\n\nOrthogonality Catastrophe in open quantum
systems?\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Ori Alberton
DTSTART;VALUE=DATE-TIME:20180117T100000
DTEND;VALUE=DATE-TIME:20180117T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001151@events.thp.uni-koeln.de
DESCRIPTION:Ori Alberton\n\nPhase transitions between Rydberg-polariton BE
Cs close to a Feshbach resonance\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Vivek Lohany
DTSTART;VALUE=DATE-TIME:20180110T100000
DTEND;VALUE=DATE-TIME:20180110T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001152@events.thp.uni-koeln.de
DESCRIPTION:Vivek Lohany\n\ntba\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Gabor Halasz
DTSTART;VALUE=DATE-TIME:20171213T100000
DTEND;VALUE=DATE-TIME:20171213T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001153@events.thp.uni-koeln.de
DESCRIPTION:Gabor Halasz\, KITP\n\nParton constructions and realistic spin
models of fracton topological orders\n\nFracton phases are gapped quantum
phases in three dimensions that go beyond the standard paradigm of topolo
gical order\; they have fractionalized excitations that are immobile or on
ly mobile along lower-dimensional subsystems\, such as lines or planes. Wh
ile there are several exactly solvable models of such fracton phases\, the
se models are far from realistic because they involve interactions between
many spins at the same time. By generalizing the fermionic parton constru
ction\, a standard phenomenological description of fractionalization in qu
antum phases\, we provide simple variational states capturing fracton phas
es. Moreover\, by showing that each variational state is the asymptotic st
rong-coupling ground state of a corresponding coupled-spin-chain model\, w
e demonstrate that a large class of fracton phases can be realized in more
realistic models involving only two-spin interactions.\n\nContact Person:
Simon Trebst
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Kevin O Brien
DTSTART;VALUE=DATE-TIME:20180124T100000
DTEND;VALUE=DATE-TIME:20180124T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001154@events.thp.uni-koeln.de
DESCRIPTION:Kevin O Brien\n\nThree-dimensional Kitaev Spin Liquids\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Heinrich Froeml
DTSTART;VALUE=DATE-TIME:20180131T100000
DTEND;VALUE=DATE-TIME:20180131T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001155@events.thp.uni-koeln.de
DESCRIPTION:Heinrich Froeml\n\nLocal Dissipation in Quantum Wires\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Till Kranz
DTSTART;VALUE=DATE-TIME:20171020T163000
DTEND;VALUE=DATE-TIME:20171020T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001156@events.thp.uni-koeln.de
DESCRIPTION:Till Kranz\, ITP & DLR\n\nRheology of Granular Fluids: An Inte
gration Through Transients Approach\n\nFlows of large numbers of macroscop
ic particles (sand grains\, cereals\, ball bearings\, etc.) occur in natur
al phenomena like land slides or avalanches and are an important part of m
any industrial processes.\nThe flow behavior of granular fluids displays a
rich rheology including Newtonian\, shear thinning\, and shear thickening
regimes as well as the famous Bagnold scaling. The non-equilibrium nature
of granular\nflows and the high densities and shear rates involved make a
theoretical description challenging. I will begin with a qualitative disc
ussion of what determines the flow behavior. Based on this discussion I\nw
ill develop a theory from first principles that makes it quantitative and
allows the prediction of flow curves and transport coefficients.\n
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Peter Mörters
DTSTART;VALUE=DATE-TIME:20171124T163000
DTEND;VALUE=DATE-TIME:20171124T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001157@events.thp.uni-koeln.de
DESCRIPTION:Peter Mörters\, Mathematical Institute\, Cologne\n\nMetastabi
lity of the contact process on evolving scale-free networks\n\nWe study th
e contact process in the regime of small infection rates on scale-free net
works evolving by stationary dynamics. A parameter allows us to interpolat
e between slow (static) and fast (mean-field) network dynamics. For two pa
radigmatic classes of networks we investigate transitions between phases\n
of fast and slow extinction and in the latter case we analyse the density
of infected vertices in the metastable state. This is joint work with Emma
nuel Jacob (ENS Lyon) and Amitai Linker (Universidad de Chile).\n\n\nConta
ct Person: Joachim Krug
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Yuta Murakami
DTSTART;VALUE=DATE-TIME:20171215T140000
DTEND;VALUE=DATE-TIME:20171215T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001158@events.thp.uni-koeln.de
DESCRIPTION:Yuta Murakami\, University of Fribourg\n\nPeriodic driving of
correlated systems: high-harmonic generation in the Mott insulator and par
ametric phonon excitation in superconductors\n\nDriving systems out of equ
ilibrium can provide new ways to control properties and extract new functi
ons.\nRecent development of intense laser in a wide frequency range has le
d to intriguing observations \nsuch as light-induced superconductivity-lik
e behaviors above the transition temperature [1]\,\nenhancement of the exc
itonic condensation [2] and high-harmonic generation in solid states [3].\
n\nMotivated by this intriguing situation\, we have been developing noneq
uilibrium methods based on the dynamical mean-field theory (DMFT). \nHere
we would like to present recent two applications of the nonequilibrium DMF
T for the time-periodic steady states (Floquet DMFT).\n\nIn the first part
\, we discuss the high-harmonic generation (HHG) in the Mott insulator und
er periodic AC driving [4]. \nWe show that qualitative behavior of the HHG
spectrum is different between weak and strong field regimes\,\nwhich orig
inates from qualitative difference in doublon/holon dynamics under the dri
ving. \nWe also discuss the similarity and the difference of the HHG inten
sity in the Mott insulator compared to that of semiconductors and disorder
ed systems.\n\nIn the second part\, we discuss the effects of the parametr
ic-phonon driving on conventional SC\, which has been considered to enhanc
e SC[5][6]. \nBy studying transient dynamics and steady states\, we demons
trate that even though the attractive interaction can be enhanced by the d
riving\, \nSC is always suppressed\, in particular\, at the parametric res
onance. Our systematic analysis shows that\, in a wide parameter range\, \
nthe heating of the system is the dominant effect and the parametric phono
n driving has a negative effect on SC.\n\n[1] M. Mitrano et al.\, Nature 5
30\, 461 (2016).\n[2] S. Mor et al.\, PRL 119\, 086401 (2017).\n[3] S. Ghi
mire et al.\, Nat. Phys. 7\, 138 (2011).\n[4] Y. Murakami\, M. Eckstein\,
P. Werner to be published.\n[5] M. Knap et al.\, PRB 94\, 214504 (2016)\;
M. Babadi et al.\, PRB 96\, 014512 (2017).\n[6] Y. Murakami et al\, PRB 96
\, 045125 (2017).\n\nContact Person: Zala Lenarcic
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Francois Dubin
DTSTART;VALUE=DATE-TIME:20171213T143000
DTEND;VALUE=DATE-TIME:20171213T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001159@events.thp.uni-koeln.de
DESCRIPTION:Francois Dubin\n\nImaging the Superfluid Crossover of Trapped
Two-Dimensional Dipolar Excitons\n\nState-of-the-art nano-fabrication proc
ess allow to control the spatial confinement of electronic carriers\, with
close to atomic precision. Structures are thus designed to separate\nspat
ially oppositely charged electrons and holes\, notably bilayer heterostruc
tures. When\nelectrons and hole are separated in such adjacent layers they
experience a strong\nCoulomb attraction pairing them into spatially indir
ect excitons\, i.e. boson-like particles\,\nwhich exhibit a giant electric
dipole of about 500 Debye. Excitons then experience a\nrepulsive dipolar
potential stabilizing cold gases against collapse while providing access t
o\na rich variety of collective quantum phases\, possibly ranging from sup
erfluidity to\nsupersolidity [1].\n\nHere\, first signatures for the super
fluid crossover of such dipolar excitons are reported [2].\nWhen confined
in a microscopic trap we show that they realize a four-component\nsuperflu
id at sub-Kelvin temperatures\, distributed between two optically active a
nd two\noptically inactive spin states. By imaging the condensate bright p
art\, we study in-situ the\nprofiles of the exciton density and the phase
coherence in the trap. We thus reveal\nquantum spatial coherence\, in a su
b-Kelvin regime bound to very dilute densities and\nprobably limited by th
e strength of dipolar interactions. Also\, we evidence quantized\nvortices
\, efficiently trapped in the slight electrostatic disorder of our trappin
g potential [2].\nAnalyzing the interplay between quasi long-range order\,
vortex formation\, and density\nprofiles across the range of explored par
ameters it is finally shown that our experimental\nfindings provide a dire
ct evidence for a Berezinskii-Kosterlitz-Thouless crossover [3].\n\nThe wo
rk presented here results from contributions of S.Dang\, R.Anankine\, M.Be
ian\,\nM.Alloing\, E.Cambril\, A.Lemaitre and M.Holzmann.\n\nContact Perso
n: Sebastian Diehl
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Stefan Floerchinger
DTSTART;VALUE=DATE-TIME:20180110T143000
DTEND;VALUE=DATE-TIME:20180110T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001160@events.thp.uni-koeln.de
DESCRIPTION:Stefan Floerchinger\, University of Heidelberg\n\nDynamics of
entanglement in expanding quantum fields\n\nWe develop a novel real-time a
pproach to computing the entanglement between spatial regions for Gaussian
states in quantum field theory. The entanglement entropy is characterized
in terms of local correlation functions on space-like Cauchy hypersurface
s. The framework is applied to explore an expanding light cone geometry in
the particular case of the Schwinger model for quantum electrodynamics in
1+1 space-time dimensions. We observe that the entanglement entropy becom
es extensive in rapidity at early times and that the corresponding local r
educed density matrix is a thermal density matrix for excitations around a
coherent field with a time dependent temperature. Since the Schwinger mod
el successfully describes many features of multiparticle production in ele
ctron-positron collisions\, our results provide an attractive explanation
in this framework for the apparent thermal nature of multiparticle product
ion even in the absence of significant final state scattering.\n\n\nContac
t Person: Sebastian Diehl
LOCATION:Seminar room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Lukas Sieberer
DTSTART;VALUE=DATE-TIME:20171117T140000
DTEND;VALUE=DATE-TIME:20171117T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001161@events.thp.uni-koeln.de
DESCRIPTION:Lukas Sieberer\, University of Innsbruck\n\nDesigning quantum
paths in adiabatic quantum computing\n\nThe computational superiority of a
computer that operates according to the laws\nof quantum mechanics relies
crucially on quantum parallelism: different sets of\ndata stored as a sup
erposition of quantum states can be processed in\nparallel. To play out th
is advantage\, however\, one has to be able to prepare\nsuch superposition
s in the first place --- using only a minimum of computational\nresources.
We present a framework to efficiently prepare superpositions of\nmany-bod
y spin configurations with programmable squared amplitudes. The spin\nconf
igurations are encoded in the degenerate ground states of the lattice-gaug
e\nrepresentation of an all-to-all connected Ising spin glass. The ground
state\nmanifold is invariant under variations of the gauge degrees of free
dom\, which\ntake the form of four-body parity constraints. Our framework
makes use of these\ndegrees of freedom by individually tuning them to dyna
mically prepare\nprogrammable superpositions. The dynamics combines an adi
abatic protocol with\ncontrolled diabatic transitions.\n\nContact Person:
Sebastian Diehl
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Lukasz Plucinski
DTSTART;VALUE=DATE-TIME:20171206T143000
DTEND;VALUE=DATE-TIME:20171206T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001162@events.thp.uni-koeln.de
DESCRIPTION:Lukasz Plucinski\, FZ Juelich\n\nBand structure engineering in
3D topological insulators\n\n\n\nContact Person: Alexander Grueneis
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Istvan Kezsmarki
DTSTART;VALUE=DATE-TIME:20180124T143000
DTEND;VALUE=DATE-TIME:20180124T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001180@events.thp.uni-koeln.de
DESCRIPTION:Istvan Kezsmarki\, Uni Augsburg\n\nUnidirectional light propag
ation in multiferroics and multi-antiferroics\n\nMultiferroics permit the
magnetic control of the electric polarization and the electric control of
the magnetization. These static magnetoelectric (ME) effects are of enormo
us interest: The ability to read and write a magnetic state current-free b
y an electric voltage would provide a huge technological advantage. Dynami
c or optical ME effects are equally interesting\, because they give rise t
o unidirectional light propagation as recently observed in several multife
rroic compounds [1].\n\nIn conventional media light propagation is recipro
cal\, that is counter-propagating beams experience the same refractive ind
ex. However\, reciprocity can be violated in multiferroic materials\, wher
e the refractive index depends not only on the polarization of light but a
lso on the +- k direction of the propagation [1]. Such unidirectional tran
smission is the consequence of the dynamic magnetoelectric effect emerging
in materials with simultaneously broken time reversal and spatial inversi
on symmetries. This phenomenon\, exclusively observed in multiferroic and
magnetoelectric materials [2-5]\, may allow the development of optical dio
des transmitting unpolarized light in one\, but not in the opposite\, dire
ction [5]. Recently\, the emergence such unidirectional light propagation\
, governed the dynamic magnetoelectric effect\, has also been demonstrated
in multi-antiferroics [6]\, i.e. in materials with coexisting purely anti
ferroelectric and antiferromagnetic orders.\n\n\nReferences\n\n[1] D. Szal
ler et al.\, Phys. Rev. B 87\, 014421 (2014)\n[2] I. Kezsmarki et al.\, Ph
ys. Rev. Lett. 106\, 057403 (2011)\n[3] S. Bordacs et al.\, Nat. Phys. 8\,
734 (2012)\n[4] I. Kezsmarki et al.\, Nat. Commun. 5\, 3203 (2014)\n[5] I
. Kezsmarki et al.\, Phys. Rev. Lett. 115\, 127203 (2015)\n[6] V. Kocsis e
t al.\, arXiv:1711.08124 (2017)\n\nContact Person: Joachim Hemberger
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Frank Schindler
DTSTART;VALUE=DATE-TIME:20171128T140000
DTEND;VALUE=DATE-TIME:20171128T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001163@events.thp.uni-koeln.de
DESCRIPTION:Frank Schindler\, University of Zurich\n\nHigher-order topolec
trical circuits\n\nHigher-order topological insulators have been recently
proposed as unprecedented quantum states of matter. In two spatial dimensi
ons\, they incorporate quantized electric quadrupole insulators\, which fe
ature zero-dimensional topological corner midgap states. These states are
protected by the bulk gap\, reflection symmetries\, and a spectral symmetr
y\, while their edges are gapped. Although such novel topological phases a
re often hard to come by in real materials\, there are various analogue pl
atforms that enable us to realize the corresponding band theory concepts i
n classical systems. I will talk about how we developed and measured a top
olectrical circuit design for a quadrupole insulator\, the midgap states o
f which manifest themselves as topological boundary resonances in the corn
er impedance profile of the circuit. This establishes an instance where to
polectrical circuitry is employed to bridge the gap between quantum theore
tical modeling and the experimental realization of topological band struct
ures.\n\nContact Person: Finn Lasse Buessen
LOCATION:Seminarraum Kernphysik
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Jürgen Berges
DTSTART;VALUE=DATE-TIME:20180119T163000
DTEND;VALUE=DATE-TIME:20180119T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001164@events.thp.uni-koeln.de
DESCRIPTION:Jürgen Berges\, University of Heidelberg\n\nUniversality far
from equilibrium: From the early universe to ultracold quantum gases\n\nIn
recent years there have been important advances in understanding isolated
quantum systems far from equilibrium. Prominent examples include the (pre
-)heating process in the early universe after inﬂation\, the initial sta
ges in collisions of relativistic nuclei at giant laboratory facilities\,
as well as table-top experiments with ultracold quantum gases. Even though
the typical energy scales of these systems vastly diﬀer\, they can show
very similar dynamical properties. Certain characteristic numbers can eve
n be quantitatively the same\, defining nonthermal universality classes. O
ne may use this universality to learn from experiments with cold atoms asp
ects about the dynamics during the early stages of our universe.\n\nContac
t Person: Alexander Altland
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Nina Mueller
DTSTART;VALUE=DATE-TIME:20171121T164500
DTEND;VALUE=DATE-TIME:20171121T171500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001165@events.thp.uni-koeln.de
DESCRIPTION:Nina Mueller\, Institut für Theoretische Physik\, Köln\n\nCa
ncer evolution and stochastic modeling of resistance to therapy\n\n
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Oliver Zingsheim
DTSTART;VALUE=DATE-TIME:20171121T171500
DTEND;VALUE=DATE-TIME:20171121T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001166@events.thp.uni-koeln.de
DESCRIPTION:Oliver Zingsheim\, I. Physik\, Uni Köln\n\nRotational spectro
scopy: A powerful analytical tool\n\n
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Rainer Klages
DTSTART;VALUE=DATE-TIME:20171201T163000
DTEND;VALUE=DATE-TIME:20171201T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001167@events.thp.uni-koeln.de
DESCRIPTION:Rainer Klages\, Queen Mary University London\n\nStatistical Ph
ysics and Anomalous Dynamics of Foraging\n\nA question that attracted a lo
t of attention in the past two decades is whether biologically relevant se
arch strategies can be identified by statistical data analysis and mathema
tical modeling. A\nfamous paradigm in this field is the Levy Flight Foragi
ng Hypothesis. It states that under certain mathematical conditions Levy d
ynamics\, which defines a key concept in the theory of anomalous stochasti
c processes\, leads to an optimal search strategy for foraging organisms.
This hypothesis is discussed very controversially in the current literatur
e. I will review examples and counterexamples of experimental data and the
ir analyses confirming and refuting it. Related to this debate is own work
about\nbiophysical modeling of bumblebee flights under predation thread a
nd biological cell migration\, both based on experimental data analysis\,
which I briefly outline.\n\nContact Person: Joachim Krug
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:SPS | Martin Greiner
DTSTART;VALUE=DATE-TIME:20171018T160000
DTEND;VALUE=DATE-TIME:20171018T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001168@events.thp.uni-koeln.de
DESCRIPTION:Martin Greiner\, Aarhus University\n\nThe benefit of cooperati
on in a simplified highly renewable European electricity infrastructure\n\
nWe consider a simplified model of a future European electricity network w
ith a high share of renewable generation. In a cost optimal design of such
a system\, most of the renewable generation capacity is placed at locatio
ns with favorable weather conditions\, that is for instance onshore wind i
n countries bordering the North Sea and solar PV in South European countri
es. Countries with less favorable renewable generation conditions benefit
from this capacity by importing the respective electricity as power flows
through the transmission grid. Using flow tracing techniques\, which are r
elated to directed diffusion processes on networks\, we disentangle the em
erging pattern of imports and exports and assign shares of the distributed
generation capacity in the European system to the countries which actuall
y make use of them. This procedures yields nodal levelized costs\, which i
ncorporate both internal and external generation as well as transmission c
osts associated with the electricity consumption in a country. Compared to
a scenario without transmission\, these nodal levelized costs are reduced
by about 15% and represent the benefit of cooperation.\n\nContact Person:
Dirk Witthaut
LOCATION:Seminar room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Bahram Mashhoon
DTSTART;VALUE=DATE-TIME:20171114T164500
DTEND;VALUE=DATE-TIME:20171114T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001169@events.thp.uni-koeln.de
DESCRIPTION:Bahram Mashhoon\, University of Missouri\n\nNonlocal gravity a
nd dark matter\n\nThe conceptual basis for a classical nonlocal generaliza
tion of\nEinstein's theory of gravitation is presented. The framework of g
eneral\nrelativity is enlarged by the introduction of a preferred frame fi
eld\; then\,\nhistory dependence is introduced. Nonlocality --- in the sen
se of an\ninfluence ("memory") from the past that endures --- could be a n
atural\nfeature of the universal gravitational interaction. Nonlocal gravi
ty is\nformally analogous to the nonlocal electrodynamics of media. The no
nlocal\naspect of gravity can simulate dark matter. The implications of no
nlocal\ngravity theory for the problem of dark matter in galaxies\, cluste
rs of\ngalaxies\, and cosmology are discussed. \n\nSpecial Colloquium hono
ring Friedrich Hehl's 80th birthday.\n\nContact Person: Claus Kiefer
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Felix Gunkel
DTSTART;VALUE=DATE-TIME:20171107T150000
DTEND;VALUE=DATE-TIME:20171107T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001171@events.thp.uni-koeln.de
DESCRIPTION:Felix Gunkel\, FZ Juelich\n\nThermodynamic processes and defec
t concentration profiles at engineered complex oxide interfaces and surfac
es \n\nThe properties of thin films and heterostructures of complex and st
rongly correlated oxides are one of the most fascinating and demanding top
ics in today´s solid state physics research. Oxide heterostructures give
rise to novel and unexpected physical phenomena such as metallicity in nom
inally non-metallic materials\, magnetism in nominally non-magnetic materi
als\, ferroelectricity in nominally non-ferroelectric materials\, or so fa
r unobserved topological effects. Many of these phenomena are affected or
even more driven by the nanoscale defect structure established during mate
rial synthesis and processing\, ultimately limited by the thermodynamics o
f the system. Tuning the thermodynamic processes by engineering dedicated
heterostructures may be used to tailor their defect structure in a desire
d way\, hence\, to deplete or accumulate defects at interfaces\, to spatia
lly separate electronic and ionic charge carriers\, or to confine defects
to dedicated regions.\nIn this talk\, I discuss the low-dimensional electr
on transport observed along complex oxide heterointerfaces\, such as the o
ne in LaAlO3/SrTiO3 heterostructures. While the formation of these 2-dimen
sional electron gases is attributed to electronic charge transfer triggere
d by a built-in electric field\, the ionic defect structure at these inter
faces is still being discussed controversially. I address the thermodynami
c processes associated with built-in electric fields and derive ionic defe
ct concentration profiles established at polar/non-polar oxide interfaces.
[1] The specific ionic-electronic defect structure stabilized within such
interfacial space charge layers strongly depends on ambient oxygen partia
l pressure applied during sample fabrication and on the strength of the bu
ilt-in electric field. \nAs will be discussed\, the low-temperature behavi
or of these novel electron system is unambiguously correlated to the adjac
ent ionic structure typically set at high temperature\, making thermodynam
ic considerations indispensable in order to understand novel phenomena occ
urring at cryostatic temperatures. Therefore\, a comprehensive study of lo
w temperature physics on the one hand and high temperature thermodynamics
on the other hand is essential for a unified understanding of the manifold
(and sometimes contradictory) phenomena observed in these low-dimensional
electron systems. Here\, we explicitly compare the thermodynamic ground s
tates obtained for various oxide heterostructure systems [2] and discuss r
esulting implications for important measures characterizing the electron g
as\, such as electron mobility [3] as well as its magnetic signature [4]\,
both controllable by thermodynamic means. The thermodynamic model obtaine
d for oxide heterointerfaces is furthermore linked to kinetic space charge
formation occurring at complex oxide surfaces [5\, 6]. \n[1] F. Gunkel et
al.\, “Defect concentration profiles at complex oxide interfaces”\, P
hysical Review B 93\, 245431 (2016) \n[2] F. Gunkel et al.\, “Thermodyna
mic ground states of complex oxide heterointerfaces”\, ACS Applied Mater
ials & interfaces\, ACS Appl. Mater. Interfaces\, 9 (1)\, 1086 (2017) \n[3
] C. Xu et al.\, “Disentanglement of growth dynamic and thermodynamic ef
fects in LaAlO3/SrTiO3 heterostructures”\, Scientific Reports 6\, 22410
(2016) \n[4] F. Gunkel\, et al.\, “Defect-control of anomalous and conve
ntional electron transport in NdGaO3/SrTiO3 heterostructures”\, Physical
Review X\, 6\, 031035 (2016) \n[5] R. Meyer et al.\, “Dynamics of the m
etal-insulator transition of donor-doped SrTiO3”\, Physical Review B 94\
, 115408 (2016)\n[6] M. Andrae et al.\, “Oxygen partial pressure depende
nce of surface space charge formation in donor-doped SrTiO3”\, APL Mater
ials 5\, 056106 (2017)\n\n\nContact Person: Paul van Loosdrecht
LOCATION:SR Kernphysik
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Tilman Disselkamp
DTSTART;VALUE=DATE-TIME:20171026T110000
DTEND;VALUE=DATE-TIME:20171026T120000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001172@events.thp.uni-koeln.de
DESCRIPTION:Tilman Disselkamp\n\nSpin textures in spin-orbit entangled Mot
t insulators\n\nMaster Colloquium
LOCATION:Seminar room of the Institute of Physics 2
END:VEVENT
BEGIN:VEVENT
SUMMARY:SPS | Tirthankar Banerjee
DTSTART;VALUE=DATE-TIME:20171121T120000
DTEND;VALUE=DATE-TIME:20171121T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001173@events.thp.uni-koeln.de
DESCRIPTION:Tirthankar Banerjee\, Saha Institute of Nuclear Physics\, Kolk
ata\n\nUniversality in directed single-file motion in closed heterogeneous
landscapes\n\nSingle-file motion in quasi one-dimensional geometry appear
s in wide-ranging systems\, ranging from ion transport in biological chann
els\, fluids absorbed in materials with nanopores\, colloidal particles mo
ving along circular grooves to pedestrian dynamics regulated along a line.
In this talk\, we focus on the steady state density profiles in directed
single-file motions of a collection of particles along closed\nheterogeneo
us landscapes. Modeling these as asymmetric exclusion processes with heter
ogeneous hopping rates along a closed ring\, we explore generic localised
(LDW) and delocalised (DDW) domain walls and delocalisation of LDWs in the
steady states. We further show how the interplay between heterogeneity an
d particle non-conserving Langmuir kinetics leads to a phase transition be
tween a two-phase coexistence and a three-phase coexistence state. We even
tually discuss the more generic\nproblem of heterogeneities with arbitrary
spatial variation and extract a notion of universality\, hitherto unknown
\, for the steady state density profiles and the associated phase diagrams
.\n\nContact Person: Joachim Krug
LOCATION:Seminar room TP 0.02
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Mathias Wickleder
DTSTART;VALUE=DATE-TIME:20180117T143000
DTEND;VALUE=DATE-TIME:20180117T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001174@events.thp.uni-koeln.de
DESCRIPTION:Mathias Wickleder\, Department of Chemistry\, University of Co
logne\n\nOxoanionic Compounds Syntheses\, Properties\, Perspectives\n\n\n\
nContact Person: M. Braden
LOCATION:Seminar room of the Institute of Physics 2
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Philip Hofmann
DTSTART;VALUE=DATE-TIME:20171221T110000
DTEND;VALUE=DATE-TIME:20171221T120000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001177@events.thp.uni-koeln.de
DESCRIPTION:Philip Hofmann\, University Aarhus\n\nELECTRONIC STRUCTURE AND
ELECTRON DYNAMICS IN TWO-DIMENSIONAL DIRAC MATERIALS\n\n\n\nContact Perso
n: Thomas Michely
LOCATION:SR II. Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Ipsita Mandal
DTSTART;VALUE=DATE-TIME:20171116T140000
DTEND;VALUE=DATE-TIME:20171116T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001178@events.thp.uni-koeln.de
DESCRIPTION:Ipsita Mandal\, MPI-PKS Dresden\n\nCritical Fermi Surface: UV/
IR mixing and Superconducting Instability\n\nWe discuss the perturbative c
ontrol of low-energy effective theory of strongly-interacting systems whic
h cannot be treated within the Landau Fermi liquid framework. These are ge
nerically called non-Fermi liquids where quasiparticles do not exist. In p
articular\, we focus on critical Fermi surface states where there is a wel
l-defined Fermi surface\, but no quasiparticle resulting from the strong i
nteraction between the\nFermi surface and a massless boson. We will show t
hat for Fermi surface having a dimension m>1\, the Fermi momentum k_F ente
rs the expressions for physical quantities as a dimensionful parameter lea
ding to UV/IR mixing\, thus modifying the naive scaling arguments\, wherea
s for a one-dimensional Fermi surface there is an emergent locality with n
o such k_F dependence.\n\nContact Person: Alex Altland
LOCATION:Seminarraum Altbau Theorie
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Dennis Wawrzik
DTSTART;VALUE=DATE-TIME:20171127T153000
DTEND;VALUE=DATE-TIME:20171127T163000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001179@events.thp.uni-koeln.de
DESCRIPTION:Dennis Wawrzik\n\nTopological semimetals and insulators in thr
ee-dimensional honeycomb materials (Masterkolloquium)\n\n
LOCATION:Seminarraum E0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Igor Boettcher
DTSTART;VALUE=DATE-TIME:20171220T143000
DTEND;VALUE=DATE-TIME:20171220T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001181@events.thp.uni-koeln.de
DESCRIPTION:Igor Boettcher\n\nComplex tensor order and quantum criticality
in spin-orbit coupled superconductors\n\nA revolutionary new direction in
the field of superconductivity emerged recently with the synthesis of sup
erconductors with strong inherent spin-orbit coupling of electrons\, such
as the half-Heusler compounds YPtBi or LuPdBi. Due to band inversion\, the
low-energy degrees of freedom are electrons at a three-dimensional quadra
tic band touching point with an effective spin 3/2\, which allows for Coop
er pairs with spins ranging from 0 to 3. I will illuminate some of the unc
onventional superconducting properties that arise from this band structure
and attractive short-range interaction: (i) At strong coupling\, the syst
em features an s-wave superconducting quantum critical point with non-Ferm
i liquid scaling of fermions and several other unusual scaling properties.
(ii) The system may further undergo a transition into a phase with comple
x tensor order\, which is a superconducting state captured by a complex-va
lued matrix order parameter describing Cooper pairs having spin 2. Here th
e interplay of both tensorial and complex nature results in a rich and int
riguing phenomenology. I will discuss the mean-field phase structure as a
function of doping and temperature\, and relate our finding to experiments
in YPtBi. Further\, the critical properties of this new paradigm for supe
rconductivity will be addressed. \n\nContact Person: Sebastian Diehl
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Fabian Holling
DTSTART;VALUE=DATE-TIME:20171222T140000
DTEND;VALUE=DATE-TIME:20171222T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001182@events.thp.uni-koeln.de
DESCRIPTION:Fabian Holling\n\nNon-equilibrium criticality of an Ising fiel
d theory with competing unitary and relaxational dynamics (Master colloqiu
m)\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Bernd Grosse Juettermann
DTSTART;VALUE=DATE-TIME:20171208T140000
DTEND;VALUE=DATE-TIME:20171208T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001183@events.thp.uni-koeln.de
DESCRIPTION:Bernd Grosse Juettermann\n\nMagnetic skyrmions in oscillating
magnetic fields\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPK | Pierre Le Doussal
DTSTART;VALUE=DATE-TIME:20180130T164500
DTEND;VALUE=DATE-TIME:20180130T174500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001184@events.thp.uni-koeln.de
DESCRIPTION:Pierre Le Doussal\, ENS Paris\n\nPinning\, growth and memory(i
es)\n\nStarting from examples of experimental systems which exhibit growth
and pinning I will give an introduction into the physics of elastic syste
ms with quenched disorder in non-equilibrium situations. We review develop
ments in the description of depinning and avalanches\, as well as in the s
tudy of the Kardar-Parisi-Zhang (KPZ) class of stochastic growth. We intro
duce some of the analytical methods which lead to predictions testable (an
d sometimes tested) in experiments. Our last example is the calculation of
memory effects in the KPZ class in expanding geometries which illustrates
the remarkable connections between growth and disordered systems.\n\n\nCo
ntact Person: Joachim Krug
LOCATION:HS III
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Adam Smith
DTSTART;VALUE=DATE-TIME:20171207T140000
DTEND;VALUE=DATE-TIME:20171207T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001185@events.thp.uni-koeln.de
DESCRIPTION:Adam Smith\, University of Cambridge\n\nDisorder-Free Localiza
tion\n\n\n\nContact Person: Achim Rosch
LOCATION:Seminarraum Alte Theorie
END:VEVENT
BEGIN:VEVENT
SUMMARY:SPS | Timothy Halpin-Healy
DTSTART;VALUE=DATE-TIME:20180118T170000
DTEND;VALUE=DATE-TIME:20180118T180000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001186@events.thp.uni-koeln.de
DESCRIPTION:Timothy Halpin-Healy\, Barnard College\, Columbia University\n
\nWithin & Beyond the Realm of KPZ\n\nWe discuss significant events in the
recent Renaissance triggered by the enigmatic and elusive\, but rich stoc
hastic nonlinear PDE of Kardar\, Parisi & Zhang\, a celebrated equation wh
ose reach far exceeds its grasp\, touching such diverse phenomena as non-e
quilibrium stochastic growth\, extremal paths through disordered landscape
s\, driven lattice gases & dissipative condensates\, as well as the statis
tics of\nrandom matrices & permutations.\n\n\nContact Person: Joachim Krug
LOCATION:Seminarraum Theoretische Physik (Altbau)
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Aris Alexandradinata
DTSTART;VALUE=DATE-TIME:20171222T150000
DTEND;VALUE=DATE-TIME:20171222T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001187@events.thp.uni-koeln.de
DESCRIPTION:Aris Alexandradinata\, Yale\n\nUnveiling the hidden topology i
n the Fermi-surface wavefunction of metals\n\nA metal is a solid with a Fe
rmi surface. It is known how to reconstruct the shape of the Fermi surface
– by immersing the metal in a magnetic field and measuring the period o
f field-induced oscillations of the magnetization/resistivity. I will show
how to extract information about the quantum-mechanical wavefunction of t
he Fermi surface – from measuring the phase offset of these same oscilla
tions. In some metals\, this information is robust against deformations of
the Hamiltonian (describing the metal)\, and may therefore be viewed as a
topological invariant.\n\n\nContact Person: Simon Trebst
LOCATION:Seminarraum E0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Leonardo Mazza
DTSTART;VALUE=DATE-TIME:20171221T160000
DTEND;VALUE=DATE-TIME:20171221T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001188@events.thp.uni-koeln.de
DESCRIPTION:Leonardo Mazza\, ENS Paris\n\nMajorana fermions in particle-co
nserving settings\n\nThe paradigmatic condensed-matter models where zero-e
nergy localized Majorana fermions have been studied so far have the distin
guishing feature of not conserving the number of fermions. Moreover\, the
accepted definition of "Majorana fermion" naturally belongs to this scenar
io. Is it possible to discuss Majorana fermions in "canonical" particle-co
nserving settings?\n\nIn this seminar I will present several exact and num
erical results on Majorana fermions in particle-conserving scenarios. I wi
ll start from the discussion of a model for bosons and fermions where\, in
a proper limit\, the physics of the celebrated Kitaev's chain appears. I
will continue by presenting exact results on Majorana fermions in ladder m
odels where the two legs of the system can only exchange pair of particles
. Finally\, I will comment on the possibility of making experiments with M
ajorana fermions in particle-conserving settings using cold atoms.\n\n\nCo
ntact Person: Simon Trebst
LOCATION:Seminarraum E0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Pieter Naaijkens
DTSTART;VALUE=DATE-TIME:20171218T140000
DTEND;VALUE=DATE-TIME:20171218T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001189@events.thp.uni-koeln.de
DESCRIPTION:Pieter Naaijkens\, RWTH Aachen\n\nThe mathematics of topologic
ally ordered phases\n\nOne of the most interesting properties of topologic
ally ordered models with\nlong ranged entanglement\, such as Kitaev's tori
c code\, is that they have\nanyonic excitations. The properties of these a
nyons can be recovered from\nfirst principles using techniques from mathem
atical physics\, making it\npossible to put conjectures about such systems
in a precise mathematical\nlanguage. After explaining the main ideas behi
nd this construction\, I will\ndiscuss recent results on the stability of
the excitation structure and on\napplications to quantum information theor
y.\n\nContact Person: Simon Trebst
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Christian Gogolin
DTSTART;VALUE=DATE-TIME:20171218T160000
DTEND;VALUE=DATE-TIME:20171218T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001190@events.thp.uni-koeln.de
DESCRIPTION:Christian Gogolin\, ICFO Barcelona\n\nPure state quantum stati
stical mechanics - an overview\n\nIn this talk I will given an overview of
pure state quantum statistical mechanics\, which is a new way of understa
nding issues at the foundation of statistical mechanics and thermodynamics
. In particular\, I will explain recent developments concerning equilibrat
ion and thermalization in closed quantum many-body systems. We will see ho
w equilibration and thermalization can be defined in unitarily evolving an
d finite dimensional quantum systems\, under which conditions they can be
proved to happen\, and what we know about the apparent equilibrium states.
I will further speak about general results on structural properties both
short- and long-range interacting many-body systems\, with a focus on the
decay of correlations in their thermal states. Finally\, I will provide a
glimpse of ongoing work concerning the use of machine learning tools form
many-body physics and point out opportunities for future work.\n\n\nContac
t Person: Simon Trebst
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | Paul Busch
DTSTART;VALUE=DATE-TIME:20180202T163000
DTEND;VALUE=DATE-TIME:20180202T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001191@events.thp.uni-koeln.de
DESCRIPTION:Paul Busch\, University of York\n\nMeasurement uncertainty rel
ations for qubits: theory and experiment\n\nIn standard formulations of th
e uncertainty principle\, two fundamental features are typically cast as i
mpossibility statements: two noncommuting observables cannot in general bo
th be sharply defined (for\nthe same state)\, nor can they be measured joi
ntly. The pioneers of quantum mechanics were acutely aware and puzzled by
this fact\, and it motivated Heisenberg to seek a mitigation\, which he fo
rmulated in his seminal paper of 1927. He provided intuitive arguments to
show that the values of\, say\, the position and momentum of a particle ca
n at least be unsharply defined\, and they can be measured together provid
ed some approximation errors are allowed. Only now\, nine decades later\,
a working theory of approximate joint measurements is taking shape\, leadi
ng to rigorous and experimentally testable formulations of associated erro
r tradeoff relations. Here we briefly review this new development\, explai
ning the concepts and steps taken in the construction of optimal joint app
roximations of pairs of incompatible observables. As a case study\, we ded
uce measurement uncertainty relations for qubit observables using two dist
inct error measures. We provide an operational\ninterpretation of the erro
r bounds and discuss some of the first experimental tests of such relation
s.\nThe talk is based on the review paper arXiv:1512.00104v3.\n\nContact P
erson: David Gross
LOCATION:SR 0.03 TP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Luca Perfetti
DTSTART;VALUE=DATE-TIME:20180328T143000
DTEND;VALUE=DATE-TIME:20180328T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001192@events.thp.uni-koeln.de
DESCRIPTION:Luca Perfetti\, Ecole Polytechnique\, Paris-Saclay\, France \n
\nTime resolved photoelectrons spectroscopy of novel materials for optoele
ctronic applications\n\nI will review our recent investigations of semicon
ducting materials at the focus of optoelectronic research. We measure the
surface of CH3NH3PbI3 single crystals by making use of two-photon photoemi
ssion spectroscopy. By these means\, we explicitly discriminate the initia
l thermalization of the electrons from slower dynamical processes. The pic
osecond localization of excited electrons in degraded CH3NH3PbI3 samples i
s consistent with the progressive reduction of photoconversion efficiency
in operating devices. In the second part of the seminar I will discuss the
dynamics of hot carriers in InSe. The electrons excited by photons of 3.1
eV experience a manifold relaxation. First\, they thermalize to the elect
ronic states degenerate with the M valley within 0.35 ps. Subsequently\, t
he electronic cooling is solely dictated by Froehlich coupling to phonon o
f small momentum transfer. Ab-initio calculations of the electron-phonon c
oupling are in excellent agreement with the observed dynamics.\n\nContact
Person: P. van Loosdrecht
LOCATION:Seminar room 201\, Institute of Physics 2
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Carolin Wille
DTSTART;VALUE=DATE-TIME:20180112T140000
DTEND;VALUE=DATE-TIME:20180112T150000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001193@events.thp.uni-koeln.de
DESCRIPTION:Carolin Wille\, FU Berlin\n\nA tensor network approach to topo
logical quantum phases\n\nTensor network states\, and in particular projec
ted entangled pair\nstates\, play an important role in the description of
strongly correlated\nquantum lattice systems. They do not only serve as va
riational states in\nnumerical simulation methods\, but also provide a fra
mework for\nclassifying phases of quantum matter and capture notions of to
pological\norder in a stringent and rigorous language. In this talk I will
present\nhow virtual symmetries in tensor networks\, summarized by the fr
amework\nof matrix product operator (MPO) injectivity\, are substantial to
the\nclassification of not only bosonic but also fermionic topological or
der\nin two dimensional systems. I will briefly discuss how this fact rela
tes\nto Levin-Wen string net models and Tuarev-Viro state sum construction
s.\nFor the sake of concreteness\, two examples of fermionic topological\n
order\, the fermionic toric code and the Majorana dimer model\, are\ndiscu
ssed using the language of fermionic tensor networks.\n\n\nContact Person:
Alex Altland
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Markus Mueller
DTSTART;VALUE=DATE-TIME:20180131T160000
DTEND;VALUE=DATE-TIME:20180131T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001194@events.thp.uni-koeln.de
DESCRIPTION:Markus Mueller\n\nCould the physical world be emergent instead
of fundamental\, and why should we ask?\n\nIn physics\, there is the prev
ailing intuition that we are part of a unique external world\, and that th
e goal of physics is to understand and describe this world. This assumptio
n of the fundamentality of objective reality is often seen as a major prer
equisite of any kind of scientific reasoning\, delineating science from ps
eudoscience\, and explaining why successful empirical science is possible
in the first place. However\, here I argue that we should consider relaxin
g this assumption in a specific way in some contexts. Namely\, there is a
collection of open questions in and around physics that can arguably be ad
dressed in a substantially more consistent and rigorous way if we consider
the possibility that the first-person perspective is ultimately more fund
amental than our usual notion of external world. These are questions like:
which probabilities should an observer assign to future experiences if sh
e is told that she will be simulated on a computer? How should we think of
cosmology’s Boltzmann brain problem or assign probabilities to properti
es of ‘possible worlds’? What can we learn from the fact that measurem
ents in quantum theory seem to do more than just reveal preexisting proper
ties? Why are there simple computable laws of physics in the first place?
In the talk\, I sketch a mathematically rigorous approach along these line
s\, suggesting a simple and unified framework (rooted in algorithmic infor
mation theory) to address questions like those above. It is not meant as a
‘theory of everything’ (in fact\, it predicts its own limitations)\,
but it shows how a notion of objective external world\, looking very much
like our own\, can provably emerge from a starting point in which (only) t
he first-person perspective is primary.\n\nBased on arXiv:1712.01826 (full
version) and arXiv:1712.01816 (short version).\n\n\n\nContact Person: D.
Gross
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:TPK | T. P. Singh
DTSTART;VALUE=DATE-TIME:20180427T163000
DTEND;VALUE=DATE-TIME:20180427T173000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001195@events.thp.uni-koeln.de
DESCRIPTION:T. P. Singh\, Tata Institute\, Mumbai\n\nIs quantum theory exa
ct\, or approximate?\n\nWhy does the wave-function of a quantum system col
lapse during a measurement? It maybe possible to answer this question\, as
in the many-worlds interpretation\, without modifying the theory. In this
case\, quantum theory is exact. On the other hand\, it maybe that the the
ory has to be modified\, as in\nthe phenomenological model of Spontaneous
Collapse. This model proposes that every quantum particle in nature underg
oes spontaneous collapse\, and that collapse is a fundamental property of
nature\, along with Schrödinger evolution. The predictions of this model
differ from those of quantum theory\, and we review the current experiment
al bounds on these models. We also review work which attempts to provide a
theoretical underpinning for this phenomenological model\, including the
possible role of gravity\, and a possible inter-connection between the mea
surement problem and the problem of time in quantum theory.\n\nContact Per
son: Claus Kiefer
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Enej Ilievski
DTSTART;VALUE=DATE-TIME:20180119T140000
DTEND;VALUE=DATE-TIME:20180119T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001196@events.thp.uni-koeln.de
DESCRIPTION:Enej Ilievski\, University of Amsterdam\n\nHydrodynamic equati
on for thermodynamic classical and quantum soliton gases\n\nExactly solvab
le nonlinear wave equations -- colloquially known as the soliton systems -
- are widely regarded as one of the greatest achievements of mathematical
physics. But somehow\, aside of several mathematical frameworks and other
formal aspects\, not a lot seems to be known about statistical properties
of classical integrable field theories and\, in particular\, classical tra
nsport properties at finite temperature. In this talk\, we present a kinet
ic equation to deal with dense soliton gases\, expressed in terms of a lin
ear integral dressing equation for the soliton spectral function which acc
ounts for renormalization of the soliton velocities due to the interaction
s with a soliton many-body state. This is accomplished in the framework of
the algebro-geometric integration technique which permits to classify all
quasi-periodic solutions of an integrable equation of motion in terms of
the moduli of finite-genus Riemann surfaces. By identifying soliton excita
tions\, applying Born-Sommerfeld quantization for soliton orbits\, extract
ing the two-body S-matrix\, and finally taking the thermodynamic finite-de
nsity\, the free energy functional is expressed as the saddle point of the
action-space path-integral. Our hydrodynamic equations can understood as
the thermodynamic analogue of the celebrated Whitham's modulation equation
s. The equations are universal\, and even apply to the quantum theories of
solitons. If time permits\, we show how to obtain a closed compact formul
a for the Drude weight in the quantum Heisenberg spin chain\, and discuss
peculiarities related to it.\n\nContact Person: Zala Lenarcic
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Denis Golez
DTSTART;VALUE=DATE-TIME:20180126T140000
DTEND;VALUE=DATE-TIME:20180126T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001197@events.thp.uni-koeln.de
DESCRIPTION:Denis Golez\, University of Fribourg \n\nRelaxation dynamics i
n Mott insulators: the role of collective modes\n\nStrong correlations bet
ween spin\, charge and orbital degrees of freedom play an important role i
n materials and a recent development of ultrafast spectroscopies enabled t
o disentangle these relevant degrees of freedom by their temporal evolutio
n.\nI will start with a summary of the charge carrier relaxation after the
photo-excitation in Mott insulators described within the dynamical mean f
ield theory (DMFT) and continue how this formalism can be extended to incl
uding the role of dynamical screening and non-local fluctuations (GW+EDFMT
)[1\,2]. Then I will open the question how to use the laser pulse to manip
ulate screening in Mott insulators. As an extreme example I will present a
self-trapping of the system in the negative temperature state by a proper
manipulation of the screening environment\, which leads to the enhanced s
ubgap response in the charge susceptibility. This population inversion lea
ds to the low-energy anti-screening and I will comment on its experimental
relevance. In the second part I will shed light on the role of spin fluct
uations in the relaxation dynamics\, which can be analysed by an extension
of DMFT[3]. I will exemplify how optical pump probe techniques can be use
d to detect some basic theoretical ideas in higher dimensional doped antif
erromagnets\, like string states\, Trugman paths and the lack of spin-char
ge separation. At the end I will provide an outlook how to extend these to
ols to an ab-initio description of strongly correlated materials out of eq
uilibrium.\n\n[1] D. Golez\, M. Eckstein\, and P. Werner. Phys. Rev. B\, 9
2:195123\, Nov (2015).\n[2] D. Golez\, L. Boehnke\, H. U. R. Strand\, M. E
ckstein\, and P. Werner. Phys. Rev. Lett. 118:246402 (2017).\n[3] N. Bittn
er\, D. Golez\, M. Eckstein\, P. Werner\, in preparation.\n\nContact Perso
n: Zala Lenarcic
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Jan Mueller
DTSTART;VALUE=DATE-TIME:20180226T140000
DTEND;VALUE=DATE-TIME:20180226T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001198@events.thp.uni-koeln.de
DESCRIPTION:Jan Mueller\n\nMagnetic Skyrmions and Topological Domain Walls
(PhD Defense)\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Eddy Ardonne
DTSTART;VALUE=DATE-TIME:20180228T100000
DTEND;VALUE=DATE-TIME:20180228T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001199@events.thp.uni-koeln.de
DESCRIPTION:Eddy Ardonne\, Stockholm University\n\nExact (ground) states a
nd zero-modes of interacting Spin and Clock models\n\nIn this blackboard t
alk\, I will first review the old results of Peschel en Emery\, who devise
d a\nset of interacting spin-1/2 models\, for which the degenerate ground
states can be\nwritten in terms of product states. This model has more int
eresting properties\, such\nas excited states that can be constructed expl
icitly\, and one can find exact\, local\noperators that swap the ground st
ates. These results can be generalized to three\nstate Clock models\, and
models with arbitrary spin. If time allows\, I will comment\non how to ada
pt the construction to arbitrary lattices.\n\nContact Person: Simon Trebst
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Jonas Wassmer
DTSTART;VALUE=DATE-TIME:20180119T153000
DTEND;VALUE=DATE-TIME:20180119T160000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001200@events.thp.uni-koeln.de
DESCRIPTION:Jonas Wassmer \n\nBachelor Kolloquium\n\n\n\nContact Person: S
imon Trebst
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Davide Bossini
DTSTART;VALUE=DATE-TIME:20180227T143000
DTEND;VALUE=DATE-TIME:20180227T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001201@events.thp.uni-koeln.de
DESCRIPTION:Davide Bossini\, TU Dortmund\n\nFemtosecond manipulation of ma
gnets via photoconducted magnons at the edge of the brillouin zone\n\n\n\n
Contact Person: Paul van Loosdrecht
LOCATION:SR II. Physik
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Bjoern Ladewig
DTSTART;VALUE=DATE-TIME:20180202T140000
DTEND;VALUE=DATE-TIME:20180202T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001202@events.thp.uni-koeln.de
DESCRIPTION:Bjoern Ladewig\n\nNon-equilibrium Phase Transitions in the pre
sence of fluctuation less States (Master colloquium)\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Semyon Klevtsov
DTSTART;VALUE=DATE-TIME:20180205T100000
DTEND;VALUE=DATE-TIME:20180205T104500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001203@events.thp.uni-koeln.de
DESCRIPTION:Semyon Klevtsov\, Mathematical Institute\, Cologne\n\nMathemat
ics of the Fractional Quantum Hall wave functions\n\nQuantum Hall effect i
s one of the most interesting examples quantum many-particles systems. It
occurs in certain two-dimensional electron systems at low temperatures and
in high magnetic fields\, which exhibit plateaux with the quantized value
s of the Hall conductance. The Fractional Quantum Hall effect (FQHE)\, whe
n the Hall conductance takes on fractional values\, is an example of the s
trongly-interacting quantum many-particles. The standard physics approach
to the FQHE is to assign a certain many-body wave function to each plateau
x. I will talk about a program as to how one can use a combination of prob
abilistic\, asymptotic and geometric methods to learn more about the physi
cs and mathematics of the FQHE wave functions\, in particular\, describe t
he electromagnetic and gravitational responses\, asymptotics for a large n
umber particles\, novel quantized coefficients for the adiabatic transport
.\n\nContact Person: Joachim Krug
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Jean-Sebastian Bernier
DTSTART;VALUE=DATE-TIME:20180205T110500
DTEND;VALUE=DATE-TIME:20180205T115000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001204@events.thp.uni-koeln.de
DESCRIPTION:Jean-Sebastian Bernier\, University of Bonn\n\nPropagation of
correlations in dissipative systems: ballistic\, diffusive and aging dynam
ics\n\nIn recent years\, considerable experimental efforts have been devot
ed to dynamically generate complex states and monitor their evolution. Des
pite remarkable advances\, the theoretical principles behind the non-equil
ibrium dynamics of strongly correlated quantum matter are still far from b
eing fully understood. In particular\, very few studies have sought to cla
rify the influence of environmental couplings on the propagation of correl
ations. We attempt here to fill this gap. Considering first an interaction
quench in the Bose-Hubbard model under the effect of dephasing\, we obser
ve that dissipation effectively speeds up the propagation of single-partic
le correlations while reducing their coherence. In contrast\, for two-poin
t density correlations\, the initial ballistic propagation regime gives wa
y to diffusion at intermediate times. In a second time\, considering the X
XZ spin-1/2 model in contact with a similar environment\, we find this sys
tem to display aging. A dynamical phenomenon characterized by a breakdown
of time-translation invariance\, a slow non-exponential relaxation of two-
time correlations and the presence of dynamical scaling.\n\nContact Person
: Joachim Krug
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Wojciech de Roeck
DTSTART;VALUE=DATE-TIME:20180205T143000
DTEND;VALUE=DATE-TIME:20180205T151500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001205@events.thp.uni-koeln.de
DESCRIPTION:Wojciech de Roeck\, KU Leuven\n\nDynamics and slowdown of quan
tum spin systems\n\nI will discuss several results (also in the mathematic
al sense) about the dynamics of quantum spin systems. The main theme will
be 'localization' which is a term that has been much in vogue in the last
years. Usually\, it is understood as 'absence of dissipative behaviour'. I
will explain what this means and how it comes about. The phenomenon that
is probably to be expected to apply more broadly than 'localization' is 's
parsity of resonances'\, sometimes also called 'asymptotic localization' o
r 'quasi-localization'. It manifests itself in quantum and classical syste
ms\, where transport and thermalization take place only due to effects tha
t are non-perturbative (smaller than any power) in the natural parameters
of the system.\n\nContact Person: Joachim Krug
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Sebastian Diehl
DTSTART;VALUE=DATE-TIME:20180205T162000
DTEND;VALUE=DATE-TIME:20180205T170500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001209@events.thp.uni-koeln.de
DESCRIPTION:Sebastian Diehl\, ITP\n\nFrom Micro- to Macrophysics in Driven
Open Quantum Systems\n\nRecent developments in diverse areas - ranging fr
om cold atomic gases over light driven semiconductors to microcavity array
s - move systems into the focus\, which are located on the interface of qu
antum optics\, many-body physics and statistical mechanics. These "driven
open quantum systems" share in common that coherent and driven-dissipative
dynamics occur on an equal footing\, creating genuine non-equilibrium sce
narios without immediate counterpart in equilibrium condensed matter physi
cs. A case in point are so-called exciton-polaritons in two spatial dimens
ions. We briefly explain the physical basis\, their description\, and how
to detect the violation of thermal equilibrium conditions in the formalism
. We then show that a paradigmatic hallmark of low-temperature equilibrium
systems -- the presence of quasi-long range order\, i.e. the algebraic de
cay of spatial correlation functions -- must be absent due to non-equilibr
ium conditions. This conclusion is drawn based on a connection to the prob
lem of surface roughening.\n\nContact Person: Joachim Krug
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Gunter Schütz
DTSTART;VALUE=DATE-TIME:20180205T152000
DTEND;VALUE=DATE-TIME:20180205T160500
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001208@events.thp.uni-koeln.de
DESCRIPTION:Gunter Schütz\, FZ Jülich\n\nExact density matrix for the di
ssipative Heisenberg quantum spin chain\n\nWe demonstrate that the exact n
onequilibrium steady state of the one-dimensional Heisenberg XXZ spin chai
n driven by boundary Lindblad operators can be constructed explicitly with
a matrix product ansatz for the nonequilibrium density matrix. For spin 1
/2 the matrices satisfy the quantum algebra U_q[sl(2)]. For the isotropic
Heisenberg chain\, coupled at the ends to boundary reservoirs polarized in
different directions with twist angle theta\, we calculate the exact magn
etization profiles and magnetization currents in the nonequilibrium steady
state of a chain N sites. For large N the in-plane steady-state magnetiza
tion profiles are harmonic functions with a frequency proportional to the
twist angle. In-plane steady-state magnetization currents are subdiffusive
\, while the transverse current saturates when the coupling strength is su
fficiently large. For the anisotropic chain we find a current resonance at
the specific values of the anisotropic interaction strength where the tra
nsverse current is independent of system size\, even for non-integrable hi
gher-spin chains.\n\nContact Person: Joachim Krug
LOCATION:TP seminar room 0.03
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | John Gracey
DTSTART;VALUE=DATE-TIME:20180319T160000
DTEND;VALUE=DATE-TIME:20180319T170000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001210@events.thp.uni-koeln.de
DESCRIPTION:John Gracey\, University of Liverpool\n\n Perturbative and la
rge N computations for critical behaviour of Gross-Neveu models of graphen
e\n\nCertain phase transitions in a graphene sheet are known to be\ndescri
bed at criticality by an underlying continuum quantum field theory which\n
is the Gross-Neveu model. While the Ising Gross-Neveu model has been widel
y\nstudied for many years\, perturbative and large N computations in the r
elated\nchiral Heisenberg Gross-Neveu model have not been carried out to t
he same level\nof precision. In the talk we will review recent four loop r
enormalization of\nthe Ising Gross-Neveu model before developing the large
N expansion for the\nchiral Heisenberg Gross-Neveu case. In the latter ca
se the first three terms of\nvarious critical exponents are determined inc
luding eta at O(1/N^3). To achieve\nthis accuracy the large N conformal bo
otstrap method is used. Finally estimates\nof exponents are given for the
values of N relevant to the graphene transitions\nand compared to Monte Ca
rlo and functional renormalization group results as\nwell as the epsilon e
xpansion of four dimensional perturbation theory.\n\n\nContact Person: Mic
hael Scherer
LOCATION:Seminar room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMTgroup | Zhong-Chao Wei
DTSTART;VALUE=DATE-TIME:20180207T100000
DTEND;VALUE=DATE-TIME:20180207T113000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001211@events.thp.uni-koeln.de
DESCRIPTION:Zhong-Chao Wei\n\nSign Problem in Quantum Monte Carlo\n\n
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Rossitza Pentcheva
DTSTART;VALUE=DATE-TIME:20180516T143000
DTEND;VALUE=DATE-TIME:20180516T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001212@events.thp.uni-koeln.de
DESCRIPTION:Rossitza Pentcheva\, Uni Duisburg\n\nDesigning electronic phas
es at oxide interfaces for electronic\, spintronic and energy applications
\n\n\n\nContact Person: Ionela Lindfors-Vrejoiu
LOCATION:Seminar Room of the Institute Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Arun Paramekanti
DTSTART;VALUE=DATE-TIME:20180718T143000
DTEND;VALUE=DATE-TIME:20180718T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001213@events.thp.uni-koeln.de
DESCRIPTION:Arun Paramekanti\, University of Toronto\n\nOxide heterostruct
ures: Impact of spin-orbit coupling and strain.\n\nRecent progress in maki
ng oxide interfaces and heterostructures has led to an interest in underst
anding how one might realize topological phases or flat bands in such corr
elated systems. In particular\, this might be accomplished by spin-orbit c
oupling or strain effects. In this context\, I will discuss our theory wor
k on understanding the "atomic limit" of spin-orbit coupled oxides\, showi
ng that one can use resonant inelastic X-ray spectroscopy of such systems
to extract microscopic couplings. Using such "lego" building blocks\, I wi
ll discuss mixed oxide 2DEGs comprised of local moments coupled to a "cond
uction fluid" of electrons with strong spin-orbit coupling\, to show that
one can realize high temperature quantum anomalous Hall insulators. I will
also discuss a different setting in which strain in Dirac materials acts
as a pseudo-gauge field. This provides a way to realize Landau-like levels
of Bogoliubov quasiparticles in high Tc d-wave superconducting oxides. Sp
in-orbit coupling and strain can thus pave the way to realizing novel topo
logical quantum phases in solids.\n\nContact Person: Simon Trebst
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Eun-Ah Kim
DTSTART;VALUE=DATE-TIME:20180620T143000
DTEND;VALUE=DATE-TIME:20180620T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001214@events.thp.uni-koeln.de
DESCRIPTION:Eun-Ah Kim\, Cornell\n\nMachine Learning Data from Electronic
Quantum Matter\n\nIn recent years\, enormous data sets have begun to appea
r in real-space visualizations (scanning probes) and reciprocal-space vis
ualizations (scattering probes) of electronic quantum matter. Increasing v
olume and variety of such data present new challenges and opportunities th
at are ripe for a new approach: machine learning. However\, the scientific
questions in the field of electronic quantum matter require fundamentally
new approaches to data science for two reasons: (1) quantum mechanical im
aging of electronic behavior is probabilistic\, (2) inference from data sh
ould be subject to fundamental laws governing microscopic interactions. In
this talk\, I will review the aspects of machine learning that are appeal
ing for dealing with quantum complexity and present how we implemented a m
achine learning approach to analysis of scanning tunneling spectroscopy da
ta.\n\nContact Person: Simon Trebst
LOCATION:Seminar Room of the Institute of Physics II
END:VEVENT
BEGIN:VEVENT
SUMMARY:OTHER | Maike Schön
DTSTART;VALUE=DATE-TIME:20180219T120000
DTEND;VALUE=DATE-TIME:20180219T130000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001215@events.thp.uni-koeln.de
DESCRIPTION:Maike Schön\n\nPhysical properties of entangled Majorana ferm
ion states on textured surfaces of topological insulators\n\n\n\nContact P
erson: Dmitry Bagrets
LOCATION:Seminarraum Theoretische Physik (Altbau)
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Elio Koenig
DTSTART;VALUE=DATE-TIME:20180518T140000
DTEND;VALUE=DATE-TIME:20180518T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001216@events.thp.uni-koeln.de
DESCRIPTION:Elio Koenig\n\nQuantum field theory of nematic transitions in
spin orbit coupled spin-1 polar bosons\n\nWe theoretically study an ultra-
cold gas of spin-1 polar bosons in one spatial dimension which are subject
to a quadratic Zeeman field and a Raman induced spin-orbit coupling. Conc
entrating on the regime in which the background fields can be treated pert
urbatively we analytically solve the model in its low-energy sector\, i.e.
we characterize the relevant phases and the quantum phase transitions bet
ween them. Depending on the sign of the effective quadratic Zeeman field e
psilon\, two superfluid phases with distinct nematic order appear. In addi
tion\, we uncover a spin-disordered superfluid phase at strong coupling. W
e employ a combination of renormalization group calculations and duality t
ransformations to access the nature of the phase transitions. At epsilon=0
\, a line of spin-charge separated pairs of Luttinger liquids divides the
two nematic phases and the transition to the spin disordered state at stro
ng coupling is of the Berezinskii-Kosterlitz-Thouless type. In contrast\,
at epsilon not equal to 0\, the quantum critical theory separating nematic
and strong coupling spin disordered phases contains a Luttinger liquid in
the charge sector that is coupled to a Majorana fermion in the spin secto
r (i.e. the critical theory at finite epsilon maps to a quantum critical I
sing model that is coupled to the charge Luttinger liquid). Due to an emer
gent Lorentz symmetry\, both have the same\, logarithmically diverging vel
ocity. We discuss the experimental signatures of our findings that are rel
evant to ongoing experiments in ultra-cold atomic gases of 23Na. \n\nCont
act Person: Achim Rosch
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:QM2 | Jairo Sinova
DTSTART;VALUE=DATE-TIME:20180226T110000
DTEND;VALUE=DATE-TIME:20180226T123000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001218@events.thp.uni-koeln.de
DESCRIPTION:Jairo Sinova\, Mainz University\n\nTopological Antiferromagnet
ic Spin-orbitronics: A Dormant Giant Awakens\n\nAntiferromagnets and ferro
magnets represent two fundamental forms of magnetism with antiferromagnets
being the more abundant of the two. However\, it has been notoriously dif
ficult to manipulate and detect antiferromagnetic order by any practical m
eans due to the compensated magnetic moment. This has left antiferromagnet
s over their hundred-year history poorly explored\, in striking contrast t
o the thousands of years of fascination and utility of ferromagnets. This
has changed with the proposal and subsequent discovery of a new relativist
ic spin-torque phenomenon\, the Neél spin-orbit torque\, that allow us to
efficiently control antiferromagnetic moments in spintronic devices. This
allows for antiferromagnets to become active elements in devices. An addi
tional concept that has emerged is that antiferromagnets provide a unifyin
g platform for realizing synergies among three prominent fields of contemp
orary condensed matter physics: Dirac quasiparticles and topological phase
s. These recent developments have unlocked a multitude of known and newly
identified unique features of this "dormant-giant" class of materials that
the community is beginning to explore.\n\nContact Person: Achim Rosch
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMT | Alexander Seidel
DTSTART;VALUE=DATE-TIME:20180608T140000
DTEND;VALUE=DATE-TIME:20180608T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001219@events.thp.uni-koeln.de
DESCRIPTION:Alexander Seidel\, Washington University in Saint Louis\n\nEnt
angled Pauli Principles: The DNA of fractional quantum Hall fluids\n\nA ma
jor challenge in the study of strongly correlated electron systems is to e
stablish a firm link between microscopic models and effective field theory
. Quite often\, this step involves a leap of faith\, and/or extensive nume
rical studies. For fractional quantum Hall model wave functions\, there ex
ists - in some cases - a scheme to infer the long distance physics of the
state that is both compelling and simple\, and leaves very little room for
ambiguity. This scheme involves a local parent Hamiltonian for the state\
, which unambiguously defines a "zero mode space" of elementary excitation
s\, and what’s known as a "generalized Pauli principle"\, which efficie
ntly organizes the zero mode space through one-dimensional patterns satisf
ying local rules.\nWhere this works\, universal properties of the state un
ambiguously emerge from counting exercises in terms of these patterns\, wh
ich efficiently encode degeneracies\, quasi-particle types and charges\, a
nd which completely determine an edge conformal field theory. There is eve
n a natural scheme to infer braiding statistics directly\, for both Abelia
n and non-Abelian states. Unfortunately\, such a framework thus far exist
s for some quantum Hall states but not for others. In this talk\, I will r
eview the state of the art of this formalism\, give reasons of why its "pl
ain vanilla form" is insufficient to describe some important fractional qu
antum Hall states (e.g.\, Jain states)\, \nand explain how to address this
deficiency through a new\, more general concept\, called "entangled Pauli
principles". It will turn out that for some interesting quantum Hall sta
tes\, the efficient description advertised here involves simple matrix-pro
duct-type entanglement. \n\n[1] arXiv:1803.00975\n\nContact Person: Achim
Rosch
LOCATION:Seminar Room 0.03\, ETP
END:VEVENT
BEGIN:VEVENT
SUMMARY:SFB1238 | Jens Brede
DTSTART;VALUE=DATE-TIME:20180321T143000
DTEND;VALUE=DATE-TIME:20180321T153000
DTSTAMP;VALUE=DATE-TIME:20210117T025721Z
UID:0000001220@events.thp.uni-koeln.de
DESCRIPTION:Jens Brede \, Centro de Física de Materiales\, UPV (Spain)\n\
nOn-surface synthesis and magnetic characterization of graphene nanoribbon
s on top of a two-dimensional magnetic surface alloy\n\nThe high reactivit
y of magnetic substrates toward molecular overlayers has so far inhibited
the realization of more sophisticated on-surface reactions\, thereby depri
ving these interfaces of a significant class of chemically tailored organi
cs such as graphene nanoribbons (GNRs)\, oligonuclear spin-chains\, and me
tal−organic networks. \nIn the first part of this talk\, I will present
a multi-technique characterization of the polymerization of 4\,4″-dibrom
o-p-terphenyl precursors into ordered poly(p-phenylene)[1] arrays on top o
f an emerging class of two-dimensional magnetic surface alloys[2\,3]. The
chemical reaction was followed by temperature-dependent X-ray photoelectro
n spectroscopy (XPS) and the structural characterizations of supramolecula
r and polymeric phases were performed by low-energy electron diffraction (
LEED) and scanning tunneling microscopy (STM). Taking advantage of the hig
h homogeneity of the samples\, the electronic structure of the valence ban
d was determined with angle-resolved photoemission spectroscopy (ARPES). M
oreover\, ferromagnetic ordering in the two-dimensional GdAu2 alloy was de
monstrated for all phases by X-ray absorption spectroscopy (XAS)[4]. \nIn
the second part\, I will briefly show that GdAu2 is not only a suitable t
emplate for the surface-confined Ullmann-like coupling reaction but is als
o thermally sufficiently stable to sustain a cyclodehydrogenation reaction
for the on-surface synthesis of more complex GNRs. Thus\, the system is d
emonstrated to close a longstanding experimental gap in the study of GNRs
as it enables spin-polarized STM characterizations[5] of e.g. the spin-po
larization of the elusive GNR edge-states\, which were theoretically predi
cted for chiral GNRs[6] and experimentally\, albeit lacking spin-sensitivi
ty\, observed on Au(111)[7]. However\, successive theoretical studies ques
tioned [8] and refined [9]\, respectively\, the experimental prerequisites
under which magnetic ordering of edge-states in GNRs may be observed\, th
ereby highlighting the need for direct experimental access of the spin-pol
arization of these states.\nReferences:\n[1] Vasseur\, G.\; Abadía\, M.\;
Miccio\, L. A.\; Brede\, J.\; Garcia-Lekue\, A.\; de Oteyza\, D. G.\; Rog
ero\, C.\; Lobo-Checa\, J. & Ortega\, J. E. Pi Band Dispersion along Conj
ugated Organic Nanowires Synthesized on a Metal Oxide Semiconductor J. Am.
Chem. Soc. 138\, 5685-5692 (2016)\n[2] Corso\, M.\; Fernández\, L.\; Sch
iller\, F. & Ortega\, J. E. Au(111)-Based Nanotemplates by Gd Alloying ACS
Nano 4\, 1603-1611 (2004)\n[3] Ormaza\, M.\; Fernández\, L.\; Lafuente\,
S.\; Corso\, M.\; Schiller\, F.\; Xu\, B.\; Diakhate\, M.\; Verstraete\,
M. J. & Ortega\, J. E. LaAu2 and CeAu2 surface intermetallic compounds gro
wn by high-temperature deposition on Au(111) Phys. Rev. B 88\, 125405 (201
3)\n[4] Abadía\, M.\; Ilyn\, M.\; Piquero-Zulaica\, I.\; Gargiani\, P.\;
Rogero\, C.\; Ortega\, J. E. & Brede\, J. Polymerization of Well-Aligned O
rganic Nanowires on a Ferromagnetic Rare-Earth Surface Alloy\, ACS Nano 11
\, 12392-12401 (2017)\n[5] Brede\, J. & Wiesendanger\, R. Spin-resolved im
aging and spectroscopy of individual molecules with sub-molecular spatial
resolution MRS Bulletin 39\, 608-613 (2014)\n[6] Yazyev\, O. V.\; Capaz\,
R. B. & Louie\, S. G. Theory of magnetic edge states in chiral graphene na
noribbons Phys. Rev. B 84\, 115406 (2011)\n[7] Tao\, C.\; Jiao\, L.\; Yazy
ev\, O. V.\; Chen\, Y.-C.\; Feng\, J.\; Zhang\, X.\; Capaz\, R. B.\; Tour\
, J. M.\; Zettl\, A.\; Louie\, S. G.\; Dai\, H. & Crommie\, M. F. Spatiall
y resolving edge states of chiral graphene nanoribbons\, Nature Physics 7\
, 616-620 (2011)\n[8] Kunstmann\, J.\; Özdoğan\, C.\; Quandt\, A. & Fehs
ke\, H. Stability of edge st