| January 21, 12:00
Bose-Fermi mixtures in a 1D disordered potential
One-dimensional systems allow for a detailed study of the competing e ects of disor-
der and interactions on the localization of a Fermi or Bose gas.[1] While non-interacting
fermions are always localized in a random potential, a transition to a superconducting
phase occurs for strong enough attractive interactions. Similarly, strong repulsive in-
teractions will trigger the localization of a Bose gas.[1,2] During this talk, I will present
the study of an interacting mixture of bosons and spinless fermions in a random po-
tential. Super
uid correlations are enhanced by interspecies interactions, while the
disordered potential tries to pin each component of the gas. Using renormalization
group methods, supplemented by a variational calculation, we have found several lo-
calized or super
uid phases, including a new insulating phase, similar to the Bose glass,
in which both species are coupled and localized.[3] We also computed the dynamical
structure factor for typical parameters of various ultra-cold atoms experiments. Each
phase exhibits its own signature, that could be probed in Bragg scattering experiments.
[1] T. Giamarchi and H. J. Schulz, Phys. Rev. B 37, 325 (1988)
[2] M. P. A. Fisher et al., Phys. Rev. B 40, 546 (1989)
[3] F. Crépin, G. Zaránd, P. Simon, Phys. Rev. Lett. 105, 115301 (2010)
Laboratoire de Physique des Solides, Université Paris Sud
Seminar room of the Institute of Theoretical Physics
Contact: not specified