Erez Berg

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Traditionally, condensed matter physicists have classified phases of
matter according to their symmetries. Over the last few decades, it
became clear that near zero temperature, there are plenty of phases
which lie beyond this classification scheme. These intrinsically
quantum mechanical states of matter lack any ordinary order parameter;
they can be thought of as a strongly fluctuating quantum liquids.
Nevertheless, they posses a hidden underlying order, known as
"topological order". The quantum Hall effect is a celebrated example
of such a phase; several others have been discovered recently, and
many more have been predicted theoretically. The elementary
excitations of topologically ordered states can be thought of as
emergent particles; intriguingly, these particles can obey unusual
exchange statistics rules which resemble neither those of bosons nor
of fermions. This property makes topological phases potentially useful
as building blocks for future decoherence-free quantum processing
devices. In this talk, I will describe some modern insights into the
nature of these phases, and their characterization in term of their
quantum entanglement. I will also discuss a new route to realize novel
phases that arise on the boundaries of other, previously known
topologically ordered states.

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Weizmann Institute
Seminar Room of the Institute of Physics II (R201)
Contact: Simon Trebst