Physics Colloquium: Lukasz Fidkowski, How Dynamical Quantum Systems Forget

The City College of the City University of New York
160 Convent Avenue
New York, NY 10031

Physics Department
Marshak Science Building, Room 419
Phone: 212-650-6832
fax: 212-650-6940
email: physdept@ccny.cuny.edu
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Wednesday, September 30, 2020 from 04:00 PM to 05:00 PM

Where                         Contact Prof. Ganeshan for details.

Contact Name                         Sriram Ganeshan

Contact Email                         sganeshan@ccny.cuny.edu

 

Physics Colloquium

 

The interplay of symmetry and topology in quantum condensed matter 

 

Lukasz Fidkowski

Associate Professor

Department of Physics

University of Washington

Seattle, WA

 

Abstract: Many quantum phases of matter can be understood on the basis of symmetry.  For example, the universal properties magnets, crystals, and even superfluids are a consequence of their spontaneous breaking of rotational, translational, and charge conservation symmetries, respectively.  The fractional quantum Hall effect, discovered in 1982, is the first striking example of a phase that transcends this symmetry breaking framework, and instead exhibits a non-local `topological’ order, which does not rely on symmetry at all, but instead is characterized by emergent fractionalized excitations and chiral edge modes.  More recently, with the discovery of topological insulators, it has been realized that in general, the interplay between symmetry and topology is more subtle, and a much richer phenomenology than previously thought can result.  In this talk, I will discuss these new phases and the mathematical frameworks used to describe them.

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My research focus is on identifying and classifying exotic phases of matter. In particular, our group focuses on phases which cannot be understood in terms of traditional symmetry breaking Ginzburg-Landau theory, such as fractional quantum Hall phases and topological insulators (TIs). Recently we have been classifying strongly interacting versions of TIs, termed ‘symmetry protected topological’ phases, using tools such as topological quantum field theory and exactly solved models. We are also interested in other settings for realizing topological order, such as at non-zero energy density or in driven (Floquet) systems, aided by many-body localization.