“Disordered Floquet topological insulators”

Dr. Kun Woo Kim
Korea Institute for Advanced Study

May. 11 (Fri.), 02:30 PM
E6-2. 1st fl. #1323

Abstract:
The development of topological field theory in condensed matter physics has a long history since its successful but not yet fully resolved applications in 2-dim quantum Hall systems. As opposed to static systems where our concern is limited to the energy close to the Fermi level, in Floquet systems all eigenmodes in quasi-energy domain must be considered as neither temperature nor Fermi energy is well defined. This requires different approaches to construct the effective field theory of Floquet systems in long distance limit. Making use of the color flavor transformation, we were able to obtain the effective field theory of 2-dim quantum kicked rotors and its topological actions almost identical to the Pruisken’s term in conventional quantum Hall systems. We identify the physical origin of the appearance of topological terms, and the conceptual unification of topological quantum kicked rotors and the anomalous Floquet Anderson insulators are successfully made. The study of 4-dim systems that could show additional structures of topological actions is still ongoing. I will also discuss experimental proposals in cold atom lattices to probe topological characters uniquely present in Floquet systems.