Topological bands in periodically-driven systems

by Prof. Mark Rudner (Niels Bohr International Academy)

Tuesday 25 Mar 2014, 11:00 → 12:00 Europe/Stockholm

Nordita West (122:026)

Recent work on topological materials has revealed a wide variety of intriguing phenomena that may arise when particles move in so-called "non-trivial" bands. Recent advances in experimental capabilities for controlling electronic, atomic, and optical systems raise the possibility that analogous phenomena may be generated dynamically in driven systems. In this talk I will review the basic ideas behind topological band theory, and then discuss the corresponding situation for non-interacting periodically driven systems. While analogues of the complete periodic table of topological classes for non-interacting systems can be realized in driven systems, the topological classification in the driven case actually turns out to be much richer. In particular, a two dimensional driven system in which all "Floquet bands" have Chern number zero may still host robust chiral edge modes. I will explain how this occurs, and what it means, and give some outlook on recent and proposed exper iments on these so-called "Floquet topological insulators."