Effective action of topological insulators

Kuang-Ting Chen, MIT.

Abstract: In the last few years, people have discovered there are different topological invariants characterizing insulators under various symmetries and dimensions. The measurable effect, however, are mostly deduced from the protected edge states, sometimes with the symmetries broken locally around the edge. In this talk I would like to discuss a systematic approach of deriving bulk effective actions and clarify the relationship between the topological indices and the response functions.