When: December 6th at 11am Where: ATL 4402 Speaker: Dr. Maissam Barkeshli (UMD) Title: Discrete shift and quantized charge polarization: New topological invariants and quantized response of crystalline topological states Abstract: I will describe our recent advances in understanding how to define and calculate invariants for topological phases of matter with crystalline symmetry. These invariants define a quantized contribution to fractional charge bound to lattice disclinations and dislocations. They also, as a dual response, determine the angular and linear momentum of magnetic flux in the ground state. I will show how our invariants give, for the first time since TKNN's seminal work in 1982 on quantized Hall conductance, a new class of topological invariants that can be defined throughout Hofstadter's famous butterfly.