Condensed Matter Physics Seminar

In this talk I will discuss the connection between anomalies and topological responses in topological insulators. The primary focus will be on new anomalies connected to geometric deformations of topological phases. I will review the common appearance of torsion in solids as well as some new developments. Torsion typically appears in condensed matter physics associated with topological defects known as dislocations. Now we are beginning to uncover new asects of the coupling of torsion to materials. Recently, a dissipationless viscosity has been studied in the quantum Hall effect and Chern insulators. I will connect the viscosity in Chern insulators to a 2+1-d torsion Chern-Simons term and discuss the resulting bulk-boundary correspondence. If time permits, I will discuss the appearance of a full 2+1-d chiral gravity response exhibited by topological insulators.