ABSTRACT:
The effective action encoding elastic transport properties of topological insulators involves effective (non-dynamical) 'gravitational' variables. In the case of 2+1-dimensional time-reversal breaking topological insulators, the leading term in the action is a 'Chern-Simons' action involving the torsion of the connection. The coefficient of this term is the dissipationless Hall viscosity, a direct analogue of the Hall conductivity. In this talk, we review the calculation of the Hall viscosity in a simple model, and discuss its interesting renormalization properties. |