Abstract
We study constraints imposed by the Galilean invariance on linear electromagnetic and elastic responses of two-dimensional gapped systems in a background magnetic field. Exact relations between response functions following from the Ward identities are derived. In addition to the viscosity-conductivity relations known in the literature, we find new relations between the density-curvature response and the thermal Hall response.
- Received 15 July 2014
DOI:https://doi.org/10.1103/PhysRevLett.113.266802
© 2014 American Physical Society