Topologically driven nonequilibrium phase transitions in diagonal ensembles
Abstract
We identify a new class of topologically driven phase transitions when calculating the Hall conductance of two-band Chern insulators in the long-time limit after a global quench of the Hamiltonian. The Hall conductance is expressed as the integral of the Berry curvature in the diagonal ensemble. Even if the topological invariant of the wave function is conserved under unitary evolution, the Hall conductance as a function of the energy gap in the post-quench Hamiltonian displays a continuous but nonanalytic behavior, that is it has a logarithmically divergent derivative as the gap closes. The coefficient of this logarithmic function is the ratio of the change of Chern number in the ground state of the post-quench Hamiltonian to the energy gap in the initial state. This nonanalytic behavior is universal in two-band Chern insulators.
Cite
@article{arxiv.1504.05689,
title = {Topologically driven nonequilibrium phase transitions in diagonal ensembles},
author = {Pei Wang and Stefan Kehrein},
journal= {arXiv preprint arXiv:1504.05689},
year = {2016}
}
Comments
11 pages, 2 figures, including supplementary materials. In the new version, we generalize our results to a general two-band Chern insulator and provide a strict proof of it