报告题目： Nonequilibrium phase transitions in a two-dimensional topological insulator
报告摘要： In this talk, we introduce some results about the topological order in general two-dimensional topological insulators after a quench of Hamiltonian. We show that the time-dependent Chern number is a constant and then cannot be used to distinguish different quenched states. Instead, the winding number of Green’s function depends on the post-quench Hamiltonian and severs as the topological order parameter of quenched states. Whenever the winding number jumps, the measurable quantity (the Hall conductance) displays universal nonanalytic behavior. This behavior addresses a steady-state phase transition. Furthermore, we discuss the dynamical quantum phase transition in such a system, including both the causal one and the topologically-protected one, and show its connection with the steady-state phase transition.