Physics (Internal)

Revivals of a closed quantum system and Lieb-Robinson speed

This event is part of the Condensed Matter Theory Seminar Series.

Abstract:
We study the structure of the revivals in a closed quantum many body system away from equilibrium, after a quantum quench. If the Hamiltonian is local, there exists an effective light cone given by the maximum speed of signals $v_{LR}$ in the system. We study the nonequilibrium dynamics by means of the Loschmidt echo (LE), magnetization and entanglement. We find that the revival times are given by the size of the system divided by the Lieb-Robinson speed. As a concrete example, we study the XY spin chain in a transverse field.