Quasiclassical approach to quantum quench dynamics in the presence of an excited-state quantum phase transition

TL;DR

This paper uses quasiclassical methods to analyze how excited-state quantum phase transitions influence the dynamics of quantum systems after a sudden quench, linking quantum features to classical phase space evolution.

Contribution

It introduces a quasiclassical approach to understand quantum quench dynamics in the presence of excited-state quantum phase transitions, connecting quantum phenomena to classical phase space behavior.

Findings

Features of equilibration linked to excited-state quantum phase transitions are explained via classical Wigner function evolution.

Quasiclassical techniques effectively reproduce quantum quench dynamics in systems with excited-state quantum phase transitions.

Classical phase space analysis provides insights into quantum relaxation processes post-quench.

Abstract

The dynamics of a quantum system following a sudden, highly non-adiabatic change of its control parameter (quantum quench) is studied with quasiclassical techniques. Recent works have shown, using exact quantum mechanical approach, that equilibration after quantum quench exhibits specific features in the presence of excited-state quantum phase transitions. In this paper, we demonstrate that these features can be understood from the classical evolution of the Wigner function in phase space.