Quantum quenches as classical critical films

TL;DR

This paper maps quantum quench dynamics onto classical film geometries to analyze non-equilibrium phase transitions and oscillations of the order parameter in quantum systems.

Contribution

It introduces a mean-field framework connecting quantum quenches to classical critical films, revealing a shifted critical point and oscillatory behavior.

Findings

Identification of a non-equilibrium transition as a shifted critical point in film geometry

Prediction of anharmonic oscillations as a universal feature of mean-field quench dynamics

Extension of the transition phenomenon to higher spatial dimensions

Abstract

We study the unitary time evolution of the order parameter of a quantum system after a sudden quench in the parameter driving the transition. By mapping the dynamics onto the imaginary time path-integral in a film geometry we derive the full mean-field non-equilibrium phase diagram for a one-component order parameter. The recently discovered non-equilibrium transition is identified with the shifted critical point in films and therefore it is generally expected to occur in more than one spatial dimension. We also find that anharmonic oscillations of the order parameter are a general feature of the mean-field quench dynamics.