Universal post-quench prethermalization at a quantum critical point

TL;DR

This paper studies the universal scaling behavior of open quantum systems near a critical point after a sudden quench, revealing a new critical exponent governing prethermalization dynamics.

Contribution

It introduces a novel critical exponent that describes universal prethermalization dynamics in open quantum systems near a quantum critical point.

Findings

Identification of a new critical exponent governing non-equilibrium dynamics.

Universal power-law rise of order and correlations during prethermalization.

Crossover to thermalization occurs at arbitrarily late times for shallow quenches.

Abstract

We consider an open system near a quantum critical point that is suddenly moved towards the critical point. The bath-dominated diffusive non-equilibrium dynamics after the quench is shown to follow scaling behavior, governed by a critical exponent that emerges in addition to the known equilibrium critical exponents. We determine this exponent and show that it describes universal prethermalized coarsening dynamics of the order parameter in an intermediate time regime. Implications of this quantum critical prethermalization are a powerlaw rise of order and correlations after an initial collapse of the equilibrium state and a crossover to thermalization that occurs arbitrarily late for sufficiently shallow quenches.