Dynamical crossovers in prethermal critical states

TL;DR

This paper investigates the prethermal dynamics of an interacting quantum field theory near a dynamical critical point, revealing crossovers between different universal scaling regimes and connecting theory with recent experiments.

Contribution

It introduces a comprehensive analysis of dynamical crossovers in prethermal states using renormalization group and large-N techniques, highlighting new universal behaviors.

Findings

Identification of quantum and classical prethermal fixed points

Observation of Gaussian to non-Gaussian dynamical scaling crossover

Experimental relevance for exploring non-equilibrium quantum criticality

Abstract

We study the prethermal dynamics of an interacting quantum field theory with a N-component order parameter and $O(N)$ symmetry, suddenly quenched in the vicinity of a dynamical critical point. Depending on the initial conditions, the evolution of the order parameter, and of the response and correlation functions, can exhibit a temporal crossover between universal dynamical scaling regimes governed, respectively, by a quantum and a classical prethermal fixed point, as well as a crossover from a Gaussian to a non-Gaussian prethermal dynamical scaling. Together with a recent experiment, this suggests that quenches may be used in order to explore the rich variety of dynamical critical points occurring in the non-equilibrium dynamics of a quantum many-body system. We illustrate this fact by using a combination of renormalization group techniques and a non-perturbative large-$N$ limit.