Universality of fast quenches from the conformal perturbation theory

TL;DR

This paper investigates the universal scaling behavior of quantum systems subjected to fast global quenches, demonstrating that conformal perturbation theory accurately describes the response and late-time thermalization.

Contribution

It provides a detailed analysis of the universal response during fast quenches using conformal perturbation theory and extends previous results on correlation functions.

Findings

Universal scaling laws for one and two-point functions during fast quenches

Confirmation of conformal perturbation theory's applicability in non-equilibrium dynamics

Evidence that local quantities thermalize after the quench

Abstract

We consider global quantum quenches, a protocol when a continuous field theoretic system in the ground state is driven by a homogeneous time-dependent external interaction. When the typical inverse time scale of the interaction is much larger than all relevant scales except for the UV-cutoff the system's response exhibits universal scaling behavior. We provide both qualitative and quantitative explanations of this universality and argue that physics of the response during and shortly after the quench is governed by the conformal perturbation theory around the UV fixed point. We proceed to calculate the response of one and two-point correlation functions confirming and generalizing universal scalings found previously. Finally, we discuss late time behavior after the quench and argue that all local quantities will equilibrate to their thermal values specified by an excess energy acquired by the system during the quench.