Quantum Quench of the "Speed of Light": Quantum Dynamical Universality Classes and Short-time Universal Behavior

TL;DR

This paper investigates the universal quantum dynamical behavior following a sudden quench of the 'speed of light' in a critical quantum system, revealing new universal classes and a quantum aging exponent.

Contribution

It introduces a novel quantum quench scenario at criticality, uncovering universal dynamical classes and a new exponent for quantum aging.

Findings

Prethermal states exhibit genuine quantum and dynamical universality.

Universal approach to prethermal states characterized by a new quantum aging exponent.

Identification of quantum dynamical universality classes related to speed of light quench.

Abstract

A long-lived prethermal state may emerge upon a sudden quench of a quantum system. In this paper, we study a quantum quench of an initial {\it critical} state, and show that the resulting prethermal state exhibits a genuinely quantum and dynamical universal behavior. Specifically, we consider a scenario where the "speed of light" characterizing the propagation of local perturbations is suddenly quenched at criticality. We also find that the system approaches the prethermal state in a universal way described by a new exponent that characterizes a kind of quantum aging.