Universal Symmetry-Breaking Dynamics at Continuous Phase Transitions: Evidence for a New Dynamical Critical Exponent

TL;DR

This paper uncovers a new universal dynamical behavior after symmetry-breaking quenches at continuous phase transitions, characterized by a novel critical exponent and scaling form in Ising models.

Contribution

It identifies a previously unrecognized universal scaling regime with a new dynamical critical exponent in Ising models after symmetry-breaking quenches.

Findings

Order-parameter fluctuations collapse temporally across various system sizes.

Evidence for a new dynamical critical exponent in the universal regime.

Universal behavior observed in 2D quantum, 3D and 4D classical Ising models.

Abstract

Uncovering and understanding universal dynamics in matter far from equilibrium remains a key challenge. In this work, we identify a so far unrecognized form of universal behavior that emerges after a sudden symmetry-breaking quench at continuous phase transitions. Our key observation is that the order-parameter fluctuations in Ising models exhibit a compelling temporal collapse across a wide range of system sizes and quench strengths, indicative of an emergent single-variable scaling form. This phenomenon can be explained by introducing a so far unknown dynamical critical exponent for the underlying continuous phase transition. We find evidence for a lower critical effective dimension of this universal regime: it is observed in the 2D quantum and 3D and 4D classical Ising models, but not in the 1D quantum or 2D classical cases. Our results suggest that our observed universal far-from-equilibrium scaling may extend beyond the Ising models studied here and could more broadly characterize systems with non-conserved order parameters, opening new avenues for exploring universal dynamics both theoretically and in current experimental platforms.