Universal Family-Vicsek scaling in quantum gases far from equilibrium

TL;DR

This paper demonstrates that the universal Family-Vicsek scaling observed in classical surface growth also applies to quantum many-body systems, specifically a one-dimensional Bose gas, unifying classical and quantum nonequilibrium universality.

Contribution

It provides experimental evidence of FV scaling in a quantum system, extending the concept from classical to quantum regimes.

Findings

FV scaling observed in a quantum Bose gas

Universal scaling function captures relaxation dynamics

Extends classical surface growth laws to quantum systems

Abstract

Fluctuations in the growing surfaces of classical systems can exhibit universal scaling behavior, known as Family-Vicsek (FV) scaling. Although this phenomenon was originally discovered in classical stochastic models, recent theoretical studies have demonstrated the presence of FV scaling in quantum many-body systems as well. Here, we observe the universal FV scaling in a one-dimensional Bose gas in an optical lattice. By monitoring the fluctuations of particle number in half of the system, which corresponds to the surface roughness, we extract all scaling exponents and demonstrate that the entire relaxation-from the growth of quantum fluctuations to their saturation-is captured by a single universal scaling function. Our results demonstrate that universal scaling laws of classical surface growth extend to quantum many-body systems, establishing a unified framework for nonequilibrium universality across classical and quantum systems.