Observation of universal dynamics in an isolated one-dimensional Bose gas far from equilibrium

TL;DR

This paper presents experimental evidence of universal dynamics in an isolated one-dimensional Bose gas far from equilibrium, demonstrating scaling behavior and a non-thermal fixed point during relaxation.

Contribution

It provides the first experimental observation of universal scaling and non-thermal fixed points in a 1D Bose gas, supporting the concept of universality far from equilibrium.

Findings

Universal scaling in time and space observed

Single universal function describes the evolution

Independence from initial state details

Abstract

We provide experimental evidence of universal dynamics far from equilibrium during the relaxation of an isolated one-dimensional Bose gas. Following a rapid cooling quench, the system exhibits universal scaling in time and space, associated with the approach of a non-thermal fixed point. The time evolution within the scaling period is described by a single universal function and scaling exponent, independent of the specifics of the initial state. Our results provide a quantum simulation in a regime, where to date no theoretical predictions are available. This constitutes a crucial step in the verification of universality far from equilibrium. If successful, this may lead to a comprehensive classification of systems based on their universal properties far from equilibrium, relevant for a large variety of systems at different scales.