Classification of Quench Dynamical Behaviours in Spinor Condensates

TL;DR

This paper classifies various quench dynamical behaviors in spin-1 Bose-Einstein condensates, exploring thermalization, revivals, and nonthermal states, and proposes methods to predict collapse and revival times relevant for experiments.

Contribution

It provides a comprehensive classification of dynamical behaviors in spinor condensates and analyzes the conditions for ETH validity, introducing a predictive method for collapse and revival times.

Findings

Identification of regions where ETH holds or fails.

Existence of nonthermal states in the spectrum.

Method to predict collapse and revival time scales.

Abstract

Thermalization of isolated quantum systems is a long-standing fundamental problem where different mechanisms are proposed over time. We contribute to this discussion by classifying the diverse quench dynamical behaviours of spin-1 Bose-Einstein condensates, which includes well-defined quantum collapse and revivals, thermalization, and certain special cases. These special cases are either nonthermal equilibration with no revival but a collapse even though the system has finite degrees of freedom or no equilibration with no collapse and revival. Given that some integrable systems are already shown to demonstrate the weak form of eigenstate thermalization hypothesis (ETH), we determine the regions where ETH holds and fails in this integrable isolated quantum system. The reason behind both thermalizing and nonthermalizing behaviours in the same model under different initial conditions is linked to the discussion of `rare' nonthermal states existing in the spectrum. We also propose a method to predict the collapse and revival time scales and how they scale with the number of particles in the condensate. We use a sudden quench to drive the system to non-equilibrium and hence the theoretical predictions given in this paper can be probed in experiments.