Spontaneous emissions and thermalization of cold bosons in optical lattices

TL;DR

This paper investigates how spontaneous emission events induce thermalization or hinder it in cold bosons within optical lattices, revealing a transition-dependent behavior affecting experimental heating and equilibration.

Contribution

It provides a detailed analysis of thermalization dynamics post spontaneous emission, highlighting the dependence on the system's phase and low-energy spectrum.

Findings

Rapid thermalization in certain regimes

Lack of thermalization near the Mott insulator transition

Implications for heating and equilibration in experiments

Abstract

We study the thermalization of excitations generated by spontaneous emission events for cold bosons in an optical lattice. Computing the dynamics described by the many-body master equation, we characterize equilibration timescales in different parameter regimes. For simple observables, we find regimes in which the system relaxes rapidly to values in agreement with a thermal distribution, and others where thermalization does not occur on typical experimental timescales. Because spontaneous emissions lead effectively to a local quantum quench, this behavior is strongly dependent on the low-energy spectrum of the Hamiltonian, and undergoes a qualitative change at the Mott Insulator-superfluid transition point. These results have important implications for the understanding of thermalization after localized quenches in isolated quantum gases, as well as the characterization of heating in experiments.