Thermalization of strongly interacting bosons after spontaneous emissions in optical lattices

TL;DR

This paper investigates how strongly interacting bosons in a 1D optical lattice thermalize after spontaneous emission events, revealing the dynamics of relaxation and the role of eigenstate thermalization, with analytical insights into the strongly interacting regime.

Contribution

It provides a detailed analysis of the out-of-equilibrium dynamics of bosons post-spontaneous emission, especially in the strongly interacting limit, using an effective low-energy Hamiltonian.

Findings

In the superfluid regime, observables relax to thermal values within experimental timescales.

In the Mott insulator regime, relaxation behavior deviates from thermalization.

Analytical results describe the dynamics in the strongly interacting limit based on doublon-holon pairs.

Abstract

We study the out-of-equilibrium dynamics of bosonic atoms in a 1D optical lattice, after the ground-state is excited by a single spontaneous emission event, i.e. after an absorption and re-emission of a lattice photon. This is an important fundamental source of decoherence for current experiments, and understanding the resulting dynamics and changes in the many-body state is important for controlling heating in quantum simulators. Previously it was found that in the superfluid regime, simple observables relax to values that can be described by a thermal distribution on experimental time-scales, and that this breaks down for strong interactions (in the Mott insulator regime). Here we expand on this result, investigating the relaxation of the momentum distribution as a function of time, and discussing the relationship to eigenstate thermalization. For the strongly interacting limit, we provide an analytical analysis for the behavior of the system, based on an effective low-energy Hamiltonian in which the dynamics can be understood based on correlated doublon-holon pairs.