Hard-core bosons on optical superlattices: Dynamics and relaxation in the superfluid and insulating regimes

TL;DR

This paper investigates the nonequilibrium dynamics of hard-core bosons in one-dimensional optical superlattices, focusing on phase transitions, relaxation processes, and how equilibrium properties can be predicted after quenches.

Contribution

It provides a detailed analysis of the relaxation dynamics and introduces a generalized Gibbs distribution to predict time-averaged observables in integrable systems.

Findings

Collapse and revival of zero-momentum peak after superlattice switch-on

Relaxation of observables can be described by a generalized Gibbs distribution

System reaches equilibrium states that depend on initial conditions

Abstract

We study the ground-state properties and nonequilibrium dynamics of hard-core bosons confined in one-dimensional lattices in the presence of an additional periodic potential (superlattice) and a harmonic trap. The dynamics is analyzed after a sudden switch-on or switch-off of the superlattice potential, which can bring the system into insulating or superfluid phases, respectively. A collapse and revival of the zero-momentum peak can be seen in the first case. We study in detail the relaxation of these integrable systems towards equilibrium. We show how after relaxation time averages of physical observables, like the momentum distribution function, can be predicted by means of a generalization of the Gibbs distribution.