Generalized Hydrodynamics of Bloch Oscillations in the Absence of a Lattice

TL;DR

This paper develops a generalized hydrodynamic theory to describe Bloch oscillations in continuum quantum gases without a lattice, revealing persistent oscillations and density-dependent period renormalization.

Contribution

It introduces a novel hydrodynamic framework for Bloch oscillations in continuum systems, extending understanding beyond lattice models.

Findings

Bloch oscillations persist with a superimposed drift in continuum gases.

The oscillation period is renormalized at finite impurity densities.

Results are applicable to ultracold atom experiments with controllable impurity densities.

Abstract

Objects subjected to a constant force generally increase their velocity over time. This expectation fails whenever their energy is a smooth and periodic function of momentum, resulting in periodic Bloch oscillations instead. Periodic dispersions, typical of lattice systems, can also emerge in continuum media through strong interactions. Here, we study the phenomenon of such Bloch oscillations in the absence of a lattice in a paradigmatic model of integrable quantum gases: the two-component Yang-Gaudin model. We derive a generalized-hydrodynamic theory of Bloch oscillations for a finite density of impurities embedded in a homogeneous interacting background, which we show to persist superimposed to a drift due to the acceleration of the center of mass. Moreover, we show the single-impurity oscillation period is renormalized at finite impurity density when two-magnon bound states are populated. Our results are relevant for ultracold atom experiments, where impurities can be created at controllable densities.