Excitation and damping of collective modes of a Bose-Einstein condensate in a one-dimensional lattice

TL;DR

This paper investigates how a Bose-Einstein condensate behaves when suddenly loaded into a one-dimensional optical lattice, revealing excitation damping, re-thermalization, and changes in interference visibility and temperature.

Contribution

It introduces a simple model predicting the initial decrease in interference visibility and provides experimental observations of damping and re-thermalization in the condensate.

Findings

Visibility decreases shortly after loading into the lattice

Heavily damped radial oscillations are observed

Condensate temperature increases due to re-thermalization

Abstract

The mode structure of a Bose-Einstein condensate non-adiabatically loaded into a one-dimensional optical lattice is studied by analyzing the visibility of the interference pattern as well as the radial profile of the condensate after a time-of-flight. A simple model is proposed that predicts the short-time decrease of the visibility as a function of the condensate parameters. In the radial direction, heavily damped oscillations are observed, as well as an increase in the condensate temperature. These findings are interpreted as a re-thermalization due to dissipation of the initial condensate excitations into high-lying modes.