Instabilities of a Bose-Einstein condensate in a periodic potential: an experimental investigation

TL;DR

This paper experimentally studies the stability of a Bose-Einstein condensate in a 1D optical lattice by accelerating it across the Brillouin zone edge, analyzing interference patterns to identify instability onset.

Contribution

It provides experimental insights into the stability behavior of Bose-Einstein condensates near the zone edge in optical lattices, complementing recent theoretical predictions.

Findings

Instability onset correlates with decreased lattice acceleration.

Visibility of interference patterns decreases near the zone edge.

Interference peak widths increase as instability develops.

Abstract

By accelerating a Bose-Einstein condensate in a controlled way across the edge of the Brillouin zone of a 1D optical lattice, we investigate the stability of the condensate in the vicinity of the zone edge. Through an analysis of the visibility of the interference pattern after a time-of-flight and the widths of the interference peaks, we characterize the onset of instability as the acceleration of the lattice is decreased. We briefly discuss the significance of our results with respect to recent theoretical work.