Role of interactions in time-of-flight expansion of atomic clouds from optical lattices

TL;DR

This paper investigates how atomic interactions affect the expansion and interference patterns of ultracold atoms released from optical lattices, finding negligible effects generally but notable impact near scattering resonances.

Contribution

It provides a theoretical analysis of interaction effects on time-of-flight expansion, highlighting conditions where interactions significantly alter interference visibility.

Findings

Interactions are negligible for typical strengths during expansion.

Interactions reduce interference visibility near scattering resonances.

Theoretical predictions align with experimental observations.

Abstract

We calculate the effect of interactions on the expansion of ultracold atoms from a single site of an optical lattice. We use these results to predict how interactions influence the interference pattern observed in a time of flight experiment. We find that for typical interaction strengths their influence is negligible, yet that they reduce visibility near a scattering resonance.