Visibility of a Bose-condensed gas released from an optical lattice at finite temperatures

Fabrice Gerbier, Simon Foelling, Artur Widera, Immanuel Bloch

Published 2007-01-17Version 1

In response to a recent manuscript [cond-mat/0609685] on the analysis of interference patterns produced by ultracold atoms released from an optical lattice, we point out that in the presence of a Bose-Einstein condensate the interference pattern can be strongly modified by interaction effects and the presence of a harmonic trap superimposed on the lattice potential. Our results show that the visibility of the interference pattern is significant only if a sizeable condensate fraction is present in the trap.