2008/08/15 by F. Gerbier, S. Trotzky, S. Foelling +9 · 1 citation
Physics and Astronomy · #cond-mat.other
paper · pdf · doi:10.1103/physrevlett.101.155303
published as Phys. Rev. Lett. 101, 155303 (2008) · 5 pages, 3 figures
arxiv created 2008/08/15 · arxiv updated 2009/12/01
We analyze the interference pattern produced by ultracold atoms released from an optical lattice. Such interference patterns are commonly interpreted as the momentum distributions of the trapped quantum gas. We show that for finite time-of-flights the resulting density distribution can, however, be significantly altered, similar to a near-field diffraction regime in optics. We illustrate our findings with a simple model and realistic quantum Monte Carlo simulations for bosonic atoms, and compare the latter to experiments.