@article{2008-gerbier-svistunov-phys-rev-lett-v101-p155303, Abstract = {We analyze the interference pattern produced by ultracold atoms released from an optical lattice, commonly interpreted as the momentum distributions of the trapped quantum gas. We show that for finite times of flight 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.}, Author = {Gerbier, F. AND Trotzky, S. AND Fölling, S. AND Schnorrberger, U. AND Thompson, J. D. AND Widera, A. AND Bloch, I. AND Pollet, L. AND Troyer, M. AND Capogrosso-Sansone, B. AND Prokof'ev, N. V. AND Svistunov, B. V.}, Journal = {Phys. Rev. Lett.}, Pages = {155303}, Title = {{Expansion of a Quantum Gas Released from an Optical Lattice}}, Volume = {101}, Year = {2008} }