Observation of Phase Defects in Quasi-2D Bose-Einstein Condensates
  We have observed phase defects in quasi-2D Bose-Einstein condensates close to the condensation temperature. Either a single or several equally spaced condensates are produced by selectively evaporating the sites of a 1D optical lattice. When several clouds are released from the lattice and allowed to overlap, dislocation lines in the interference patterns reveal nontrivial phase defects. 
Sabine Stock (LKB - Lhomond), Zoran Hadzibabic (LKB - Lhomond),   Baptiste Battelier (LKB - Lhomond), Marc Cheneau (LKB - Lh...