Bose-Einstein condensation of atoms in a uniform potential
  We have observed Bose-Einstein condensation of an atomic gas in the (quasi-)uniform three-dimensional potential of an optical box trap. Condensation is seen in the bimodal momentum distribution and the anisotropic time-of-flight expansion of the condensate. The critical temperature agrees with the theoretical prediction for a uniform Bose gas. The momentum distribution of our non-condensed quantum-degenerate gas is also clearly distinct from the conventional case of a harmonically trapped sample and close to the expected distribution in a uniform system. We confirm the coherence of our condensate in a matter-wave interference experiment. Our experiments open many new possibilities for fundamental studies of many-body physics. 
Alexander L. Gaunt, Tobias F. Schmidutz, Igor Gotlibovych, Robert P.   Smith, Zoran Hadzibabic
cond-mat.quant-gas cond-mat.stat-mech physics.atom-ph quant-ph