Bose-Einstein Condensation of Atoms in a Uniform Potential

TLDR

The experiments aim to enable fundamental studies of many-body physics. Coherence of the condensate was verified using a matter-wave interference experiment. Bose–Einstein condensation was observed in a uniform optical box trap, evidenced by a bimodal momentum distribution, anisotropic time‑of‑flight expansion, and a critical temperature matching theoretical predictions for a uniform gas.

Abstract

We have observed the 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 a noncondensed 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.