Momentum Spectroscopy of Phase Fluctuations of an Elongated Bose-Einstein Condensate

Alain Aspect (1) , Simon Richard (1) , Fabrice Gerbier (1) , Mathilde Hugbart (1) , Jocelyn A. Retter (1) , Joseph H. Thywissen (1) , Philippe Bouyer (1)

1 laboratoire Charles Fabry de l'Institut d'Optique / Optique atomique

We have measured the momentum distribution of an elongated BEC (aspect ratio of 152), for temperatures below the critical temperature. The corresponding coherence length is significantly smaller than the condensate length in a wide range of temperature, in quantitative agreement with theoretical predictions. The Lorentzian shape of the momentum spectrum supports the image of a phase fluctuating quasicondensate.

Keywords: Bose-Einstein Condensates; 1D; phase fluctuations; momentum distribution; Bragg diffraction

Domains: Statistical Mechanics [cond-mat.stat-mech]; Optics [physics.optics]

Alain Aspect, Simon Richard, Fabrice Gerbier, Mathilde Hugbart, Jocelyn A. Retter, et al.. Momentum Spectroscopy of Phase Fluctuations of an Elongated Bose-Einstein Condensate. Proceedings of the International Conference on Laser Spectroscopy (ICOLS 03), Jul 2003, Cairns, Australia. ⟨hal-00000592⟩