Momentum spectroscopy of 1D phase fluctuations in Bose-Einstein condensates

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

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

We measure the axial momentum distribution of Bose-Einstein condensates with an aspect ratio of 152 using Bragg spectroscopy. We observe the Lorentzian momentum distribution characteristic of one-dimensional phase fluctuations. The temperature dependence of the width of this distribution provides a quantitative test of quasi-condensate theory. In addition, we observe a condensate length consistent with the absence of density fluctuations, even when phase fluctuations are large.

Domaines: Matière Molle [cond-mat.soft]

Simon Richard, Fabrice Gerbier, Joseph H. Thywissen, Mathilde Hugbart, Philippe Bouyer, et al.. Momentum spectroscopy of 1D phase fluctuations in Bose-Einstein condensates. Physical Review Letters, 2003, 91 (1), pp.010405. ⟨10.1103/PhysRevLett.91.010405⟩. ⟨hal-00116296⟩