Coherence length of an elongated condensate: a study by matter-wave interferometry

Mathilde Hugbart (1) , Jocelyn A. Retter (1) , Fabrice Gerbier , Andrès F. Varòn (1) , Simon Richard (2) , Joseph Thywissen (3) , David Clément (1) , Philippe Bouyer (1) , Alain Aspect (1)

1 laboratoire Charles Fabry de l'Institut d'Optique / Optique atomique
2 TRT - Thales Research and Technologies [Orsay]
3 Department of Physics [Toronto]

We measure the spatial correlation function of Bose-Einstein condensates in the cross-over region between phase-coherent and strongly phase-fluctuating condensates. We observe the continuous path from a gaussian-like shape to an exponential-like shape characteristic of one-dimensional phase-fluctuations. The width of the spatial correlation function as a function of the temperature shows that the condensate coherence length undergoes no sharp transition between these two regimes.

Domains: Soft Condensed Matter [cond-mat.soft]; Optics [physics.optics]

Mathilde Hugbart, Jocelyn A. Retter, Fabrice Gerbier, Andrès F. Varòn, Simon Richard, et al.. Coherence length of an elongated condensate: a study by matter-wave interferometry. The European Physical Journal D : Atomic, molecular, optical and plasma physics, 2005, 35, pp.155-163. ⟨10.1140/epjd/e2005-00056-2⟩. ⟨hal-00003938⟩