title: Momentum spectroscopy of 1D phase fluctuations in Bose-Einstein condensates.
abstract: 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 quasicondensate theory. In addition, we observe a condensate length consistent with the suppression of density fluctuations, even when phase fluctuations are large.
authors.affiliation: Laboratoire Charles Fabry de l'Institut d'Optique, UMR 8501 du CNRS, 91403 Orsay Cedex, France.
authors.forename: S
authors.initials: S
authors.lastname: Richard
authors.forename: F
authors.initials: F
authors.lastname: Gerbier
authors.forename: J H
authors.initials: JH
authors.lastname: Thywissen
authors.forename: M
authors.initials: M
authors.lastname: Hugbart
authors.forename: P
authors.initials: P
authors.lastname: Bouyer
authors.forename: A
authors.initials: A
authors.lastname: Aspect