Measurement of Phase Coherence during the Growth of an Elongated Condensate
Résumé
We study the growth of an elongated condensate from a non-equilibrium thermal cloud obtained by shock-cooling. Quantitative measurements using momentum Bragg spectroscopy reveal the evolution of the phase coherence length as the condensate grows to equilibrium. A broadening of the momentum distribution compared to that expected at equilibrium is observed at early times. This broadening is compatible with damped quadrupole oscillations.