Population and Phase Coherence during the Growth of an Elongated   Bose-Einstein Condensate
  We study the growth of an elongated phase-fluctuating condensate from a non-equilibrium thermal cloud obtained by shock-cooling. We compare the growth of the condensate with numerical simulations, revealing a time delay and a reduction in the growth rate which we attribute to phase fluctuations. We measure the phase coherence using momentum Bragg spectroscopy, and thereby observe the evolution of the phase coherence as a function of time. Combining the phase coherence results with the numerical simulations, we suggest a simple model for the reduction of the growth rate based on the reduction of bosonic stimulation due to phase fluctuations and obtain improved agreement between theory and experiment. 
Mathilde Hugbart (LCFIO), Jocelyn A. Retter (LCFIO), Andres Var\`on   (LCFIO), Philippe Bouyer (LCFIO), Alain Aspect (LCFIO)...