Population and Phase Coherence during the Growth of an Elongated Bose-Einstein Condensate

Mathilde Hugbart (1) , Jocelyn A. Retter (1) , Andrès Varòn (1) , Philippe Bouyer (1) , Alain Aspect (1) , Matthew J. Davis (2)

1 laboratoire Charles Fabry de l'Institut d'Optique / Optique atomique
2 ARC Centre of Excellence for Quantum-Atom Optics

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.

Mots clés: BEC; formation; kinetics; evaporative cooling

Domaines: Autre [cond-mat.other]; Optique [physics.optics]

Mathilde Hugbart, Jocelyn A. Retter, Andrès Varòn, Philippe Bouyer, Alain Aspect, et al.. Population and Phase Coherence during the Growth of an Elongated Bose-Einstein Condensate. Physical Review A : Atomic, molecular, and optical physics [1990-2015], 2007, 75, pp.011602. ⟨10.1103/PhysRevA.75.011602⟩. ⟨hal-00018350v3⟩