Genuine phase diffusion of a Bose-Einstein condensate in the microcanonical ensemble: A classical field study

Alice Sinatra (1) , Yvan Castin (1)

1 LKB (Lhomond) - Laboratoire Kastler Brossel

Within the classical field model, we find that the phase of a Bose-Einstein condensate undergoes a true diffusive motion in the microcanonical ensemble, the variance of the condensate phase change between time zero and time $t$ growing linearly in $t$. The phase diffusion coefficient obeys a simple scaling law in the double thermodynamic and Bogoliubov limit. We construct an approximate calculation of the diffusion coefficient, in fair agreement with the numerical results over the considered temperature range, and we extend this approximate calculation to the quantum field.

Mots clés: Beliaev-Landau damping.; Bose-Einstein condensates; phase coherence; phase diffusion; non zero temperaure; microcanonical ensemble; classical field method; Beliaev-Landau damping

Domaines: Autre [cond-mat.other]

Alice Sinatra, Yvan Castin. Genuine phase diffusion of a Bose-Einstein condensate in the microcanonical ensemble: A classical field study. Physical Review A : Atomic, molecular, and optical physics [1990-2015], 2008, 78, pp.053615. ⟨hal-00310488⟩