A Non-Equilibrium Kinetic Theory for Trapped Binary Condensates

Abstract

We derive a non-equilibrium finite-temperature kinetic theory for a binary mixture of two interacting atomic Bose-Einstein condensates and use it to explore the degree of hydrodynamicity attainable in realistic experimental geometries. Based on the standard separation of timescale argument of kinetic theory, the dynamics of the condensates of the multi-component system are shown to be described by dissipative Gross-Pitaevskii equations, self-consistently coupled to corresponding Quantum Boltzmann equations for the non-condensate atoms: on top of the usual mean field contributions, our scheme identifies a total of eight distinct collisional processes, whose dynamical interplay is expected to be responsible for the systems equilibration. In order to provide their first characterization, we perform a detailed numerical analysis of the role of trap frequency and geometry on collisional rates for experimentally accessible mixtures of ${}^{87}$Rb-${}^{41}$K and ${}^{87}$Rb-${}^{85}$Rb, discussing the extent to which the system may approach the hydrodynamic regime with regard to some of those processes, as a guide for future experimental investigations of ultracold Bose gas mixtures.

30 pages, 9 figures

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Cited by in corpus (6)

• Phase Separation and Dynamics of two-component Bose-Einstein condensates
• Quantum and thermal fluctuations in two-component Bose gases
• Time-of-flight expansion of binary Bose-Einstein condensates at finite temperature
• Immiscible and miscible states in binary condensates in the ring geometry
• Non-equilibrium Atomic Condensates and Mixtures: Collective Modes, Condensate Growth and Thermalization
• Nonlinear dynamics of coupled superfluids