A Phenomenological Model of the Growth of Two-Species Atomic Bose-Einstein Condensates

Pattinson, R. W.; Parker, N. G.; Proukakis, N. P.

doi:10.1088/1742-6596/497/1/012029

Cited by 10 publications

(11 citation statements)

References 73 publications

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“…We analyse a sudden temperature and chemical potential quench of a prolate (aspect ratio ≈ 10) two-component atomic cloud of approximately 1.4 × 10 6 87 Rb and 8 × 10 5 133 Cs atoms, equilibrated in slightly displaced traps at T 0 = 80 nK (close to the ideal gas critical temperature T c ). Based on a characteristic example ( Dynamical two-component BEC simulations to date have been based on coupled ordinary [55,56,62,63] or dissipative [20,64,65] Gross-Pitaevskii equations (GPEs), classical field [66], truncated Wigner [45,46], or ZNG (coupled GPE-Boltzmann) [67] methods. The effects of thermal fluctuations during condensate growth are best captured by 3D coupled stochastic projected Gross-Pitaevskii equations [53,68,69],…”

Section: Quench Protocol and Modeling Detailsmentioning

confidence: 99%

Stochastic growth dynamics and composite defects in quenched immiscible binary condensates

et al. 2016

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We study the sensitivity of coupled condensate formation dynamics on the history of initial stochastic domain formation in the context of instantaneously quenched elongated harmonically-trapped immiscible twocomponent atomic Bose gases. The spontaneous generation of defects in the fastest condensing component, and subsequent coarse-graining dynamics, can lead to a deep oscillating microtrap into which the other component condenses, thereby establishing a long-lived composite defect in the form of a dark-bright solitary wave. We numerically map out diverse key aspects of these competing growth dynamics, focussing on the role of shot-to-shot fluctuations and global parameter changes (initial state choices, quench parameters and condensate growth rates). We conclude that phase-separated structures observable on experimental timescales are likely to be metastable states whose form is influenced by the stability and dynamics of the spontaneously-emerging dark-bright solitary wave.

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Section: Quench Protocol and Modeling Detailsmentioning

confidence: 99%

Stochastic growth dynamics and composite defects in quenched immiscible binary condensates

et al. 2016

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“…Depending on the strength of the intraspecies (g 11 , g 22 ) and interspecies (g 12 ) interaction, the two components can either overlap in space ( > 0) or phase separate ( < 0). This spatial overlap has practical consequences on, e.g., rethermalization rate [24], coarse-graining dynamics [25][26][27], structures of vortex lattice [28], or instabilities in fluid dynamics [29]. Based on the assumption of overlapping trap centers of the two components, numerical studies [30][31][32][33][34][35] have shown three different types of density profiles [ Fig.…”

Section: Introductionmentioning

confidence: 99%

Phase separation and dynamics of two-component Bose-Einstein condensates

et al. 2016

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The miscibility of two interacting quantum systems is an important testing ground for the understanding of complex quantum systems. Two-component Bose-Einstein condensates enable the investigation of this scenario in a particularly well controlled setting. In a homogeneous system, the transition between mixed and separated phases is fully characterized by a miscibility parameter based on the ratio of intra-to interspecies interaction strengths. Here we show, however, that this parameter is no longer the optimal one for trapped gases, for which the location of the phase boundary depends critically on atom numbers. We demonstrate how monitoring of damping rates and frequencies of dipole oscillations enables the experimental mapping of the phase diagram by numerical implementation of a fully self-consistent finite-temperature kinetic theory for binary condensates. The change in damping rate is explained in terms of surface oscillation in the immiscible regime, and counterflow instability in the miscible regime, with collisions becoming only important in the long time evolution.

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“…In the context of multi-component condensates, which have been extensively studied with coupled Gross-Pitaevskii equations (GPEs) [31][32][33][91][92][93][94][95][96][97][98][99], or their dissipative generalisations [100][101][102], their finite temperature dynamics remains a partly open problem. Approaches considered to date include classical field [103], truncated Wigner [104][105][106], coupled stochastic projected Gross-Pitaevskii equations [107][108][109][110], or numberconserving approaches [111].…”

Section: Introductionmentioning

confidence: 99%

Nonequilibrium kinetic theory for trapped binary condensates

2015

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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 8 distinct collisional processes, whose dynamical interplay is expected to be responsible for the system's 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.

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A Phenomenological Model of the Growth of Two-Species Atomic Bose-Einstein Condensates

Cited by 10 publications

References 73 publications

Stochastic growth dynamics and composite defects in quenched immiscible binary condensates

Stochastic growth dynamics and composite defects in quenched immiscible binary condensates

Phase separation and dynamics of two-component Bose-Einstein condensates

Nonequilibrium kinetic theory for trapped binary condensates

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