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Wave chaos as signature for depletion of a Bose-Einstein condensate

We study the expansion of repulsively interacting Bose-Einstein condensates (BECs) in shallow one-dimensional potentials. We show for these systems that the onset of wave chaos in the Gross-Pitaevskii equation (GPE), that is, the onset of exponential separation in Hilbert space of two nearby condens...

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Bibliographic Details
Main Authors: Březinová, Iva (Author) , Lode, Axel U. J. (Author) , Streltsov, Alexej Iwanowitsch (Author) , Cederbaum, Lorenz S. (Author)
Format: Article (Journal)
Language:English
Published: 20 July 2012
In: Physical review. A, Atomic, molecular, and optical physics
Year: 2012, Volume: 86, Issue: 1
ISSN:1094-1622
DOI:10.1103/PhysRevA.86.013630
Online Access:Verlag, Volltext: http://dx.doi.org/10.1103/PhysRevA.86.013630
Verlag, Volltext: https://link.aps.org/doi/10.1103/PhysRevA.86.013630
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Author Notes:Iva Březinová, Axel U. J. Lode, Alexej I. Streltsov, Ofir E. Alon, Lorenz S. Cederbaum, and Joachim Burgdörfer
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Summary:We study the expansion of repulsively interacting Bose-Einstein condensates (BECs) in shallow one-dimensional potentials. We show for these systems that the onset of wave chaos in the Gross-Pitaevskii equation (GPE), that is, the onset of exponential separation in Hilbert space of two nearby condensate wave functions, can be used as an indication for the onset of depletion of the BEC and the occupation of excited modes within a many-body description. Comparison between the multiconfigurational time-dependent Hartree for bosons method and the GPE reveals a close correspondence between the many-body effect of depletion and the mean-field effect of wave chaos for a wide range of single-particle external potentials. In the regime of wave chaos the GPE fails to account for the fine-scale quantum fluctuations because many-body effects beyond the validity of the GPE are non-negligible. Surprisingly, despite the failure of the GPE to account for the depletion, coarse-grained expectation values of the single-particle density such as the overall width of the atomic cloud agree very well with the many-body simulations. The time-dependent depletion of the condensate could be investigated experimentally, for example, via decay of coherence of the expanding atom cloud.
Item Description:Gesehen am 19.07.2018
Physical Description:Online Resource
ISSN:1094-1622
DOI:10.1103/PhysRevA.86.013630

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