Thermal and quantum fluctuations of confined Bose–Einstein condensate beyond the Bogoliubov approximation

Y. Nakamura, T. Kawaguchi, Y. Torii, Yoshiya Yamanaka

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    The formulation for zero mode of a Bose–Einstein condensate beyond the Bogoliubov approximation at zero temperature [Y. Nakamura et al., Phys. Rev. A 89 (2014) 013613] is extended to finite temperature. Both thermal and quantum fluctuations are considered in a manner consistent with a concept of spontaneous symmetry breakdown for a finite-size system. Therefore, we need a proper treatment of the zero mode operators, which invoke non-trivial enhancements in depletion condensate and thermodynamical quantities such as the specific heat. The enhancements are visible in the weak interaction case. Our approach reproduces the results of a homogeneous system in the Bogoliubov approximation in a large particle number limit.

    Original languageEnglish
    Pages (from-to)484-498
    Number of pages15
    JournalAnnals of Physics
    Publication statusPublished - 2017 Jan 1



    • Bose–Einstein condensation
    • Cold atom
    • Finite temperature
    • Quantum field theory
    • Spontaneous symmetry breaking
    • Zero mode

    ASJC Scopus subject areas

    • Physics and Astronomy(all)

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