Unifying treatment of nonequilibrium and unstable dynamics of cold bosonic atom system with time-dependent order parameter in Thermo Field Dynamics

Y. Nakamura, Yoshiya Yamanaka

    Research output: Contribution to journalArticle

    5 Citations (Scopus)


    The coupled equations which describe the temporal evolution of the Bose-Einstein condensed system are derived in the framework of nonequilibrium Thermo Field Dynamics. The key element is that they are not the naive assemblages of assumed equations, but are the self-consistent ones derived by appropriate renormalization conditions. While the order parameter is time-dependent, an explicit quasiparticle picture is constructed by a time-dependent expansion. Our formulation is valid even for the system with a unstable condensate, and describes the condensate decay caused by the Landau instability as well as by the dynamical one.

    Original languageEnglish
    Pages (from-to)1070-1083
    Number of pages14
    JournalAnnals of Physics
    Issue number4
    Publication statusPublished - 2011 Apr



    • Bose-Einstein condensation
    • Kinetic equation
    • Nonequilibrium
    • Thermal field theory
    • Transport equation

    ASJC Scopus subject areas

    • Physics and Astronomy(all)

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