Inflationary Quasiparticle Creation and Thermalization Dynamics in Coupled Bose-Einstein Condensates

Anna Posazhennikova, Mauricio Trujillo-Martinez, Johann Kroha

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A Bose gas in a double-well potential, exhibiting a true Bose-Einstein
condensate (BEC) amplitude and initially performing Josephson oscillations,
is a prototype of an isolated, non-equilibrium many-body system.
We investigate the quasiparticle creation and thermalization dynamics of
this system by solving the time-dependent Keldysh-Bogoliubov equations.
We find slow, exponential relaxation to a thermal state at an elevated temperature,
controlled by the initial excitation energy of the oscillating BEC
above its ground state. Interestingly, the relaxation is preceded by an effective decoupling of the quasiparticle subsystem from the BEC oscillations. The thermalization occurs because the BEC acts as a grand canonical reservoir for the quasiparticle system.
Original languageEnglish
Article number225304
Pages (from-to)1-5
Number of pages5
JournalPhysical Review Letters
Issue number22
Publication statusPublished - 2 Jun 2016

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