2014/06/30 by Mauricio Trujillo-Martinez, Anna Posazhennikova, Johann Kroha · 8 citations
Computer Science · Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Dynamics (music) #Eigenvalues and eigenvectors #Josephson effect #Mechanical and Optical Resonators #Quantum Information and Cryptography #Quasiparticle #Scale (ratio) #Time evolution #Trap (plumbing) #cond-mat.quant-gas
paper · pdf · doi:10.1088/1367-2630/17/1/013006
published in New Journal of Physics 17(1), 013006 (IOP Publishing) · 30 pages, 12 figures, typos corrected, discussion of results and the model elaborated
arxiv created 2014/11/27 · openalex publication_date 2015/01/09 · arxiv updated 2015/01/13 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The time-dependent non-equilibrium dynamics of a Bose–Einstein condensate (BEC) typically generates incoherent excitations out of the condensate due to the finite frequencies present in the time evolution. We present a detailed derivation of a general non-equilibrium Greenʼs function technique that describes the coupled time evolution of an interacting BEC and its single-particle excitations in a trap, based on an expansion in terms of the exact eigenstates of the trap potential. We analyze the dynamics of a Bose system in a small double-well potential with initially all particles in the condensate. When the trap frequency is larger than the Josephson frequency, , the dynamics changes at a characteristic time, , abruptly from the slow Josephson oscillations of the BEC to fast Rabi oscillations driven by quasiparticle excitations in the trap. For times , the Josephson oscillations are undamped, in agreement with the experiments. We analyze the physical origin of the finite scale as well as its dependence on the trap parameter Δ .