Fock State Sampling Method - Characteristic Temperature of Maximal Fluctuations for Interacting Bosons in Box Potentials

M.B. Kruka, b, T. Vibelc, J. Arltc, P. Kulika, K. Pawłowskia, K. Rzążewskia aCenter for Theoretical Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warsaw, Poland bInstitute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warsaw, Poland cCenter for Complex Quantum Systems, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark

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We study the statistical properties of a gas of interacting bosons trapped in a box potential in two and three dimensions. Our primary focus is the characteristic temperature Tp, i.e., the temperature at which the fluctuations of the number of condensed atoms (or, in 2D, the number of motionless atoms) are maximal. Using the Fock state sampling method, we show that Tp increases due to interaction. In 3D, this temperature converges to the critical temperature in the thermodynamic limit. In 2D, we show the general applicability of the method by obtaining a generalized dependence of the characteristic temperature on the interaction strength. Finally, we discuss the experimental conditions necessary for the verification of our theoretical predictions.

DOI:10.12693/APhysPolA.143.171 topics: Bose-Einstein condensate, statistical ensembles, quantum gases