S. J. Rooney, T. W. Neely, B. P. Anderson, A. S. Bradley
We quantitatively model a stirred Bose-Einstein condensate at high temperature using grand-canonical c-field theory, comparing simulations with available experimental data. Stirring generates a chaotic array of quantum vortices that decays, via thermal damping and noise, to form a macroscopic persistent current in a toroidal confining potential. We perform 3D numerical simulations of the full dynamical evolution of the system within the truncated-Wigner representation using a consistent energy cutoff and a priori determined reservoir parameters. This work gives the first quantitative comparison of theory with experiment for dissipative vortex dynamics in a trapped Bose-Einstein condensate from first principles, with no fitted parameters. We find that both damping and noise are required to give a quantitative account of the dynamics, and that the size of the persistent current and timescale of its formation are in close agreement with experimental data. In contrast, comparison of experimental data with damped Gross-Pitaevskii theory excludes it as a quantitative model of high temperature vortex dynamics.
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http://arxiv.org/abs/1208.4421
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