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Physical Review A

Expansion cooling and heating for a thermal magnetic trapped gas

Huang Wu, E. Arimondo

Published Nov 1, 1998• 2 citations
Publisher

Abstract

We analyze the expansion process of a thermal trapped gas taking place during the detection of Bose-Einstein condensation through an expansion of the condensate. By extending our Monte Carlo method to study this phenomenon, we demonstrate that the velocity distributions of the thermal trapped atoms are anisotropic due to anisotropic explosion of atoms. The radial and axial components of translational temperature are different from the trap temperature and have opposite evolution tendencies with the gas expansion.

DOI
10.1103/physreva.58.3822

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We analyze the expansion process of a thermal trapped gas taking place during the detection of Bose-Einstein condensation through an expansion of the condensate. By extending our Monte Carlo method to study this phenomenon, we demonstrate that the velocity distributions of the thermal trapped atoms are anisotropic due to anisotropic explosion of atoms. The radial and axial components of translational temperature are different from the trap temperature and have opposite evolution tendencies with the gas expansion.
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We investigate the zero-temperature collective excitations of a Bose-condensed atomic gas in anisotropic parabolic traps. The condensate density is determined by solving the Gross-Pitaevskii (GP) equation using a spherical harmonic expansion. The GP eigenfunctions are then used to solve the Bogoliubov equations to obtain the collective excitation frequencies and mode densities. The frequencies of the various modes, classified by their parity and the axial angular momentum quantum number, m, are mapped out as a function of the axial anisotropy. Specific emphasis is placed upon the evolution of these modes from the modes in the limit of an isotropic trap.
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