Bose Condensates in a Harmonic Trap Near the Critical Temperature

Published

June 1, 2000

Author(s)

T Bergeman, D L. Feder, N L. Balazs, B I. Schneider

Abstract

The mean-field properties of finite-temperature Bose-Einstein gases confined in spherically symmetric harmonic traps are surveyed numerically. The solutions of the Gross-Pitaevskii (GP) and Hartree-Fock-Bogoliubov (HFB) equations for the condensate and low-lying quasiparticle excitations are calculated self-consistently using the discrete variable representation, while the most high-lying states are obtained with a local density approximation. Consistency of the theory for temperatures through the Bose condensation point T_c requires that the thermodynamic chemical potential differ from the eigenvalue of the GP equation; the appropriate modifications lead to results that are continuous as a function of the particle interactions. The HFB equations are made gapless either by invoking the Popov approximation or by renormalizing the particle interactions. The latter approach effectively reduces the strength of the effective scattering length α_sc, increases the number of condensate effect increases approximately with the log of the atom number, and is most pronounced at temperatures near T_c. Comparisons with the results of quantum Monte Carlo calculations and various local density approximations are presented, and experimental consequences are discussed.

Citation

Physical Review A (Atomic, Molecular and Optical Physics)

Volume

61

Issue

No. 6

Pub Type

Journals

Keywords

Bose-Einstein condensation, finite temperature, many-body theories

Citation

Bergeman, T. , Feder, D. , Balazs, N. and Schneider, B. (2000), Bose Condensates in a Harmonic Trap Near the Critical Temperature, Physical Review A (Atomic, Molecular and Optical Physics) (Accessed October 31, 2024)