中国物理B ›› 2006, Vol. 15 ›› Issue (9): 1960-1964.doi: 10.1088/1009-1963/15/9/010

• GENERAL • 上一篇    下一篇

Variational Monte Carlo analysis of Bose--Einstein condensation in a two-dimensional trap

郑荣杰, 金晶, 唐翌   

  1. Institute of Modern Physics, Xiangtan University, Xiangtan 411105, China
  • 收稿日期:2005-12-27 修回日期:2006-05-18 出版日期:2006-09-20 发布日期:2006-09-20
  • 基金资助:
    Project supported by the Outstanding Young Researcher's Foundation of Hunan Province of China (Grant No 03JJY1001).

Variational Monte Carlo analysis of Bose--Einstein condensation in a two-dimensional trap

Zheng Rong-Jie(郑荣杰), Jin Jing(金晶), and Tang Yi(唐翌)†   

  1. Institute of Modern Physics, Xiangtan University, Xiangtan 411105, China
  • Received:2005-12-27 Revised:2006-05-18 Online:2006-09-20 Published:2006-09-20
  • Supported by:
    Project supported by the Outstanding Young Researcher's Foundation of Hunan Province of China (Grant No 03JJY1001).

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摘要： The ground-state properties of a system with a small number of interacting bosons over a wide range of densities are investigated. The system is confined in a two-dimensional isotropic harmonic trap, where the interaction between bosons is treated as a hard-core potential. By using variational Monte Carlo method, we diagonalize the one-body density matrix of the system to obtain the ground-state energy, condensate wavefunction and the condensate fraction. We find that in the dilute limit the depletion of central condensate in the 2D system is larger than in a 3D system for the same interaction strength; however as the density increases, the depletion at the centre of 2D trap will be equal to or even lower than that at the centre of 3D trap, which is in agreement with the anticipated in Thomas--Fermi approximation. In addition, in the 2D system the total condensate depletion is still larger than in a 3D system for the same scattering length.

Abstract: The ground-state properties of a system with a small number of interacting bosons over a wide range of densities are investigated. The system is confined in a two-dimensional isotropic harmonic trap, where the interaction between bosons is treated as a hard-core potential. By using variational Monte Carlo method, we diagonalize the one-body density matrix of the system to obtain the ground-state energy, condensate wavefunction and the condensate fraction. We find that in the dilute limit the depletion of central condensate in the 2D system is larger than in a 3D system for the same interaction strength; however as the density increases, the depletion at the centre of 2D trap will be equal to or even lower than that at the centre of 3D trap, which is in agreement with the anticipated in Thomas--Fermi approximation. In addition, in the 2D system the total condensate depletion is still larger than in a 3D system for the same scattering length.

Key words: Bose--Einstein condensation, variational Monte Carlo method, two-dimensional trap

中图分类号:  (Tunneling, Josephson effect, Bose-Einstein condensates in periodic potentials, solitons, vortices, and topological excitations)

  • 03.75.Lm
03.75.Kk (Dynamic properties of condensates; collective and hydrodynamic excitations, superfluid flow)