大学物理 ›› 2022, Vol. 41 ›› Issue (12): 1-.doi: 10.16854/j.cnki.1000-0712.220272

• 教学研究 •    下一篇

最概然分布的少粒子修正是必要的吗?

侯吉旋   

  1. 东南大学物理学院,江苏南京211189
  • 收稿日期:2022-05-27 修回日期:2022-06-22 出版日期:2023-02-20 发布日期:2023-02-16
  • 作者简介:侯吉旋(1983—),男,江西南昌人,东南大学物理学院副教授,博士,主要从事大学物理教学和统计物理的研究工作
  • 基金资助:
    教育部高等学校物理学类专业教学指导委员会项目资助

Is it necessary to improve themost probable approximation  by considering the finite size effect?

HOU Ji-xuan   

  1. School of Physics, Southeast University, Nanjing, Jiangsu 211189, China
  • Received:2022-05-27 Revised:2022-06-22 Online:2023-02-20 Published:2023-02-16

摘要: 统计物理教材中推导最概然分布的过程存在数学缺陷,当粒子数较少时无法自圆其说.于是许多研究者利用更精确的公式对该推导进行少粒子修正.本文通过计算一维谐振子势阱中的理想玻色气体的基态布居数指出,经过少粒子修正后的结果与严格解反而相差更远.因此本文认为计算最概然分布时进行少粒子修正是没有必要的.

关键词: 最概然分布, 少粒子效应, 玻色气体

Abstract: The derivations of the most probable distribution are not self-consistent in most statistical physics textbooks since the Stirling’s approximation adopted in the derivations is not valid for systems with few particles. Thus, many attempts are devoted by adding higher Stirling terms to improve the prediction. However, by calculating the ground-state fraction of the ideal Bose system in one-dimensional harmonic trap, we show that the predictions considering the finite size effect are much worse than the predicitons given by the original version without modification. Hence, the finite-size modification to the most probable approximation is not necessary at all.

Key words: the most probable distribution, finite size effect, Bose gas