大学物理 ›› 2021, Vol. 40 ›› Issue (8): 29-.doi: 10.16854 / j.cnki.1000-0712.200361

• 教学讨论 • 上一篇    下一篇

麦克斯韦-玻尔兹曼分布在易辛模型中的应用

应 涛,裴延波,王晓鸥,张 宇   

  1. 哈尔滨工业大学 物理学院,黑龙江 哈尔滨 150001
  • 收稿日期:2020-08-08 修回日期:2020-12-09 出版日期:2021-08-20 发布日期:2021-08-30
  • 通讯作者: 张宇,E-mail: zhangyunn@ hit.edu.cn
  • 作者简介:应涛( 1986—) ,男,安徽阜阳人,哈尔滨工业大学物理学院副教授,博士,主要从事大学物理教学和量子多体理论研究工作.
  • 基金资助:
    哈尔滨工业大学教学改革项目“新时代新工科大学物理教学体系”资助

Application of Maxwell-Boltzmann distribution in Ising model

YING Tao,PEI Yan-bo,WANG Xiao-ou,ZHANG Yu   

  1. School of Physics,Harbin Institute of Technology,Harbin,Heilongjiang 150001,China
  • Received:2020-08-08 Revised:2020-12-09 Online:2021-08-20 Published:2021-08-30

摘要: 麦克斯韦-玻尔兹曼分布给出了系统在任一微观状态下的玻尔兹曼概率,从而可以计算系统中宏观观测量的统计平均值.但在实际计算中,由于系统可能微观状态数随系统晶格格点数增大而指数增大,往往无法进行计算. 本文以易辛模型为例,介绍了如何从玻尔兹曼概率的角度研究系统可能微观状态的演化过程,从而可以只考虑高概率的微观状态. 使用该方法,研究了二维易辛模型的平均每自旋的基态能量和平均每自旋的磁化率随温度的变化关系.

关键词: 麦克斯韦-玻尔兹曼分布, 玻尔兹曼概率, 易辛模型, 统计平均值

Abstract: Maxwell-Boltzmann distribution has broad application prospect in statistical physics.

This distribu- tion gives the Boltzmann probability of any microstate of the system,so we

can calculate the statistical average of the macroscopic observation of the system.

However,most of the real calculations are hard to be done,due to the fact that the number of

all the possible microstates increases exponentially with the number of the lattice

sites. In this paper,we take the Ising model as an example,to introduce the evolution of the

possible microstates from the view of the Boltzmann probability,hence we only need to consider

the microstates with large Boltzmann probability. In this way,we study the ground-state energy per

site and magnetization per site as functions of temperature,in a two-dimensional Ising model.

Key words: Maxwell-Boltzmann distribution, Boltzmann probability, Ising model, statistical average