大学物理 ›› 2023, Vol. 42 ›› Issue (3): 41-.doi: 10.16854/j.cnki.1000-0712.220167

• 大学生园地 • 上一篇    下一篇

随机游走概率密度函数的一种推导方法

赵天润,韦纪霆   

  1. 南京大学物理学院,江苏  南京210023
  • 收稿日期:2022-03-31 修回日期:2022-05-22 出版日期:2023-05-04 发布日期:2023-05-04
  • 作者简介:赵天润(2001—),男,北京人,南京大学物理学院2020级本科生.E-mail:201840164@smail.nju.edu.cn

A derivation of random walk probability density function

ZHAO Tian-run, WEI Ji-ting   

  1. School of Physics, Nanjing University, Nanjing, Jiangsu 210023, China 
  • Received:2022-03-31 Revised:2022-05-22 Online:2023-05-04 Published:2023-05-04

摘要: 随机游走模型是一类经典的物理模型,能应用在诸多物理场景之中,甚至在很多其他领域也能找到它的身影.但一般教材中对这个问题的计算较为复杂,或使用到过于高深的数学工具,或使用了没有必要引入的近似.本文在多步数的近似之下,应用中心极限定理,推导出随机游走问题在某一方向分量的概率密度函数.接着利用随机游走问题的球对称性和上一步中得到的结果,推导出径向的概率密度分布函数.

关键词: 随机游走, 高维空间, 中心极限定理, 概率密度函数

Abstract:  Random walks are one of the classical models studied in physics, which can be applied to multiple physical problems, even in other fields. However, most textbooks concerning this topic may use complicated math methods or introduce unnecessary approximations when calculating the result. In this paper, the random walk probability density function of one particular direction is derived using the central limit theorem under many steps approximation. The radial probability density function can be derived using the result above and introducing the isotropic postulation. 

Key words: random walk, multidimensional space, central limit theorem, probability density function