角动量和赝角动量的拓展讨论
More on Difference between Angular Momentum and Pseudo-angular Momentum
戴琦 1陈子维 1华邦辉 1陈相松2
作者信息
- 1. 华中科技大学 物理学院,湖北 武汉 430074
- 2. 海南师范大学 物理与电子工程学院,海南 海口 571158;华中科技大学 物理学院,湖北 武汉 430074
- 折叠
摘要
本文拓展了场论中对角动量与赝角动量区别的讨论,指出在Streib文章中经常提及的角动量表达式只适合于非线性系统,同时给出了Navier-Cauchy方程所描述的线性弹性系统所对应的转动对称性以及角动量表达式.通过把研究弹性波的方法运用于电磁理论,本文认为光场角动量的正则表达式和Belinfante表达式实际为赝角动量.最后,得到了自由电磁波在真空传播过程中的"牛顿"动量∫ d3xE和角动量∫ d3x(r × E).
Abstract
We extend the discussion on the difference between angular momentum and pseudo-angular momentum in field theory.We show that the often quoted expressions in the paper of Streib only apply to a non-linear system,and derive the correct rotation symmetry and the corresponding angular momentum for a linear elastic system governed by Navier-Cauchy equation.By mapping the concepts and methods for the elastic wave into electromagnetic theory,we argue that the renowned canonical and Benlinfante angular momentum of light are actually pseudo-angular momentum.Then,we derive the"Newtonian"momentum ∫ d3xE and angular momentum ∫ d3 x(r × E)for a free electromagnetic wave,which are conserved quantities during propagation in vacuum.
关键词
角动量/赝角动量/转动对称/弹性波/电磁波Key words
angular momentum/pseudo-angular momentum/rotation symmetry/elastic wave/electromagnetic wave引用本文复制引用
出版年
2024
国家科技期刊平台
NSTL
万方数据