摘要
根据狄拉克-麦克斯韦方程组和推广的洛伦兹力公式,讨论了磁单极和电磁对偶性的基本概念和物理意义.麦克斯韦方程组和洛伦兹力公式可以通过对偶变化转化为电荷与磁荷并存的形式;但是狄拉克磁单极假设改变了麦克斯韦方程组的结构,任何对偶变换都不能将狄拉克-麦克斯韦方程组简化为只有电荷而没有磁荷的原始形式.采用推广的洛伦兹力公式,还证明了狄拉克-麦克斯韦电磁场的能量密度和玻印亭矢量,以及动量密度和动量流张量形式不变.最后,我们还将狄拉克-麦克斯韦方程组分解为仅仅分别包含电荷与磁荷的两组麦克斯韦方程,传统的电动力学理论可以直接推广应用于磁单极问题.
Based on the Dirac-Maxwell＇s equations and generalized Lorentz force formula, the concepts and meaning of magnetic monopole and electromagnetic duality are introduced and discussed. According to the electromagnetic duality,the Maxwell＇s equations and Lorentz force formula can be transformed into a new form with coexistence of electric charges and magnetic charges,but the conjecture of Dirac monopole changes significantly the structure of Maxwell＇s equations, so that no duality transformation can reduce the Dirac-Maxwell＇s equations to the original form of Maxwell＇s equations. By using the generalized Lorentz force formula,it is also proven that both of the Dirac-Maxwell field and Maxwell electromagnetic field share the same formulae of energy density,Poyinting vector, density of kinetic momentum and tensor of kinetic momentum flow. Finally, we state that the fields of Dirac- Maxwell＇s equations can be decomposed into two groups of Maxwell＇s equations, one for electrical charges and the other for magnetic charges,and therefore the problem of monopole can be described and solved by employing the traditional theory of electrodynamics.
出处
《大学物理》
北大核心
2014年第11期1-4,19,共5页
College Physics
