There are a number of reasons to think that the electron cannot truly be spinning. Given how small the electron is generally taken to be, it would have to rotate superluminally to have the right angular momentum and magnetic moment. Also, the electron's gyromagnetic ratio is twice the value one would expect for an ordinary classical rotating charged body. These obstacles can be overcome by examining the flow of mass and charge in the Dirac field (interpreted as giving the classical state of the electron). Superluminal velocities are avoided because the electron's mass and charge are spread over sufficiently large distances that neither the velocity of mass flow nor the velocity of charge flow need to exceed the speed of light. The electron's gyromagnetic ratio is twice the expected value because its charge rotates twice as fast as its mass.

中文翻译：

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电子如何旋转

有很多理由认为电子不能真正旋转。给定电子通常要多小，它将必须超发光旋转以具有合适的角动量和磁矩。同样，电子的旋磁比是普通经典旋转带电体所期望值的两倍。通过检查狄拉克场中的质量和电荷流（可以解释为给出电子的经典态），可以克服这些障碍。避免了超光速，因为电子的质量和电荷分布在足够大的距离上，以至于质量流速度和电荷流速度都不需要超过光速。电子'