3 votes
Accepted

How to calculate the time derivative of electromagnetic field?

As the problem is posed, this is impossible. just knowing the spacial variation of an electric field at a specific moment in time does not mean you have any knowledge of its time variance. I assume ...
jensen paull's user avatar
  • 6,580
3 votes
Accepted

Covariant derivative property

\begin{align} \not{\!\!D}^2 &= \gamma^\mu \gamma^\nu D_\mu D_\nu \\ &= \frac{1}{2} \{ \gamma^\mu , \gamma^\nu \}D_\mu D_\nu + \frac{1}{2} [ \gamma^\mu , \gamma^\nu ] D_\mu D_\nu \\ &= \...
Prahar's user avatar
  • 25.6k
1 vote

Why is the derivative necessary to connect left and right-hand spinors?

Index notation is rather useful here. Left-handed spinors have $\psi_\alpha$ and right-handed spinors have ${\bar \psi}_{\dot \alpha}$ (or the other way around, I can never remember what the ...
Prahar's user avatar
  • 25.6k

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