Recent content by retardedgreensfunc

Turns out I was overthinking it, and once I had the mode expansion it was very easy to just take the commutator by using the defining commutation relations for the creation and anihilation operators.

I know the mode expansion can be written:

Hi, so I'm currently reading the book "QFT for the gifted amateur", and doing the exercises. In exercise 14.2, which in itself is fine, the authors say that you can show using Noether's theorem that for a transverse polarized photon of momentum q, the z-component of the spin operator obeys the...