Recent content by Cirrus79

Can you provide a reference to better solution for this problem? This one is from lecture notes. This made me think, and i realized that I should use (fg)'=f'g+fg' to the first \partial _{\mu} not the second one. Now I get it. Of course. I tried to transform \Psi twice. Thank you...

Hello, I don't understand two steps in solution to the problem: I. Homework Statement Show that QED action is invariant under gauge transformation. II. Relevant equations QED action: S= \int{d^{4} x \left[\overline{\Psi}\left(i\gamma^{\mu} D_{\mu} -m \right)\Psi...