Neitrino
- 133
- 0
Could anyone help/advise me please how to draw graphs for self-energy and Vertex functions given in attachments one and two.
In attachment one Sigma is self energy in coordinate space, S - fermion propagator, here I have one question: I was reading something where I found these exppresions, but how it can be that self-energy in attachment one is expressed only in terms of Propagator S(0), it's a just a vacuum bubble, just circle isn't it?
Irealy need someones help.
Thks a lot
In attachment one Sigma is self energy in coordinate space, S - fermion propagator, here I have one question: I was reading something where I found these exppresions, but how it can be that self-energy in attachment one is expressed only in terms of Propagator S(0), it's a just a vacuum bubble, just circle isn't it?
Irealy need someones help.
Thks a lot