5
votes
0answers
71 views

Functional integral aproach for Feynman rules

I am familiar with the basic ideas of quantum field theory but I feel uncomfortable when I have to derive Feynman rules by myself for a given action (for example in non-linear sigma models or ...
2
votes
1answer
98 views

Ghost fields in particle physics

In my particle physics lecture, ghost fields were briefly mentioned. As far as I understand, these come up when computing cross sections by the path integral method, to compensate for equivalent ...
1
vote
1answer
213 views

Does path integral and loop integral in a Feynman diagram violate special relativity?

Consider a correlation function between two points A(x1,t1) and B(x2,t2), we need to integrate over paths which could be ...
13
votes
2answers
278 views

Applications of the Feynman-Vernon Influence Functional

I am looking for a reference where the Feynman-Vernon influence functional was defined and used in the context of relativistic quantum field theory. This functional is one method to describe ...