Recent content by topper

Hey, there is something I don't really understand about the path integral (functional integral) formalism in QFT: Why do you need to introduce a coherent-state representation of the Dirac fields in order to evaluate their path integral? Where is the crucial point why it doesn't work like...

Ok, I think I got it. I will now read in some books and (hopefully) tighten my knowledge. Thanks for your time!

Ok thank you very much. That was very helpful :) One last question: A one particle state in QED is e.g. |k,\mu> = a^\dagger^\mu_k |0> I could now write the a in terms of A^\mu and its conjugate momentum and then apply a gauge transformation. Do I get the same result as if I do...

Thank you very much for your insightful comment. You wrote : 1. How do you define the physical Hilbert space in general? Is the equation G^a |\text{physical state}\rangle = 0 a proper definition of a physical state or do we neglect something?

There are a few things I still don't understand: Maybe this first question is stupid, but I don't get it: 1. How does a general state (of the Hilbert space) of any QFT transform under a gauge transformation? Where is the connection to the charge? I think there are just too many concepts I...

Thank you very much, I will do that tonight, if there are any more questions I will let you know :) topper

Does anyone know anything about it or is my question not good? Thank you :)

Hey! I am stuck at a passage in the QFT book of Peskin & Schroeder and I need your help :) It is about page 698, last break. The sentence is: "At long wavelength, the Goldstone bosons become infinitesimal symmetry rotations of the vacuum, Q |0> , where Q is the global charge associated...