Hello,
I would appreciate it if anyone could help me with this problem: can there be any instantonic contribution to the following generic two-points function?
\left \langle \varphi(x) \varphi(y) \right\rangle= \int D\varphi D A \varphi(x) \varphi(y) \exp \left( -S_E...
I am not sure if I understood your question exactly and my reply may sound trivial. Anyway,
when you have a symmetry there are invariants associated with each of those symmetries (Noether's Theorem). In other words some quantities will be conserved during, let's say, a collision experiment like...
Hello,
Assuming that I have a pure U(1) gauge theory. The partition function can be written as
Z=\int D(A) \exp (-F_{\mu\nu} F^{\mu\nu})
If I want to find the effective action in terms of an external classical field I can write it in terms of
A\rightarrow A+B where B is background and then...
Could anyone please, explain the connection between the Free Energy and the Action?
I know the definitions of each but not sure about the connection.
I read somewhere that the free energy is the same as the action when calculated "on-shell". What does this "on-shell" thing mean in this...