In euclidean quantum field theory, the imaginary part of the free energy, defined as the logaritm of the partition function, is it connected to the decay rate?
The action is Euclidean Yang Mills couled with an heavy static source (this is the imaginary current):
$$F_{\mu\nu}F^{\mu\nu}+i\delta_{\mu0}A_{\mu}$$
Solving the euclidean yang mills equation, I have an imaginary solution.
1) My action has an imaginary current as interaction (due to Wick rotation in from the theory in Minkowski space).
2) From the symmetry if the action I know that the functional integral is positive so the partition function is well defined (it's like the integral of Exp(-x^2+ i x)
3) I want to...
I have a partition function in euclidean quantum field theory. I have a parameter, let's say a charge, that I can change in the action that define the partition function.
I found that for small charge the partition function is positive, but there is a critical charge, above the one the...