All Questions
5
questions
3
votes
1
answer
190
views
Wick Rotation and sign of the integrand in Weinberg's book
I'm studying from Weinberg's QFT volume 1, chapter 11. I have a problem with equation $(11.2.7)$.
Starting from eq. $(11.2.5)$
$$
\begin{align}
\Pi^{\rho\sigma} (q) = \frac{-ie^2}{(2\pi)^4} \int_0^...
- 2,347
1
vote
0
answers
1k
views
Euclidean fermion propagator
I want to write the fermion propagator
$$
i\dfrac{p^\mu\gamma_\mu+m}{p^2-m^2}
$$
in Euclidean space.
In Minkowski, the conventions are $g^{\mu\nu}=\{+,-,-,-\}$; $\gamma^\mu\gamma^\nu+\gamma^\nu\gamma^...
- 2,921
1
vote
0
answers
153
views
Having trouble evaluating a spacetime integral, using Feynman parameterization and wick rotation
I am trying to evaluate the following integral,
$$\int \frac{d^4k}{(2\pi)^2k^2} \left(\frac{\mu}{4M} \right)^2 \frac{k^4 + \frac{1}{3}\vec{k}(k^2 - 2Mk_0)}{(k^4 - 4m^2k_0^2)(k^2 - 2Mk_0)} .$$
My ...
- 145
2
votes
0
answers
2k
views
The Feynman propagator and the $i\epsilon$ prescription
The Feynman propagator is usually represented in the i-epsilon form and texts solve the integral in this form (as opposed to doing the Feynman (time-ordered) contour on the real axis). Restricting ...
- 71
4
votes
0
answers
3k
views
Feynman Propagator in Position Space through Schwinger Parameter
So I am aware of a thread at Propagator of a scalar in position space but it does not answer my question, which is more about poles in position space.
Starting from
$$D_F(x_1-x_2) = \int \frac{d^4 ...
- 2,095