# Tag Info

1 vote
Accepted

### Understanding operator valued distributions

This is a common abuse of notation when using distributions in Physics in general, so not something specific to operator-valued ones. Given a test function $f(x)$ you can always define a distribution ...
• 30.9k
1 vote

### Wick rotation in Peskin and Schroeder's QFT

My first question is why $\ell^0 \equiv i \ell_E^0$ imply this counterclockwise rotation. The integration variable $\ell_E^0$ is supposed to be real. If $\ell_E^0$ runs from $-\infty$ to $\infty$ ...
• 9,412

### Wick rotation in Peskin and Schroeder's QFT

The euclidean variabile is on the $x$-axis of the Gauss plane, so the imaginary variable is on the vertical axis. And about the scalar product, you are in Minkowski spacetime, so there is not the ...
• 740

• 174k
1 vote

### Continuum limit of lattice field theory

This isn't really specific to lattice theory - doing stuff in "imaginary time" means you're doing Euclidean QFT. This isn't so much "relativistic" or "non-relativistic" ...
• 111k

### Propagators for a generic Lagrangian density

Formally speaking, if the Hessian matrix of the quadratic action is non-degenerate, the free propagator is given by the inverse matrix, cf. e.g. my related Phys.SE answer here. Concerning OP's last ...
• 174k

Top 50 recent answers are included