# Imaginary time in spin foams

1. Jan 31, 2012

### atyy

In QM and QFT, imaginary time is used to make the oscillatory path integral converge, and also to handle terms that are not semibounded in Minkowski spacetime.

In CDT, imaginary time is also used after the path integral is restricted to "causal" configurations.

How is the oscillatory term handled in spin foams?

Last edited: Jan 31, 2012
2. Feb 1, 2012

### genneth

Is this not the point of Euclidean spin-foams?

3. Feb 1, 2012

### atyy

Looking in Perez's notes, Eq 27 for a Euclidean spin foam, it looks like he still has the i in the path integral. I guess the Euclidean means that it produces a geometry with Euclidean signature (I guess he takes only one of the two imaginary time replacements)?