Exact Schwinger Proper Time Renormalisation

Abstract

We derive an exact version of the Schwinger Proper Time Renormalisation Group flow equation from first principles from the complete path integral, without using any perturbative expansion. We study the advantages of this flow equation as compared to the canonical Exact Renormalisation Group flow equation, which uses a regulator in momentum space. We use our flow equation to recover the convexity of the effective scalar potential in the IR limit and apply it to the study of false-vacuum decay.

Added details regarding the derivation of the flow equation and one figure sketching its interpretation in terms of Feynman diagrams. Improved discussion of the results