Loop expansion of the average effective action in the functional renormalization group approach

TL;DR

This paper introduces a novel perturbation expansion for the effective action within a functional renormalization group framework that utilizes composite fields, highlighting fundamental differences from traditional methods even at the one-loop level.

Contribution

It presents a new approach to the functional renormalization group using composite fields for regulators, providing insights into the properties of effective actions.

Findings

Explicit demonstration of differences in effective actions at one-loop level

Introduction of a perturbation expansion based on composite fields

Clarification of the role of regulator functions in the new approach

Abstract

We formulate a perturbation expansion for the effective action in a new approach to the functional renormalization group method based on the concept of composite fields for regulator functions being their most essential ingredients. We demonstrate explicitly the principal difference between the properties of effective actions in these two approaches existing already on the one-loop level in a simple gauge model.