Two-Loop Effective Action for Theories with Fermions

TL;DR

This paper introduces a new formalism for calculating the two-loop effective action in fermionic models, successfully applying it to the Nambu-Jona-Lasinio model where the two-loop contribution vanishes.

Contribution

A novel approach for computing the two-loop effective action in fermionic theories, demonstrated on the Nambu-Jona-Lasinio model.

Findings

Two-loop effective potential for the Nambu-Jona-Lasinio model is zero.

The formalism accurately computes fermionic contributions up to two loops.

Method improves precision in effective action calculations for fermionic models.

Abstract

On the basis of a new approach proposed in our previous work we develope a formalism for calculating of the effective action for some models containing fermion fields. This method allows us to calculate the fermionic part of the effective action (up to two-loop level) properly. The two-loop contribution to the effective potential for the Nambu-Jona-Lasinio model is calculated and is shown to vanish.