Counterterm resummation for 2PI-approximation in constant background

TL;DR

This paper develops a method for explicit counterterm construction in the 2PI effective action framework for scalar fields with symmetry breaking, extending previous work to include skeleton diagrams up to second order in the coupling.

Contribution

It introduces an extended counterterm resummation technique for the 2PI effective action in symmetry breaking backgrounds, applicable to both one-component and O(N) scalar models.

Findings

Counterterm construction for 2PI effective action in symmetry breaking backgrounds.

Extension of previous 2PI-Hartree approximation to include skeleton diagrams up to O(λ^2).

Application to both one-component and O(N) scalar models.

Abstract

Explicit counterterm construction is presented in a symmetry breaking background for the 2PI effective action of the self-interacting one-component scalar field including skeleton diagrams to O(\lambda^2). The applied strategy is an extension of our treatment of the 2PI-Hartree approximation [G. Fejos, A. Patkos and Zs. Szep, Nucl. Phys. A803 (2008) 135]. The procedure is also applied to the O(N) model.