Eur. Phys. J. B 59, 357-365 (2007)
https://doi.org/10.1140/epjb/e2007-00296-x

Correlation functions in the Non Perturbative Renormalization Group and field expansion

Instituto de Física, Facultad de Ingeniería, Univ. de la República, J.H.y Reissig 565, 11000 Montevideo, Uruguay

Corresponding authors: ^a dguerra@fing.edu.uy - ^b mendezg@fing.edu.uy - ^c nicws@fing.edu.uy

Received: 10 April 2007
Revised: 25 August 2007
Published online: 1 November 2007

Abstract

The usual procedure of including a finite number of vertices in Non Perturbative Renormalization Group equations in order to obtain n-point correlation functions at finite momenta is analyzed. This is done by exploiting a general method recently introduced which includes simultaneously all vertices although approximating their momentum dependence. The study is performed using the self-energy of the tridimensional scalar model at criticality. At least in this example, low order truncations miss quantities as the critical exponent η by as much as 60%. However, if one goes to high order truncations the procedure seems to converge rapidly.