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
Revised: 25 August 2007
Published online: 1 November 2007
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.
PACS: 03.75.Hh – Static properties of condensates; thermodynamical, statistical, and structural properties / 05.30.Jp – Boson systems
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2007