Correlation functions in the Non Perturbative Renormalization Group and field expansion

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 $\eta$ by as much as 60%. However, if one goes to high order truncations the procedure seems to converge rapidly.

20 pages, 6 figures. Minor changes. Version to be published in EPJ B

References in corpus (1)

• An analytical approximation scheme to two point boundary value problems of ordinary differential equations

Cited by in corpus (5)

• Infrared behavior and spectral function of a Bose superfluid at zero temperature
• Unified picture of superfluidity: From Bogoliubov's approximation to Popov's hydrodynamic theory
• Analytical approximation schemes for solving exact renormalization group equations in the local potential approximation
• On the 2-point function of the O(N) model
• Non-perturbative renormalization-group approach to lattice models