Precision calculation of universal amplitude ratios in O(N) universality classes: Derivative Expansion results at order O(∂4).

Abstract

In the last few years the derivative expansion of the Non-Perturbative Renormalization Group has proven to be a very e cient tool for the precise computation of critical quantities. In particular, recent progress in the understanding of its convergence properties allowed for an estimate of the error bars as well as the precise computation of many critical quantities. In this work we extend previous studies to the computation of several universal amplitude ratios for the critical regime of O(N) models using the derivative expansion of the Non-Perturbative Renormalization Group at order O(@4) for three dimensional systems.