A modern approach to deal with problems from statistical mechanichs to high energy physics

Department of Physics (Nanoscience Laboratory)

Abstract

In the many years since K. Wilson first conceived of the Renormalization Group (RG), the non-perturbative functional renormalization group has become a powerful technique that can be used to investigate a wide range of physical systems, from statistical physics to high energy, without relying on perturbation theory. Its modern formulation is based on an exact flow equation for the Effective Average Action (EAA), which is a functional that interpolates between the bare action and the Effective Action. In this talk, I will present a small review of this method and how it works. Then I will consider the generalized form of the flow equation for the EAA which incorporates field redefinitions. This new equation allows implementing essential schemes, i.e. schemes where we can decouple essential couplings from inessential ones. From the practical point of view, this produces simplifications in the calculations, while from the conceptual point of view it provides a clearer picture of renormalization itself since the redundant, non-physical content is automatically disregarded in favor of a description based only on quantities that enter expressions for physical observables.
 

Scientific Coordinator

Lorenzo Pavesi