EPJ Web of Conferences 3, 02003 (2010)
https://doi.org/10.1051/epjconf/20100302003

Nonperturbative Renormalisation Group: Applications to the few and many-body systems

¹ School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
² Institute for Theoretical and Experimental Physics, 117259, Moscow, Russia

^a e-mail: boris.krippa@manchester.ac.uk

Abstract

We consider the applications of functional renormalisation group to few and many-body systems. As an application to the few-body dynamics we study the ratio between the fermion-fermion scattering length and the dimer-dimer scattering length for systems of few nonrelativistic fermions. We find a strong dependence on the cutoff function used in the renormalisation flow for a two-body truncation of the action. Adding a simple threebody term substantially reduces this dependence. In the context of many-body physics we study the dynamics of both symmetric and asymmetric many-fermion systems using the same functional renormalisation technique. It is demonstrated that functional renormalisation group gives sensible and reliable results and provides a solid theoretical ground for the future studies. Open questions as well as lines of further developments are discussed.