Investigations of the Renormalization Group approach to the nucleon-nucleon interaction and the Nuclear Many-body Problem

Description 
One of the main challenges of nuclear physics is to build up a microscopic theory for finite nuclei and nuclear matter. Conventional nuclear many-body calculations are strongly non-perturbative in the inter-nucleon interactions. This non-perturbative behavior arises from several sources: 1. a strongly repulsive short-range interaction, 2. a tensor force, e.g. from pion exchange, which is highly singular at short-distances, 3. the presence of low-energy bound states or nearly bound states (in the S waves). It turns out that these sources of non-perturbative physics are density and/or cut-off dependent. This fact is exploited by using the low-momentum Renormalization Group based interactions as input, which makes nuclear matter calculation in particle-particle channel perturbative. 

In this talk, I will quantify the idea of ``perturbativeness'' through the Weinberg Eigenvalue Analysis. Close to the Fermi surface, we observe signatures of pairing in these eigenvalues and the momentum independent pairing gap can be easily extracted, which is in very good agreement with the BCS calculation.

Organised by Prof.Marcello Baldo