Shear viscosity of neutron matter from realistic nucleon-nucleon interactions

TL;DR

This paper calculates the shear viscosity of neutron matter using realistic nucleon-nucleon interactions, considering medium modifications, which is crucial for understanding neutron star stability.

Contribution

It provides a numerical study of neutron matter shear viscosity incorporating medium effects with a state-of-the-art interaction model.

Findings

Medium modifications significantly increase viscosity at higher densities.

Viscosity increases notably beyond 0.1 fm^{-3}.

Results impact neutron star stability analysis.

Abstract

The calculation of transport properties of Fermi liquids, based on the formalism developed by Abrikosov and Khalatnikov, requires the knowledge of the probability of collisions between quasiparticles in the vicinity of the Fermi surface. We have carried out a numerical study of the shear viscosity of pure neutron matter, whose value plays a pivotal role in determining the stability of rotating neutron stars, in which these processes are described using a state-of-the-art nucleon-nucleon potential model. Within our approach medium modifications of the scattering cross section are consistently taken into account, through an effective interaction obtained from the matrix elements of the bare interaction between correlated states. Inclusion of medium effects lead to a large increase of the viscosity at densities larger than $\sim 0.1$ fm^{-3}.