Extended Skyrme interaction (I): spin fluctuations in dense matter

TL;DR

This paper proposes a modified Skyrme interaction that removes spin instabilities in dense nuclear matter, affecting nuclear response functions and increasing neutrino transparency, with implications for astrophysical models.

Contribution

A new density-dependent modification to the Skyrme interaction is introduced to eliminate ferromagnetic instabilities in dense matter.

Findings

Dense matter becomes more transparent to neutrinos, with a factor increase of 2 to 10.

The modified interaction removes spin instabilities predicted by standard Skyrme models.

Impacts on nuclear response functions and neutrino mean free paths are demonstrated.

Abstract

Most of the Skyrme interactions are known to predict spin or isospin instabilities beyond the saturation density of nuclear matter which contradict predictions based on realistic interactions. A modification of the standard Skyrme interaction is proposed so that the ferromagnetic instability is removed. The new terms are density dependent and modify only the spin p-h interaction in the case of spin-saturated system. Consequences for the nuclear response function and neutrino mean free path are shown. The overall effect of the RPA correlations makes dense matter more transparent for neutrino propagation by a factor of 2 to 10 depending of the density.