Spin polarization phenomena in dense nuclear matter

TL;DR

This paper investigates various spin polarized phase transitions in dense nuclear matter using Fermi liquid theory, revealing multiple possible scenarios depending on the interaction models and density conditions.

Contribution

It identifies and characterizes different spin ordered phase transition scenarios in nuclear matter across a range of densities and isospin asymmetries using effective nucleon-nucleon interactions.

Findings

Multiple spin phase transition scenarios depending on density and interaction model.

Existence of spin polarized states with opposite and same spin directions at critical densities.

Different phase transition pathways for neutron-proton spin configurations.

Abstract

Spin polarized states in nuclear matter with an effective nucleon-nucleon interaction are studied for a wide range of isospin asymmetries and densities. Based on a Fermi liquid theory, it is shown that there are a few possible scenarios of spin ordered phase transitions: (a) nuclear matter undergoes at some critical density a phase transition to a spin polarized state with the oppositely directed spins of neutrons and protons (Skyrme SLy4 and Gogny D1S interactions); (b) at some critical density, a spin polarized state with the like-directed neutron and proton spins appears (Skyrme SkI5 interaction); (c) nuclear matter under increasing density, at first, undergoes a phase transition to the state with the opposite directions of neutron and proton spins, which goes over at larger density to the state with the same direction of nucleon spins (Skyrme SkI3 interaction).