Phase diagram of nuclear "pasta" and its uncertainties in supernova cores

TL;DR

This paper investigates how different quantum molecular dynamics models affect the predicted phase diagram of nuclear pasta in supernova cores, highlighting the role of symmetry energy and neutron matter properties in these uncertainties.

Contribution

It demonstrates the model dependence of nuclear pasta phase diagrams and links uncertainties to properties like symmetry energy and neutron matter energy.

Findings

Pasta phase mass fraction exceeds 10-20% in collapsing cores.

Differences in phase diagrams are explained by neutron matter energy and saturation density.

Density dependence of symmetry energy influences phase diagram uncertainties.

Abstract

We examine the model dependence of the phase diagram of inhomogeneous nulcear matter in supernova cores using the quantum molecular dynamics (QMD). Inhomogeneous matter includes crystallized matter with nonspherical nuclei - "pasta" phases - and the liquid-gas phase separating nuclear matter. Major differences between the phase diagrams of the QMD models can be explained by the energy of pure neutron matter at low densities and the saturation density of asymmetric nuclear matter. We show the density dependence of the symmetry energy is also useful to understand uncertainties of the phase diagram. We point out that, for typical nuclear models, the mass fraction of the pasta phases in the later stage of the collapsing cores is higher than 10-20 %.