The effect of the energy functional on the pasta-phase properties of catalysed neutron stars

TL;DR

This study investigates how the choice of energy functional influences the properties of nuclear pasta in neutron star crusts, using Bayesian methods to incorporate theoretical and experimental constraints.

Contribution

It introduces a Bayesian framework to constrain the energy functional parameters affecting pasta-phase predictions in neutron stars.

Findings

High-order empirical parameters significantly impact pasta properties.

Surface tension plays a crucial role in pasta-phase formation.

Uncertainties in models are systematically quantified.

Abstract

Nuclear pasta, that is an inhomogeneous distribution of nuclear matter characterised by non-spherical clustered structures, is expected to occur in a narrow spatial region at the bottom of the inner crust of neutron stars, but the width of the pasta layer is strongly model dependent. In the framework of a compressible liquid-drop model, we use Bayesian inference to analyse the constraints on the sub-saturation energy functional and surface tension imposed by both ab-initio chiral perturbation theory calculations and experimental measurements of nuclear masses. The posterior models are used to obtain general predictions for the crust-pasta and pasta-core transition with controlled uncertainties. A correlation study allows extracting the most influential parameters for the calculation of the pasta phases. The important role of high-order empirical parameters and the surface tension is underlined.