An Asymptotically Causal Metamodel for Neutron Star Equations of State

Fuente: arXiv
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Autores principales: Montefusco, Gabriele, Antonelli, Marco, Gulminelli, Francesca
Formato: Preprint
Publicado: 2026
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author Montefusco, Gabriele
Antonelli, Marco
Gulminelli, Francesca
author_facet Montefusco, Gabriele
Antonelli, Marco
Gulminelli, Francesca
contents Nuclear metamodels - phenomenological parametrizations of the energy of nuclear matter - are convenient tools to explore the space of realistic neutron star configurations constrained by astrophysical and nuclear data. While much recent work has focused on composition-agnostic barotropic models, the metamodel approach is designed to describe the composition dependence of the relevant thermodynamic potential. We revise a previously proposed non-relativistic metamodel by introducing a more controlled high-density behaviour, improving both its causal properties and its accuracy in reproducing the pressure and the beta-equilibrium composition of microscopically motivated equations of state. Since causality is automatically enforced at high density, the fraction of discarded models due to superluminal sound speeds is substantially reduced, facilitating metamodel-based explorations of equilibrium neutron star configurations. We further assess our framework by performing a Bayesian inference of neutron star properties beyond standard observables such as masses and radii, exploiting the metamodel's ability to probe composition-dependent quantities including the dUrca threshold and the Ledoux criterion for g-mode stability.
format Preprint
id arxiv_https___arxiv_org_abs_2604_00196
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle An Asymptotically Causal Metamodel for Neutron Star Equations of State
Montefusco, Gabriele
Antonelli, Marco
Gulminelli, Francesca
Nuclear Theory
High Energy Astrophysical Phenomena
Nuclear metamodels - phenomenological parametrizations of the energy of nuclear matter - are convenient tools to explore the space of realistic neutron star configurations constrained by astrophysical and nuclear data. While much recent work has focused on composition-agnostic barotropic models, the metamodel approach is designed to describe the composition dependence of the relevant thermodynamic potential. We revise a previously proposed non-relativistic metamodel by introducing a more controlled high-density behaviour, improving both its causal properties and its accuracy in reproducing the pressure and the beta-equilibrium composition of microscopically motivated equations of state. Since causality is automatically enforced at high density, the fraction of discarded models due to superluminal sound speeds is substantially reduced, facilitating metamodel-based explorations of equilibrium neutron star configurations. We further assess our framework by performing a Bayesian inference of neutron star properties beyond standard observables such as masses and radii, exploiting the metamodel's ability to probe composition-dependent quantities including the dUrca threshold and the Ledoux criterion for g-mode stability.
title An Asymptotically Causal Metamodel for Neutron Star Equations of State
topic Nuclear Theory
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2604.00196