arXiv subjects

Jaquelyn Noronha-Hostler

Publications and source records attributed to Jaquelyn Noronha-Hostler.

3 recordsLinked to original sources

arXiv2026

Phase Stability in the 3-Dimensional Open-source Code for the Chiral mean-field Model

In this paper we explore independently for the first time three chemical potentials (baryon $μ_B$, charged $μ_Q$, and strange $μ_S$) in the Chiral Mean Field (CMF) model. We designed and implemented \texttt{CMF++}, a new version of the CMF model rewritten in \texttt{C++} that is optimized, modular, and well-documented. \texttt{CMF++} has been integrated into the MUSES Calculation Engine as a free and open-source software module. The runtime improved in more than 4 orders of magnitude across all 3 chemical potentials, when compared to the legacy code. Here we focus on the zero temperature case and study stable, as well as metastable and unstable, vacuum, hadronic, and quark phases, showing how phase boundaries vary with the different chemical potentials. Due to the significant numerical improvements in \texttt{CMF++}, we can now for the first time sweep the entire $μ_B$, $μ_S$, $μ_Q$ phase space, investigate metastable phases, and calculate high-order susceptibilities within the CMF framework. This allows us to find phases of matter that include a light hadronic phase, a strangeness-dominated hadronic phase, and a quark phase. The numerical improvements also allow us to identify the order of the transitions among these phases, finding a first-order chiral symmetry restoration phase transition among the hadronic phases (favored for negative $μ_Q$ and/or $μ_S$ for some coupling schemes), in addition to third-order phase transitions. In particular, we identify for the first time triple points in the CMF model, where both chiral symmetry restoration and deconfinement phase transitions meet in the chemical potential phase space. Such points could potentially be identified in low-energy heavy-ion collisions.

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arXiv2025

Highly-accurate neutron star modeling in the Hartle-Thorne Approximation

Future X-ray missions, such as NICER and LOFT, together with gravitational-wave observations from ground-based detectors, will provide new insights into neutron stars. Interpreting accurate observations in the future will require accurate models of their gravitational fields. In this first paper of a two-part series, we construct the perturbation equations for slowly-rotating, isolated, and unmagnetized neutron stars, extending the Hartle-Thorne approximation to seventh order in a slow-rotation expansion. We obtain exact, closed-form, analytical solutions for the exterior metric at each order in spin. From these solutions, we derive expressions for the mass and mass-current scalar multipole moments, $M_{\ell}$ and $S_{\ell}$, respectively, up to seventh order in spin frequency, using two distinct methods. This high-order expansion allows us to calculate second-, fourth-, and sixth-order relative spin corrections to the observed mass and moment of inertia; second- and fourth-order relative spin corrections to the quadrupole and octopole moments; second-order relative spin corrections to the hexadecapole and dotriacontapole moments; and leading-order-in-spin expressions for the hexacontatetrapole and hectoicosaoctapole moments. Going to seventh order in the spin-frequency approximation will enable very precise calculations of X-ray pulse profiles, as well as the I-Love-Q and three-hair relations for slowly-rotating neutron stars. These results will be valuable for breaking parameter degeneracies in future multimessenger observations.

gr-qc↗

arXiv2025

Building Neutron Stars with the MUSES Calculation Engine

Exploring the equation of state of dense matter is an essential part of interpreting the observable properties of neutron stars. We present here the first results for dense matter in the zero-temperature limit generated by the MUSES Calculation Engine, a composable workflow management system that orchestrates calculation and data processing stages comprising a collection of software modules designed within the MUSES framework. The modules presented in this work calculate equations of state using algorithms spanning three different theories/models: (1) Crust Density Functional Theory, valid starting at low densities, (2) Chiral Effective Field Theory, valid around saturation density, and (3) the Chiral Mean Field model, valid beyond saturation density. Lepton contributions are added through the Lepton module to each equation of state, ensuring charge neutrality and the possibility of $β$-equilibrium. Using the Synthesis module, we match the three equations of state using different thermodynamic variables and different methods. We then couple the complete equation of state to a novel full-general-relativity solver (QLIMR) module that calculates neutron star properties. We find that the matching performed using different thermodynamic variables affects differently the range obtained for neutron star masses and radii (although never beyond a few percent difference). We also investigate the universality of equation of state-independent relations for our matched stars. Finally, for the first time, we use the Flavor Equilibration module to estimate bulk viscosity and flavor relaxation charge fraction and rates (at low temperature) for Chiral Effective Field Theory and the Chiral Mean Field model.

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