Extracting nuclear matter properties from the neutron star matter equation of state using deep neural networks

TL;DR

This paper employs deep neural networks to accurately infer nuclear matter properties from neutron star observations, advancing the understanding of the symmetry energy and related parameters in nuclear physics.

Contribution

It introduces a novel DNN-based approach to extract nuclear matter properties from neutron star data, demonstrating high accuracy and robustness across multiple nuclear models.

Findings

DNN achieved high accuracy in predicting nuclear matter parameters.

Standard deviations for key parameters were 12.85 MeV and 41.02 MeV.

The method successfully recovers properties from diverse nuclear models.

Abstract

The extraction of the nuclear matter properties from neutron star (NS) observations is nowadays an important issue, in particular, the properties that characterize the symmetry energy which are essential to describe correctly asymmetric nuclear matter. We use deep neural networks (DNNs) to map the relation between cold $\beta$-equilibrium NS matter and the nuclear matter properties. Assuming a quadratic dependence on the isospin asymmetry for the energy per particle of homogeneous nuclear matter and using a Taylor expansion up to fourth order in the iso-scalar and iso-vector contributions, we generate a dataset of different realizations of $\beta$-equilibrium NS matter and the corresponding nuclear matter properties. The DNN model was successfully trained, attaining great accuracy in the test set. Finally, a real case scenario was used to test the DNN model, where a set of 33 nuclear models, obtained within a relativistic mean field approach or a Skyrme force description, were fed into the DNN model and the corresponding nuclear matter parameters recovered with considerable accuracy, in particular, the standard deviations $\sigma(L_{\text{sym}})= 12.85$ MeV and $\sigma(K_{\text{sat}})= 41.02$ MeV were obtained, respectively, for the slope of the symmetry energy and the nuclear matter incompressibility at saturation.