Structure of Quark Star: A Comparative Analysis of Bayesian Inference and Neural Network Based Modeling

Silvia Traversi,Prasanta Char

doi:10.3847/1538-4357/abbfb4

Abstract

Abstract In this work, we compare two powerful parameter estimation methods, namely Bayesian inference and neural network based learning, to study the quark matter equation of state with constant speed of sound parameterization and the structure of the quark stars within the two-family scenario. We use the mass and radius estimations from several X-ray sources and also the mass and tidal deformability measurements from gravitational wave events to constrain the parameters of our model. The results found from the two methods are consistent. The predicted speed of sound is compatible with the conformal limit.

Highlights

The equation of state (EOS) of dense nuclear matter is subject to extensive studies throughout the last few decades (Oertel et al 2017; Baiotti 2019)
We present our results for Bayesian and neural networks (NN) calculations following the methodology developed in 4 and 5 respectively for two cases in separate subsections, first keeping the c2s fixed, only varying the e0, and varying both of them
While we have found that results from these two methods are in agreement with each other, from the construction of our NN we do not get any correlation between the predicted parameters

Summary

Introduction

The equation of state (EOS) of dense nuclear matter is subject to extensive studies throughout the last few decades (Oertel et al 2017; Baiotti 2019). A consensus is yet to be reached on the composition of matter at densities higher than the nuclear saturation density In nature, such densities appear only inside the compact remnants formed after the collapse of the core of massive stars ( 8M ). Observing such objects can be very useful in understanding their interior. The discoveries of a few pulsars over 2M have put stringent constraints on the EOS of supranuclear matter (Demorest et al 2010; Antoniadis et al 2013; Fonseca et al 2016; Arzoumanian et al 2018; Cromartie et al 2019) It requires the matter inside such compact stars (CSs) to be stiff to reach such massive stable configurations. The measurement of tidal deformability from the event GW170817 indicates towards smaller radii for the low mass CSs (Abbott et al 2019), meaning the EOS to be soft at the densities corresponding to the low mass configurations

Objectives

Results

Conclusion