Mass and radius relations of quarkyonic stars using an excluded volume model

TL;DR

This paper develops an excluded volume model for quarkyonic neutron matter to predict neutron star mass-radius relations, demonstrating that with suitable nuclear interactions, the model aligns with observational constraints.

Contribution

It introduces a novel excluded volume model for charge neutral quarkyonic neutron matter and shows how nuclear interactions can produce realistic neutron star properties.

Findings

Model predicts mass-radius relations consistent with observations.

Inclusion of nuclear interactions improves model accuracy.

The model can match constraints from gravitational wave data.

Abstract

Inspired by the excluded volume model for isospin symmetric quarkyonic matter, we construct an `excluded volume' model for a charge neutral quarkyonic phase whose hadronic sector contains only neutrons. We refer to this model as quarkyonic neutron matter. We compute the equation of state for this model and solve the Tolman-Oppenhermer-Volkoff equations to obtain mass and radius relations relevant for neutron stars. The most straightforward extension of the model for symmetric quarkyonic matter to quarkyonic neutron matter does not satisfy the mass radius constraints from neutron star measurements. However, we show that by incorporating appropriate nuclear interactions in the excluded volume model one can produce mass-radius relations that lie within the constraints obtained from gravitational waves of binary neutron star mergers and maximum mass measurements of neutron stars.