Kaon condensation in skyrmion matter and compact stars

TL;DR

This paper investigates the emergence of charged kaon condensates in neutron star cores using a Skyrme model, predicting their onset density, effects on dense matter, and implications for neutron star properties.

Contribution

It introduces a novel application of the Bound State Approach within a Skyrme model to study kaon condensation in neutron stars, providing new predictions on onset density and star characteristics.

Findings

Kaon condensation occurs at 1.5 to 2.5 times nuclear saturation density.

Kaon condensates significantly alter the equation of state of dense matter.

Neutron star mass-radius relations are affected by kaon condensed cores.

Abstract

We address the possibility of the appearance of a charged kaon condensate in neutron star cores described within a generalized Skyrme model. Our treatment of strange degrees of freedom is based on the Bound State Approach by Callan and Klebanov, which allows to obtain an in-medium effective potential for the $s$-wave kaon condensate. We predict the onset of kaon condensation at a certain threshold density - whose value depends on the parameters of the model, and ranges between 1.5 and 2.5 times saturation density -, and obtain both the particle fractions and equation of state for dense matter in the kaon condensed phase. Finally, we discuss the effect of such condensates on the mass-radius curves and other observable properties of neutron stars with kaon condensed cores.