Compact Stars as Hideouts For Color-spin-locked Quark Matter: Implications for Powering High-energy Electromagnetic Emissions

TL;DR

This paper explores the role of color-spin-locked quark matter in compact stars, proposing mechanisms for magnetic field behavior and electromagnetic emissions, with implications for understanding fast radio bursts.

Contribution

It demonstrates that stable massive strange quark stars can host CSL quark matter and suggests a phase transition during cooling as a potential source for fast radio bursts.

Findings

Stable massive strange quark stars can contain CSL quark matter in the MIT bag model.

Most magnetic fields are trapped inside the quark core due to the Meissner effect.

The energy release process could explain fast radio bursts but not gamma-ray bursts or giant flares.

Abstract

The possibility of compact stars as hideouts for color-spin-locked (CSL) quark matter (QM) is investigated in both MIT bag model and Nambu-Jona-Lasinio (NJL) model. Within the framework of NJL model, the idea of absolutely stable quark matter and the existence of conventional pure quark star (QS) are not supported; in addition, there appears to be no stable hybrid configuration above $2M_\odot$ as the hideout for CSL QM. The stable configurations of massive strange quark stars could be reproduced in the MIT bag model with QCD corrections being taken into account; moreover, they could act as the hiding place for the CSL QM. An interesting scenario is proposed that the phase transition to the CSL phase could occur in the cooling process. The CSL quark matter is an electromagnetic (EM) superconductor of Type-I, and a complete Meissner effect is expected. However, the analysis for this sizable superconductor indicates that most of the magnetic field is frozen inside the quark core with a critical strength, while in some special cases a small fraction could be expelled from a thin layer near the surface in a short time. The analysis on energetics and time scale suggests that this process could act as an inducement mechanism to power typical fast radio bursts, but as a single source of energy, it is unlikely to generate other EM emissions such as gamma-ray bursts and giant flares.