Is gluonic color-spin locked phase stable?

TL;DR

This paper investigates the stability of the gluonic color-spin locked phase in dense two-flavor quark matter, demonstrating it is free from certain instabilities and describing an anisotropic superconducting medium.

Contribution

It provides the first detailed analysis of the GCSL phase's stability and symmetry breaking, including gluon Meissner masses and the absence of chromomagnetic and Sarma instabilities.

Findings

GCSL phase is stable across its existence region.

The phase exhibits anisotropic color and electromagnetic superconductivity.

It is free from chromomagnetic and Sarma instabilities.

Abstract

We study the gluonic color-spin locked (GCSL) phase in dense two-flavor quark matter. In this phase, the color and spatial rotational symmetries are spontaneously broken down to SO(2)_{diag} with the generator being an appropriate linear combination of the color and rotational ones. The Meissner masses of gluons and the mass of the radial mode of the diquark field in the GCSL phase are calculated and it is shown that this phase is free from the chromomagnetic and Sarma instabilities in the whole parameter region where it exists. The GCSL phase describes an anisotropic color and electromagnetic superconducting medium. Because most of the initial symmetries in this phase are spontaneously broken, its dynamics is very rich.