The properties of strange quark matter under strong rotation

TL;DR

This paper studies how strong rotation affects the properties of strange quark matter using the NJL model, revealing complex influences on chiral condensation, spin polarization, and phase transitions at finite temperature and chemical potential.

Contribution

It provides a detailed analysis of the effects of rotation on quark matter properties and phase diagram, including the interplay with chemical potential and temperature, which is a novel extension in the NJL model context.

Findings

Rotation suppresses chiral condensation.

Rotation enhances first-order quark spin polarization.

Phase transition lines shift with angular velocity and chemical potential.

Abstract

We investigate the rotating quark matter in the three-flavor Nambu and Jona-Lasinio (NJL) model. The chiral condensation, spin polarization and number susceptibility of the light and strange quarks are carefully studied at finite temperature without or with finite chemical potential in this model. We find that the rotation suppresses the chiral condensation and enhances the first-order quark spin polarization, however for the second-order quark spin polarization and quark number susceptibility the effect is complicated and interesting. When extending to the situation with finite chemical potential, we find the angular velocity also plays a crucial role, at small angular velocity the chemical potential enhances the susceptibility, however in the middle region of angular velocity the effect of the chemical potential is suppressed by the angular velocity and susceptibility can be changed considerably, it can be observed that at very low temperature in the presence of quark chemical potential the quark number susceptibility has two maxima with increasing angular velocity. Furthermore, it is found that at sufficiently large angular velocity the contributions played by light quark and strange quark to these phenomena are almost equal. we also explored the phase diagram in the $T$-$\omega$ plane, we observe that there exist first order phase transitions for the rotating system and the first order phase transition lines move toward a higher temperature for decreasing angular velocity. It is also found that the different chemical potentials change the boundary of phase diagram, and that a larger chemical potential shifts down the critical temperature. We expect these studies to be used to understand the chiral symmetry breaking and restoration as well as probe the QCD phase transition.