Chiral Phase Transition in Rotating Quark Matter with Chiral Imbalance: A Medium Separation Scheme Regularized NJL Model Study

TL;DR

This study uses a regularized NJL model to analyze how rotation and chiral imbalance influence the QCD chiral phase transition, revealing opposing effects and the importance of medium separation scheme regularization.

Contribution

It demonstrates that chiral imbalance buffers the rotation-induced suppression of chiral symmetry breaking, resolving previous regularization discrepancies and highlighting radius-dependent effects.

Findings

Chiral chemical potential enhances chiral symmetry breaking and raises the pseudocritical temperature.

Rotation suppresses chiral symmetry breaking, lowering the pseudocritical temperature.

Medium separation scheme regularization aligns model predictions with lattice QCD results.

Abstract

We investigate the chiral phase transition in rotating quark matter with chiral imbalance using the two-flavor Nambu-Jona-Lasinio (NJL) model regularized by the Medium Separation Scheme (MSS). Our numerical calculations demonstrate that the chiral chemical potential $\mu_5$ and angular velocity $\omega$ exert opposite effects on chiral symmetry breaking: $\mu_5$ enhances the breaking, raising the pseudocritical temperature $T_{pc}$ and sharpening the phase transition, while $\omega$ suppresses the breaking, lowering $T_{pc}$ and smearing the transition. Notably, chiral imbalance buffers the rotation-induced softening of the phase transition-the suppression of $T_{pc}$ by $\omega$ weakens progressively as $\mu_5$ increases. The MSS predicts a monotonic increase of $T_{pc}$ with $\mu_5$, in qualitative agreement with LQCD, resolving the discrepancy found in traditional regularization. Furthermore, the rotational suppression of $T_{pc}$ exhibits strong radius dependence: larger rotation radii amplify the suppression due to enhanced spacetime curvature and centrifugal effects, and can even induce an abrupt drop in $T_{pc}$ in the high-rotation region. These findings clarify the interplay between rotation and chiral imbalance in modulating the QCD chiral phase transition and validate the MSS as a reliable regularization framework for such extreme systems.