Chiral phase transition in rotating quark matter with chiral imbalance: a medium separation scheme regularized NJL model study

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 μ ₅ μ 5 and angular velocity ω ω exert opposite effects on chiral symmetry breaking: μ ₅ μ 5 enhances the breaking, raising the pseudocritical temperature Tpc T pc and sharpening the phase transition, while ω ω suppresses the breaking, lowering Tpc T pc and smearing the transition. Notably, chiral imbalance buffers the rotation-induced softening of the phase transition – the suppression of Tpc T pc by ω ω weakens progressively as μ ₅ μ 5 increases. The MSS predicts a monotonic increase of Tpc T pc with μ ₅ μ 5 , in qualitative agreement with LQCD, resolving the discrepancy found in traditional regularization. Furthermore, the rotational suppression of Tpc 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 Tpc T pc in the high-rotation region. These extended studies 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.