2025/11/27 by Nam, Seung-il · 1 citation
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High-Energy Particle Collisions Research #Pulsars and Gravitational Waves Research #Quantum Chromodynamics and Particle Interactions
paper · doi:10.48550/arxiv.2511.22412
openalex publication_date 2025/11/27 · openalex created_date 2025/12/03 · openalex updated_date 2026/07/28
We investigate chiral symmetry restoration in hot and dense quark matter using a correlator-based chirality-reduced entropy in the in-medium Nambu--Jona-Lasinio (NJL) model. Starting from the lesser Green's function G<(k) in the real-time formalism, we construct the equal-time correlation matrix C(\bmk) and define the left-handed reduced correlator CL(\bmk) = PL C(\bmk) PL. The corresponding von Neumann entropy, Sχ= -Tr[CL ln CL + (1-CL)ln(1-CL)], characterizes the mixedness of the chirality-reduced subsystem. We show that the reduced correlator retains a nontrivial helicity structure and must therefore be described by its full eigenvalue spectrum rather than by a single scalar occupation probability. The self-consistent dynamical quark mass Mq(T,μq) reproduces the expected QCD-like phase structure, with a second-order transition in the chiral limit and a smooth crossover for finite current quark mass. The chirality-reduced entropy correlates with chiral restoration but is not itself an order parameter; instead, it provides complementary information via the full spectrum of the reduced correlator. Our numerical results show that Sχ exhibits characteristic nontrivial behavior across the chiral transition region and serves as an information-theoretic diagnostic of reduced chiral-sector mixedness.