Axial Symmetry Breaking and Chiral Separation Effect in Nambu-Jona-Lasinio Model
Abstract
We investigate the chiral separation effect (CSE) and the axial-partner susceptibility splittings within the three-flavor Nambu--Jona-Lasinio (NJL) model, providing two complementary aspects of axial dynamics in hot and dense magnetized matter. We compare a field-dependent scalar coupling, which leads to inverse magnetic catalysis (IMC), with a constant coupling, which exhibits magnetic catalysis (MC). In the weak-field limit, the CSE conductivity is suppressed at low temperature and approaches its chiral-limit value as the temperature increases. Its magnetic-field dependence is reversed between the IMC and MC scenarios. On the other hand, the susceptibility splittings ΔA = χπ0 − χδ0 and Δχ= χπ0 −χσl are suppressed at high temperature or density, reflecting the substantial restoration of axial symmetries. Their difference develops a pronounced peak near the cross-over or first-order transition, implying that the U(1)A(0) and U(1)A(3) symmetries are restored at different temperatures or chemical potentials. Both the weak-field CSE and the IMC susceptibility splittings at vanishing chemical potential agree qualitatively with lattice-QCD calculations. We also provide model predictions for the susceptibility splittings at finite density.
Related
- Axial U(1) Symmetry Breaking in Hot QCD: From Topology to the Chiral Phase Transition
- Exact chiral symmetry, non-Hermiticity, and the axial anomaly on the lattice: A symmetry-class criterion for disorder-induced undoubling
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- Chiral-symmetry breaking and degeneracy in Koch fractal geometries
BibTeX
@misc{zhu2026axial,
title = {{Axial Symmetry Breaking and Chiral Separation Effect in Nambu-Jona-Lasinio Model}},
author = {Xin-Nan Zhu and Xin-Li Sheng and Shu-Yun Yang and Shijun Mao and Defu Hou},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.39886},
eprint = {2609.39886},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.39886},
}
RIS
TY - UNPB
TI - Axial Symmetry Breaking and Chiral Separation Effect in Nambu-Jona-Lasinio Model
AU - Xin-Nan Zhu
AU - Xin-Li Sheng
AU - Shu-Yun Yang
AU - Shijun Mao
AU - Defu Hou
PY - 2026
DA - 2026/09/30
PB - arXiv
DO - 10.48550/arxiv.2609.39886
UR - https://arxiv.org/abs/2609.39886
AB - We investigate the chiral separation effect (CSE) and the axial-partner susceptibility splittings within the three-flavor Nambu--Jona-Lasinio (NJL) model, providing two complementary aspects of axial dynamics in hot and dense magnetized matter. We compare a field-dependent scalar coupling, which leads to inverse magnetic catalysis (IMC), with a constant coupling, which exhibits magnetic catalysis (MC). In the weak-field limit, the CSE conductivity is suppressed at low temperature and approaches its chiral-limit value as the temperature increases. Its magnetic-field dependence is reversed between the IMC and MC scenarios. On the other hand, the susceptibility splittings Δ_A = χ_π^0 − χ_δ^0 and Δχ= χ_π^0 −χ_σ_l are suppressed at high temperature or density, reflecting the substantial restoration of axial symmetries. Their difference develops a pronounced peak near the cross-over or first-order transition, implying that the U(1)_A^(0) and U(1)_A^(3) symmetries are restored at different temperatures or chemical potentials. Both the weak-field CSE and the IMC susceptibility splittings at vanishing chemical potential agree qualitatively with lattice-QCD calculations. We also provide model predictions for the susceptibility splittings at finite density.
ER -