三味NJL模型下有限同位旋密度与磁场中的QCD相变
QCD phase transition at finite isospin density and magnetic field within the three-flavor NJL model
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中文总结 AI 辅助
该研究在三味NJL模型中，结合Ginzburg-Landau近似等方法，探究有限同位旋密度与磁场下的QCD相变，明确了不同磁场下的主导相及临界同位旋化学势的变化规律。
中文摘要 AI 辅助
此前，人们在两味Nambu-Jona-Lasinio（NJL）模型中研究了有限同位旋密度与磁场下的QCD相变。本工作将该研究扩展至更现实的三味情形，其中充分考虑了奇异夸克贡献以及强磁场中的夸克质量劈裂。采用Ginzburg-Landau近似和费米子传播子的Landau表示，我们重新研究了从正常手征对称性破缺相到π介子超流相或ρ介子超导相的转变。与此前研究不同，我们将介子场投影到磁场中带电点粒子的本征态上，并证明来自夸克圈的相应自能是规范不变的，且相对于额外的横向自由度简并。不过，数值结果与此前发现在定性上一致：随着同位旋化学势的增加，小磁场下更倾向于π介子超流相，而大磁场下更倾向于ρ介子超导相。在三味模型中，由于ρ介子的最低能量随磁场增强而增加，对应的临界同位旋化学势也随磁场增大。
英文摘要
Previously, the QCD phase transition at finite isospin density and magnetic field was explored within the two-flavor Nambu--Jona-Lasinio model. This work extends the study to the more realistic three-flavor case, where not only strange quark contributions but also quark mass splitting in a strong magnetic field are fully taken into account. Adopting the Ginzburg-Landau approximation and the Landau representation for fermion propagators, we re-explore the transitions from the normal chiral symmetry breaking phase to pion superfluidity or rho superconductivity. Unlike the previous study, we project the mesonic fields onto the eigenstates of a charged point particle in a magnetic field and prove that the corresponding self-energies from quark loops are gauge invariant and degenerate with respect to the extra transverse degrees of freedom. However, the numerical results are qualitatively consistent with previous findings: as the isospin chemical potential increases, pion superfluidity is favored at small magnetic fields, while rho superconductivity is favored at large magnetic fields. In the three-flavor model, since the lowest energy of the rho meson increases with stronger magnetic field, the corresponding critical isospin chemical potential also increases with the magnetic field.
