发表机构
Instituto de Física Teórica, Universidade Estadual Paulista; Programa de Pós-graduação em Física, Universidade Federal do Maranhão（圣保罗州立大学理论物理研究所; 马拉尼昂联邦大学物理研究生项目）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文在NJL模型中重新审视致密夸克物质的自旋极化相，发现介质分离方案下自旋极化随密度持续增强，可为磁星强磁场提供微观贡献。
AI 中文摘要
高重子密度下强相互作用物质的相结构仍是QCD中的一个开放问题，对中子星的内部结构和磁性质具有重要意义。我们在具有张量相互作用的双味Nambu-Jona-Lasinio模型中重新审视冷致密夸克物质中夸克自旋极化（QSP）相的出现，重点关注其对正则化的依赖性。我们比较了传统正则化方案（TRS）与介质分离方案（MSS），前者对真空和介质贡献均施加尖锐动量截断，后者则分离紫外发散的真空项，同时使有限的介质相关相空间贡献保持无截断。两种方案导致定性不同的结果。在TRS中，QSP凝聚体在高化学势下最终坍缩，导致非单调的热力学行为，并且对于某些耦合，违反因果性。在MSS中，QSP凝聚体反而随密度单调增加，状态方程保持因果性，相关的自发磁化强度向高密度方向增长。自旋极化在高密度下的持续存在可能为致密星（包括磁星）的强磁场提供微观贡献。一项探索性的混合星构造进一步表明，QSP相可以显著改变状态方程、稳定性趋势和质量-半径关系。这些结果强调了介质相空间处理一致性的重要性，并展示了持续自旋极化夸克相对中子星物理的潜在影响。
英文摘要
The phase structure of strongly interacting matter at high baryon density remains an open problem in QCD, with important implications for the internal structure and magnetic properties of neutron stars. We reexamine the emergence of a quark spin-polarized (QSP) phase in cold, dense quark matter within the two-flavor Nambu-Jona-Lasinio model with tensor interactions, focusing on its dependence on regularization. We compare the traditional regularization scheme (TRS), where a sharp momentum cutoff is applied to both vacuum and medium contributions, with the medium separation scheme (MSS), where ultraviolet-divergent vacuum terms are isolated while finite medium-dependent phase-space contributions remain cutoff free. The two prescriptions lead to qualitatively different results. In TRS, the QSP condensate eventually collapses at high chemical potential, leading to nonmonotonic thermodynamic behavior and, for some couplings, violations of causality. In MSS, the QSP condensate instead increases monotonically with density, the equation of state remains causal, and the associated spontaneous magnetization grows toward high density. The persistence of spin polarization at high density may provide a microscopic contribution to the strong magnetic fields of compact stars, including magnetars. An exploratory hybrid-star construction further shows that the QSP phase can significantly modify the equation of state, stability trends, and mass-radius relations. These results highlight the importance of a consistent treatment of medium phase space and demonstrate the potential impact of a persistent spin-polarized quark phase on neutron-star physics.
