强磁场下QCD真空极化及夸克物质相关前沿问题研究

The stability of the strange matter under a strong magnetic field is of crucial importance to modern nuclear physics, astrophysics, and cosmology. This project aims at studying magnetized strange matter and its relevant modern frontiers such as the structure of compact stars and color superconductivity etc. We first calculate, according to QCD, the vacuum polarization tensor in a magnetic field, and derive the magnetic field dependence of the QCD running coupling constant. We then combine phenomenological models such as NJL model, as well as the equivparticle model, with the magnetic-field- dependent running coupling to study the properties of strange mater and QCD phase structure. After constructing the self-consistent thermodynamic treatment, we calculate the surface tensor that is specially important for the survival of the strange matter in the deconfinement phase transition. Furthermore, we study the effect of both the strong magnetic field and quark pairing mechanism on the stability of strange quark matter, the existence form of magnetized strange matter, and the structure of compact stars with a strong magnetic field. By comparing our model calculation with the experimental and observational data, we improve our theoretical model continuously with the hope to further increase our knowledge on strong interactions and strongly interacting matter.

强磁场下奇异物质稳定性对于现代核物理、核天文及宇宙学都具有重要意义。本项目研究强磁场下的奇异夸克物质性质及其相关现代核物理中的前沿问题如致密星结构、色超导等。我们首先根据QCD基本理论计算强磁场下的真空极化张量和QCD跑动耦合常数随磁场变化的动力学行为。在此基础上，将得到的磁场依赖跑动耦合常数与NJL和质量禁闭等唯象模型结合起来研究强磁场下的夸克物质性质及QCD相结构，建立一套自洽热力学处理方案,计算有限体积效应中对夸克物质稳定性十分重要的表面张力。进一步研究强磁场效应和夸克配对机制对奇异夸克物质稳定性的影响，强磁场下奇异夸克物质的存在形式和致密星结构等。注意和实验、观测数据比较，不断验证和改进理论模型。期望有助于更深刻认识强相互作用规律和强作用物质性质。

我们利用Nambu-Jona-Lasinio模型和质量禁闭模型研究了强磁场下和有限温度下的奇异夸克物质性质和QCD手征相变。首先通过QCD单圈图近似和Landau最低能级近似，计算出强磁场条件下的真空极化张量，并由此给出QCD跑动耦合常数的磁场依赖性。将该跑动耦合常数引入NJL 模型和质量禁闭模型，建立了自洽的热力学处理方案。我们分别研究了大块夸克物质、色超导物质和有限体积奇异夸克物质、稳定性条件和电荷状态，给出了Landau能级量子数随磁场强度的函数关系。我们发现一定强度的磁场能够增强夸克物质的稳定性。在有限温度下，我们给出了强磁场下QCD手征相变与磁场强度的关系，以及瞬子诱导作用与同位旋对称性的关系。重点指出通过拟合格点数据得到的磁场相关的跑动耦合常数可以很好地解释QCD反磁催化现象。最后，利用包含夸克线性禁闭势和领头阶微扰作用的夸克质量禁闭模型，我们发现奇异夸克质量可以使夸克-强子混合相的状态方程变硬，从而得到较大混杂星质量。