奇异夸克物质及夸克-强子界面效应的研究

Strange quark matter is a new type of matter predicted by QCD, which can be obtained with the deconfinement phase transition of hadronic matter under extreme conditions. As the implementation of more powerful scientific facilities, we will have more opportunities to study quark matter based on heavy-ion collisions and astronomical observations. The quark-hadron interface effects are essential to understand the properties of quark matter and the deconfinement phase transition, which are unfortunately poorly constrained. Adopting various treatments for the quark-hadron interface, we investigate the properties of quark-baryon mixed phase and analyze the factors that are contributing to the interface effects. Specifically, based on the Maxwell and Gibbs phase transition constructions, the structures of hybrid stars are investigated and compared with the observational masses and radii of pulsars, where the possible existence of quark matter inside compact stars are discussed. To investigate the nonuniform quark-baryon mixed phase, we employ a Wigner-Seitz approximation and consider particle depletion on the quark-hadron interface. The effects of strong magnetic fields on the structures of quark-baryon mixed phase and hybrid stars are also discussed. Moreover, by allowing baryons entering quark matter, we investigate its consequences on the quark-hadron interface and quark-baryon mixed phase, where the effects of Pauli Blocking and quark-baryon interaction are treated with an effective baryon mass. Based on this project, we expect to have a proper treatment for the quark-hadron interface and obtain reliable surface tension values, which will provide valuable inputs for the proper descriptions of the quark-hadron mixed phase, the nucleation process of quark matter in compact stars and heavy-ion collisions, the creation and propagation of strangelets and nuclearites.

奇异夸克物质是QCD预言的一种新型物质，可以由强子物质在极端条件下解禁闭相变得到。随着各类科学装置的投入和更新，应用重离子碰撞实验和天文观测研究夸克物质的机会越来越多。作为影响夸克物质性质及解禁闭相变过程的重要因素，人们对夸克-强子界面效应缺乏足够的了解。项目从研究夸克重子混合物质的性质入手，采用不同的夸克-强子界面处理方法，分析影响界面效应的各种因素。具体来说，应用不同的混合相构造理论得到混杂星的状态方程及相应的质量半径关系，探讨脉冲星内部存在夸克物质的可能性；应用W-S原胞近似构造混合物质的非均匀相，研究粒子数耗损、强磁场以及重子进入夸克物质之后夸克-强子界面及混合物质结构的演化。通过本项目的研究，给出更加合理的夸克-强子界面处理方法，得到可靠的表面张力数值，为准确描述夸克强子混合物质、致密星以及重离子碰撞实验中夸克物质的成核过程、奇异子和奇异核素的产生机制和传播过程提供重要依据。

夸克-强子界面效应对夸克物质性质及解禁闭相变过程存在重要影响。在基金委资助下，本项目着重研究夸克-强子界面效应及相关的前沿问题，尝试给出更加合理的夸克-强子界面处理方法，得到可靠的表面张力数值。项目主要研究进展归纳如下：1. 利用实验及天文观测来约束核物质对称能、非均匀核物质的结构、以及致密星内部存在超子物质和Δ共振态的可能性，发展了丰富的理论和程序来研究致密星内部强子物质的性质，并得到了较为合理的强子物质状态方程；2. 结合各类QCD唯象模型，研究夸克物质的性质及夸克-真空界面效应，其中包含了色味锁定奇异子、夸克-真空界面的表面张力、夸克物质中重子的等效质量标度、夸克物质声速随密度的变化关系、带电夸克物质集团正负电子对的生成速率、以及处于有限温、有限密、强磁场、以及有限同位旋化学势下夸克物质的性质等; 3. 结合前两个部分对重子物质和夸克物质的研究，系统研究了界面效应对夸克强子混合物质以及混杂星结构和性质的影响，发现只要致密星内部出现夸克物质，夸克-强子界面就会对混杂星的结构和性质产生重要影响，而在最重的致密星内部有较大的可能性存在夸克物质。这些研究有助于揭示由夸克-强子界面所带来的丰富物理过程，约束表面张力的取值范围，为理解夸克强子混合物质、致密星以及重离子碰撞实验中夸克物质的成核过程、奇异子和奇异核素的产生机制和传播过程提供理论依据和参考。