致密星体与QCD相图的唯象模型研究

The investigation of the properties of strong interaction matter is one of the fundamental issues in contemporary nuclear physics, astrophysics, and cosmology, which plays a central role in understanding the nuclear structures and reactions, many critical issues in astrophysics, and the matter state at early universe. People can study compact stars and QCD phase diagram to explore the properties of strong interaction matter. The ab initio lattice QCD(LQCD) numerical Monte Carlo calculations provide a solid basis for our knowledge of strong interaction matter at finite temperature regime with zero baryon density. However, the regime of finite baryon density is still inaccessible by LQCD because of the Fermion sign problem. This project will devote to the following investigation for the properties of compact stars and QCD phase diagram by using phenomenological models:.1..By using quark phenomenological models, especially confined density dependent mass model, equation of state of strong interaction matter will be calculated and the properties of compact stars can also be studied in combination with the observational data..2..Based on the ENJL and EPNJL models, the chiral symmetry restoration for quark condensation and the confinement feature for quarks will be studied, which is useful to describe the QCD phase diagram..3..The properties of the compact stars and QCD phase diagram will be further studied at finite temperature under strong magnetic fields..The work will be helpful to reveal essential properties of strong interaction matter at finite baryon density, and make predictions for the research on compact stars and QCD phase diagram.

研究强相互作用物质的性质对理解核物理、天体物理以及早期宇宙的物质形态意义巨大，引起人们广泛的关注。研究致密星体以及QCD相图对于探索强相互作用物质的性质具有非常重要的作用。目前，有限重子数密度强相互作用物质的性质无法用格点QCD来计算，为致密星体和QCD相图的研究带来困难。针对这个难点，本项目将对致密星体和QCD相图的性质展开以下研究：（1）以夸克唯象模型为突破口，计算有限重子数密度强相互作用物质的物态方程，结合天文观测结果给出致密星体性质；（2）通过扩展的NJL、PNJL模型，研究夸克凝聚的手征对称性恢复相变以及夸克的禁闭性质，进而描述QCD相图；（3）重离子碰撞以及致密星体研究均涉及强磁场和有限温度的情况，可以借此进一步研究强磁场有限温度情况致密星体和QCD相图的性质。通过本项目的研究，有助于揭示有限重子数密度下强相互作用物质的性质，为致密星体和QCD相图的研究提供理论预言。

项目组成员们基于夸克物质的唯象模型，研究了强相互作用物质的性质、致密星体以及量子色动力学（QCD）相图等相关物理问题。目前取得了如下结果：1.在SU(3)Nambu-Jona_Lasinio（NJL）模型里考虑同位旋矢量-矢量道以及同位旋矢量-标量道计算零温的夸克星以及对称能；2.在SU(3) NJL模型里加入同位旋矢量道的同时，考虑了夸克物质有限温度情况，给出了原生夸克星的星体发展阶段；3.在SU(3) NJL模型里考虑强磁场计算夸克物质热力学性质，给出零温磁星性质；4.利用SU(3) NJL模型加入同位旋矢量道，给出QCD相图的相关性质；5.在同位旋质量密度相关模型里引入温度，给出此模型下原生夸克星的星体发展阶段并讨论有限温度下夸克物质对称自由能的性质；6.建立同位旋夸克禁闭质量模型，计算了奇异夸克物质和夸克星的性质；7.利用CIDDM模型计算有限温度下磁星的性质。我们的结果表明，同位旋效应对于夸克物质对称能、夸克物质以及夸克星的性质影响很大，并且我们可以基于不同的唯象模型，通过调节同位旋相互作用，描述两倍太阳质量的夸克星。