Equations of State of Superdense Nuclear Matter for Use in Neutron Star Merger Simulations

LIGO和VIRGO首次观测到名为GW170817的双中子星并合，将科学界带入了利用引力波进行多信使天文学的时代。数值相对论模拟表明，热物质和致密物质的压力-密度关系（即状态方程）在模拟中子星碰撞中起着重要作用。中子星的质量是太阳的两倍，但直径通常只有20公里左右。在如此特殊的密度下，原子核坍缩，中子和质子被紧紧地挤在一起，以至于它们可能分裂成由上下夸克组成的等离子体，而上下夸克是物质的最基本组成部分。该项目的目标是为研究中子星合并模拟的研究人员确定一套全面的超致密核物质状态方程的最先进模型。特别是，该小组将研究夸克在中子星合并中的作用，并通过夸克可能在合并中子星产生的引力波信号中记录自己的方法来识别可能的信号。状态方程的模型将通过在线服务（CompOSE, StellarCollapse）提供给社区。圣地亚哥州立大学的研究生和本科生将在物理领域接受丰富的跨学科培训，丰富他们在课堂上学到的教育经验。该项目的首要目标是确定一套全面的、最先进的模型，用于热和致密核物质的状态方程，供从事中子星合并模拟的研究人员使用。当代有效的场论模型，即相对论密度相关的Hartree （DDRMF）模型和（局部和非局部）3-flavor Polyakov-Nambu-Jona-Lasinio （3PNJL）模型，将用于实现这一目标。DDRMF是一个通用的、数值上易于处理的核多体理论，非常适合于研究密集和密集强子物质。3PNJL模型是量子色动力学的一个有效模型，它允许对夸克物质进行当代建模。它为量子色动力学提供了一种功能和数值上易于处理的方法。该模型解释了手性对称的动态破缺，并通过波利亚科夫环势模拟了夸克约束。夸克在零温度和有限温度下的反定义将使用相平衡的吉布斯和麦克斯韦条件进行研究。核理论、核实验和天体物理学中目前可能存在的最强约束将用于确定有效场论的参数，并测试状态方程的有效性。该项目推进了“宇宙之窗：多信使天体物理学时代”的目标，这是美国国家科学基金会未来投资的十大理念之一。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The observation of the first binary neutron star merger named GW170817 using LIGO and VIRGO led the scientific community into the era of multi-messenger astronomy with gravitational waves. Numerical relativity simulations have shown that the pressure-density relationship (known as equation of state) of hot and dense matter plays a fundamental role in simulating the collisions of neutron stars. Neutron stars are up to twice as massive as our Sun but are typically only around 20 kilometers across. At such extraordinary densities, atomic nuclei collapse, and neutrons and protons are squeezed so tightly together that they may disintegrate into a plasma made of up and down quarks, which are the most fundamental building blocks of matter. The goal of this project is to determine a comprehensive set of state-of-the art models for the equation of state of superdense nuclear matter for use by researchers working on neutron-star merger simulations. In particular, the group will investigate the role of quarks for neutron-star mergers and identify possible signals by means of which quarks may register themselves in the gravitational-wave signals produced by merging neutron stars. The models for the equation of state will be made available to the community at online services (CompOSE, StellarCollapse). Graduate and undergraduate students at San Diego State University will be trained in areas of physics which are richly interdisciplinary and enrich their educational experience beyond what they learn in the classroom.The overarching goal of this project is to determine a comprehensive set of state-of-the art models for the equation of state of hot and dense nuclear matter for use by researchers working on neutron-star merger simulations. Contemporary effective field theoretical models, i.e., the relativistic density-dependent Hartree (DDRMF) model and the (local and the non-local) 3-flavor Polyakov-Nambu-Jona-Lasinio (3PNJL) model, will be used to accomplish this goal. The DDRMF is a versatile and numerically tractable nuclear many-body theory well suited for studies of dense and dense hadronic matter. The 3PNJL model is an effective model of quantum chromodynamics which allows for a contemporary modeling of quark matter. It provides a functional and numerically tractable approach to quantum chromodynamics. The model accounts for the dynamical breaking of chiral symmetry and mimics quark confinement via the Polyakov-loop potential. Quark deconfinement at zero and finite temperature will be studied using both the Gibbs and Maxwell condition for phase equilibrium. The strongest, currently possible constraints from nuclear theory, nuclear experiment, and astrophysics will be used to fix the parameters of the effective field theories and test the validity of the equations of state.This project advances the objectives of "Windows on the Universe: the Era of Multi-Messenger Astrophysics", one of the 10 Big Ideas for Future NSF Investments.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.