Toward a unified equation of state for multi-messenger astronomy
Toward a unified equation of state for multi-messenger astronomy
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DOI：
10.1051/0004-6361/202038211
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发表时间：
2020-04
影响因子：
6.5
通讯作者：
Michał Marczenko;D. Blaschke;K. Redlich;C. Sasaki
中科院分区：
文献类型：
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作者：
Michał Marczenko;D. Blaschke;K. Redlich;C. Sasaki
目标。我们的目标是提出一个基准状态方程（EoS）模型的多信使天文学，统一的夸克和强子自由度的热力学的第一步。方法.采用拉格朗日方法计算夸克-介子-核子物质的热力学势。在这种方法中，动力学手征对称性破缺被描述为标量平均场动力学耦合到夸克和核子及其手征伙伴，从而其恢复发生在强子阶段的宇称加倍，以及在夸克阶段。夸克禁闭是通过一个辅助标量场来实现的，该标量场参数化了夸克扇区中的动态红外截止，作为核子相空间的紫外截止。差距方程求解的同位旋对称的情况下，以及中子星星（NS）的条件。计算了NS的质量-半径关系及其潮汐变形性参数。结果得到的EoS与饱和密度下的核物质性质和重离子碰撞实验中的流动约束是一致的。对于同位旋不对称的物质，轻夸克的味道的顺序发生，得到的手征对称的核子物质与deconfined下降夸克的混合相。紧凑型恒星的MR关系和TD满足PSR J 0740 +6620、PSR J 0030 +0451和NS合并GW 170817的最新天体物理观测的约束，其中最大质量和紧凑性约束之间的张力相当独特地固定了模型参数。该模型预测存在的恒星的核心手征恢复，但纯粹的强子（限制）的质量超过1.8兆焦耳的问题。具有纯夸克物质核的恒星被发现对引力坍缩是不稳定的。这种不稳定性转移到更高的密度，如果夸克之间的排斥相互作用。
Aims. We aim to present a first step in developing a benchmark equation-of-state (EoS) model for multi-messenger astronomy that unifies the thermodynamics of quark and hadronic degrees of freedom. Methods. A Lagrangian approach to the thermodynamic potential of quark-meson-nucleon matter was used. In this approach, dynamical chiral-symmetry breaking is described by the scalar mean-field dynamics coupled to quarks and nucleons and their chiral partners, whereby its restoration occurs in the hadronic phase by parity doubling, as well as in the quark phase. Quark confinement was achieved by an auxiliary scalar field that parametrizes a dynamical infrared cut-off in the quark sector, serving as an ultraviolet cut-off for the nucleonic phase space. The gap equations were solved for the isospin-symmetric case, as well as for neutron star (NS) conditions. We also calculated the mass-radius (MR) relation of NSs and their tidal deformability (TD) parameter. Results. The obtained EoS is in accordance with nuclear matter properties at saturation density and with the flow constraint from heavy ion collision experiments. For isospin-asymmetric matter, a sequential occurrence of light quark flavors is obtained, allowing for a mixed phase of chirally-symmetric nucleonic matter with deconfined down quarks. The MR relations and TDs for compact stars fulfill the constraints from the latest astrophysical observations for PSR J0740+6620, PSR J0030+0451, and the NS merger GW170817, whereby the tension between the maximum mass and compactness constraints rather uniquely fixes the model parameters. The model predicts the existence of stars with a core of chirally restored but purely hadronic (confined) matter for masses beyond 1.8 M⊙. Stars with pure-quark matter cores are found to be unstable against the gravitational collapse. This instability is shifted to even higher densities if repulsive interactions between quarks are included.