Constraints on the Nuclear Eos From Neutron Star Observables

Abstract

Depending on the density reached in the cores of neutron stars, such objects may contain stable phases of novel matter found nowhere else in the Universe. This article gives a brief overview of these phases of matter and discusses astrophysical constraints on the high-density equation of state associated with ultra-dense nuclear matter.

Exploring Cosmic Matter in the Laboratory—The Compressed Baryonic Matter Experiment at FAIR

“…Figure 2 depicts results of calculations based on the Tolman-Oppenheimer-Volkoff (TOF) equation for the mass of neutron stars as a function of central density for different EOS. Depending on the chosen EOS, the density in the core of neutron stars reaches values of 3-5 ρ 0 for star masses between 1.3 and 1.8 solar masses, and values of 5-8 ρ 0 for star masses between 1.8 and 2.0 solar masses [6]. The most recent relativistic Shapiro delay measurements of an extremely massive millisecond pulsar found a mass of 2.14 + 0.10 − 0.09 solar masses [7].…”

Neutron Stars and the High Density Equation of State

“…It starts with a discussion of potential promising constraints on the EoS of ultra-dense matter from NS mass and mass-radius measurements and the elliptic flow in heavy ion collisions. These, other constraints and more detailed discussions can be found in [2,3,4]. The two following sections consider the EoS in nuclear and quark matter.…”

Effective Field Theories for Hot and Dense Matter

“…Three examples are given: (1) the QCD model phase diagram with chiral symmetry restoration and color superconductivity [3], (2) the Schrödinger equation for heavy-quarkonia [4], and (2) Pions [5] as well as Kaons and D-mesons in the finite-temperature Bethe-Salpeter equation [6]. We discuss recent applications of this quantum field theoretical approach to hot and dense quark matter for a description of anomalous J/ψ supression in heavy-ion collisions [7] and for the structure and cooling of compact stars with quark matter interiors [8].The second part provides a detailed introduction to the Polyakov-loop Nambu-Jona-Lasinio model [9] for thermodynamics and mesonic correlations [10] in the phase diagram of quark matter. Important relationships of low-energy QCD like the Gell-Mann-Oakes-Renner relation are generalized to finite temperatures.…”

“…Three examples are given: (1) the QCD model phase diagram with chiral symmetry restoration and color superconductivity [3], (2) the Schrödinger equation for heavy-quarkonia [4], and (2) Pions [5] as well as Kaons and D-mesons in the finite-temperature Bethe-Salpeter equation [6]. We discuss recent applications of this quantum field theoretical approach to hot and dense quark matter for a description of anomalous J/ψ supression in heavy-ion collisions [7] and for the structure and cooling of compact stars with quark matter interiors [8].…”