2014/02/28 by Thomas Hell, Wolfram Weise · 1 citation
Physics and Astronomy · #Astrophysics #Baryon #Equation of state #Neutron #Neutron star #Nuclear matter #Nuclear physics #Nuclear physics research studies #Nucleon #Particle physics #Physics #Pulsars and Gravitational Waves Research #Quantum Chromodynamics and Particle Interactions #Quantum mechanics #Quark star #Strange matter #Strangeness #nucl-th
paper · pdf · doi:10.1103/physrevc.90.045801
v2; substantial revisions with respect to v1; 17 pages, 15 figures
arxiv created 2014/09/24 · openalex publication_date 2014/10/13 · arxiv updated 2015/06/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Updated constraints from neutron star masses and radii impose stronger restrictions on the equation of state for baryonic matter at high densities and low temperatures. The existence of 2M_\ensuremath\bigodot neutron stars rules out many soft equations of state with prominent ``exotic'' compositions. The present work reviews the conditions required for the pressure as a function of baryon density to satisfy these constraints. Several scenarios for sufficiently stiff equations of state are evaluated. The common starting point is a realistic description of both nuclear and neutron matter based on a chiral effective field theory approach to the nuclear many-body problem. Possible forms of hybrid matter featuring a quark core in the center of the star are discussed using a three-flavor Polyakov--Nambu--Jona-Lasinio model. It is found that a conventional equation of state based on nuclear chiral dynamics meets the astrophysical constraints. Hybrid matter generally turns out to be too soft unless additional strongly repulsive correlations, e.g., through vector current interactions between quarks, are introduced. The extent to which strangeness can accumulate in the equation of state is also discussed.