Phenomenological QCD equations of state for neutron star mergers

Abstract

We delineate the properties of dense QCD matter through equations of state constrained by the neutron star observations. The two solar mass constraint, the radius constraint of 11-13 km, and the causality constraint on the speed of sound, are used to develop the picture of hadron-quark continuity in which hadronic matter continuously transforms into quark matter. A unified equation of state at zero temperature and β -equilibrium is constructed by a phenomenological interpolation between nuclear and quark matter equations of state. For applications to supernovae and neutron star mergers, the unified equation of state is perturbed by temperature corrections. Critical Point and Onset of Deconfinement

Tribaryon configurations and the inevitable three nucleon repulsions at short distance

“…Phenomenologically, the long distance part of the three nuclear force is obtained using the pion mediated interactions [6,7] which gives the additional attraction necessary to fit the experimental 3 H binding energy. However, as one tries to go beyond the few body system and understand the saturation properties of nuclear matter [6,8] and the compressibility consistent with experiments [9], it becomes clear that the three body nuclear force including those involving hyperons [10] are repulsive at short distance.Recently, there is a renewed interest in the three body nuclear force as there are compelling evidences that the force should be repulsive at short distance from analyzing the extrapolated dense nuclear matter equation of state (EOS) in the neutron stars [11,12]. The naive extrapolation of two body interaction fitted to hypernuclear data leads to Λ hyperon condensation at 2 ∼ 3 times nuclear matter density in neutron stars, which leads to maximum neutron star mass of less than 1.5 M ⊙ [13].…”

“…Recently, there is a renewed interest in the three body nuclear force as there are compelling evidences that the force should be repulsive at short distance from analyzing the extrapolated dense nuclear matter equation of state (EOS) in the neutron stars [11,12]. The naive extrapolation of two body interaction fitted to hypernuclear data leads to Λ hyperon condensation at 2 ∼ 3 times nuclear matter density in neutron stars, which leads to maximum neutron star mass of less than 1.5 M ⊙ [13].…”