Sound velocity and tidal deformability in compact stars

Abstract

The sound velocity $v_s$ and dimensionless tidal deformability $\Lambda$ are analyzed using the pseudo-conformal model we developed before. In contrast to the conclusion obtained in the previous works in the literature, our model with the upper bound of the sound velocity $v_s=1/\sqrt{3}$, the so-called conformal sound velocity, set in at a { density relevant to compact stars} $\gsim 2 n_0$ where $n_0$ is the normal nuclear matter density, can accommodate {\it all} presently established nuclear matter and compact-star properties including the maximum star-mass constraint $\simeq 2.3M_{\odot }$. This observation is associated with a possible emergence of pseudoconformal structure in compact star matter---in which the trace of energy-momentum tensor is a nearly density-independent nonzero constant---brought in by a topology change at $2.0\lesssim n_{1/2}/n_0\lesssim 4.0$ commensurate with a possible change of degrees of freedom from hadrons.

Version to appear in Phys. Rev. D

References in corpus (5)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• Shapiro delay measurement of a two solar mass neutron star
• A Massive Pulsar in a Compact Relativistic Binary
• Sound velocity bound and neutron stars
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• Excluded-volume model for quarkyonic matter II: Three-flavor shell-like distribution of baryons in phase space
• Sound velocity in dense stellar matter with strangeness and compact stars
• Insights on the peak in the speed of sound of ultradense matter
• Effects of $\varphi$-meson on properties of hyperon stars in density dependent relativistic mean field model
• Speed of sound constraints on maximally rotating neutron stars
• A pseudo-conformal structure in dense baryonic matter
• Topology and emergent symmetries in dense compact star matter
• Speed of sound in dense matter and two families of compact stars
• Causality violation and the speed of sound of hot and dense quark matter in the Nambu--Jona-Lasinio model
• Holographic cold dense matter constrained by neutron stars
• Analyzing the speed of sound in neutron star with machine learning
• Topology change, emergent symmetries and compact star matter
• Scale symmetry and composition of compact star matter
• Neutron Stars and Gravitational Waves: the Key Role of Nuclear Equation of State
• Relativistic stellar modeling with perfect fluid core and anisotropic envelope fluid
• Topology change and emergent scale symmetry in compact star matter via gravitational wave detection
• Topology change and nuclear symmetry energy in compact-star matter
• Tracing the Trace Anomaly of Dense Matter inside Neutron Stars