Constraints on Phase Transitions in Neutron Star Matter

Abstract

Recent inference results of the sound velocity in the cores of neutron stars are summarized. Implications for the equation of state and the phase structure of highly compressed baryonic matter are discussed. In view of the strong constraints imposed by the heaviest known pulsars, the equation of state must be very stiff in order to ensure the stability of these extreme objects. This required stiffness limits the possible appearance of phase transitions in neutron star cores. For example, a Bayes factor analysis quantifies strong evidence for squared sound velocities $c_s^2>0.1$ in the cores of 2.1 solar-mass and lighter neutron stars. Only weak first-order phase transitions with a small phase coexistence density range $\Delta \rho /\rho <0.2$ (at the 68\% level) in a Maxwell construction still turn out to be possible within neutron stars. The central baryon densities in even the heaviest neutron stars do not exceed five times the density of normal nuclear matter. In view of these data-based constraints, much discussed issues such as the quest for a phase transition towards restored chiral symmetry, and the active degrees of freedom in cold and dense baryonic matter, are reexamined.

References in corpus (35)

• Shapiro delay measurement of a two solar mass neutron star
• A Massive Pulsar in a Compact Relativistic Binary
• PSR J0030+0451 Mass and Radius from NICER Data and Implications for the Properties of Neutron Star Matter
• A NICER View of PSR J0030+0451: Millisecond Pulsar Parameter Estimation
• A NICER View of the Massive Pulsar PSR J0740+6620 Informed by Radio Timing and XMM-Newton Spectroscopy
• Refined Mass and Geometric Measurements of the High-Mass PSR J0740+6620
• PSR J0952-0607: The Fastest and Heaviest Known Galactic Neutron Star
• Hyperon Puzzle: Hints from Quantum Monte Carlo Calculations
• Constraining Neutron-Star Matter with Microscopic and Macroscopic Collisions
• On the Sound Speed in Neutron Stars
• Neutron star mass and radius measurements from atmospheric model fits to X-ray burst cooling tail spectra
• Phase structure of three and four flavor QCD
• How perturbative QCD constrains the Equation of State at Neutron-Star densities
• The chiral and deconfinement crossover transitions: PNJL model beyond mean field
• Strongly interacting matter exhibits deconfined behavior in massive neutron stars
• Trace anomaly as signature of conformality in neutron stars
• The Radius of PSR J0740+6620 from NICER with NICER Background Estimates
• Reaching percolation and conformal limits in neutron stars
• Phase Transitions in Particle Physics -- Results and Perspectives from Lattice Quantum Chromo-Dynamics
• Hard-core deconfinement and soft-surface delocalization from nuclear to quark matter
• Implications of NICER for neutron star matter: the QHC21 equation of state
• Evidence against a strong first-order phase transition in neutron star cores: impact of new data
• Inference of the sound speed and related properties of neutron stars
• A general, scale-independent description of the sound speed in neutron stars
• Functional renormalization group studies of nuclear and neutron matter
• Plausible presence of new state in neutron stars with masses above $0.98M_{\mathrm{TOV}}$
• Investigating Signatures of Phase Transitions in Neutron-Star Cores
• Phase Transition Phenomenology with Nonparametric Representations of the Neutron Star Equation of State
• Constraints on strong phase transitions in neutron stars
• Fluctuations and phases in baryonic matter
• Constraining neutron star properties with a new equation of state insensitive approach
• Topology and emergent symmetries in dense compact star matter
• Spectral functions of nucleon form factors: Three-pion continua at low energies
• Testing the Paradigm of Nuclear Many-Body Theory
• Equation of state in neutron stars and supernovae

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• Speed of sound bounds and first-order phase transitions in compact stars
• Effective Field Theories for Neutron Stars Physics
• Effects of Nontrivial Topology on Neutron Star Rotation and its Potential Observational Implications
• Finite density nuclear matter and neutron stars in hard-wall AdS/QCD model
• Classification of $g$-modes for neutron stars with a strong transition: Novel universal relation including slow stable hybrid stars
• Bayesian Constraints on the Neutron Star Equation of State with a Smooth Hadron-Quark Crossover
• Finding strangelets in cosmic rays from HESS J1731-347, a possible strange quark star using the Cherenkov Telescope Array Observatory