Related papers: Bounds on the minimum sound speed above neutron st…
Information on the phase structure of strongly interacting matter at high baryon densities can be gained from observations of neutron stars and their detailed analysis. In the present work Bayesian inference methods are used to set…
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…
Generating an ensemble of equations of state that fulfill multimessenger constraints, we statistically determine the properties of dense matter found inside neutron stars (NSs). We calculate the speed of sound and trace anomaly and…
Neutron stars are cosmic laboratories to study dense matter in Quantum Chromodynamics (QCD). The observable mass-radius relations of neutron stars are determined by QCD equations of state, and can reflect the properties of QCD phase…
It has been suggested in the literature that the sound velocity of the nuclear matter $v_s$ violates the so-called sound velocity bound $v_s \le c/\sqrt{3}$ at high density, where $c$ is the speed of light. In this paper, we revisit this…
Using more than a million randomly generated equations of state that satisfy theoretical and observational constraints we construct a novel, scale-independent description of the sound speed in neutron stars where the latter is expressed in…
This presentation in two parts starts with a brief review on the speed of sound in neutron star matter as inferred from observational data. It is pointed out that, in view the strong constraints imposed by observed properties of the…
The observation of maximally rotating neutron stars (in comparison to nonrotating ones) may provide more information on the behavior of nuclear matter at high densities. We provide a theoretical treatment concerning the effects of the upper…
We point out that there is an upper bound on the speed of sound squared given by $c_s^2 \leq 0.781$ valid for all known systems described by relativistic transient hydrodynamics where calculations of certain ratios of hydrodynamic transport…
We revisit the derivation of the Rhoades-Ruffini bound on the upper limit for the maximum mass of neutron stars and find that the assumption made there for the onset of an ultimately stiff phase of high-density matter is not stringent.…
The accurate determination of the maximum mass of the neutron stars is one of the most important tasks in astrophysics. It is directly related to the identification of the black holes in the universe, the production of neutron stars from…
From the observation of both heavy neutron stars and light ones with small radii, one anticipates a steep rise in the speed of sound of nuclear matter as a function of baryon density up to values close to the causal limit. A question…
Using the most recent realistic effective interactions for nuclear matter with a smooth extrapolation to high densities including causality, we constrain the equation of state and calculate maximum masses of rotating neutron stars. First…
Matter properties at the intermediate densities are still unknown to us. In this work, we use a neural network approach to study matter at intermediate densities to analyze the variation of the speed of sound and the measure of trace…
It has been conjectured that the velocity of sound in any medium is smaller than the velocity of light in vacuum divided by $\sqrt{3}$. Simple arguments support this bound in non-relativistic and/or weakly coupled theories. The bound has…
The properties of dense QCD matter are delineated through the construction of equations of state which should be consistent with the low and high density limits of QCD, nuclear laboratory experiments, and the neutron star observations.…
The implications of perturbative QCD (pQCD) calculations on neutron stars are carefully examined. While pQCD calculations above baryon chemical potentials $\mu_B\simeq2.4$ GeV demonstrate the potential of ruling out a wide range of neutron…
Determining the sound speed $c_s$ in compact stars is an important open question with numerous implications on the behaviour of matter at large densities and hence on gravitational-wave emission from neutron stars. To this scope, we…
In recent years, there have been several successful attempts to constrain the equation of state of neutron star matter using input from low-energy nuclear physics and observational data. We demonstrate that significant further restrictions…
We build upon the remarkable, model independent constraints on the equation of state of dense baryonic matter established recently by Annala et al. [1]. Using the quark-meson coupling model, an approach to nuclear structure based upon the…