The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
James M. Lattimer - One of the best experts on this subject based on the ideXlab platform.
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the Equation of State of hot dense matter and neutron stars
Physics Reports, 2016Co-Authors: James M. Lattimer, Madappa PrakashAbstract:Abstract Recent developments in the theory of pure neutron matter and experiments concerning the symmetry energy of nuclear matter, coupled with recent measurements of high-mass neutron stars, now allow for relatively tight constraints on the Equation of State of dense matter. We review how these constraints are formulated and describe the implications they have for neutron stars and core-collapse supernovae. We also examine thermal properties of dense matter, which are important for supernovae and neutron star mergers, but which cannot be nearly as well constrained at this time by experiment. In addition, we consider the role of the Equation of State in medium-energy heavy-ion collisions.
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the nuclear Equation of State and neutron star masses
Annual Review of Nuclear and Particle Science, 2012Co-Authors: James M. LattimerAbstract:Neutron stars are valuable laboratories for the study of dense matter. Recent observations have uncovered both massive and low-mass neutron stars and have also set constraints on neutron star radii. The largest mass measurements are powerfully influencing the high-density Equation of State because of the existence of the neutron star maximum mass. The smallest mass measurements, and the distributions of masses, have implications for the progenitors and formation mechanisms of neutron stars. The ensemble of mass and radius observations can realistically restrict the properties of dense matter and, in particular, the behavior of the nuclear symmetry energy near the nuclear saturation density. Simultaneously, various nuclear experiments are progressively restricting the ranges of parameters describing the symmetry properties of the nuclear Equation of State. In addition, new theoretical studies of pure neutron matter are providing insights. These observational, experimental, and theoretical constraints of dense matter, when combined, are now revealing a remarkable convergence.
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The Nuclear Equation of State
Proceedings of 11th Symposium on Nuclei in the Cosmos — PoS(NIC XI), 2011Co-Authors: James M. LattimerAbstract:Recent observations from cooling neutron stars and of photospheric radius expansions in X-ray bursters are used to simultaneously estimate their masses and radii. Although the observational uncertainties for these sources are considerable, as a group they snugly constrain the mass-radius relation and the Equation of State. The results of a Bayesian analysis using a parametrized Equation of State are discussed. It is shown that the low-density Equation of State is consistent with that obtained from recent estimates for pure neutron matter. Also, the deduced nuclear incompressibility is surprisingly compatible with nuclear systematics and experiment. The density dependence of the nuclear symmetry energy is predicted to be relatively small, leading to correspondingly small values for the predicted neutron skin thickness of lead and for the radii of 1.4 M⊙ stars. The high-density Equation of State stiffens, however, and the neutron star maximum mass, to 90% confidence, is predicted to be greater than 1.85 solar masses.
Madappa Prakash - One of the best experts on this subject based on the ideXlab platform.
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the Equation of State of hot dense matter and neutron stars
Physics Reports, 2016Co-Authors: James M. Lattimer, Madappa PrakashAbstract:Abstract Recent developments in the theory of pure neutron matter and experiments concerning the symmetry energy of nuclear matter, coupled with recent measurements of high-mass neutron stars, now allow for relatively tight constraints on the Equation of State of dense matter. We review how these constraints are formulated and describe the implications they have for neutron stars and core-collapse supernovae. We also examine thermal properties of dense matter, which are important for supernovae and neutron star mergers, but which cannot be nearly as well constrained at this time by experiment. In addition, we consider the role of the Equation of State in medium-energy heavy-ion collisions.
Gabriele Sadowski - One of the best experts on this subject based on the ideXlab platform.
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application of the perturbed chain saft Equation of State to associating systems
Industrial & Engineering Chemistry Research, 2002Co-Authors: Joachim Gross, Gabriele SadowskiAbstract:The perturbed-chain SAFT (PC−SAFT) Equation of State is applied to pure associating components as well as to vapor−liquid and liquid−liquid equilibria of binary mixtures of associating substances. For these substances, the PC−SAFT Equation of State requires five pure-component parameters, two of which characterize the association. The pure-component parameters were identified for 18 associating substances by correlating vapor pressure and liquid density data. A comparison to an earlier version of SAFT confirms the good results for pure substances. When only one associating compound is present in a mixture, the PC−SAFT Equation of State does not require mixing rules for the association term. Using one binary interaction parameter kij for the dispersion term only, the model was applied to azeotropic and nonazeotropic vapor−liquid equilibria at low and at high pressures, as well as to liquid−liquid equilibria. Simple mixing and combining rules were adopted for mixtures with more than one associating compound...
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perturbed chain saft an Equation of State based on a perturbation theory for chain molecules
Industrial & Engineering Chemistry Research, 2001Co-Authors: Gabriele SadowskiAbstract:A modified SAFT Equation of State is developed by applying the perturbation theory of Barker and Henderson to a hard-chain reference fluid. With conventional one-fluid mixing rules, the Equation of State is applicable to mixtures of small spherical molecules such as gases, nonspherical solvents, and chainlike polymers. The three pure-component parameters required for nonassociating molecules were identified for 78 substances by correlating vapor pressures and liquid volumes. The Equation of State gives good fits to these properties and agrees well with caloric properties. When applied to vapor−liquid equilibria of mixtures, the Equation of State shows substantial predictive capabilities and good precision for correlating mixtures. Comparisons to the SAFT version of Huang and Radosz reveal a clear improvement of the proposed model. A brief comparison with the Peng−Robinson model is also given for vapor−liquid equilibria of binary systems, confirming the good performance of the suggested Equation of State. ...
Masanobu Yahiro - One of the best experts on this subject based on the ideXlab platform.
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Equation of State and transition temperatures in the quark hadron hybrid model
Physical Review D, 2016Co-Authors: Akihisa Miyahara, Yuhei Torigoe, Hiroaki Kouno, Masanobu YahiroAbstract:We analyze the Equation of State of 2+1 flavor lattice QCD at zero baryon density by constructing the simple quark-hadron hybrid model that has both quark and hadron components simultaneously. We calculate hadron and quark contribution separately and parameterizing those to match with LQCD data. Lattice data on the Equation of State are decomposed into hadron and quark components by using the model. The transition temperature is defined by the temperature at which the hadron component is equal to the quark one in the Equation of State. The transition temperature thus obtained is about 215 MeV and somewhat higher than the chiral and the deconfinement pseudocritical temperatures defined by the temperature at which the susceptibility or the absolute value of the derivative of the order parameter with respect to temperature becomes maximum.
Luca Baiotti - One of the best experts on this subject based on the ideXlab platform.
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constraining the Equation of State of neutron stars from binary mergers
Journal of Physics: Conference Series, 2015Co-Authors: Kentaro Takami, Luciano Rezzolla, Luca BaiottiAbstract:Determining the Equation of State of matter at nuclear density and hence the structure of neutron stars has been a riddle for decades. We show how the imminent detection of gravitational waves from merging neutron star binaries can be used to solve this riddle. Using a large number of accurate numerical-relativity simulations of binaries with nuclear Equations of State, we have found that the postmerger emission is characterized by two distinct and robust spectral features. While the high-frequency peak has already been associated with the oscillations of the hypermassive neutron star produced by the merger and depends on the Equation of State, a new correlation emerges between the low-frequency peak, related to the merger process, and the compactness of the progenitor stars. More importantly, such a correlation is essentially universal, thus providing a powerful tool to set tight constraints on the Equation of State. If the mass of the binary is known from the inspiral signal, the combined use of the two frequency peaks sets four simultaneous constraints to be satisfied. Ideally, even a single detection would be sufficient to select one Equation of State over the others. We have tested our approach with simulated data and verified it works well for all the Equations of State considered.
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constraining the Equation of State of neutron stars from binary mergers
Physical Review Letters, 2014Co-Authors: Kentaro Takami, Luciano Rezzolla, Luca BaiottiAbstract:: Determining the Equation of State of matter at nuclear density and hence the structure of neutron stars has been a riddle for decades. We show how the imminent detection of gravitational waves from merging neutron star binaries can be used to solve this riddle. Using a large number of accurate numerical-relativity simulations of binaries with nuclear Equations of State, we find that the postmerger emission is characterized by two distinct and robust spectral features. While the high-frequency peak has already been associated with the oscillations of the hypermassive neutron star produced by the merger and depends on the Equation of State, a new correlation emerges between the low-frequency peak, related to the merger process, and the total compactness of the stars in the binary. More importantly, such a correlation is essentially universal, thus providing a powerful tool to set tight constraints on the Equation of State. If the mass of the binary is known from the inspiral signal, the combined use of the two frequency peaks sets four simultaneous constraints to be satisfied. Ideally, even a single detection would be sufficient to select one Equation of State over the others. We test our approach with simulated data and verify it works well for all the Equations of State considered.
