VARIATIONAL CALCULATION FOR THE NUCLEAR EQUATION OF STATE TOWARD SUPERNOVA EXPLOSIONS

2008 ◽  
Vol 23 (27n30) ◽  
pp. 2455-2458
Author(s):  
MASATOSHI TAKANO ◽  
HIROAKI KANZAWA ◽  
KAZUHIRO OYAMATSU ◽  
KOHSUKE SUMIYOSHI
Keyword(s):  
Equation Of State ◽  
Variational Method ◽  
Symmetry Energy ◽  
Nuclear Force ◽  
Variational Calculation ◽  
Expectation Value ◽  
Nuclear Equation Of State ◽  
Supernova Explosions ◽  
Three Body ◽  
Stability Line

The equation of state (EOS) is calculated for uniform nuclear matter at zero and finite temperatures with the variational method. Making use of uncertainty of the three-body nuclear force, adjustable parameters in the nuclear EOS are tuned so that the Thomas-Fermi calculations for β-stable nuclei with the EOS reproduce the empirical data. The calculated nuclear properties imply that larger symmetry energy of the EOS is preferable to reproduce the empirical β-stability line. The expectation value of the nuclear Hamiltonian caused by the 2π-exchange three-body nuclear force is uncertain and related to the symmetry energy.

CONSISTENT THREE-BODY FORCE WITH BONN B POTENTIAL AND NEUTRON STAR STRUCTURE

2010 ◽  
Vol 19 (08n09) ◽  
pp. 1727-1733 ◽  
Author(s):  
Z. H. LI ◽  
U. LOMBARDO ◽  
H.-J. SCHULZE ◽  
W. ZUO
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Symmetry Energy ◽  
Body Force ◽  
Nucleon Force ◽  
Nucleon Potential ◽  
Saturation Properties ◽  
Nuclear Equation Of State ◽  
Neutron Star Mass ◽  
Three Body

Microscopic three-nucleon force consistent with the Bonn B two-nucleon potential is constructed, which includes Δ(1232), Roper, and nucleon-antinucleon excitation contributions. Recent results for the choice of the meson parameters are discussed. The forces are used in Brueckner calculations and the saturation properties of nuclear matter are determined. At the high densities, the nuclear equation of state and the symmetry energy are calculated. The corresponding neutron star mass-radius relations are presented.

Nuclear equation of state with the variational method and its application to supernova simulations

2014 ◽  
Vol 29 ◽  
pp. 1460221 ◽  
Author(s):  
Hajime Togashi ◽  
Masatoshi Takano ◽  
Kohsuke Sumiyoshi ◽  
Ken'ichiro Nakazato
Keyword(s):  
Equation Of State ◽  
Variational Method ◽  
Free Energies ◽  
Nuclear Equation Of State ◽  
Variational Calculations ◽  
General Relativistic ◽  
Hypernetted Chain ◽  
Cluster Variational Method ◽  
Three Body ◽  
Body Potential

We report on an equation of state (EOS) of hot asymmetric nuclear matter constructed using the variational method and its application to hydrodynamic simulations of core-collapse supernovae. This nuclear EOS is based on the AV18 two-body potential and UIX three-body potential, and the energy per nucleon at zero temperature is constructed with the cluster variational method. At finite temperatures, the free energies per nucleon are calculated with an extension of the variational method devised by Schmidt and Pandharipande. This EOS is in good agreement with that by the Fermi hypernetted chain variational calculations at zero and finite temperatures, and the structure of neutron stars calculated with this EOS is consistent with recent observational data. Using this nuclear EOS, we perform a spherically symmetric general-relativistic adiabatic simulation of the SN explosion. The explosion energy calculated with our EOS in the present simulation is larger than that obtained with the Shen EOS, implying that the variational EOS is softer than the Shen EOS.

THE BETHE–BRUECKNER–GOLDTONE THEORY OF THE NUCLEAR EQUATION OF STATE AND NEUTRON STARS

2003 ◽  
Vol 17 (28) ◽  
pp. 5127-5137 ◽  
Author(s):  
M. BALDO ◽  
G. F. BURGIO
Keyword(s):  
Equation Of State ◽  
Neutron Stars ◽  
Gluon Plasma ◽  
Many Body ◽  
Static Properties ◽  
Many Body Theory ◽  
Nuclear Equation Of State ◽  
Pure Neutron Matter ◽  
Particle Potential ◽  
Three Body

The microscopic many-body theory of the Nuclear Equation of State is discussed in the framework of the Bethe–Brueckner–Goldstone method. The expansion is extended up to the three hole-line diagrams contribution. The Brueckner equation for the two-body G-matrix and the Bethe–Fadeev equation for the three-body scattering matrix are solved both for the gap and continuous choices of the single particle potential. For symmetric and pure neutron matter strong evidence of convergence in the expansion is found. Once three-body forces are introduced, the phenomenological saturation point is reproduced. In order to study neutron stars static properties, the theory is extended to include strangeness, and the possible quark-gluon plasma component is described in the simplified MIT bag model. The results for the mass and radius of neutron stars are briefly discussed.

EFFECTS OF THE NUCLEAR SYMMETRY ENERGY ON GRAVITATIONAL WAVES FROM THE AXIAL W-MODES OF ISOLATED NEUTRON STARS

2010 ◽  
Vol 19 (08n09) ◽  
pp. 1712-1719
Author(s):  
DE-HUA WEN ◽  
BAO-AN LI ◽  
PLAMEN G. KRASTEV
Keyword(s):  
Equation Of State ◽  
Neutron Stars ◽  
Gravitational Waves ◽  
Symmetry Energy ◽  
Laboratory Data ◽  
High Density ◽  
Nuclear Symmetry Energy ◽  
Nuclear Equation Of State ◽  
Eigen Frequencies ◽  
Density Behavior

The frequencies and damping times of the axial w-mode oscillations of neutron stars are investigated using a nuclear equation of state (EOS) partially constrained by the available terrestrial laboratory data. It is found that the nuclear symmetry energy E sym (ρ), especially its high density behavior, plays an important role in determining both the eigen-frequencies and the damping times of these oscillations.

scholarly journals Nuclear Equation of State in the Relativistic Point-Coupling Model Constrained by Excitations in Finite Nuclei

Universe ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 71
Author(s):  
Esra Yüksel ◽  
Tomohiro Oishi ◽  
Nils Paar
Keyword(s):  
Experimental Data ◽  
Equation Of State ◽  
Energy Density ◽  
Symmetry Energy ◽  
Ground State ◽  
Density Functional ◽  
Dipole Polarizability ◽  
Energy Density Functional ◽  
Nuclear Equation Of State ◽  
Ground State Properties

Nuclear equation of state is often described in the framework of energy density functional. However, the isovector channel in most functionals has been poorly constrained, mainly due to rather limited available experimental data to probe it. Only recently, the relativistic nuclear energy density functional with an effective point-coupling interaction was constrained by supplementing the ground-state properties of nuclei with the experimental data on dipole polarizability and isoscalar monopole resonance energy in 208Pb, resulting in DD-PCX parameterization. In this work, we pursue a complementary approach by introducing a family of 8 relativistic point-coupling functionals that reproduce the same nuclear ground-state properties, including binding energies and charge radii, but in addition have a constrained value of symmetry energy at saturation density in the range J = 29, 30, …, 36 MeV. In the next step, this family of functionals is employed in studies of excitation properties such as dipole polarizability and magnetic dipole transitions, and the respective experimental data are used to validate the optimal choice of functional as well as to assess reliable values of the symmetry energy and slope of the symmetry energy at saturation.

scholarly journals KIDS Energy Density Functional and Mass–Radius Relation of Neutron Stars

2019 ◽  
Vol 26 ◽  
pp. 112
Author(s):  
G. Ahn ◽  
P. Papakonstantinou
Keyword(s):  
Equation Of State ◽  
Energy Density ◽  
Neutron Stars ◽  
Symmetry Energy ◽  
Density Functional ◽  
Nuclear Symmetry Energy ◽  
Unified Framework ◽  
Energy Density Functional ◽  
Nuclear Equation Of State ◽  
Derivatives Of

Many efforts are made to determine the nuclear equation of state which governs the properties and evolution of neutron stars. Especially important is to constrain the parameters of the nuclear symmetry energy. In those efforts, nuclear energy density functional (EDF) theory has been a very useful tool, as it provides a unified framework for the description both of nuclei, which can be studied on Earth, and of infinite matter and its nuclear equation of state, which is a necessary input in the modelling of neutron stars. In the present study, a new nuclear EDF, the KIDS functional, is explored with a focus on the nuclear symmetry energy. The form of the functional allows us to vary at will the poorly constrained high-order derivatives of the symmetry energy and examine how the maximum possible mass of a neutron star is affected. Some tentative constraints on the skewness are presented, which will help guide further refinements. It is noteworthy that the pressure of neutron-rich matter is found strongly affected by skewness variations, both at low and high densities.

scholarly journals Neutron star structure with nuclear force mediated by hypothetical X17 boson

2021 ◽  
Vol 252 ◽  
pp. 04008
Author(s):  
Vlasios Petousis ◽  
Martin Veselský ◽  
Jozef Leja
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Force ◽  
Nuclear Equation Of State ◽  
Upper Limit ◽  
Merger Event ◽  
Star Structure

A reported 17 MeV boson, which has been proposed as an explanation to the 8Be and 4He anomaly, is investigated in the context of its possible influence to neutron stars structure. Implementing a mX =17 MeV to the nuclear equation of state using different incompressibility values K0=245 MeV and K0=260 MeV and solving Tolman-Oppenheimer-Volkoff equations, we estimate an upper limit of MTOV ≈ 2.4M⊙ for a non rotating neutron star with span in radius R between 11.5 km to 14 km. Moving away from pure -NN with admixture of 10% protons and simulating possible softening of equation of state due to hyperons, we see that our estimated limits fit quite well inside the newest reported studies, coming from neutron stars merger event, GW190814

scholarly journals Nuclear equation of state constraints from tidal deformability of neutron stars

2019 ◽  
Vol 21 ◽  
pp. 44
Author(s):  
Ch. C. Moustakidis
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Symmetry Energy ◽  
State Constraints ◽  
Equations Of State ◽  
Recent Observation ◽  
Nuclear Symmetry Energy ◽  
Nuclear Equation Of State ◽  
Theoretical Predictions

We study the effect of nuclear equation of state on the tidal polarizability of neutron stars. The predicted equations of state for the β-stable nuclear matter are parameterized by varying the slope L of the symmetry energy at saturation density on the interval 65 MeV≤L≤115 MeV. The effects of the density dependence of the nuclear symmetry energy on the neutron star tidal polarizability are presented and analyzed. A comparison of theoretical predictions with the recent observation predictions is also performed and analyzed.

scholarly journals The Symmetry Energy of the Nuclear Equation of State

2011 ◽  
Vol 312 (8) ◽  
pp. 082005
Author(s):  
V Greco ◽  
Liu Bo ◽  
M Colonna ◽  
M Di Toro
Keyword(s):  
Equation Of State ◽  
Symmetry Energy ◽  
Nuclear Equation Of State
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