scholarly journals Holographic cold nuclear matter and neutron star

2014 ◽  
Vol 29 (10) ◽  
pp. 1450060 ◽  
Author(s):  
Kazuo Ghoroku ◽  
Kouki Kubo ◽  
Motoi Tachibana ◽  
Fumihiko Toyoda
Keyword(s):  
Gauge Theory ◽  
Neutron Star ◽  
Equation Of State ◽  
Nuclear Matter ◽  
Fermi Momentum ◽  
The Other ◽  
Holographic Model ◽  
Cold Nuclear Matter ◽  
Theoretical Approaches ◽  
New Phase

We have previously found a new phase of cold nuclear matter based on a holographic gauge theory, where baryons are introduced as instanton gas in the probe [Formula: see text] branes. In our model, we could obtain the equation of state (EOS) of our nuclear matter by introducing Fermi momentum. Then, here we apply this model to the neutron star and study its mass and radius by solving the Tolman–Oppenheimer–Volkoff (TOV) equations in terms of the EOS given here. We give some comments for our holographic model from a viewpoint of the other field theoretical approaches.

scholarly journals Nuclear equation of state and neutron star cooling

2017 ◽  
Vol 26 (04) ◽  
pp. 1750015 ◽  
Author(s):  
Yeunhwan Lim ◽  
Chang Ho Hyun ◽  
Chang-Hwan Lee
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Matter ◽  
Thermal Evolution ◽  
Observation Data ◽  
Nuclear Equation Of State ◽  
The Core ◽  
Dense Nuclear Matter ◽  
Nuclear Models

In this paper, we investigate the cooling of neutron stars with relativistic and nonrelativistic models of dense nuclear matter. We focus on the effects of uncertainties originated from the nuclear models, the composition of elements in the envelope region, and the formation of superfluidity in the core and the crust of neutron stars. Discovery of [Formula: see text] neutron stars PSR J1614−2230 and PSR J0343[Formula: see text]0432 has triggered the revival of stiff nuclear equation of state at high densities. In the meantime, observation of a neutron star in Cassiopeia A for more than 10 years has provided us with very accurate data for the thermal evolution of neutron stars. Both mass and temperature of neutron stars depend critically on the equation of state of nuclear matter, so we first search for nuclear models that satisfy the constraints from mass and temperature simultaneously within a reasonable range. With selected models, we explore the effects of element composition in the envelope region, and the existence of superfluidity in the core and the crust of neutron stars. Due to uncertainty in the composition of particles in the envelope region, we obtain a range of cooling curves that can cover substantial region of observation data.

scholarly journals Neutron star masses

2012 ◽  
Vol 8 (S291) ◽  
pp. 146-146
Author(s):  
David Nice
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Nuclear Matter ◽  
Observational Data ◽  
Mass Distribution ◽  
Binary Star ◽  
Star Mass ◽  
Star Evolution ◽  
Neutron Star Mass ◽  
Present Understanding

AbstractNeutron star masses can be inferred from observations of binary pulsar systems, particularly by the measurement of relativistic phenomena within these orbits. The observed distribution of masses can be used to infer or constrain the equation of state for nuclear matter and to study astrophysical processes such as supernovae and binary star evolution. In this talk, I will review our present understanding of the neutron star mass distribution with an emphasis on the observational data.

The equation of state for cold nuclear matter as seen in nucleus-nucleus scattering

1998 ◽  
Vol 111 (8-9) ◽  
pp. 971-975 ◽  
Author(s):  
F. Nuoffer ◽  
G. Bartnitzky ◽  
H. Clement ◽  
A. Blazevic ◽  
H. G. Bohlen ◽  
...  
Keyword(s):  
Equation Of State ◽  
Nuclear Matter ◽  
Cold Nuclear Matter ◽  
Nucleus Scattering

scholarly journals Thermal properties of hot and dense matter: Influence of rapid rotation on protoneutron stars, hot neutron stars, and neutron star merger remnants

2021 ◽  
Vol 252 ◽  
pp. 05004
Author(s):  
Polychronis Koliogiannis ◽  
Charalampos Moustakidis
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Matter ◽  
Equations Of State ◽  
Interaction Model ◽  
Dense Matter ◽  
Baryon Density ◽  
Dense Nuclear Matter ◽  
Protoneutron Stars

The knowledge of the equation of state is a key ingredient for many dynamical phenomena that depend sensitively on the hot and dense nuclear matter, such as the formation of protoneutron stars and hot neutron stars. In order to accurately describe them, we construct equations of state at FInite temperature and entropy per baryon for matter with varying proton fractions. This procedure is based on the momentum dependent interaction model and state-of-the-art microscopic data. In addition, we investigate the role of thermal and rotation effects on microscopic and macroscopic properties of neutron stars, including the mass and radius, the frequency, the Kerr parameter, the central baryon density, etc. The latter is also connected to the hot and rapidly rotating remnant after neutron star merger. The interplay between these quantities and data from late observations of neutron stars, both isolated and in matter of merging, could provide useful insight and robust constraints on the equation of state of nuclear matter.

scholarly journals Relativistic equation of state of nuclear matter for supernova and neutron star

1998 ◽  
Vol 637 (3) ◽  
pp. 435-450 ◽  
Author(s):  
H. Shen ◽  
H. Toki ◽  
K. Oyamatsu ◽  
K. Sumiyoshi
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Nuclear Matter ◽  
Relativistic Equation

scholarly journals THE MICROSCOPIC APPROACH TO NUCLEAR MATTER AND NEUTRON STAR MATTER

2010 ◽  
Vol 19 (07) ◽  
pp. 1259-1313 ◽  
Author(s):  
FRANCESCA SAMMARRUCA
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Nuclear Matter ◽  
Symmetry Energy ◽  
Heavy Ion ◽  
Experimental Investigations ◽  
Common Denominator ◽  
Neutron Skin ◽  
Microscopic Approach ◽  
Ion Collisions

We review a variety of theoretical and experimental investigations aimed at improving our knowledge of the nuclear matter equation of state. Of particular interest are nuclear matter extreme states in terms of density and/or isospin asymmetry. The equation of state of matter with unequal concentrations of protons and neutrons has numerous applications. These include heavy-ion collisions, the physics of rare, short-lived nuclei and, on a dramatically different scale, the physics of neutron stars. The "common denominator" among these (seemingly) very different systems is the symmetry energy, which plays a crucial role in both the formation of the neutron skin in neutron-rich nuclei and the radius of a neutron star (a system 18 orders of magnitude larger and 55 orders of magnitudes heavier). The details of the density dependence of the symmetry energy are not yet sufficiently constrained. Throughout this article, our emphasis will be on the importance of adopting a microscopic approach to the many-body problem, which we believe to be the one with true predictive power.

scholarly journals Equation of state of dense nuclear matter and neutron star structure from nuclear chiral interactions

2018 ◽  
Vol 609 ◽  
pp. A128 ◽  
Author(s):  
Ignazio Bombaci ◽  
Domenico Logoteta
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Matter ◽  
Symmetric Nuclear Matter ◽  
Heavy Nuclei ◽  
Hartree Fock ◽  
Binary Neutron Star ◽  
Dense Nuclear Matter ◽  
Three Body

Aims. We report a new microscopic equation of state (EOS) of dense symmetric nuclear matter, pure neutron matter, and asymmetric and β-stable nuclear matter at zero temperature using recent realistic two-body and three-body nuclear interactions derived in the framework of chiral perturbation theory (ChPT) and including the Δ(1232) isobar intermediate state. This EOS is provided in tabular form and in parametrized form ready for use in numerical general relativity simulations of binary neutron star merging. Here we use our new EOS for β-stable nuclear matter to compute various structural properties of non-rotating neutron stars. Methods. The EOS is derived using the Brueckner–Bethe–Goldstone quantum many-body theory in the Brueckner–Hartree–Fock approximation. Neutron star properties are next computed solving numerically the Tolman–Oppenheimer–Volkov structure equations. Results. Our EOS models are able to reproduce the empirical saturation point of symmetric nuclear matter, the symmetry energy Esym, and its slope parameter L at the empirical saturation density n0. In addition, our EOS models are compatible with experimental data from collisions between heavy nuclei at energies ranging from a few tens of MeV up to several hundreds of MeV per nucleon. These experiments provide a selective test for constraining the nuclear EOS up to ~4n0. Our EOS models are consistent with present measured neutron star masses and particularly with the mass M = 2.01 ± 0.04 M⊙ of the neutron stars in PSR J0348+0432.

NEUTRON STAR MASS CORRELATION WITH SOUND VELOCITY AND INCOMPRESSIBILITY AT THE STAR CENTER IN THE POLYTROPIC APPROXIMATION

2010 ◽  
Vol 19 (08n10) ◽  
pp. 1575-1582
Author(s):  
L. FERRARI ◽  
P. C. R. ROSSI ◽  
M. MALHEIRO
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Nuclear Matter ◽  
Sound Velocity ◽  
Mean Field ◽  
Star Mass ◽  
Mean Field Models ◽  
Neutron Star Mass ◽  
Analytic Expressions ◽  
Walecka Model

In this paper we use a polytropic approximation to the equation of state for the interior of neutrons stars, described by relativistic hadronic mean field models. In this approximation, it is possible to obtain analytic expressions for the sound velocity and the incompressibility at the star center. We found a correlation between these quantities and the star mass. Using two well-known parametrizations of the nonlinear Walecka model for nuclear matter composed only of protons, neutrons and electron in β equilibrium, we obtain for a star mass of 1.43 M⊙ a central incompressibility Kc = (3000±100), around ten times the nuclear matter incompressibility, and a central sound velocity (v/c)2 ~ 0.3.

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