Neutron star properties from optimised chiral nuclear interactions

2018 ◽  
Vol 35 ◽  
Author(s):  
D. Logoteta ◽  
I. Bombaci
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Nuclear Matter ◽  
Nuclear Interaction ◽  
Binding Energies ◽  
Leading Order ◽  
Nuclear Forces ◽  
Hartree Fock ◽  
First Case ◽  
Three Body

AbstractWe adopt two- and three-body nuclear forces derived at the next-to-next-to-leading-order in the framework of effective chiral perturbation theory to calculate the equation of state of β-stable neutron star matter using the Brueckner–Hartree–Fock many-body approach. We use the recent optimized chiral two-body nuclear interaction at next-to-next-to-leading-order derived by Ekström et al. and two different parametrizations of the three-body next-to-next-to-leading-order interaction: the first one is fixed to reproduce the saturation point of symmetric nuclear matter while the second one is fixed to reproduce the binding energies of light atomic nuclei. We show that in the second case the properties of nuclear matter are not well determined whereas in the first case various empirical nuclear matter properties around the saturation density are well reproduced. We finally calculate various neutron star properties and in particular the mass-radius and mass-central density relations. We find that the adopted interactions based on a fully microscopic framework, are able to provide an equation of state which is consistent with the present data of measured neutron star masses.

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.

scholarly journals Impact of chiral hyperonic three-body forces on neutron stars

2019 ◽  
Vol 55 (11) ◽  
Author(s):  
Domenico Logoteta ◽  
Isaac Vidaña ◽  
Ignazio Bombaci
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Nucleon Nucleon ◽  
Effective Field ◽  
Many Body ◽  
Chiral Effective Field Theory ◽  
Hartree Fock ◽  
The Many ◽  
Three Body

Abstract.We study the effects of the nucleon-nucleon-lambda (NN$ \Lambda$Λ three-body force on neutron stars. In particular, we consider the NN$ \Lambda$Λ force recently derived by the Jülich-Bonn-Munich group within the framework of chiral effective field theory at next-to-next-to-leading order. This force, together with realistic nucleon-nucleon, nucleon-nucleon-nucleon and nucleon-hyperon interactions, is used to calculate the equation of state and the structure of neutron stars within the many-body non-relativistic Brueckner-Hartree-Fock approach. Our results show that the inclusion of the NN$ \Lambda$Λ force leads to an equation of state stiff enough such that the resulting neutron star maximum mass is compatible with the largest currently measured ( $ \sim 2 M_\odot$∼2M⊙ neutron star masses. Using a perturbative many-body approach we calculate also the separation energy of the $ \Lambda$Λ in some hypernuclei finding that the agreement with the experimental data improves for the heavier ones when the effect of the NN$ \Lambda$Λ force is taken into account.

scholarly journals Compatibility of Neutron Star Masses and Hyperon Coupling Constants

1999 ◽  
Vol 54 (1) ◽  
pp. 77-82 ◽  
Author(s):  
H. Huber ◽  
M. K. Weigel ◽  
F. Weber
Keyword(s):  
Neutron Star ◽  
Lower Bound ◽  
Nuclear Matter ◽  
Satisfactory Agreement ◽  
Equations Of State ◽  
Binding Energies ◽  
Coupling Constants ◽  
Neutron Star Matter ◽  
Hartree Fock ◽  
Neutron Star Mass

Abstract It is shown that the modern equations of state for neutron star matter based on microscopic calculations of symmetric and asymmetric nuclear matter are compatible with the lower bound on the maximum neutron-star mass for a certain range of hyperon coupling constants, which are constrained by the binding energies of hyperons in symmetric nuclear matter. The hyperons are included by means of the relativistic Hartree-or Hartree-Fock approximation. The obtained couplings are also in satisfactory agreement with hypernuclei data in the relativistic Hartree scheme. Within the relativistic Hartree-Fock approximation, hypernuclei have not been investigated so far.

scholarly journals Hot nuclear matter equation of state with a three-body force

2004 ◽  
Vol 69 (6) ◽  
Author(s):  
W. Zuo ◽  
Z. H. Li ◽  
A. Li ◽  
G. C. Lu
Keyword(s):  
Equation Of State ◽  
Nuclear Matter ◽  
Body Force ◽  
Three Body

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.

scholarly journals 1S0 Pairing Gaps, Chemical Potentials and Entrainment Matrix in Superfluid Neutron-Star Cores for the Brussels–Montreal Functionals

Universe ◽  
2021 ◽  
Vol 7 (12) ◽  
pp. 470
Author(s):  
Valentin Allard ◽  
Nicolas Chamel
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Physical Meaning ◽  
Outer Core ◽  
Time Dependent ◽  
Hartree Fock ◽  
Chemical Potentials ◽  
Bogoliubov Equations ◽  
Flow Velocities

Temperature and velocity-dependent 1S0 pairing gaps, chemical potentials and entrainment matrix in dense homogeneous neutron–proton superfluid mixtures constituting the outer core of neutron stars, are determined fully self-consistently by solving numerically the time-dependent Hartree–Fock–Bogoliubov equations over the whole range of temperatures and flow velocities for which superfluidity can exist. Calculations have been made for npeμ in beta-equilibrium using the Brussels–Montreal functional BSk24. The accuracy of various approximations is assessed and the physical meaning of the different velocities and momentum densities appearing in the theory is clarified. Together with the unified equation of state published earlier, the present results provide consistent microscopic inputs for modeling superfluid neutron-star cores.

scholarly journals Nuclear-matter equation of state with consistent two- and three-body perturbative chiral interactions

2014 ◽  
Vol 89 (4) ◽  
Author(s):  
L. Coraggio ◽  
J. W. Holt ◽  
N. Itaco ◽  
R. Machleidt ◽  
L. E. Marcucci ◽  
...  
Keyword(s):  
Equation Of State ◽  
Nuclear Matter ◽  
Chiral Interactions ◽  
Three Body
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