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Related papers: From $\chi$EFT to Multi-Region Modeling: Neutron s…

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We explore supervised machine learning methods in extracting the non-linear maps between neutron stars (NS) observables and the equation of state (EoS) of nuclear matter. Using a Taylor expansion around saturation density, we have generated…

Nuclear Theory · Physics 2021-07-22 Márcio Ferreira , Constança Providência

We calculate neutrino processes involving two nucleons at subnuclear densities using chiral effective field theory. Shorter-range noncentral forces reduce the neutrino rates significantly compared with the one-pion exchange approximation…

Nuclear Theory · Physics 2009-11-06 S. Bacca , K. Hally , C. J. Pethick , A. Schwenk

We present a multi-polytrope approach to describe high-mass twins fulfilling chiral effective field theory estimations of the neutron star equation state and test it against the appearance of mixed phases at the hadron-quark interface. In…

Nuclear Theory · Physics 2017-12-27 David Alvarez-Castillo , David Blaschke , Stefan Typel

We calculate neutron star masses and radii from equations of state based on recent high-quality chiral nucleon-nucleon potentials up to fifth order of the chiral expansion and the leading chiral three- nucleon force. Our focus is on the…

Nuclear Theory · Physics 2019-02-20 Francesca Sammarruca , Randy Millerson

We combine equation of state of dense matter up to twice nuclear saturation density ($n_{\rm sat}=0.16\, \text{fm}^{-3}$) obtained using chiral effective field theory ($\chi$EFT), and recent observations of neutron stars to gain insights…

We present a self-consistent model for the study of the structure of a neutron star in strong magnetic fields. Starting from a microscopic Lagrangian, this model includes the effect of the magnetic field on the equation of state, the…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Debarati Chatterjee , Thomas Elghozi , Jerome Novak , Micaela Oertel

We conduct a direct comparison of three different representative numerical codes for constructing models of rapidly rotating neutron stars in general relativity. Our aim is to evaluate the accuracy of the codes and to investigate how the…

General Relativity and Quantum Cosmology · Physics 2011-05-23 Tetsuo Nozawa , Nikolaos Stergioulas , Eric Gourgoulhon , Yoshiharu Eriguchi

We review the nuclear forces currently in use, i.e., the high-precision NN potentials of the 1990's and the nuclear two- and many-body forces based upon chiral effective field theory (EFT). We argue that the EFT approach is superior to any…

Nuclear Theory · Physics 2009-11-11 R. Machleidt , D. R. Entem

Neutron stars with the isovector scalar $\delta$-field are studied in the framework of the relativistic mean field ($RMF$) approach in a pure nucleon plus lepton scheme. The $\delta$-field leads to a larger repulsion in dense neutron-rich…

Nuclear Theory · Physics 2009-11-10 B. Liu , H. Guo , M. Di Toro , V. Greco

Neutron stars are compact objects of large interest in the nuclear astrophysics community. The extreme conditions present in such systems impose big challenges to our current microscopic models of nuclear structure. Equation of states (EoS)…

Nuclear Theory · Physics 2022-03-01 Ronaldo V. Lobato , Emanuel V. Chimanski , Carlos A. Bertulani

We study the equation of state (EOS) for dense matter in the core of the compact star with hyperons and calculate the star structure in an effective model in the mean field approach. With varying incompressibility and effective nucleon…

Nuclear Theory · Physics 2014-11-18 T. K. Jha , P. K. Raina , P. K. Panda , S. K. Patra

The effective chiral model is extended by introducing the contributions from the cross-couplings between isovector and isoscalar mesons. These cross-couplings are found to be instrumental in improving the density content of the nuclear…

Nuclear Theory · Physics 2017-09-08 Tuhin Malik , Kinjal Banerjee , T. K. Jha , B. K. Agrawal

We review on a chiral power counting scheme for in-medium chiral perturbation theory with nucleons and pions as degrees of freedom \cite{ref}. It allows for a systematic expansion taking into account local as well as pion-mediated…

Nuclear Theory · Physics 2012-06-13 J. A. Oller

The difficulty in describing the equation of state (EoS) for nuclear matter at densities above the saturation density ($\rho_0$) has led to the emergence of a multitude of models based on different assumptions and techniques. These EoSs,…

Nuclear Theory · Physics 2024-01-17 Ameya Thete , Kinjal Banerjee , Tuhin Malik

We study nuclear and neutron matter by combining chiral effective field theory with non-perturbative lattice methods. In our approach nucleons and pions are treated as point particles on a lattice. This allows us to probe larger volumes,…

Nuclear Theory · Physics 2009-11-10 Dean Lee , Bugra Borasoy , Thomas Schaefer

Neutrino scattering and absorption rates of relevance to supernovae and neutron star mergers are obtained from nuclear matter dynamical structure functions that encode many-body effects from nuclear mean fields and correlations. We employ…

Nuclear Theory · Physics 2023-06-09 Eunkyoung Shin , Ermal Rrapaj , Jeremy W. Holt , Sanjay K. Reddy

The inner structure of neutron star is considered from theoretical point of view and is compared with the observed data. We have proposed a form of an equation of state relating pressure with matter density which indicates the stiff…

General Relativity and Quantum Cosmology · Physics 2015-10-26 Mehedi Kalam , Sk. Monowar Hossein , Sajahan Molla

One very promising technique for measuring the dense matter Equation of State exploits hotspots that form on the neutron star surface due to the pulsar mechanism, accretion streams, or during thermonuclear explosions in the neutron star…

High Energy Astrophysical Phenomena · Physics 2019-09-04 Anna L. Watts

We have recently developed a set of equations of state based on the nuclear energy density functional theory providing a unified description of the different regions constituting the interior of neutron stars and magnetars. The nuclear…

Recent years continue to be an exciting time for the neutron star physics, providing many new observations and insights to these natural laboratories of cold dense matter. To describe them, there are many models on the market but still none…

Nuclear Theory · Physics 2020-04-22 Sofija Antic , Jirina R. Stone , Anthony W. Thomas