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Related papers: Neutron Stars in Scalar-tensor Gravity with Quarti…

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We investigate theoretical and observational constraints on the mass-radius relations for neutron stars. For that purpose we consider the model of neutron stars taking into considerations strong, weak, electromagnetic and gravitational…

High Energy Astrophysical Phenomena · Physics 2016-06-28 Kuantay Boshkayev , Jorge A. Rueda , Marco Muccino

Inspired by the excluded volume model for isospin symmetric quarkyonic matter, we construct an `excluded volume' model for a charge neutral quarkyonic phase whose hadronic sector contains only neutrons. We refer to this model as quarkyonic…

High Energy Astrophysical Phenomena · Physics 2021-09-01 Srimoyee Sen , Lars Sivertsen

The equation of state for neutron stars in a wide-density range at zero temperature is constructed. The chiral quark-meson coupling model within relativistic Hartree-Fock approximation is adopted for uniform nuclear matter. The coupling…

High Energy Astrophysical Phenomena · Physics 2013-10-15 Tsuyoshi Miyatsu , Sachiko Yamamuro , Ken'ichiro Nakazato

We perform the first study of the oscillation frequencies of rapidly rotating neutron stars in alternative theories of gravity, focusing mainly on the fundamental $f$-modes. We concentrated on a particular class of alternative theories -…

General Relativity and Quantum Cosmology · Physics 2017-09-13 Stoytcho S. Yazadjiev , Daniela D. Doneva , Kostas D. Kokkotas

In this work, we systematically derive the Einstein field equations in general relativity and $f(\mathcal{R})$ gravity, the Tolman-Oppenheimer-Volkoff (TOV) equation, and the expressions for axial and polar Tidal Love Numbers (TLNs) for…

General Relativity and Quantum Cosmology · Physics 2023-06-14 Pinaki Roy , Bharat Kumar

We compute families of spherically symmetric neutron-star models in two-derivative scalar-tensor theories of gravity with a massive scalar field. The numerical approach we present allows us to compute the resulting spacetimes out to…

General Relativity and Quantum Cosmology · Physics 2021-05-21 Roxana Rosca-Mead , Christopher J. Moore , Ulrich Sperhake , Michalis Agathos , Davide Gerosa

Tiny violation of Lorentz invariance has been the subject of theoretic study and experimental test for a long time. We use the Standard-Model Extension (SME) framework to investigate the effect of the minimal Lorentz violation on the…

General Relativity and Quantum Cosmology · Physics 2020-02-17 Rui Xu , Junjie Zhao , Lijing Shao

The effects of the isovector-scalar $\delta$-meson field on the properties of finite nuclei, infinite nuclear matter and neutron stars are investigated within the Relativistic Mean Field (RMF) model which includes non-linear couplings.…

It is shown how the Equation of State (EoS) depends on nucleon properties inside Nuclear Matter (NM). We propose to benefit from the concept of enthalpy in order to include volume corrections to the nucleon rest energy, which are…

Nuclear Theory · Physics 2017-02-28 Jacek Rożynek

In the present paper we construct novel non-topological, spontaneously scalarized neutron stars in multi-scalar Gauss-Bonnet gravity with maximally symmetric target space, and nontrivial map $\varphi:spacetime \rightarrow target\ space$.…

General Relativity and Quantum Cosmology · Physics 2022-02-23 Kalin V. Staykov , Radostina Z. Zheleva

We address the question of the role of low-energy nuclear physics data in constraining neutron star global properties, e.g., masses, radii, angular momentum, and tidal deformability, in the absence of a phase transition in dense matter. To…

Nuclear Theory · Physics 2023-04-06 Brett V. Carlson , Mariana Dutra , Odilon Lourenço , Jérôme Margueron

Neutron star matter spans a wide range of densities, from that of nuclei at the surface to exceeding several times normal nuclear matter density in the core. While terrestrial experiments, such as nuclear or heavy-ion collision experiments,…

High Energy Astrophysical Phenomena · Physics 2023-12-19 Suprovo Ghosh , Debarati Chatterjee , Jürgen Schaffner-Bielich

We study the structural and dynamical consequences of introducing a distributional density profile inside a neutron star, representing a massless, topological shell located at an arbitrary radius. We incorporate this effect into the…

General Relativity and Quantum Cosmology · Physics 2026-04-15 Debojoti Kuzur , Kamal Krishna Nath

We use neutron star mass and radius measurements to constrain the spontaneous scalarization phenomenon in scalar-tensor theories using Bayesian analysis. Neutron star structures in this scenario can be significantly different from the case…

General Relativity and Quantum Cosmology · Physics 2022-07-06 Semih Tuna , Kıvanç İ. Ünlütürk , Fethi M. Ramazanoğlu

We investigate the oscillations of neutron stars using a purely Newtonian approach and three other pseudo-Newtonian formulations. Our work is motivated by the fact that pseudo-Newtonian formulations are commonly used in core-collapse…

High Energy Astrophysical Phenomena · Physics 2023-09-08 Yat-To Tang , Lap-Ming Lin

By using a bottom-up reconstruction technique for non-minimally coupled scalar-tensor theories, we realize the Einstein frame attractor cosmologies in the $\Omega (\phi)$-Jordan frame. For our approach, what is needed for the reconstruction…

General Relativity and Quantum Cosmology · Physics 2018-04-04 S. D. Odintsov , V. K. Oikonomou

We construct a class of nuclear equations of state based on a schematic potential model, that originates from the work of Prakash et. al. \cite{Prakash-88}, which reproduce the results of most microscopic calculations. The equations of…

Nuclear Theory · Physics 2008-11-26 V. P. Psonis , Ch. C. Moustakidis , S. E. Massen

We consider the scalar field profile around relativistic compact objects such as neutron stars for a range of modified gravity models with screening mechanisms of the chameleon and Damour-Polyakov types. We focus primarily on inverse power…

General Relativity and Quantum Cosmology · Physics 2017-04-19 Philippe Brax , Anne-Christine Davis , Rahul Jha

We present the first numerical models of differentially rotating stars in alternative theories of gravity. We chose a particular class of scalar-tensor theories of gravity that is indistinguishable from GR in the weak field regime but can…

General Relativity and Quantum Cosmology · Physics 2018-12-05 Daniela D. Doneva , Stoytcho S. Yazadjiev , Nikolaos Stergioulas , Kostas D. Kokkotas

We investigate equilibrium configurations of uniformly rotating neutron stars in $R^2$ gravity with axion scalar field for GM1 equation of state (EoS) for nuclear matter. The mass-radius diagram, mass-central energy density are presented…

General Relativity and Quantum Cosmology · Physics 2020-09-09 Artyom V. Astashenok , Sergey D. Odintsov
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