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

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We study the existence and structure of static and slowly rotating neutron stars (NSs) in a particular truncation of scalar torsion theory with a scalar field $ \phi $ non-minimally coupled to the torsion scalar, and a potential of the form…

General Relativity and Quantum Cosmology · Physics 2024-12-31 Youcef Kehal , Khireddine Nouicer , Hamza Boumaza

We discuss the Mass -Radius diagram for static neutron star models obtained by the numerical solution of modified Tolman-Oppenheimer-Volkoff equations in $f(R)$ gravity where the Lagrangians $f(R)=R+\alpha R^2 (1+\gamma R)$ and…

General Relativity and Quantum Cosmology · Physics 2016-01-13 Salvatore Capozziello , Mariafelicia De Laurentis , Ruben Farinelli , Sergei D. Odintsov

In this work we shall study the implications of a subclass of $E$-models cosmological attractors, namely of $a$-attractors, on hydrodynamically stable slowly rotating neutron stars. Specifically, we shall present the Jordan frame theory of…

General Relativity and Quantum Cosmology · Physics 2021-03-16 S. D. Odintsov , V. K. Oikonomou

Neutron star properties, such as its mass, radius, and moment of inertia, are calculated by solving the Tolman-Oppenheimer-Volkov (TOV) equations using the ring-diagram equation of state (EOS) obtained from realistic low-momentum NN…

Nuclear Theory · Physics 2009-12-31 Huan Dong , T. T. S. Kuo , R. Machleidt

We study the structure of neutron stars in scalar-tensor theories for the nonminimal coupling of the form $(1+\kappa \xi \phi^{2})\cal R$. We solve the hydrostatic equilibrium equations for two different types of scalar field potentials and…

General Relativity and Quantum Cosmology · Physics 2019-04-02 A. Savaş Arapoğlu , K. Yavuz Ekşi , A. Emrah Yükselci

We study static neutron stars in the context of a class of non-minimally coupled inflationary potentials, the universal attractors. Universal attractors are known to generate a viable inflationary era, and they fall into the same category…

General Relativity and Quantum Cosmology · Physics 2021-09-01 V. K. Oikonomou

Cartan $F(R)$ gravity introduces the equivalent scalar-tensor theory by extending the gravity sector. From the solution of the modified Cartan equation leads to the interaction with the scalar field and the fermion. We derived the effective…

General Relativity and Quantum Cosmology · Physics 2025-03-12 Hiroki Sakamoto , Masahiko Taniguchi

We study static, spherically symmetric neutron stars in a class of scalar-tensor theories with non-canonical kinetic terms (K-essence) obeying all causality and hyperbolicity conditions. These models have non-trivial dynamics that lead to a…

General Relativity and Quantum Cosmology · Physics 2025-09-12 Mark P. Hertzberg , Oleksandr S. Stashko

We study the structure of spherically symmetric and static objects in the presence of a nonminimally coupled scalar field having a potential of the form $V(\phi)=-\mu^2\phi^2/2+\lambda\phi^4/4$. We numerically solve equations of the system…

General Relativity and Quantum Cosmology · Physics 2020-02-14 A. Savaş Arapoğlu , A. Emrah Yükselci

This study focuses on the static neutron star perspective for two types of cosmological inflationary attractor theories, namely the induced inflationary attractors and the quadratic inflationary attractors. The two cosmological models can…

General Relativity and Quantum Cosmology · Physics 2023-03-29 V. K. Oikonomou

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

We utilize the top-down holographic QCD model, the Witten-Sakai-Sugimoto model, in a hybrid setting with the SLy4, soft chiral EFT and stiff chiral EFT equations of state to describe neutron stars with high precision. In particular, we…

High Energy Physics - Phenomenology · Physics 2024-01-02 Lorenzo Bartolini , Sven Bjarke Gudnason

We numerically construct compact stars in the scalar-tensor theory of gravity with non-minimal derivative coupling of a scalar field to the curvature and nonzero cosmological constant. There are two free parameters in this model of gravity:…

General Relativity and Quantum Cosmology · Physics 2025-04-08 P. E. Kashargin , A. A. Lebedev , S. V. Sushkov

We study the Starobinsky or $R^2$ model of $f(R)=R+\alpha R^2$ for neutron stars with the structure equations represented by the coupled differential equations and the \emph{polytropic} type of the matter equation of state. The junction…

General Relativity and Quantum Cosmology · Physics 2017-10-11 Wei-Xiang Feng , Chao-Qiang Geng , W. F. Kao , Ling-Wei Luo

We derive a Tolman-Oppenheimer-Volkoff equation in neutron star systems within the modified $f(T, \mathcal{T})$-gravity class of models using a perturbative approach. In our approach $f(T, \mathcal{T})$-gravity is considered to be a static…

General Relativity and Quantum Cosmology · Physics 2017-05-08 Mark Pace , Jackson Levi Said

We investigate the geodesic structure of realistic static and spherically symmetric spacetimes embedding neutron stars in metric $f(R)$ gravity, focusing on the quadratic Starobinsky model $f(R)=aR^2$ with $a<0$. Neutron-star solutions are…

General Relativity and Quantum Cosmology · Physics 2026-03-10 Néstor Rivero González , Álvaro de la Cruz Dombriz , Gonzalo J. Olmo

We study the structure of neutron stars in f(R) gravity theories with perturbative constraints. We derive the modified Tolman-Oppenheimer-Volkov equations and solve them for a polytropic equation of state. We investigate the resulting…

High Energy Astrophysical Phenomena · Physics 2014-11-20 Alan Cooney , Simon DeDeo , Dimitrios Psaltis

In this work we study the neutron star phenomenology of $R^p$ attractor theories in the Einstein frame. The Einstein frame $R^p$ attractor theories have the attractor property that they originate from a large class of Jordan frame scalar…

General Relativity and Quantum Cosmology · Physics 2023-02-08 V. K. Oikonomou

The macroscopic properties of compact stars in modified gravity theories can be significantly different from the general relativistic (GR) predictions. Within the gravitational context of scalar-tensor theories, with a scalar field $\phi$…

General Relativity and Quantum Cosmology · Physics 2023-12-05 Juan M. Z. Pretel , Sergio E. Jorás , Ribamar R. R. Reis , Sergio B. Duarte , José D. V. Arbañil

We present the field equations governing the equilibrium of rapidly rotating neutron stars in scalar-tensor theories of gravity, as well as representative numerical solutions. The conditions for the presence of a nontrivial scalar field and…

General Relativity and Quantum Cosmology · Physics 2014-02-25 Daniela D. Doneva , Stoytcho S. Yazadjiev , Nikolaos Stergioulas , Kostas D. Kokkotas
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