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Related papers: Neutron stars in $f(\mathbb{Q})$ gravity

200 papers

In this work we investigate the effects of a non-minimally coupled quartic order scalar model on static neutron stars, with the non-minimal coupling in the Jordan frame being of the form $f(\phi ) = 1 + \xi\phi^2$. Particularly we derive…

General Relativity and Quantum Cosmology · Physics 2022-04-13 S. D. Odintsov , V. K. Oikonomou

Due to our ignorance of the equation of state (EOS) beyond nuclear density, there is still no unique theoretical model for neutron stars (NSs). It is therefore surprising that universal EOS-independent relations connecting different…

General Relativity and Quantum Cosmology · Physics 2015-06-18 Y. -H. Sham , L. -M. Lin , P. T. Leung

The realistic models of neutron stars are considered for simple $R+\alpha R^2$ gravity and equivalent Brance-Dicke theory with dilaton field in Einsein frame. For negative values of $\alpha$ we have no acceptable results from astrophysical…

General Relativity and Quantum Cosmology · Physics 2018-12-27 Artyom V. Astashenok , Alexey S. Baigashov , Sergey A. Lapin

In this work, we study the influence of $f(R,T)$ gravity on rapidly rotating neutron stars. First we discuss the main aspects of this modified theory of gravity where the gravitational Lagrangian is an arbitrary function of the Ricci scalar…

General Relativity and Quantum Cosmology · Physics 2023-05-03 F. M. da Silva , L. C. N. Santos , C. E. Mota , T. O. F. da Costa , J. C. Fabris

Recently, theoretical studies on the bumblebee gravity model, a nonminimally-coupled vector-tensor theory that violates the Lorentz symmetry, have flourished, with a simultaneous increase in the utilization of observations to impose…

General Relativity and Quantum Cosmology · Physics 2024-11-26 Peixiang Ji , Zhuhai Li , Lirui Yang , Rui Xu , Zexin Hu , Lijing Shao

$f(R)$ theories of gravity are one of the most popular alternative explanations for dark energy and therefore studying the possible astrophysical implications of these theories is an important task. In the present paper we make a…

General Relativity and Quantum Cosmology · Physics 2015-06-23 Stoytcho S. Yazadjiev , Daniela D. Doneva , Kostas D. Kokkotas

We report on general relativistic calculations of quasiequilibrium configurations of binary neutron stars in circular orbits with zero vorticity. These configurations are expected to represent realistic situations as opposed to corotating…

General Relativity and Quantum Cosmology · Physics 2009-10-31 S. Bonazzola , E. Gourgoulhon , J. -A. Marck

In the context of f(R) gravity theories, we show that the apparent mass of a neutron star as seen from an observer at infinity is numerically calculable but requires careful matching, first at the star's edge, between interior and exterior…

General Relativity and Quantum Cosmology · Physics 2016-09-14 Miguel Aparicio Resco , Alvaro de la Cruz-Dombriz , Felipe J. Llanes-Estrada , Victor Zapatero Castrillo

The higher-curvature gravity with boundary terms i.e the $f(Q)$ theories, grounded on non-metricity as a fundamental geometric quantity, exhibit remarkable efficacy in portraying late-time universe phenomena. The aim is to delineate…

General Relativity and Quantum Cosmology · Physics 2024-02-20 Pooja Vishwakarma , Parth Shah

This thesis aims at improving our understanding of the strong-field regime of gravity, where deviations from General Relativity (GR) are expected to be found on theoretical grounds. In particular, we have been concerned with the formulation…

General Relativity and Quantum Cosmology · Physics 2023-12-08 Adrián Casado-Turrión

We consider the evolution in full general relativity of a family of linearly unstable isolated spherical neutron stars under the effects of very small, perturbations as induced by the truncation error. Using a simple ideal-fluid equation of…

General Relativity and Quantum Cosmology · Physics 2011-07-18 David Radice , Luciano Rezzolla , Thorsten Kellermann

We discuss neutron stars with strong magnetic mean fields in the framework of Extended Theories of Gravity. In particular, we take into account models derived from $f(R)$ and $f(\cal G)$ extensions of General Relativity where functions of…

General Relativity and Quantum Cosmology · Physics 2015-06-22 Artyom V. Astashenok , Salvatore Capozziello , Sergei D. Odintsov

Thermal evolution of neutron stars is studied in the $f(R)=R+\alpha R^{2}$ theory of gravity. We first describe the equations of stellar structure and evolution for a spherically symmetric spacetime plus a perfect fluid at rest. We then…

General Relativity and Quantum Cosmology · Physics 2023-06-08 Martín Nava-Callejas , Dany Page , Mikhail V. Beznogov

We investigate static spherically symmetric spacetimes within the framework of symmetric teleparallel $f(Q)$ gravity in order to describe relativistic stars. We adopt a specific ansatz for the background geometry corresponding to a…

General Relativity and Quantum Cosmology · Physics 2026-02-12 Nikolaos Dimakis , Alex Giacomini , Andronikos Paliathanasis , Grigorios Panotopoulos

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 present interesting aspects of neutron stars (NSs) from the standpoint of a modified theory of gravity called Ho\v{r}ava-Lifshitz (HL) gravity. A deviation from general relativity (GR) in HL gravity can change typical features of the NS…

General Relativity and Quantum Cosmology · Physics 2021-03-03 Kyungmin Kim , John J. Oh , Chan Park , Edwin J. Son

Neutron star models in perturbative $f(R)$ gravity are considered with realistic equations of state. In particular, we consider the FPS, SLy and other equations of state and a case of piecewise equation of state for stars with quark cores.…

General Relativity and Quantum Cosmology · Physics 2015-06-17 Artyom V. Astashenok , Salvatore Capozziello , Sergei D. Odintsov

We present new sequences of general relativistic, quasiequilibrium black hole-neutron star binaries. We solve for the gravitational field in the conformal thin-sandwich decomposition of Einstein's field equations, coupled to the equations…

Astrophysics · Physics 2009-11-11 Keisuke Taniguchi , Thomas W. Baumgarte , Joshua A. Faber , Stuart L. Shapiro

We study neutron star configurations in a simple shift-symmetric subfamily of degenerate higher-order scalar-tensor (DHOST) theories, whose deviations from General Relativity (GR) are characterized by a single parameter. We compute the…

General Relativity and Quantum Cosmology · Physics 2022-11-09 Hamza Boumaza , David Langlois

The Noether Symmetry Approach can be used to construct spherically symmetric solutions in $f({\cal R})$ gravity. Specifically, the Noether conserved quantity is related to the gravitational mass and a gravitational radius that reduces to…

General Relativity and Quantum Cosmology · Physics 2018-04-04 Mariafelicia De Laurentis