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The main goal of this work is to provide a comprehensive study of relativistic structures in the context of recently proposed {$\mathcal{R}+ \alpha \mathcal{A}$} gravity, where $\mathcal{R}$ is the Ricci scalar, and $\mathcal{A}$ is the…

General Relativity and Quantum Cosmology · Physics 2023-04-11 M. Farasat Shamir , Eesha Meer

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

Model of gravitational collapse of anisotropic compact stars in a new theory of $ f(R) $ gravity has been developed. The author considers the modified gravity model of $ f(R) = \xi R^4 $ to investigate a physically acceptable model of…

General Relativity and Quantum Cosmology · Physics 2022-04-01 Jay Solanki

Despite its elegance, the theory of General Relativity is subject to experimental, observational, and theoretical scrutiny to arrive at tighter constraints or an alternative, more preferred theory. In alternative gravity theories, the…

General Relativity and Quantum Cosmology · Physics 2023-09-12 Bhaskar Biswas , Evangelos Smyrniotis , Ioannis Liodis , Nikolaos Stergioulas

We investigate the gravitational models with the non-minimal $Y(R)F^2$ coupled electromagnetic fields to gravity, in order to describe charged compact stars, where $Y(R) $ denotes a function of the Ricci curvature scalar $R$ and $F^2$…

General Relativity and Quantum Cosmology · Physics 2018-03-28 Özcan Sert

We propose an action-based $ f(R) $ modification of Einstein's gravity which admits of a modified Schwarzschild-deSitter metric. In the weak field limit this amounts to adding a small logarithmic correction to the newtonian potential. A…

Astrophysics · Physics 2009-11-11 Y. Sobouti

We investigate realistic models of compact objects, focusing on neutron and strange stars, composed by dense matter and dark energy in the form of a simple fluid or scalar field interacting with matter. For the dark energy component, we use…

General Relativity and Quantum Cosmology · Physics 2023-08-01 Artyom V. Astashenok , Sergey D. Odintsov , Vasilis K. Oikonomou

In this study we obtain interior solutions and investigate structural properties of isotropic compact stars in the framework of four-dimensional regularized Einstein-Gauss-Bonnet (4DEGB) gravity. For stellar matter content, we adopt a…

General Relativity and Quantum Cosmology · Physics 2026-01-21 G. Panotopoulos , Á. Rincón , I. Lopes

Neutron stars (NSs) are thought to be excellent laboratories for determining the equation of state (EoS) of cold dense matter. Their strong gravity suggests that they can also be used to constrain gravity models. The mass and radius (M-R)…

High Energy Astrophysical Phenomena · Physics 2014-04-16 Kazim Yavuz Ekşi , Can Güngör , Murat Metehan Türkoğlu

There is a degeneracy between the equation of state (EOS) of superdense neutron-rich nuclear matter and the strong-field gravity in understanding properties of neutron stars. While the EOS is still poorly known, there are also longstanding…

Nuclear Theory · Physics 2015-01-30 Xiao-Tao He , F. J. Fattoyev , Bao-An Li , W. G. Newton

Quark star models with realistic equation of state in nonperturbative $f(R)$ gravity are considered. The mass-radius relation for $f(R)=R+\alpha R^2$ model is obtained. Considering scalar curvature $R$ as an independent function, one can…

General Relativity and Quantum Cosmology · Physics 2015-06-23 A. V. Astashenok , S. Capozziello , S. D. Odintsov

Physically based changes to general relativity (GR) often predict significant differences in how spacetime behaves near massive neutron stars. One of these modifications is represented by $f(\mathcal{Q}, { \mathcal{T}})$, with $\mathcal{Q}$…

General Relativity and Quantum Cosmology · Physics 2024-10-21 G. G. L. Nashed , Tiberiu Harko

We investigate compact stars in the noninteger power (NIP) model of $f(R)$ gravity theory, which includes the higher-curvature correction to the Einstein-Hilbert action. The mass-radius relation of the compact stars in the NIP model…

General Relativity and Quantum Cosmology · Physics 2024-11-05 Yong-Xiang Cui , Zu Yan , Kota Numajiri , Taishi Katsuragawa , Shin'ichi Nojiri

We obtain a class of anisotropic spherically symmetric relativistic solutions of compact objects in hydrostatic equilibrium in the $f(R,T) =R+2\chi T$ modified gravity, where $R$ is the Ricci scalar, $T$ is the trace of the energy momentum…

General Physics · Physics 2020-09-18 S. Dey , A. Chanda , B. C. Paul

In this work, we investigate the neutron star structure in conservative $f(R, T)$ gravity with $f(R, T)=R+\lambda T$, where $\lambda$ denotes the matter--geometry coupling. The modified stellar structure equations are solved using realistic…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-27 Premachand Mahapatra , Prasanta Kumar Das

The physically realistic model of compact stars undergoing gravitational collapse in $ f(R) $ gravity has been developed. We consider a more general model $ R + f(R) = R + k R^m $ and describe the interior space-time of gravitationally…

General Relativity and Quantum Cosmology · Physics 2022-05-17 Jay Solanki

There are many ways to probe alternative theories of gravity, namely, via: experimental tests at solar system scale, cosmological data and models, gravitational waves and compact objects. In the present paper we consider a model of gravity…

General Relativity and Quantum Cosmology · Physics 2022-11-08 José C. N. de Araujo , Hemily G. M. Fortes

Recent multi-messenger observations, including gravitational wave detections of compact objects in the neutron star-black hole mass-gap region and precise measurements of high-mass pulsars, motivate mechanisms capable of enlarging the…

General Relativity and Quantum Cosmology · Physics 2026-04-28 Samstuti Chanda , Ranjan Sharma

We establish a well-posedness theory for the f(R) theory of modified gravity, which is a generalization of Einstein's theory of gravitation. The scalar curvature R of the spacetime, which arises in the integrand of the Einstein-Hilbert…

Analysis of PDEs · Mathematics 2014-12-30 Philippe G. LeFloch , Yue Ma

In the present investigation compact stellar models are dealt with in the framework of the modified gravity theory, specifically of $f(\mathbb{T},\mathcal{T})$ type. We have considered that the compact objects are following a spherically…

General Relativity and Quantum Cosmology · Physics 2021-06-29 Ines G. Salako , Chayan Ranjit , M. Khlopov , Saibal Ray , Utpal Mukhopadhyay