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We apply quadratic $f(R)=R+\epsilon R^2$ field equations, where $\epsilon$ has a dimension [L$^2$], to static spherical stellar model. We assume the interior configuration is determined by Krori-Barua ansatz and additionally the fluid is…

General Relativity and Quantum Cosmology · Physics 2024-09-25 G. G. L. Nashed , Waleed El Hanafy

The objective of this research is to explore compact celestial objects while considering the framework of an extended gravitational theory known as $\mathcal{R}+f(\mathcal{G})$ gravity. The notations $\mathcal{R}$ and $\mathcal{G}$ denote…

General Relativity and Quantum Cosmology · Physics 2024-07-08 G. G. L. Nashed , Kazuharu Bamba

Many physically inspired general relativity (GR) modifications predict significant deviations in the properties of spacetime surrounding massive neutron stars. Among these modifications is $f(\mathcal{R}, \mathbb{T})$, where $\mathcal{R}$…

General Relativity and Quantum Cosmology · Physics 2023-08-21 G. G. L Nashed

This work aims to investigate the behaviour of compact stars in the background of $f(R, T)$ theory of gravity. For current work, we consider the Krori-Barua metric potential i.e., $\nu(r)= Br^2+C$ and $\lambda(r)= Ar^2,$ where, $A, B$ and…

General Relativity and Quantum Cosmology · Physics 2023-04-13 M. Farasat Shamir , Zoya Asghar , Adnan Malik

In this work we examine the internal structure of compact stars within an extended gravitational framework described by the function $f(\mathcal{R},\mathcal{G},\mathcal{T})$. Throughout this work, the quantity $\mathcal{R}$ refers to the…

General Relativity and Quantum Cosmology · Physics 2025-11-25 G. G. L. Nashed

This paper aims to explore some realistic configurations of anisotropic spherical structures in the background of metric $f(R)$ gravity, where $R$ is the Ricci scalar. The solutions obtained by Krori and Barua are used to examine the nature…

General Relativity and Quantum Cosmology · Physics 2017-11-08 Z. Yousaf , M. Sharif , M. Ilyas , M. Z. Bhatti

This study simulates the characteristics of spherically symmetric, anisotropic compact stellar bodies with electrical charge within the framework of the $f(Q)$ theory of gravity. Employing the Krori-Barua metric ansatz (K.D. Krori, J.…

General Relativity and Quantum Cosmology · Physics 2024-11-05 Debadri Bhattacharjee , Pradip Kumar Chattopadhyay

In this paper, we explore the effect of charge on the stability of pulsar star SAX J1748.9-2021 in $f(Q)$ gravity, where $Q$ represents non-metricity. For this purpose, we apply the Krori-Barua metric ansatz with anisotropic fluid and use a…

General Relativity and Quantum Cosmology · Physics 2025-02-07 M. Sharif , Madiha Ajmal

This paper aims to examine the composition of various spherically symmetric star models which are coupled with anisotropic configuration in $f(\mathcal{R},\mathcal{T},\mathcal{Q})$ gravity, where…

General Relativity and Quantum Cosmology · Physics 2024-07-03 M. Sharif , T. Naseer

This paper deals with the theoretical modeling of anisotropic compact stars in the framework of $f(T)$ theory of gravity, where $T$ is torsion scalar. To this end, we have used the exact solutions of Krori and Barua metric to a static…

General Physics · Physics 2016-02-16 G. Abbas , Afshan Kanwal , M. Zubair

$f(R)$ gravity, capable of driving the late-time acceleration of the universe, is emerging as a promising alternative to dark energy. Various $f(R)$ gravity models have been intensively tested against probes of the expansion history,…

Astrophysics · Physics 2009-04-01 Xin-Juan Yang , Da-Ming Chen

For cosmologically interesting $f(R)$ gravity models, we derive the complete set of the linearized field equations in the Newtonian gauge, under environments of the solar system, galaxies and clusters respectively. Based on these equations,…

Astrophysics · Physics 2008-11-26 Pengjie Zhang

The $f(R)$ gravity can be cast into the form of a scalar-tensor theory, and scalar degree of freedom can be suppressed in high-density regions by the chameleon mechanism. In this article, for the general $f(R)$ gravity, using a…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-04 Tan Liu , Xing Zhang , Wen Zhao

This paper investigates realistic anisotropic matter configurations for spherical symmetry in the framework of $f(R)$ gravity. The solutions obtained from Buchdahl-I metric are used to determine the behavior of PSR J0740+6620, PSR…

General Relativity and Quantum Cosmology · Physics 2025-02-24 A. Zahra , S. A. Mardan , Muhammad Bilal Riaz , S. Saleem

We study the gravitational potential generated by static, spherically symmetric matter distributions in a quadratic $f(R)$ gravity model. In the weak-field regime, the linearized field equations lead to a fourth-order modified Poisson…

General Relativity and Quantum Cosmology · Physics 2026-02-10 Roger Anderson Hurtado

The present paper is devoted to investigate the possible emergence of relativistic compact stellar objects through modified $f(R,T)$ gravity. For anisotropic matter distribution, we used Krori and Barura solutions and two notable and viable…

General Physics · Physics 2018-05-29 Z. Yousaf , M. Zaeem-ul-Haq Bhatti , M. Ilyas

This paper constitutes the investigations regarding possible formation of compact stars in $f(R,T)$ theory of gravity, where $R$ is Ricci scalar and $T$ is trace of energy momentum tensor. In this connection, we use analytic solution of…

General Physics · Physics 2016-06-28 M. Zubair , G. Abbas , Ifra Noureen

Similar to Rastall gravity we introduce matter-geometry nonminimal coupling which is proportional to the gradient of quadratic curvature invariants. Those are mimicking the conformal trace anomaly when backreaction of the quantum fields to…

High Energy Astrophysical Phenomena · Physics 2024-04-08 Waleed El Hanafy

The rate of energy loss and orbital period decay of quasi-stable compact binary systems are derived in $f(R)$ theory of gravity using the method of a single vertex graviton emission process from a classical source. After linearising the…

General Relativity and Quantum Cosmology · Physics 2023-03-28 Ashish Narang , Subhendra Mohanty , Soumya Jana

We use the kinematic data of the stars in eight dwarf spheroidal galaxies to assess whether $f(R)$ gravity can fit the observed profiles of the line-of-sight velocity dispersion of these systems without resorting to dark matter. Our model…

Astrophysics of Galaxies · Physics 2023-01-18 Ivan de Martino , Antonaldo Diaferio , Luisa Ostorero
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