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The energy conditions are derived in the context of $f(R,T)$ gravity, where $R$ is the Ricci scalar and $T$ is the trace of the energy-momentum tensor, which can reduce to the well-known conditions in $f(R)$ gravity and general relativity.…

General Relativity and Quantum Cosmology · Physics 2015-06-11 Muhammad Sharif , Muhammad Zubair

The present research paper is an investigation of dark energy nature of logarithmic $f(R, T)$-gravity cosmology in a flat FLRW space-time universe. We have derived modified Einstein's field equations for the function $f(R, T)=R-16\pi…

General Relativity and Quantum Cosmology · Physics 2023-06-06 Dinesh Chandra Maurya , Jagat Singh , Lalit Kumar Gaur

In this paper, we explore classes of irrotational-fluid cosmological models in the context of f(R)-gravity in an attempt to put some theoretical and mathematical restrictions on the form of the f(R) gravitational Lagrangian. In particular,…

General Relativity and Quantum Cosmology · Physics 2016-03-16 Amare Abebe , Maye Elmardi

This article focuses on different anisotropic models within the framework of a specific modified $f(\mathcal{R},\mathcal{T},\mathcal{R}_{\zeta\gamma}\mathcal{T}^{\zeta\gamma})$ gravity theory. The study adopts a static spherically symmetric…

General Relativity and Quantum Cosmology · Physics 2025-04-22 Yihu Feng , Tayyab Naseer , G. Mustafa , S. K. Maurya

In a previously work, we undertook a static and anisotropic content in $f(T)$ theory and obtained new spherically symmetric solutions considering a constant torsion and some particular conditions for the pressure. In this paper, still in…

General Physics · Physics 2012-02-22 M. Hamani Daouda , Manuel E. Rodrigues , M. J. S. Houndjo

In the present article, we developed a dynamical system in the context of modified $f(R,G,T)$ gravity, where $R$, $G$ and $T$ are Ricci scalar, Gauss-Bonnet term and energy-momentum tensor respectively. Development of the dynamical system…

General Relativity and Quantum Cosmology · Physics 2025-05-30 Elangbam Chingkheinganba Meetei , S. Surendra Singh

A necessary and sufficient condition for linear stability of inviscid parallel shear flow is formulated by developing a novel variational principle, where the velocity profile is assumed to be monotonic and analytic. It is shown that…

Fluid Dynamics · Physics 2015-06-18 Makoto Hirota , Philip J. Morrison , Yuji Hattori

We present a complete set of the equations and matching conditions required for the description of physically meaningful charged, dissipative, spherically symmetric gravitational collapse with shear. Dissipation is described with both…

General Relativity and Quantum Cosmology · Physics 2008-11-26 A. Di Prisco , L. Herrera , G. Le Denmat , M. A. H. MacCallum , N. O. Santos

We have studied in this paper, the stability of dynamical system in $f(R)$ gravity. We have considered the $f(R)$ $\gamma$-gravity and explored its dynamical analysis. We found six critical points among which only one describes an universe…

General Relativity and Quantum Cosmology · Physics 2016-11-29 R. D. Boko , M. J. S. Houndjo , J. Tossa

In this contribution, classes of shear-free cosmological dust models with irrotational fluid flows will be investigated in the context of scalar-tensor theories of gravity. In particular, the integrability conditions describing a consistent…

General Relativity and Quantum Cosmology · Physics 2018-02-22 Heba Sami , Amare Abebe

Modified gravity is one of the potential candidates to explain the accelerated expansion of the universe. Current study highlights the materialization of anisotropic compact stars in the context of $f(R,G)$ theory of gravity. In particular,…

General Physics · Physics 2017-07-07 M. Farasat Shamir , Saeeda Zia

In the current study, we investigated a specific model of anisotropic strange stars specially Her X-1, in the background of modified f(R,T) gravity by choosing f(R,T) = R+2{\xi}T, where R is Ricci scalar, T is the trace of the…

General Relativity and Quantum Cosmology · Physics 2022-02-17 H. D. Singh , J. Kumar

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

A re-investigation of the gravothermal catastrophe is presented. By means of a linear perturbation analysis, we study the dynamical stability of a spherical self-gravitating isothermal fluid of finite volume and find that the conditions for…

Astrophysics of Galaxies · Physics 2015-06-12 M. C. Sormani , G. Bertin

We study the linear properties, nonlinear saturation and a steady, strongly nonlinear state of the Parker instability in galaxies. We consider magnetic buoyancy and its consequences with and without cosmic rays. Cosmic rays are described…

In this paper, we develop two anisotropic solutions for static self-gravitating spherical structure in the presence of electromagnetic field through gravitational decoupling approach in $f(G,T)$ theory, where $G$ and $T$ denote the…

General Relativity and Quantum Cosmology · Physics 2022-11-04 M. Sharif , Komal Hassan

In $f(T)$ gravity, the theory modifies the gravitational action by introducing a function of the torsion scalar $T$. This approach allows for a different treatment of gravity than general relativity, particularly in cosmological contexts.…

General Relativity and Quantum Cosmology · Physics 2024-10-08 S. Davood Sadatian , S. Mohamad Reza Hosseini

The main objective of this study is to investigate the viability and stability of a pulsar filled with anisotropic matter in $f(\mathcal{Q}, \mathbb{T})$ gravity, where $\mathcal{Q}$ represents non-metricity and $\mathbb{T}$ is the trace of…

General Relativity and Quantum Cosmology · Physics 2025-09-05 M. Sharif , Iqra Ibrar

Our present study involves the strange stars model in the framework of $f(R,T)$ theory of gravitation. We have taken a linear function of the Ricci scalar $R$ and the trace $T$ of the stress-energy tensor $T_{\mu \nu}$ for the expression of…

General Relativity and Quantum Cosmology · Physics 2021-06-02 Pramit Rej , Piyali Bhar

In the metric approach of $f(R)$ theories of gravity, the fourth-order field equations are often recast as effective Einstein equations in the presence of standard matter and a curvature fluid (which gathers all the extra terms), always in…

General Relativity and Quantum Cosmology · Physics 2020-12-01 Juan M. Z. Pretel , Sergio E. Jorás , Ribamar R. R. Reis
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