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Related papers: Reconstruction of f(R, T) gravity describing matte…

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We present the reconstruction method of $f(R)$ gravity for the homogeneous and anisotropic Bianchi-I spacetime, which was previously formulated only for homogeneous and isotropic FLRW spacetime. We argue in this paper that for anisotropic…

General Relativity and Quantum Cosmology · Physics 2018-07-11 Saikat Chakraborty

A novel analytical method for f(R) modified theories without matter in Friedmann-Lemaitre-Robertson-Walker spacetimes is introduced. The equation of motion for the scale factor in terms of cosmic time is reduced to the equation for the…

General Relativity and Quantum Cosmology · Physics 2013-03-29 Silvije Domazet , Voja Radovanovic , Marko Simonovic , Hrvoje Stefancic

We present a study of the generalized second law of thermodynamics in the scope of the f(R,T) theory of gravity, with R and T representing the Ricci scalar and trace of the energy-momentum tensor, respectively. From the energy-momentum…

General Relativity and Quantum Cosmology · Physics 2018-10-09 D. Momeni , P. H. R. S. Moraes , R. Myrzakulov

In this paper, a cosmological model of the Universe is presented in $f(Q,T)$ gravity and the parameters are constrained by cosmological data sets. Initially, a generalised form of $f(Q,T)$ model is used as $f(Q,T)=-\lambda_{1}…

General Relativity and Quantum Cosmology · Physics 2024-03-21 A. S. Agrawal , B. Mishra , S. K. Tripathy

A modified gravity theory with $f(R)=R^2$ coupled to a dark energy lagrangian $L=-V(\phi)F(X)$ , $X=\nabla_{\mu}\phi\nabla^{\mu}\phi$, gives plausible cosmological scenarios when the modified Friedman equations are solved subject to the…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-30 Debashis Gangopadhyay , Somnath Mukherjee

Here we analysed a particular type of $F(R)$ gravity, the so-called exponential gravity which includes an exponential function of the Ricci scalar in the action. Such term represents a correction to the usual Hilbert-Einstein action. By…

General Relativity and Quantum Cosmology · Physics 2018-01-17 Sergei D. Odintsov , Diego Saez-Chillon Gomez , German S. Sharov

We investigate a flat FLRW-model in $f(R,T)$-gravity, which includes the quadratic variation in scalar curvature $R$ and the linear term of the trace of the stress-energy tensor $T$. In turn, we establish the model has the behaviour of the…

General Relativity and Quantum Cosmology · Physics 2022-08-10 J. K. Singh , Akanksha Singh , G. K. Goswami , J. Jena

We review modified $F(R)$ gravity as realistic candidate to describe the observable universe expansion history. We show that recent cosmic acceleration, radiation/matter-dominated epoch and inflation could be realized in the framework of…

High Energy Physics - Theory · Physics 2008-07-08 Shin'ichi Nojiri , Sergei D. Odintsov

We search for viable f(R) theories of gravity, making use of the equivalence between such theories and scalar-tensor gravity. We find that models can be made consistent with solar system constraints either by giving the scalar a high mass…

Astrophysics · Physics 2008-11-26 Thomas Faulkner , Max Tegmark , Emory F. Bunn , Yi Mao

We study mimetic $F(R)$ gravity with potential and Lagrange multiplier constraint. In the context of these theories, we introduce a reconstruction technique which enables us to realize arbitrary cosmologies, given the Hubble rate and an…

General Relativity and Quantum Cosmology · Physics 2016-02-17 S. D. Odintsov , V. K. Oikonomou

In this paper, we will examine the problem of violation of causality in $f(R,T)$ modified gravity, where $R$ is the Ricci scalar and $T$ is the trace of the energy-momentum tensor $T_{\mu\nu}$. We investigate the causality problem in two…

General Relativity and Quantum Cosmology · Physics 2014-11-05 C. J. Ferst , A. F. Santos

In this study, we investigate strange quark stars within the framework of modified $f(R,T)$ gravity, where $R$ represents the Ricci scalar and $T$ denotes the trace of the energy-momentum tensor, specifically defined as $ f(R,T) = R + 2\chi…

General Relativity and Quantum Cosmology · Physics 2024-10-08 Suman Pal , Gargi Chaudhuri

We discuss the cosmological reconstruction of $f(R,R_{\alpha\beta}R^{\alpha\beta},\phi)$ (where $R$, $R_{\alpha\beta}R^{\alpha\beta}$ and $\phi$ represents the Ricci scalar, Ricci invariant and scalar field) corresponding to power law and…

General Relativity and Quantum Cosmology · Physics 2017-05-01 M. Zubair , Farzana Kousar

We present a reconstruction of the Lagrangian for $f(R)$ gravity by using a massive scalar field. The scalar field is minimally coupled to the action of $f(R)$ gravity. We demonstrate the use of a theorem based on invertible point…

General Relativity and Quantum Cosmology · Physics 2020-02-06 Soumya Chakrabarti , Kazuharu Bamba , Jackson Levi Said

The paper extends basic Einstein--Hilbert action by adding a newly proposed invariant constructed from a specific contraction between the Einstein tensor and the energy momentum tensor, encoding a non--minimal coupling between the…

General Relativity and Quantum Cosmology · Physics 2023-02-09 Mihai Marciu , Dana Maria Ioan

The main purpose of this paper is to investigate the exact solutions of cylindrically symmetric spacetime in the context of $f(R,T)$ gravity [1], where $f(R,T)$ is an arbitrary function of Ricci scalar $R$ and trace of the energy momentum…

General Relativity and Quantum Cosmology · Physics 2015-07-01 M. Farasat Shamir , Zahid Raza

In this paper, we explore the nature of scalar field potential in $f(R, R_{\alpha\beta} R^{\alpha\beta},\phi)$ gravity using a well-motivated reconstruction scheme for flat FRW geometry. The beauty of this scheme lies in the assumption that…

General Relativity and Quantum Cosmology · Physics 2017-01-25 M. Zubair , Farzana Kousar , Saira Waheed

The duality between a higher curvature $f(R)$ gravity model and a scalar-tensor theory helps to bring out the role of the additional degree of freedom originating from the higher derivative terms in the gravity action. Such a degree of…

General Relativity and Quantum Cosmology · Physics 2024-06-21 Hitender Kumar , Tanmoy Paul , Soumitra SenGupta

The $f(T)$ theory is recently proposed to explain the present cosmic accelerating expansion of the universe. $f(T)$ theory is an extension of Teleparallel theory of gravity, where $T$ is the torsion scalar. This paper contains the…

General Relativity and Quantum Cosmology · Physics 2015-02-04 M. Jamil Amir , M. Yussouf

We review the status of $f(R,T)$ cosmological models, where $T$ is the trace of the energy momentum tensor $T^{\mu\nu}$. We start focusing on the modified Friedmann equations for the minimally coupled gravitational Lagrangian of the type…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-08 Ana Paula Jeakel , Jonas Pinheiro da Silva , Hermano Velten