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The dynamical aspects of some accelerating models are investigated in the framework of an extension of symmetric teleparllel gravity dubbed as f(Q,T) gravity. In this gravity theory, the usual Ricci tensor in the geometrical action is…

General Relativity and Quantum Cosmology · Physics 2021-07-28 Laxmipriya Pati , B. Mishra , S. K. Tripathy

A general formalism to investigate Bianchi type $VI_h$ universes is developed in an extended theory of gravity. A minimally coupled geometry and matter field is considered with a rescaled function of $f(R,T)$ substituted in place of the…

General Physics · Physics 2018-03-28 B. Mishra , S. K. Tripathy , Sankarsan Tarai

Investigating the accelerated expansion of the universe with cosmography is a best method to constraint cosmological models. In this work, in the $F(G)$ modified gravity framework, we obtain equations of motion in a flat FRW metric. Then we…

General Physics · Physics 2012-06-04 M. R. Setare , N. Mohammadipour

The Universe is currently in a phase of accelerated expansion, a fact that was experimentally proven in the late 1990s. Cosmological models involving scalar fields allow the description of this accelerated expansion regime in the Cosmos and…

General Relativity and Quantum Cosmology · Physics 2023-10-11 Joao R. L. Santos , S. Santos da Costa , Romario S. Santos

$f(R,T)$ gravity is a widely used extended theory of gravity introduced in \cite{9} which is a straightforward generalization of $f(R)$ gravity. The action in this extended theory of gravity incorporates well motivated functional forms of…

General Relativity and Quantum Cosmology · Physics 2020-07-09 Snehasish Bhattacharjee , P. K. Sahoo

The Special Issue on "Modified Gravity Approaches to the Tensions of $\Lambda$CDM"} in the Universe journal tackles significant challenges faced by the $\Lambda$CDM model, including discrepancies in the Hubble constant, growth rate of…

General Relativity and Quantum Cosmology · Physics 2024-04-23 Eleonora Di Valentino , Leandros Perivolaropoulos , Jackson Levi Said

Teleparallel gravity is a modified theory of gravity for which the Ricci scalar $R$ of the underlying geometry in the action is replaced by an arbitrary functional form of torsion scalar $T$. In doing so, cosmology in $% f(T)$ gravity…

General Physics · Physics 2022-07-20 Sanjay Mandal , Snehasish Bhattacharjee , S. K. J. Pacif , P. K. Sahoo

In this paper, we have derived the field equations in an extended theory of gravity in an anisotropic space time background and in the presence of magnetic field. The physical and geometrical parameters of the models are determined with…

General Relativity and Quantum Cosmology · Physics 2022-07-19 Sankarsan Tarai , Fakhereh Md. Esmaeili , B. Mishra , S. K. Tripathy

A new class of modified theories of gravity, consisting of the superposition of the metric Einstein-Hilbert Lagrangian with an $f(\cal R)$ term constructed \`{a} la Palatini was proposed recently. The dynamically equivalent scalar-tensor…

General Relativity and Quantum Cosmology · Physics 2013-04-05 Salvatore Capozziello , Tiberiu Harko , Tomi S. Koivisto , Francisco S. N. Lobo , Gonzalo J. Olmo

Various models are under consideration with metric type flat FRW whose energy-momentum tensor is described by a perfect fluid whose generic equation state and taking into account the conservation principle, but considering some of the…

General Physics · Physics 2007-05-23 J. A. Belinchon

We consider a model for gravity that is invariant under global scale transformations. It includes one extra real scalar field coupled non-minimally to the gravity fields. In this model all the dimensionful parameters like the gravitational…

General Relativity and Quantum Cosmology · Physics 2012-02-06 Pankaj Jain , Purnendu Karmakar , Subhadip Mitra , Sukanta Panda , Naveen K. Singh

Future observations of the large-scale structure have the potential to investigate cosmological models with a high degree of complexity, including the properties of gravity on large scales, the presence of a complicated dark energy…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-26 Robert Reischke , Alessio Spurio Mancini , Björn Malte Schäfer , Philipp M. Merkel

The observed accelerated expansion of the Universe may be explained by dark energy or the breakdown of general relativity (GR) on cosmological scales. When the latter case, a modified gravity scenario, is considered, it is often assumed…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-04 Jiro Matsumoto , Teppei Okumura , Misao Sasaki

In the context of f(R) theories of gravity, we study the cosmological evolution of scalar perturbations by using a completely general procedure. We find that the exact fourth-order differential equation for the matter density perturbations…

Astrophysics · Physics 2015-05-13 A. de la Cruz-Dombriz , A. Dobado , A. L. Maroto

In this work, the $f(\mathcal{G},T)$ theory of gravity is recast in terms of the $\phi$ and $\psi$ fields within the scalar-tensor formulation, where $\mathcal{G}$ is the Gauss-Bonnet term and $T$ denotes the trace of the energy-momentum…

General Relativity and Quantum Cosmology · Physics 2023-12-20 Adam Z. Kaczmarek , Dominik Szczęśniak

We study the evolution of linear cosmological perturbations in f(R) models of accelerated expansion in the physical frame where the gravitational dynamics are fourth order and the matter is minimally coupled. These models predict a rich and…

Astrophysics · Physics 2008-11-26 Yong-Seon Song , Wayne Hu , Ignacy Sawicki

In this paper, we considered the study of Friedmann-Robertson-Walker (FRW) model in the framework of $f(Q,T)$ gravity, an extension of symmetric teleparallel gravity, recently defined by Y. Xu et al. \cite{Xu}. The non-linear model…

General Relativity and Quantum Cosmology · Physics 2021-05-05 Nisha Godani , Gauranga C Samanta

In this paper, we investigate the accelerating phase of the Universe within the context of $f(R,L_m,T)$ gravity theory, where $R$, $L_m$, and $T$ represent the Ricci scalar, matter Lagrangian, and the trace of the energy-momentum tensor,…

General Relativity and Quantum Cosmology · Physics 2025-11-19 V. A. Kshirsagar , A. S. Agrawal , S. A. Kadam , Vishwajeet S. Goswami

An accelerated expansion phase is being experienced by the universe due to the presence of an unknown energy component known as dark energy (DE). To find out the cosmic evolution scientists ever tried to modify Einstein's gravitational…

General Physics · Physics 2018-11-14 M. Zubair , M. Zeeshan

In this paper we undertake the modified theory of gravity f(R,T) where R and T are the Ricci scalar and the trace of the energy momentum tensor, respectively. Imposing the conservation of the energy momentum tensor, we obtain a model about…

General Relativity and Quantum Cosmology · Physics 2015-06-30 E. H. Baffou , A. V. Kpadonou , M. E. Rodrigues , M. J. S. Houndjo , J. Tossa