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This thesis explores the cosmological implications of modified gravity, focusing on nonmetricity-based $f(Q)$ gravity as an alternative to the $\Lambda$CDM model in explaining cosmic acceleration. Chapter I lays the theoretical groundwork…

General Relativity and Quantum Cosmology · Physics 2025-04-15 Gaurav N. Gadbail

In this paper, we present the cosmological scenario obtained from $f(R,T)$ gravity by using an exponential dependence on the trace of the energy-momentum tensor. With a numerical approach applied to the equations of motion, we show several…

General Relativity and Quantum Cosmology · Physics 2019-11-11 G. Ribeiro , R. Sfair , P. H. R. S. Moraes , J. R. L. Santos , A. de Souza Dutra

In this paper, we have presented the cosmological model of the Universe that represents late time cosmic acceleration in torsion based gravitational theory, the $f(T)$ gravity. A well motivated parametrization for the Hubble parameter has…

General Relativity and Quantum Cosmology · Physics 2025-11-04 Suraj Kumar Behera , Pratik P. Ray , B. Mishra

In this article, we examine the dynamical system of the $f(R,\mathcal{G})$ gravity model. This $f(R,G)$ model framework is composed of interactions between dark matter and scalar field through the linear coupling term. The key objective of…

General Relativity and Quantum Cosmology · Physics 2025-04-03 Shivani Sharma , R. Chaubey

We consider the geodesic deviation equation, describing the relative accelerations of nearby particles, and the Raychaudhuri equation, giving the evolution of the kinematical quantities associated with deformations (expansion, shear and…

General Relativity and Quantum Cosmology · Physics 2024-11-18 Jin-Zhao Yang , Shahab Shahidi , Tiberiu Harko , Shi-Dong Liang

Weyl's conformal theory of gravity is an extension of Einstein's theory of general relativity which associates metrics with 1-forms . In the case of locally integrable (closed non-exact) 1-forms the spacetime manifolds are no more simply…

General Relativity and Quantum Cosmology · Physics 2022-06-09 Michel Duneau

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

In this paper, we present a cosmological model within the framework of symmetric teleparallel gravity, focusing on $f(Q)$ gravity, where $Q$ represents the non-metricity scalar. Utilizing cosmological datasets, we derive an accelerating…

General Relativity and Quantum Cosmology · Physics 2024-08-09 S. A. Narawade , S. H. Shekh , B. Mishra , Wompherdeiki Khyllep , Jibitesh Dutta

The basic aim of this manuscript is to investigate the cosmological solutions in the context of the modified $f(R, T)$ theory of gravity, where $R$ is the Ricci scalar and $T$ is the trace of the energy-momentum tensor. For our current…

General Relativity and Quantum Cosmology · Physics 2024-03-26 Adnan Malik , Tayyaba Naz , Aimen Rauf , M. Farasat Shamir , Z. Yousaf

In this paper, we investigate some exact cosmological models in Myrzakulov $F(T,Q)$ gravity or the Myrzakulov gravity-III (MG-III) proposed in [arXiv:1205.5266], with observational constraints. The MG-III gravity is some kind of unification…

General Relativity and Quantum Cosmology · Physics 2024-09-05 Dinesh Chandra Maurya , K. Yesmakhanova , R. Myrzakulov , G. Nugmanova

We consider an $f(Q, T)$ gravity theory with a Schr\"{o}dinger type vectorial non-metricity. In the presence of such a non-metricity, the length of vectors is preserved under autoparallel transport. We obtain the field equations assuming a…

General Relativity and Quantum Cosmology · Physics 2025-11-25 Lei Ming , Himanshu Chaudhary , Shi-Dong Liang , Hong-Hao Zhang , Tiberiu Harko

The $f(Q,C)$ theory, which extends symmetric teleparallel gravity by including the boundary term $C$ in addition to the non-metricity scalar $Q$, provides a unifying framework that encompasses both $f(Q)$ and $f(\mathring{R})$ gravities. In…

General Relativity and Quantum Cosmology · Physics 2025-09-30 Hamid Shabani , Avik De

We consider a Weyl-invariant formulation of gravity with a cosmological constant in d-dimensional spacetime and show that near two dimensions the classical action reduces to the timelike Liouville action. We show that the renormalized…

High Energy Physics - Theory · Physics 2016-08-17 Teresa Bautista , Atish Dabholkar

We investigate FLRW cosmology in the framework of symmetric teleparallel $f(Q)$ gravity with a nonminimal coupling between dark matter and the gravitational field. In the noncoincidence gauge, the field equations admit an equivalent…

General Relativity and Quantum Cosmology · Physics 2026-03-26 A. Abebe , P. S. Apostolopoulos , A. Giacomini , G. Leon , F. Moncada , A. Paliathanasis

Here, we peruse cosmological usage of the most promising candidates of dark energy in the framework of $f(T)$ gravity theory. We reconstruct the different $f(T)$ modifed gravity models in the spatially flat FRW universe according to…

General Relativity and Quantum Cosmology · Physics 2016-10-12 Pameli Saha , Ujjal Debnath

In this first article of a series on alternative cosmological models we present an extended version of a cosmological model in Weyl-Cartan spacetime. The new model can be viewed as a generalization of a model developed earlier jointly with…

General Relativity and Quantum Cosmology · Physics 2009-04-03 Dirk Puetzfeld

In this work we study the cosmology of the general f(T) gravity theory. We express the modified Einstein equations using covariant quantities, and derive the gauge-invariant perturbation equations in covariant form. We consider a specific…

Cosmology and Nongalactic Astrophysics · Physics 2011-11-02 Baojiu Li , Thomas P. Sotiriou , John D. Barrow

In this work, we explore the cosmological stability of $f(Q, B)$ gravity using a dynamical system approach, where $Q$ denotes the nonmetricity scalar and $B$ represents the boundary term. We determine the model parameters of $f(Q, B)$…

General Relativity and Quantum Cosmology · Physics 2024-12-25 Santosh V. Lohakare , B. Mishra

In this paper, we have presented an accelerating cosmological model of the Universe in an extended symmetric teleparallel gravity or $f(Q,T)$ gravity. The parametric form of the Hubble parameter is, $H\left(z\right) =H_{0}\left[ \alpha…

General Relativity and Quantum Cosmology · Physics 2023-05-16 S. A. Narawade , M. Koussour , B. Mishra

The article communicates an alternative route to suffice the late-time acceleration considering a bulk viscous fluid with viscosity coefficient $\zeta =\zeta _{0}+ \zeta _{1} H + \zeta _{2} H^{2}$, where $\zeta _{0}, \zeta _{1}, \zeta _{2}$…

General Relativity and Quantum Cosmology · Physics 2020-07-20 Simran Arora , Snehasish Bhattacharjee , P. K. Sahoo