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Related papers: Anisotropic solutions in f(R) Gravity

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We obtain the general cosmological evolution equations for a classically consistent theory of bimetric gravity. Their analytic solutions are demonstrated to generically allow for a cosmic evolution starting out from a matter dominated FLRW…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Mikael von Strauss , Angnis Schmidt-May , Jonas Enander , Edvard Mortsell , S. F. Hassan

Three models with nonlinear realizations of conformal symmetry are discussed. The simplest model can only describe a universe expanding with a deceleration and does not include inflation. The other models are equivalent up to a variables…

General Relativity and Quantum Cosmology · Physics 2021-12-23 Stanislav Alexeyev , Daniil Krichevskiy , Boris Latosh

Despite having a reasonably successful account of accelerated cosmology, understanding the early evolution of Universe has always been difficult for mankind. Our promising strategy is based on a novel class of symmetric teleparallel…

General Relativity and Quantum Cosmology · Physics 2022-09-12 L. Anjana Devi , S. Surendra Singh , Leishingam Kumrah , Md Khurshid Alam

We study the consequences of the $f(R/\Box)$ gravity models for the Solar system and the large scale structure of the universe. The spherically symmetric solutions can be used to obtain bounds on the constant and the linear parts of the…

General Relativity and Quantum Cosmology · Physics 2008-12-18 Tomi S. Koivisto

Currently, in order to explain the accelerated expansion phase of the universe, several alternative approaches have been proposed, among which the most common are dark energy models and alternative theories of gravity. Although these…

General Relativity and Quantum Cosmology · Physics 2021-08-24 I. S. Farias , P. H. R. S. Moraes

Modified gravity theories have received increased attention lately to understand the late time acceleration of the universe. This viewpoint essentially modifies the geometric components of the universe. Among numerous extension to…

General Relativity and Quantum Cosmology · Physics 2019-05-23 Parth Shah , Gauranga C. Samanta

We propose a bigravity analogue of the $F(R)$ gravity. Our construction is based on recent ghost-free massive bigravity where additional scalar fields are added and the corresponding conformal transformation is implemented. It turns out…

High Energy Physics - Theory · Physics 2015-06-05 Shin'ichi Nojiri , Sergei D. Odintsov

In the work, we present investigation on decoupling gravitational sources under the framework of $f(R,T)$ gravity. Basically the complete geometric deformation technique has been employed here which facilitates finding exact solutions to…

General Relativity and Quantum Cosmology · Physics 2024-03-21 S. K. Maurya , B. Mishra , Saibal Ray , Riju Nag

Dynamical system methods are used in the study of the stability of spatially flat homogeneous cosmologies within a large class of generalized modified gravity models in the presence of a relativistic matter-radiation fluid. The present…

High Energy Physics - Theory · Physics 2008-12-18 Guido Cognola , Sergio Zerbini

In this article, we investigate the observed cosmic acceleration in the framework of a cosmological $f(R,L_m)$ model dominated by bulk viscous matter in an anisotropic background. We consider the LRS Bianchi type I metric and derive the…

General Relativity and Quantum Cosmology · Physics 2023-06-14 Raja Solanki , Bina Patel , Lakhan V. Jaybhaye , P. K. Sahoo

In the cosmological scenario in $f\left( T\right) $ gravity, we find analytical solutions for an isotropic and homogeneous universe containing a dust fluid and radiation and for an empty anisotropic Bianchi I universe. The method that we…

General Relativity and Quantum Cosmology · Physics 2016-08-01 Andronikos Paliathanasis , John D. Barrow , P. G. L. Leach

Within the limits of the present cosmological observations in f(R,T) gravity theory, we have analyzed a spherically symmetric space-time in 5D setting. The field equations have been carefully studied considering reasonable cosmological…

General Relativity and Quantum Cosmology · Physics 2020-10-28 Pheiroijam Suranjoy Singh , Kangujam Priyokumar Singh

Cosmography is a useful tool to constrain cosmological models, in particular dark energy models. In the case of modified theories of gravity, where the equations of motion are generally quite complicated, cosmography can contribute to…

General Relativity and Quantum Cosmology · Physics 2010-12-23 Mariam Bouhmadi-Lopez , Salvatore Capozziello , Vincenzo F. Cardone

We study the possible singularities of isotropic cosmological models that have a varying speed of light as well as a varying gravitational constant. The field equations typically reduce to two dimensional systems which are then analyzed…

General Relativity and Quantum Cosmology · Physics 2008-11-26 John Miritzis , Spiros Cotsakis

The dynamical features of Bianchi type $VI_h$ $(BVI_h)$ universe are investigated in $f(R,T)$ theory of gravity. The field equations and the physical properties of the model are derived considering a power law expansion of the universe. The…

General Relativity and Quantum Cosmology · Physics 2018-08-09 B. Mishra , Sankarsan Tarai , S. K. Tripathy

We investigate the linear growth rate of cosmological matter density perturbations of a viable f(R) model both numerically and analytically. We find that the growth rate in the scalar-tensor regime can be characterized by a simple analytic…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Tatsuya Narikawa , Kazuhiro Yamamoto

The so called $f(X)$ hybrid metric-Palatini gravity presents a unique viable generalisation of the $f(R)$ theories within the metric-affine formalism. Here the cosmology of the $f(X)$ theories is studied using the dynamical system approach.…

General Relativity and Quantum Cosmology · Physics 2015-09-28 Sante Carloni , Tomi Koivisto , Francisco S. N. Lobo

We consider Noether symmetry approach to find out exact cosmological solutions in $f(T)$-gravity. Instead of taking into account phenomenological models, we apply the Noether symmetry to the $f(T)$ gravity. As a result, the presence of such…

General Physics · Physics 2012-05-29 K. Atazadeh , F. Darabi

A general approach to find out exact cosmological solutions in f(R)-gravity is discussed. Instead of taking into account phenomenological models, we assume, as a physical criterium, the existence of Noether symmetries in the cosmological…

General Relativity and Quantum Cosmology · Physics 2010-02-10 Salvatore Capozziello , Antonio De Felice

A detailed analysis of dynamics of cosmological models based on $R^{n}$ gravity is presented. We show that the cosmological equations can be written as a first order autonomous system and analyzed using the standard techniques of dynamical…

General Relativity and Quantum Cosmology · Physics 2009-11-10 S. Carloni , P. K. S. Dunsby , S. Capozziello , A. Troisi