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Related papers: A New Model of Nonlocal Modified Gravity

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This paper is devoted to investigate cylindrical solutions in mimetic gravity. The explicit forms of the metric of this theory, namely mimetic-Kasner (say) have been obtained. In this study we have noticed that the Kasner's family of exact…

General Relativity and Quantum Cosmology · Physics 2018-10-09 Davood Momeni , Kairat Myrzakulov , Ratbay Myrzakulov , Muhammad Raza

It is shown that modified gravity theories with a Lagrangian composed of the three quadratic invariants of the Riemann curvature tensor are not appropriate. The field equations are either incompatible and/or irregular [like f(R)-gravities],…

General Relativity and Quantum Cosmology · Physics 2011-05-26 I. L. Zhogin

The theory of f(R)-gravity is one of the theories of modified Einstein gravity. The vacuum solution, on the other hand, of the field equation is the solution for black hole geometry. We establish here an asymptotically flat rotating black…

General Relativity and Quantum Cosmology · Physics 2022-11-07 Arghya Ranjan Das , Banibrata Mukhopadhyay

We investigate wormhole solutions using the modified gravity model $f(Q,T)$ with viscosity and aim to find a solution for the existence of wormholes mathematically without violating the energy conditions. We show that there is no need to…

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

We explore the recently introduced modified Gauss-Bonnet gravity [1], $f(\mathcal{G},T)$ pragmatic with $\mathcal{G}$, the Gauss-Bonnet term, and ${T}$, the trace of the energy-momentum tensor. Noether symmetry approach has been used to…

General Physics · Physics 2017-01-31 M. Farasat Shamir , Mushtaq Ahmad

A review of the new of the problem of dark energy using modified gravity approach is considered. An explanation of the difficulties facing modern cosmology is given and different approaches are presented. We show why some models of gravity…

General Relativity and Quantum Cosmology · Physics 2014-06-18 Ahmed Alhamzawi , Rahim Alhamzawi

We study the fractional gravity for spacetimes with non-integer dimensions. Our constructions are based on a geometric formalism with the fractional Caputo derivative and integral calculus adapted to nonolonomic distributions. This allows…

Mathematical Physics · Physics 2012-04-20 Sergiu I. Vacaru

We consider a modified gravity theory, f(R)=R-a/R^n+bR^m, in the metric formulation, which has been suggested to produce late time acceleration in the Universe, whilst satisfying local fifth-force constraints. We investigate the parameter…

High Energy Physics - Theory · Physics 2008-11-26 Anthony W. Brookfield , Carsten van de Bruck , Lisa M. H. Hall

In this contribution one examines the generalization of the $f(R)$ theories of gravity where one introduces a non-minimal coupling between curvature and matter. This model has new and interesting features. %, specially concerning the energy…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Orfeu Bertolami , Miguel Carvalho Sequeira

Noncommutative geometry, as conceptualized by Nicolini, Smailagic, and Spallucci, may be viewed as a slight modification of Einstein's theory. The same can be said for $f(R)$ modified gravity for an appropriate choice of the function…

General Relativity and Quantum Cosmology · Physics 2021-01-05 Peter K. F. Kuhfittig

We show that f(R)-gravity can, in general, give rise to cosmological viable models compatible with a matter-dominated epoch evolving into a late accelerated phase. We discuss the various representations of f(R)-gravity as an ideal fluid or…

Astrophysics · Physics 2008-11-26 S. Capozziello , S. Nojiri , S. D. Odintsov , A. Troisi

We investigate the cosmological dynamics of nonlocally corrected gravity involving a function of the inverse d'Alembertian acting on the Gauss-Bonnet term. Casting the dynamical equations in local form, we derive the reconstruction…

General Relativity and Quantum Cosmology · Physics 2020-03-12 Emilio Elizalde , Ekaterina O. Pozdeeva , Sergey Yu. Vernov

In this paper, we study anisotropic universe using Noether symmetries in modified gravity. In particular, we choose locally rotationally symmetric Bianchi type-$I$ universe for the analysis in $f(R,\mathcal{G})$ gravity, where $R$ is the…

General Relativity and Quantum Cosmology · Physics 2017-05-18 M. Farasat Shamir , Fiza Kanwal

In this work a new non-minimally coupled model is presented, where a generic function $f(R)$ of the scalar curvature factors the usual Einstein-Hilbert action functional, motivated by relevant results obtained from similar models. Its…

General Relativity and Quantum Cosmology · Physics 2016-11-22 R. P. L. Azevedo , J. Páramos

Modified gravity theories (MGTs) have long been studied as alternatives to general relativity (GR) and the standard Lambda CDM cosmological model. For example, exponential f(R) models often yield better fits to observational data,…

General Physics · Physics 2026-05-01 Sergiu I. Vacaru

The quantum-reduced loop-gravity technique has been introduced for dealing with cosmological models. We show that it can be applied rather generically: anytime the spatial metric can be gauge-fixed to a diagonal form. The technique selects…

General Relativity and Quantum Cosmology · Physics 2013-11-13 Emanuele Alesci , Francesco Cianfrani , Carlo Rovelli

Over the past decade, f(R) theories have been extensively studied as one of the simplest modifications to General Relativity. In this article we review various applications of f(R) theories to cosmology and gravity - such as inflation, dark…

General Relativity and Quantum Cosmology · Physics 2013-11-12 Antonio De Felice , Shinji Tsujikawa

We consider nonlocal gravity theories that include tensor nonlocalities. We show that in the cosmological context, the tensor nonlocalities, unlike scalar ones, generically give rise to growing modes. An explicit example with quadratic…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Pedro G. Ferreira , Antonio L. Maroto

We analyse the classical stability of the model proposed by Maggiore and Mancarella, where gravity is modified by a term $\sim m^2 R \Box^{-2} R$ to produce the late-time acceleration of the expansion of the universe. Our study takes into…

General Relativity and Quantum Cosmology · Physics 2015-01-19 Yves Dirian , Ermis Mitsou

A general, iterative, method for the description of evolving self-gravitating relativistic spheres is presented. Modeling is achieved by the introduction of an ansatz, whose rationale becomes intelligible and finds full justification within…

General Relativity and Quantum Cosmology · Physics 2009-11-07 L. Herrera , W. Barreto , A. Di Prisco , N. O. Santos
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