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Related papers: Exploring Plane Symmetric Solutions in $f(R)$ Grav…

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We present a framework for the study of lensing in spherically symmetric spacetimes within the context of f(R) gravity. Equations for the propagation of null geodesics, together with an expression for the bending angle are derived for any…

General Relativity and Quantum Cosmology · Physics 2011-02-25 Anne Marie Nzioki , Peter K. S. Dunsby , Rituparno Goswami , Sante Carloni

The exact solutions of spherically symmetric space-times are explored by using Noether symmetries in $f(R,\phi,X)$ gravity with $R$ the scalar curvature, $\phi$ a scalar field and $X$ the kinetic term of $\phi$. Some of these solutions can…

General Relativity and Quantum Cosmology · Physics 2019-02-20 Sebastian Bahamonde , Kazuharu Bamba , Ugur Camci

The modified gravity with 1/R term (R being scalar curvature) and the Einstein-Hilbert term is studied by incorporating the phantom scalar field. A number of cosmological solutions are derived in the presence of the phantom field in the…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Yulia A. Shaido , Akio Sugamoto

It is broadly known that Lie point symmetries and their subcase, Noether symmetries, can be used as a geometric criterion to select alternative theories of gravity. Here, we use Noether symmetries as a selection criterion to distinguish…

General Relativity and Quantum Cosmology · Physics 2020-01-10 Sebastian Bahamonde , Konstantinos Dialektopoulos , Ugur Camci

We study modified $f(R,(\nabla R)^2,\square R)$ gravity and show in detail how it can be reduced to Einstein gravity with a few scalar fields and then represented in the form of chiral self-gravitating model of the special type. In further…

General Relativity and Quantum Cosmology · Physics 2024-10-10 Tatyana Chaadaeva , Sergey Chervon

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

Axially symmetric solutions for f (R)-gravity can be derived starting from exact spherically sym- metric solutions achieved by Noether symmetries. The method takes advantage of a complex coordi- nate transformation previously developed by…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Salvatore Capozziello , Mariafelicia De Laurentis , Arturo Stabile

Symmetries of generalized gravitational actions, yielding field equations which typically involve at most second-order derivatives of the metric, are considered. The field equations for several different higher-derivative theories in the…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Simon Davis

Finding spherically symmetric exact solutions in modified gravity is usually a difficult task. In this paper we use the Noether's symmetry approach for a modified Teleparallel theory of gravity labelled as $f(T,B)$ gravity where $T$ is the…

General Relativity and Quantum Cosmology · Physics 2019-12-02 Sebastian Bahamonde , Ugur Camci

Perturbative techniques are important for modified theories of gravity since they allow to calculate deviations from General Relativity without recurring to exact solutions, which can be difficult to find. When applied to models such as…

General Relativity and Quantum Cosmology · Physics 2020-03-18 Daniel Molano , Fabián Darío Villalba , Leonardo Castañeda , Pedro Bargueño

We study spherically symmetric solutions in f(R) theories and its compatibility with local tests of gravity. We start by clarifying the range of validity of the weak field expansion and show that for many models proposed to address the Dark…

General Relativity and Quantum Cosmology · Physics 2010-10-27 I. Navarro , K. Van Acoleyen

Gravitational theories generated from Lagrangians of the form f(R) are considered. The spherically symmetric solutions to these equations are discussed, paying particular attention to features that differ from the standard Schwarzschild…

General Relativity and Quantum Cosmology · Physics 2009-11-11 T. Clifton

This paper is devoted to investigate the recently proposed modified Gauss-Bonnet $f(\mathcal{G},T)$ gravity, with $\mathcal{G}$, the Gauss-Bonnet term, coupled with ${T}$, the trace of energy-momentum tensor. We have used the Noether…

General Relativity and Quantum Cosmology · Physics 2017-07-12 M. Farasat Shamir , Mushtaq Ahmad

We consider some cosmological aspects of nonlocal modified gravity with $\Lambda$ term, where nonlocality is of the type $R \mathcal{F}(\Box) R$. Using ansatz of the form $\Box R = r R +s,$ we find a few a(t) nonsingular bounce cosmological…

General Relativity and Quantum Cosmology · Physics 2015-08-20 I. Dimitrijevic , B. Dragovich , J. Grujic , Z. Rakic

Considering an action in F(G) modified gravity, the static spherically symmetric solutions are investigated. Introducing the Lagrangian multipliers {\alpha} we obtain the Lagrangian and equations of motion. we obtain two type solutions for…

General Relativity and Quantum Cosmology · Physics 2025-07-15 Naser Mohammadipour

We briefly review f(R) theories, both in the metric and Palatini formulations, their scalar-tensor representations and the chameleon mechanism that could explain the absence of perceptible consequences in the Solar System. We also review…

General Relativity and Quantum Cosmology · Physics 2012-10-12 Rafael Ferraro

In the context of f(R) theories of gravity, we address the problem of finding a rotating charged black hole solution in the case of constant curvature. The new metric is obtained by solving the field equations and we show that the behavior…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Alexis Larranaga

The well-known energy problem is discussed in f(R) theory of gravity. We use the generalized Landau-Lifshitz energy-momentum complex in the framework of metric f(R) gravity to evaluate the energy density of plane symmetric solutions for…

General Relativity and Quantum Cosmology · Physics 2014-11-20 M. Sharif , M. Farasat Shamir

In this work, we investigate the construction of spherically symmetric solutions within the framework of modified teleparallel gravity, focusing in particular on $f({\cal T})$ theory, where ${\cal T}$ represents the torsion scalar.…

General Relativity and Quantum Cosmology · Physics 2025-08-08 G. G. L. Nashed , A. Eid

In a homogenous and isotropic cosmology, we introduce general exact solutions for some modified gravity models. In particular, we introduce exact solutions for power-law $f(R)$ gravity and Brans-Dicke theory in Einstein and Jordan conformal…

High Energy Physics - Theory · Physics 2018-06-08 Yousef Bisabr
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