Results 11 to 20 of about 22,331 (301)

Exact solutions in F(R) theory of gravity [PDF]

General Relativity and Gravitation, 2016
8 pages, 2 figures,accepted by ...
Gao, Changjun, Shen, You-Gen
openaire   +4 more sources

Cartan F(R) Gravity and Equivalent Scalar–Tensor Theory

Symmetry, 2022
We investigate the Cartan formalism in F(R) gravity. F(R) gravity has been introduced as a theory to explain cosmologically accelerated expansions by replacing the Ricci scalar R in the Einstein–Hilbert action with a function of R. As is well-known, F(R) gravity is rewritten as a scalar–tensor theory by using the conformal transformation.
Tomohiro Inagaki, Masahiko Taniguchi
openaire   +3 more sources

k-essence f(R) gravity inflation

Nuclear Physics B, 2019
In this work we study a modified version of f(R) gravity in which higher order kinetic terms of a scalar field are added in the action of vacuum f(R) gravity. This type of theory is a type of k-essence f(R) gravity, and it belongs to the general class of
S. Nojiri, S.D. Odintsov, V.K. Oikonomou
doaj   +2 more sources

Physical attributes of polytropic structures in $$\mathbb {F}(R)$$ F ( R ) theory of gravity

European Physical Journal C: Particles and Fields
The aim of this work is to study the general formalism and applications of polytropic stars within the framework of a well-famed modified theory of gravity namely $$\mathbb {F}(R)$$ F ( R ) theory.
Tayyaba Naz, Adnan Malik, Tooba Zia, Saira Waheed, Ali H. Alkhalidi   +4 more
doaj   +2 more sources

The post-Newtonian limit of hybrid f(R)-gravity

EPJ Web of Conferences, 2018
The post-Newtonian formalism is developed for hybrid f(R)-gravity. The model is tested in the weak field regime of the Solar System. Using scalartensor representation of hybrid f(R)-gravity we impose restrictions on the parameters of the theory and show ...
Dyadina Polina, Labazova Sofya
doaj   +2 more sources

Ghost-free F(R) gravity with Lagrange multiplier constraint

Physics Letters B, 2017
We propose two new versions of ghost-free generalized F(R) gravity with Lagrange multiplier constraint. The first version of such theory for a particular degenerate choice of the Lagrange multiplier, corresponds to mimetic F(R) gravity.
S. Nojiri, S.D. Odintsov, V.K. Oikonomou
doaj   +2 more sources

f(R) gravity solutions for evolving wormholes

European Physical Journal C: Particles and Fields, 2017
The scalar–tensor f(R) theory of gravity is considered in the framework of a simple inhomogeneous space-time model. In this research we use the reconstruction technique to look for possible evolving wormhole solutions within viable f(R) gravity formalism.
Subhra Bhattacharya, Subenoy Chakraborty
doaj   +2 more sources

Kinetic scalar curvature extended f(R) gravity [PDF]

Nuclear Physics B, 2018
In this work we study a modified version of vacuum f(R) gravity with a kinetic term which consists of the first derivatives of the Ricci scalar. We develop the general formalism of this kinetic Ricci modified f(R) gravity and we emphasize on cosmological
S.V. Chervon, A.V. Nikolaev, T.I. Mayorova, S.D. Odintsov, V.K. Oikonomou   +4 more
doaj   +3 more sources

Propagation and fluxes of ultra-high energy cosmic rays in $$\varvec{f(R)}$$ f ( R ) gravity theory

European Physical Journal C: Particles and Fields
In this work, we study the effect of diffusion of ultra-high energy cosmic ray (UHECR) protons in the presence of turbulent magnetic fields (TMFs) in the light of the f(R) theory of gravity.
Swaraj Pratim Sarmah, Umananda Dev Goswami   +1 more
doaj   +2 more sources

Stationary BTZ space-time in Ricci-inverse and $$f({\mathcal {R}})$$ f ( R ) gravity theories

European Physical Journal C: Particles and Fields
In this paper, we explore a stationary BTZ space-time within the framework of modified gravity theory, specifically focusing on Ricci-inverse gravity.
Faizuddin Ahmed, Abdelmalek Bouzenada
doaj   +2 more sources