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This work deals with $F(T)$ gravity models driven by real scalar fields with usual and phantom dynamics. We illustrate the results with examples of current interest, and we find some analytical solutions for scale factors and scalar fields.…

General Relativity and Quantum Cosmology · Physics 2010-06-22 K. K. Yerzhanov , Sh. R. Myrzakul , I. I. Kulnazarov , R. Myrzakulov

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

We address the issue of constraining the class of $f(\mathcal{R})$ able to reproduce the observed cosmological acceleration, by using the so called cosmography of the universe. We consider a model independent procedure to build up a…

General Relativity and Quantum Cosmology · Physics 2015-06-11 Alejandro Aviles , Alessandro Bravetti , Salvatore Capozziello , Orlando Luongo

It is shown that the accelerated expansion of the universe in the framework of the relativistic theory of gravitation can be achieved by the introduction of the quintessential term in the energy-momentum tensor. The value of the minimum…

General Relativity and Quantum Cosmology · Physics 2007-05-23 V. L. Kalashnikov

Alternative theories of gravity have been recently studied in connection with their cosmological applications, both in the Palatini and in the metric formalism. The aim of this paper is to propose a theoretical framework (in the Palatini…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Gianluca Allemandi , Mauro Francaviglia , Matteo Luca Ruggiero , Angelo Tartaglia

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

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

We study single field slow-roll inflation in the presence of $F(R)$ gravity in the Palatini formulation. In contrast to metric $F(R)$, when rewritten in terms of an auxiliary field and moved to the Einstein frame, Palatini $F(R)$ does not…

General Relativity and Quantum Cosmology · Physics 2022-07-12 Christian Dioguardi , Antonio Racioppi , Eemeli Tomberg

We search for viable f(R) theories of gravity, making use of the equivalence between such theories and scalar-tensor gravity. We find that models can be made consistent with solar system constraints either by giving the scalar a high mass…

Astrophysics · Physics 2008-11-26 Thomas Faulkner , Max Tegmark , Emory F. Bunn , Yi Mao

In this letter, we investigate the cosmic expansion scenario of the universe in the framework of $f(R,L_m)$ gravity theory. We consider a non-linear $f(R,L_m)$ model, specifically, $f(R,L_m)=\frac{R}{2}+L_m^n + \beta$, where $n$ and $\beta$…

General Relativity and Quantum Cosmology · Physics 2023-11-02 Lakhan V. Jaybhaye , Raja Solanki , Sanjay Mandal , P. K. Sahoo

The theory of nonlinear massive gravity can be extended into the F(R) form as developed in Phys.Rev.D90, 064051 (2014). Being free of the Boulware-Deser ghost, such a construction has the additional advantage of exhibiting no linear…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-08 Yi-Fu Cai , Emmanuel N. Saridakis

In this work, we analyse the late-time evolution of the universe for a particular $f(R)$ gravity model built from an exponential function of the scalar curvature. Following the literature, we write the field equations in terms of a suited…

General Relativity and Quantum Cosmology · Physics 2023-10-18 A. Oliveros , Mario A. Acero

We use metric formalism in $f(R)$ modified gravity to study the dynamics of various systems from the solar system to the cosmological scale. we assume an ansatz for the derivative of action as a function of distance and describe the Pioneer…

Astrophysics · Physics 2008-11-26 Reza Saffari , Sohrab Rahvar

In this paper, we consider the recently proposed hybrid metric-Palatini gravitational theory, which consists of adding to the Einstein-Hilbert Lagrangian an $f(\mathcal{R})$ term constructed \`{a} la Palatini. Using the respective…

General Relativity and Quantum Cosmology · Physics 2017-04-26 Iker Leanizbarrutia , Francisco S. N. Lobo , Diego Saez-Gomez

Recently, the scalar-tensor representation of $f (R,T)$ gravity was used to explore gravitationally induced particle production/annihilation. Using the framework of irreversible thermodynamics of open systems in the presence of matter…

General Relativity and Quantum Cosmology · Physics 2023-10-20 Amine Bouali , Himanshu Chaudhary , Tiberiu Harko , Francisco S. N. Lobo , Taoufik Ouali , Miguel A. S. Pinto

In this paper, we propose two new models in $f(T)$ gravity to realize universe acceleration and phantom crossing due to dark torsion in the formalism. The model parameters are constrained and the observational test are discussed. The best…

General Physics · Physics 2015-06-03 H. Farajollahi , A. Ravanpak , P. Wu

This paper delves into the late-time accelerated expansion of the universe and the evolution of cosmic structures within the context of a specific \( f(R, L_m) \) gravity model, formulated as \( f(R, L_m) = \lambda R + \beta L_m^\alpha +…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-05 Shambel Sahlu , Alnadhief H. A. Alfedeel , Amare Abebe

The role of torsion in f(R) gravity is considered in the framework of metric-affine formalism. We discuss the field equations in empty space and in presence of perfect fluid matter taking into account the analogy with the Palatini…

General Relativity and Quantum Cosmology · Physics 2008-11-26 S. Capozziello , R. Cianci , C. Stornaiolo , S. Vignolo

We analyze the cosmological implementation of Palatini $f(R)$ theories, constructed with a Nieh-Yan term and solved with respect to the torsion. We consider the relevant case of the quadratic correction to the Hilbert-Palatini action in the…

General Relativity and Quantum Cosmology · Physics 2019-05-21 Flavio Bombacigno , Giovanni Montani

$f(R)$ modifications of Einstein's gravity is an interesting possibility to explain the late time acceleration of the Universe. In this work we explore the cosmological viability of one such $f(R)$ modification proposed in (Kruglov:2013).…

General Relativity and Quantum Cosmology · Physics 2016-07-13 Koushik Dutta , Sukanta Panda , Avani Patel