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Related papers: Modified gravity: walk through accelerating cosmol…

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Modified gravity theories with the Gauss-Bonnet term $G=R^2-4R^{\mu\nu}R_{\mu\nu}+R^{\mu\nu\rho\sigma}R_{\mu\nu\rho\sigma}$ have recently gained a lot of attention as a possible explanation of dark energy. We perform a thorough phase space…

General Relativity and Quantum Cosmology · Physics 2010-10-01 Shuang-Yong Zhou , Edmund J. Copeland , Paul M. Saffin

In order to explain the Late-times accelerated expansion of the Universe we must appeal to some form of Dark Energy. In the standard model of cosmology, the latter is interpreted as a Cosmological Constant $\Lambda$. However, for a number…

General Relativity and Quantum Cosmology · Physics 2021-02-18 Leonardo Giani

We investigate the cosmological implications of $f(Q)$ gravity, which is a modified theory of gravity based on non-metricity, in non-flat geometry. We perform a detailed dynamical-system analysis keeping the $f(Q)$ function completely…

General Relativity and Quantum Cosmology · Physics 2023-06-26 Hamid Shabani , Avik De , Tee-How Loo , Emmanuel N. Saridakis

In this paper we address the issue of exploring some cosmological scenarios in modified Einstein gravity through non-dynamical (auxiliary) fields. We found that all scenarios are controlled by a specific parameter associated with an…

High Energy Physics - Theory · Physics 2014-08-27 D. Bazeia , F. A. Brito , F. G. Costa

Over the past decades, General Relativity and the concordance $\Lambda$CDM model have been successfully tested using several different astrophysical and cosmological probes based on large datasets ({\it precision cosmology}). Despite their…

General Relativity and Quantum Cosmology · Physics 2015-08-07 Ivan de Martino , Mariafelicia De Laurentis , Salvatore Capozziello

Modified gravity is one of the most favorable candidates for explaining the current accelerating expansion of the Universe. In this regard, we study the viability of an alternative gravitational theory, namely $f(R,G)$, by imposing energy…

General Relativity and Quantum Cosmology · Physics 2014-01-30 K. Atazadeh , F. Darabi

Modified gravity theories are a popular alternative to dark energy as a possible explanation for the observed accelerating cosmic expansion, and their cosmological tests are currently an active research field. Studies in recent years have…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-12 Juan J. Ceron-Hurtado , Jian-hua He , Baojiu Li

$f(R)$ 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

A number of dynamical system formulations have been proposed over the last few years to analyse cosmological solutions in $f(R)$ gravity. The aim of this article is to provide a brief introduction to the different approaches, presenting…

General Relativity and Quantum Cosmology · Physics 2022-05-06 Saikat Chakraborty , Peter K. S. Dunsby , Kelly Macdevette

The quasi-static solutions of the matter density perturbation in various dark energy models and modified gravity models have been investigated in numerous papers. However, the oscillating solutions in those models have not been investigated…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-18 Jiro Matsumoto

Here in this work we propose a modified gravity with the action of $f(R) = \sqrt{R^2 - R_0^2}$ instead of Einstein-Hilbert action to describe the late time acceleration of the universe. We obtain the equation of the modified gravity both in…

Astrophysics · Physics 2008-11-26 Shant Baghram , Marzieh Farhang , Sohrab Rahvar

It is shown that phantom scalar models can be mapped into a mathematically equivalent, modified $F(R)$ gravity, which turns out to be complex, in general. Only for even scalar potentials is the ensuing modified gravity real. It is also…

High Energy Physics - Theory · Physics 2008-11-26 F. Briscese , E. Elizalde , S. Nojiri , S. D. Odintsov

Recently, corrections of the $L(R)$ type to Einstein-Hilbert action that become important at small curvature are proposed. Those type of models intend to explain the observed cosmic acceleration without dark energy. We derive the full…

Astrophysics · Physics 2009-11-10 Xinhe Meng , Peng Wang

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

We perform a dynamical system analysis of Myrzakulov or F(R, T) gravity, which is a subclass of affinely connected metric theories, where ones uses a specific but non-special connection, which allows for non-zero curvature and torsion…

General Relativity and Quantum Cosmology · Physics 2022-11-30 G. Papagiannopoulos , Spyros Basilakos , Emmanuel N. Saridakis

We review recent developments on cosmology in extended teleparallel gravity, called "$F(T)$ gravity" with $T$ the torsion scalar in teleparallelism. We explore various cosmological aspects of $F(T)$ gravity including the evolution of the…

General Relativity and Quantum Cosmology · Physics 2015-05-05 Kazuharu Bamba

The unifying approach to early-time and late-time universe based on phantom cosmology is proposed. We consider gravity-scalar system which contains usual potential and scalar coupling function in front of kinetic term. As a result, the…

High Energy Physics - Theory · Physics 2009-09-17 Shin'ichi Nojiri , Sergei D. Odintsov

It is shown that F(R)-modified gravitational theories lead to curvature oscillations in astrophysical systems with rising energy density. The frequency and the amplitude of such oscillations could be very high and would lead to noticeable…

General Relativity and Quantum Cosmology · Physics 2015-06-12 E. V. Arbuzova , A. D. Dolgov , L. Reverberi

We study the correspondence between two theoretical frameworks for describing dark energy, $f(R)$ gravity and higher-dimensional Space-Time-Matter (STM) or induced-matter theory. We show that the Hubble expansion parameter in $f(R)$ gravity…

General Relativity and Quantum Cosmology · Physics 2010-05-12 K. Atazadeh , F. Darabi , H. R. Sepangi

The discovery of universe's late-time acceleration and dark energy has overseen a great deal of research into cosmological singularities and in this brief review, we discuss all the prominent developments in this field for the best part of…

General Relativity and Quantum Cosmology · Physics 2024-08-02 Oem Trivedi