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Using the fluid representation, we formulate the conditions for the appearance of all four types finite-time future singularity in modified gravity in accelerating FRW universe. It stressed that number of standard quintessence/phantom DE…

High Energy Physics - Theory · Physics 2014-11-20 Shin'ichi Nojiri , Sergei D. Odintsov

Scalar-tensor theory of gravity with non-minimal coupling is a fairly good candidate for dark energy, required to explain late-time cosmic evolution. Here we study the very early stage of evolution of the universe with a modified version of…

High Energy Physics - Theory · Physics 2018-05-22 Ranajit Mandal , Chandramouli Sarkar , Abhik Kumar Sanyal

A unified description of early-time inflation with the current cosmic acceleration is achieved by means of a new theory that uses a quadratic model of gravity, with the inclusion of an exponential $F(R)$-gravity contribution for dark…

General Relativity and Quantum Cosmology · Physics 2017-06-28 E. Elizalde , S. D. Odintsov , L. Sebastiani , R. Myrzakulov

We consider the modified gravity non-minimally coupled with matter Lagrangian for the description of early-time and late-time universe. Such $F(R)$ ($F(G)$) gravity in the absence of non-minimal coupling is viable theory which passes the…

High Energy Physics - Theory · Physics 2008-11-26 Shin'ichi Nojiri , Sergei D. Odintsov , Petr V. Tretyakov

We review the unification of early-time inflation with late-time acceleration in several local modified gravity models which pass Solar System and cosmological tests. It is also demonstrated that account of non-local gravitational…

High Energy Physics - Theory · Physics 2009-05-01 Shin'ichi Nojiri , Sergei D. Odintsov

A generic feature of viable $F(R)$ gravity is investigated: It is demonstrated that during the matter dominated era the large frequency oscillations of the effective dark energy may influence the behavior of higher derivatives of the Hubble…

General Relativity and Quantum Cosmology · Physics 2012-12-14 Kazuharu Bamba , Antonio Lopez-Revelles , R. Myrzakulov , S. D. Odintsov , L. Sebastiani

We study the future evolution of quintessence/phantom dominated epoch in modified $F(R)$-gravity which unifies the early-time inflation with late-time acceleration and which is consistent with observational tests. Using the reconstruction…

High Energy Physics - Theory · Physics 2008-11-26 Shin'ichi Nojiri , Sergei D. Odintsov

The role of an exponential function of the scalar curvature in the modified gravity is analyzed. Two models are proposed. A toy model that complies with local and cosmological constraints and gives appropriate qualitative description of the…

General Relativity and Quantum Cosmology · Physics 2020-07-15 L. N. Granda

Viable models of modified gravity which satisfy both local as well as cosmological tests are investigated. It is demonstrated that some versions of such highly non-linear models exhibit multiply de Sitter universe solutions, which often…

General Relativity and Quantum Cosmology · Physics 2009-02-20 G. Cognola , E. Elizalde , S. D. Odintsov , P. Tretyakov , S. Zerbini

We study FRW cosmology for a non-linear modified F(R) Horava-Lifshitz gravity which has a viable convenient counterpart. A unified description of early-time inflation and late-time acceleration is possible in this theory, but the…

High Energy Physics - Theory · Physics 2011-02-09 E. Elizalde , S. Nojiri , S. D. Odintsov , D. Saez-Gomez

We propose a new exponential f(R) gravity model with f(R)=(R-\lambda c)e^{\lambda(c/R)^n} and n>3, \lambda\geq 1, c>0 to explain late-time acceleration of the universe. At the high curvature region, the model behaves like the \LambdaCDM…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Qiang Xu , Bin Chen

We consider FRW cosmology in non-local modified gravity. Its local scalar-tensor formulation is developed. It is explicitly demonstrated that such theory may lead to the unification of early-time inflation with late-time cosmic…

High Energy Physics - Theory · Physics 2008-11-26 Shin'ichi Nojiri , Sergei D. Odintsov

We systematically review some standard issues and also the latest developments of modified gravity in cosmology, emphasizing on inflation, bouncing cosmology and late-time acceleration era. Particularly, we present the formalism of standard…

General Relativity and Quantum Cosmology · Physics 2021-05-25 S. Nojiri , S. D. Odintsov , V. K. Oikonomou

A generic feature of viable exponential $F(R)$-gravity is investigated. An additional modification to stabilize the effective dark energy oscillations during matter era is proposed and applied to two viable models. An analysis on the future…

General Relativity and Quantum Cosmology · Physics 2015-09-21 K. Bamba , A. Lopez-Revelles , R. Myrzakulov , S. D. Odintsov , L. Sebastiani

We propose a 3 + 1 dimensional model of gravity which results in inflation at early times, followed by radiation- and matter-dominated epochs and a subsequent acceleration at late times. Both the inflation and late time acceleration are…

High Energy Physics - Theory · Physics 2015-05-30 Carlos Herdeiro , Shinji Hirano

We propose the mimetic $F(R)$ theory and investigate the early-time and late-time acceleration in such theory. It is demonstrated that inflation consistent with observable data may be realized in such theory. The reconstruction of realistic…

High Energy Physics - Theory · Physics 2014-12-19 Shin'ichi Nojiri , Sergei D. Odintsov

We suggest two realistic f(R) and one F(G) modified gravities which are consistent with local tests and cosmological bounds. The typical property of such theories is the presence of the effective cosmological constant epochs in such a way…

High Energy Physics - Theory · Physics 2010-04-06 Shin'ichi Nojiri , Sergei D. Odintsov

We present a unified framework that simultaneously addresses the dynamics of early-time cosmic inflation and late-time cosmic acceleration within the context of a single scalar field non-minimally coupled to gravity. By employing an…

General Relativity and Quantum Cosmology · Physics 2025-10-27 Seong Chan Park

We construct gravitational modifications that go beyond Horndeski, namely theories with extended nonminimal derivative couplings, in which the coefficient functions depend not only on the scalar field but also on its kinetic energy. Such…

General Relativity and Quantum Cosmology · Physics 2017-03-01 Tiberiu Harko , Francisco S. N. Lobo , Emmanuel N. Saridakis , Minas Tsoukalas

The modified gravity, which eliminates the need for dark energy and which seems to be stable, is considered. The terms with positive powers of the curvature support the inflationary epoch while the terms with negative powers of the…

High Energy Physics - Theory · Physics 2008-11-26 Shin'ichi Nojiri , Sergei D. Odintsov
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