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Related papers: Formalizing Anisotropic Inflation in Modified Grav…

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In this paper, we demonstrate that a unified description of early and late-time acceleration is possible in the context of mimetic $F(R)$ gravity. We study the inflationary era in detail and demonstrate that it can be realized even in…

General Relativity and Quantum Cosmology · Physics 2016-12-21 S. Nojiri , S. D. Odintsov , V. K. Oikonomou

We investigate cosmological solutions for the modified gravity theory obtained from quantum relative entropy between the metric of spacetime and the metric induced by the geometry and matter fields. The vacuum equations admit inflationary…

General Relativity and Quantum Cosmology · Physics 2025-12-23 Udaykrishna Thattarampilly , Yunlong Zheng

We review recent trends on inflationary dynamics in the context of viable modified gravity theories. After providing a general overview of the inflationary paradigm emphasizing on what problems of hot Big Bang theory inflation solves, and a…

General Relativity and Quantum Cosmology · Physics 2023-09-20 S. D. Odintsov , V. K. Oikonomou , I. Giannakoudi , F. P. Fronimos , E. C. Lymperiadou

A viable radiation dominated era in the early universe is best described by the standard (FLRW) model of cosmology. In this short review, we demonstrate reconstruction of the forms of F(R) in the modified theory of gravity and the metric…

General Relativity and Quantum Cosmology · Physics 2024-01-23 Dalia Saha , Manas Chakrabortty , Abhik Kumar Sanyal

We investigate the $\phi^2$ inflationary model in the Bianchi-I spacetime using effective spacetime description of loop quantum cosmology to understand the issues of the resolution of initial singularity, isotropization, effect of…

General Relativity and Quantum Cosmology · Physics 2013-07-11 Brajesh Gupt , Parampreet Singh

In this paper we investigate the inflationary dynamics of an $f(R)$ gravity in the presence of a canonical scalar field. We specifically choose the cosmological evolution to be a quasi-de Sitter evolution and also the $f(R)$ gravity is…

General Relativity and Quantum Cosmology · Physics 2018-08-01 K. Kleidis , V. K. Oikonomou

We review inflationary cosmology in modified gravity such as $R^2$ gravity with its extensions in order to generalize the Starobinsky inflation model. In particular, we explore inflation realized by three kinds of effects: modification of…

High Energy Physics - Theory · Physics 2015-03-11 Kazuharu Bamba , Sergei D. Odintsov

We investigate a (super-)renormalizable and ghost-free theory of gravity, showing that under a natural (exponential) ansatz of the form factor and a suitable truncation it can give rise to the Starobinsky inflationary theory in cosmological…

High Energy Physics - Theory · Physics 2013-04-18 Fabio Briscese , Antonino Marciano , Leonardo Modesto , Emmanuel N. Saridakis

We review the accelerating (mainly, dark energy) cosmologies in modified gravity. Special attention is paid to cosmologies leading to finite-time future singularities in $F(R)$, $F(G)$ and $\mathcal{F}(R,G)$ modified gravities. The removal…

General Relativity and Quantum Cosmology · Physics 2013-02-21 Kazuharu Bamba , Shin'ichi Nojiri , Sergei D. Odintsov

We review recent progress on cosmological issues and theoretical properties of modified gravity theories. In particular, we explicitly explore the conformal transformation, the Starobinsky inflation, and a unified scenario of inflation and…

High Energy Physics - Theory · Physics 2014-03-03 Kazuharu Bamba , Sergei D. Odintsov

We review modified $F(R)$ gravity as realistic candidate to describe the observable universe expansion history. We show that recent cosmic acceleration, radiation/matter-dominated epoch and inflation could be realized in the framework of…

High Energy Physics - Theory · Physics 2008-07-08 Shin'ichi Nojiri , Sergei D. Odintsov

We consider modified gravity which may describe the early-time inflation and/or late-time cosmic acceleration of the universe. In particular, we discuss the properties of $F(R)$, $F(G)$, string-inspired and scalar-Einstein-Gauss-Bonnet…

General Relativity and Quantum Cosmology · Physics 2013-06-20 Shin'Ichi Nojiri , Sergei D. Odintsov

We investigate the inflationary realization in the context of unimodular $F(T)$ gravity, which is based on the $F(T)$ modification of teleparallel gravity, in which one imposes the unimodular condition through the use of Lagrange…

General Relativity and Quantum Cosmology · Physics 2017-06-29 Kazuharu Bamba , Sergei D. Odintsov , Emmanuel N. Saridakis

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 study a warm inflationary model for different expansions assuming an anisotropic universe described by Bianchi I metric. The universe is filled with a scalar field or inflaton, radiation, and bulk viscous pressure. We carry out the…

General Relativity and Quantum Cosmology · Physics 2022-02-07 Mehdi Shokri , Jafar Sadeghi , Ramón Herrera , Saeed Noori Gashti

By applying a particular kind of modified gravity, we study the inflation. Precisely, we extend our investigations beyond the Einstein's gravity to explore the Natural inflation model via the term $F(\phi)T$. We compute the inflation…

General Relativity and Quantum Cosmology · Physics 2025-07-30 Feyzollah Younesizadeh , Davoud Kamani

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…

General Relativity and Quantum Cosmology · Physics 2019-03-27 S. Nojiri , S. D. Odintsov , V. K. Oikonomou

The review of basic cosmological properties of four-dimensional F(R)-gravity, including FRW equations of motion and its accelerating solutions, generalized fluid and scalar-tensor representation of the theory is done. Cosmological…

High Energy Physics - Theory · Physics 2015-05-19 Shin'ichi Nojiri , Sergei D. Odintsov

We propose the study of constant-roll inflation in $F(R)$ gravity. We use two different approaches, one that relates an $F(R)$ gravity to well known scalar models of constant-roll and a second that examines directly the constant-roll…

General Relativity and Quantum Cosmology · Physics 2017-12-06 S. Nojiri , S. D. Odintsov , V. K. Oikonomou

We propose a novel modified gravity: unimodular generalization of the Born-Infeld-$f(R)$ gravity within the framework of cosmology. After formulating the action corresponding to the generalized Born-Infeld-$f(R)$ gravity, we present a…

General Relativity and Quantum Cosmology · Physics 2024-02-16 Salih Kibaroğlu , Sergei D. Odintsov , Tanmoy Paul