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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

Considering a well-motivated $f(R)$ modified-gravity model, in which an exponential function of the curvature is included, in this paper we implement a statistical data analysis to set constraints on the parameters of the model, taking into…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-01 Mario A. Acero , A. Oliveros

We study inflation for a quantum scalar electrodynamics model in curved space-time and for higher-derivative quantum gravity (QG) coupled with scalar electrodynamics. The corresponding renormalization-group (RG) improved potential is…

High Energy Physics - Theory · Physics 2017-03-15 Ratbay Myrzakulov , Sergei Odintsov , Lorenzo Sebastiani

In this work, we study the inflationary cosmology in modified gravity theory $f(R, T) = R + 2 \lambda T$ ($\lambda$ is the modified gravity parameter) with three distinct class of inflation potentials (i) $\phi^p e^{-\alpha\phi}$, (ii)…

General Relativity and Quantum Cosmology · Physics 2023-01-09 Ashmita , Payel Sarkar , Prasanta Kumar Das

Assuming that a scalar field controls the inflationary era, we examine the combined effects of string and $f(R)$ gravity corrections on the inflationary dynamics of canonical scalar field inflation, imposing the constraint that the speed of…

General Relativity and Quantum Cosmology · Physics 2020-12-30 S. D. Odintsov , V. K. Oikonomou , F. P. Fronimos

The Hubble constant tension problem is analysed in the framework of a class of modified gravity, the so-called $F(R)$ gravity. To do so, we explore two models: an exponential and a power-law $F(R)$ gravities, which includes an early dark…

General Relativity and Quantum Cosmology · Physics 2021-03-24 Sergei D. Odintsov , Diego Sáez-Chillón Gómez , German S. Sharov

Inflation in the framework of $f(R)$ modified gravity is revisited. We study the conditions that $f(R)$ should satisfy in order to lead to a viable inflationary model in the original form and in the Einstein frame. Based on these criteria…

High Energy Physics - Theory · Physics 2018-10-17 M. Amin , S. Khalil , M. Salah

In this short review, we revisit inflation in F(R)-gravity. We find several F(R)-models for viable inflation by applying some reconstruction techniques. A special attention is payed in the reproduction of the last Planck satellite data. The…

General Relativity and Quantum Cosmology · Physics 2016-09-02 Lorenzo Sebastiani , Ratbay Myrzakulov

We consider modified $f(R)$ gravity which may unify $R^m$ early-time inflation with late-time $\Lambda$CDM epoch. It is shown that such model passes the local tests (Newton law, stability of Earth-like gravitational solution, very heavy…

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

We reconsider the enhancement of primordial gravitational waves that arises from a quantum gravitational model of inflation. A distinctive feature of this model is that the end of inflation witnesses a brief phase during which the Hubble…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Maria G. Romania , N. C. Tsamis , R. P. Woodard

We investigate the cosmic inflation scenario of a specific $f(R)$ model that contains more than one higher-order term in $R$. The $f(R)$ considered here has the terms $R^2$, $R^3$, and $R^4$ along with the linear term. A rigorous…

General Relativity and Quantum Cosmology · Physics 2022-11-16 Sahazada Aziz , Sohan Kumar Jha , Anisur Rahaman

We construct an analytic f(R) gravity model that unifies early-time inflation with late-time cosmic acceleration within a single covariant framework. At high curvature, the model reproduces a Starobinsky-like inflationary plateau, while at…

General Relativity and Quantum Cosmology · Physics 2025-09-18 M. V. Pradosh Keshav , Arun Kenath

In this paper we shall study the inflationary aspects of a logarithmic corrected $R^2$ Starobinsky inflation model, in the presence of a Kalb-Ramond field in the gravitational action of $F(R)$ gravity. Our main interest is to pin down the…

General Relativity and Quantum Cosmology · Physics 2019-02-20 E. Elizalde , S. D. Odintsov , V. K. Oikonomou , Tanmoy Paul

In this paper, we study the inflationary scenario in logarithmic f(R) gravity, where the rate of inflation roll is constant. On the other hand, our gravitational f(R) model is a polynomial plus a logarithmic term. We take advantage of…

General Relativity and Quantum Cosmology · Physics 2022-12-19 J. Sadeghi , B. Pourhassan , S. Noori Gashti , E. Naghd Mezerji , A. Pasqua

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

Inflationary era of our Universe can be characterized as semi-classical because it can be described in the context of four-dimensional Einsteins's gravity involving quantum corrections. These string motivated corrections originate from…

General Relativity and Quantum Cosmology · Physics 2021-08-25 S. A. Venikoudis , F. P. Fronimos

Higher-order theories of gravity are a branch of modified gravity wherein the geometrodynamics of the four-dimensional Riemannian manifold is determined by field equations involving derivatives of the metric tensor of order higher than two.…

General Relativity and Quantum Cosmology · Physics 2024-04-19 R. R. Cuzinatto , L. G. Medeiros

Higher-order theories of gravity are extensions to general relativity (GR) motivated mainly by high-energy physics searching for GR ultraviolet completeness. They are characterized by the inclusion of correction terms in the…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-14 G. Rodrigues-da-Silva , L. G. Medeiros

The $R^2$ inflation which is an extension of general relativity (GR) by quadratic scalar curvature introduces a quasi-de Sitter expansion of the early Universe governed by Ricci scalar being an eigenmode of d'Alembertian operator. In this…

High Energy Physics - Theory · Physics 2023-07-21 Alexey S. Koshelev , K. Sravan Kumar , Alexei A. Starobinsky

In this work, we study several extensions of the higher curvature modification of $R^{2}$ inflation in the context of gravity's rainbow. We modify the $(R+R^{2})$ model by adding an $f_{1}R^3$-term, an $f_{2}R^4$-term, and an…

General Relativity and Quantum Cosmology · Physics 2024-08-05 Jureeporn Yuennan , Phongpichit Channuie , Davood Momeni