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In this paper, we use corrected $f(R)$ gravitational model which is polynomial function with a logarithmic term. In that case, we employ the slow-roll condition and obtain the number of cosmological parameter. This help us to verify the…

High Energy Physics - Theory · Physics 2019-11-12 J. Sadeghi , E. Naghd Mezerji , S. Noori Gashti

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

In this paper we investigate the inflationary phenomenology of an Einstein-Gauss-Bonnet theory with the extension of a logarithmic modified $f(R)$ gravity, compatible with the GW170817 event. The main idea of our work is to study different…

General Relativity and Quantum Cosmology · Physics 2021-03-03 S. A. Venikoudis , F. P. Fronimos

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

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

In this paper we shall consider an exponential inflationary model in the context of vacuum $F(R)$ gravity. By using well-known reconstruction techniques, we shall investigate which $F(R)$ gravity can realize the exponential inflation…

General Relativity and Quantum Cosmology · Physics 2018-03-14 V. K. Oikonomou

This paper discusses a simple procedure to reconstruct f (R)-gravity models from exact cosmological solutions of the Einstein field equations with a noninteracting classical scalar field-and-radiation background. From the kind of…

General Relativity and Quantum Cosmology · Physics 2017-09-15 Heba Sami , Joseph Ntahompagaze , Amare Abebe

Using Mukhanov-Chamseddine mimetic approach, we study $F(R)$ gravity with scalar potential and Lagrange multiplier constraint. As we demonstrate, for a given $F(R)$ gravity and for suitably chosen mimetic potential, it is possible to…

General Relativity and Quantum Cosmology · Physics 2015-11-10 S. D. Odintsov , V. K. Oikonomou

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

In this letter, we consider the theory of $F(R)$ gravity with the lagrangian density $ \pounds = R+\alpha R^2 + \beta R^2 \ln \beta R $. We obtain the constant curvature solutions and find the scalar potential of the gravitational field. We…

General Relativity and Quantum Cosmology · Physics 2016-06-09 J. Sadeghi , H. Farahani

This paper is devoted to the analysis of a class of $F(R)$ gravity, where additional logarithmic corrections are assumed. The gravitational action includes an exponential term and a $R^2$ inflationary term, both with logarithmic…

General Relativity and Quantum Cosmology · Physics 2019-01-09 Sergei D. Odintsov , Diego Saez-Chillon Gomez , German S. Sharov

In this work, we studied the slow-roll approximation of cosmic inflation within the context of $f(R,T)$ gravity, where $R$ is the scalar curvature, and $T$ is the trace of the energy-momentum tensor. By choosing a minimal coupling between…

General Relativity and Quantum Cosmology · Physics 2021-01-12 Mauricio Gamonal

We discuss the cosmological inflation in the context of $f(Q)$ non-metric gravity, where $Q$ is the non-metric scalar. After introducing conformal transformations for $f(Q)$ gravity, we first focus on the potential-slow-roll inflation by…

General Relativity and Quantum Cosmology · Physics 2022-09-23 Salvatore Capozziello , Mehdi Shokri

The previously introduced class of two-parametric phenomenological inflationary models in General Relativity in which the slow-roll assumption is replaced by the more general, constant-roll condition is generalized to the case of $f(R)$…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-15 Hayato Motohashi , Alexei A. Starobinsky

We consider the semi-classical dynamics of a free massive scalar field in a homogeneous and isotropic cosmological spacetime. The scalar field is quantized using the polymer quantization method assuming that it is described by a gaussian…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-11 Syed Moeez Hassan , Viqar Husain , Sanjeev S. Seahra

The effective inflationary Lagrangian is a prominent challenge for theoretical cosmologists, since it may contain imprints of the quantum epoch. In view of the fact that higher order curvature terms might be present in the effective…

General Relativity and Quantum Cosmology · Physics 2021-09-15 V. K. Oikonomou

Slow-roll inflation is analyzed in the context of modified gravity within the Palatini formalism. As shown in the literature, inflation in this framework requires the presence of non-traceless matter, otherwise it does not occur just as a…

General Relativity and Quantum Cosmology · Physics 2020-11-30 Sabit Bekov , Kairat Myrzakulov , Ratbay Myrzakulov , Diego Sáez-Chillón Gómez

We examine inflationary universe models driven by scalar fields with logarithmic potentials of the form $V(\phi) = V_0 \phi^p(\ln \phi)^q$. Combining the slow-roll approximation with asymptotic techniques, we identify regions of the…

Astrophysics · Physics 2009-10-28 John D. Barrow , Paul Parsons

In this work, we extend the bottom-up reconstruction framework of $F(R)$ gravity to other modified gravities, and in particular for $f(\phi)R$ and mimetic $F(R)$ gravities. We investigate which are the important conditions in order for the…

General Relativity and Quantum Cosmology · Physics 2018-03-14 S. D. Odintsov , V. K. Oikonomou

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
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