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相关论文: Logarithmic corrected $f(R)$ gravitational model a…

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In this paper, we consider an inflationary model of $f(R)$ gravity with polynomial form plus logarithmic term. We calculate some cosmological parameters and compare our results with the Plank 2015 data. We find that presence of both…

广义相对论与量子宇宙学 · 物理学 2016-06-14 J. Sadeghi , B. Pourhassan , A. S. Kubeka , M. Rostami

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…

广义相对论与量子宇宙学 · 物理学 2022-12-19 J. Sadeghi , B. Pourhassan , S. Noori Gashti , E. Naghd Mezerji , A. Pasqua

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…

广义相对论与量子宇宙学 · 物理学 2016-06-09 J. Sadeghi , H. Farahani

In this paper, we worked in the framework of an inflationary $f(R,T)$ theory, in the presence of a canonical scalar field. More specifically, the $f(R,T)=\gamma R+2\kappa\alpha T$ gravity. The values of the dimensionless parameters $\alpha$…

广义相对论与量子宇宙学 · 物理学 2023-08-01 V. K. Oikonomou , Konstantinos-Rafail Revis , Ilias C. Papadimitriou , Maria-Myrto Pegioudi

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…

广义相对论与量子宇宙学 · 物理学 2021-03-03 S. A. Venikoudis , F. P. Fronimos

In this paper, we study various cosmological parameters and quantities in scalar-tensor gravity from inflation and swampland conjecture. Therefore, by selecting different models such as power-law, exponential, and logarithmic in the…

广义相对论与量子宇宙学 · 物理学 2022-08-19 S. Noori Gashti , J. Sadeghi

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…

广义相对论与量子宇宙学 · 物理学 2017-09-15 Heba Sami , Joseph Ntahompagaze , Amare Abebe

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…

广义相对论与量子宇宙学 · 物理学 2021-09-15 V. K. Oikonomou

Inflationary models derived from $f(R)$ gravity, where the scalaron rolls down with a constant rate from the top to the minimum of the effective potential, are considered. Specifically, we take into account three $f(R)$ models…

广义相对论与量子宇宙学 · 物理学 2021-08-16 Mehdi Shokri , Mohammad Reza Setare , Salvatore Capozziello , Jafar Sadeghi

Recently researchers have been studying various conditions as swampland criteria in cosmological implications. They have studied many inflation models with different swampland conditions. Occasionally these conjectures are modified and lead…

宇宙学与河外天体物理 · 物理学 2023-02-14 S. Noori Gashti , J. Sadeghi , B. Pourhassan

Over the past few decades, inflation models have been studied by researchers from different perspectives and conditions in order to introduce a model for the expanding universe. In this paper, we introduce a modified $f(R)$ gravitational…

广义相对论与量子宇宙学 · 物理学 2021-12-01 J. Sadeghi , B. Pourhassan , S. Noori Gashti , S. Upadhyay

In this paper, we study a theory of gravity called mimetic $f(R, T)$ in the presence of swampland dS conjecture. For this purpose, we introduce several inflation solutions of the Hubble parameter H(N) from $f(R, T)= R+\delta T$ gravity…

广义相对论与量子宇宙学 · 物理学 2022-08-26 S. Noori Gashti , J. Sadeghi , S. Upadhyay , M. R. Alipour

We first derive the primordial power spectra, spectral indices and runnings of both scalar and tensor perturbations of a flat inflationary universe to the second-order approximations of the slow-roll parameters, in the framework of loop…

广义相对论与量子宇宙学 · 物理学 2016-03-25 Tao Zhu , Anzhong Wang , Klaus Kirsten , Gerald Cleaver , Qin Sheng , Qiang Wu

In this paper, we investigate hypergeometric stringy corrections in the swampland program for rescaled gravity. Precisely, we study inflationary models from Gauss-Bonnet hypergeometric scalar couplings via the falsification scenario. We…

高能物理 - 理论 · 物理学 2024-07-02 Saad Eddine Baddis , Adil Belhaj

In this paper, we study the constraints on the $f(Q)=Q/(8\pi G) - \alpha \ln(Q/Q_0)$, symmetric teleparallel model using local measurements and gravitational wave mock standard sirens. Using observational local SNIa and BAO data and energy…

广义相对论与量子宇宙学 · 物理学 2023-08-14 José Antonio Nájera , Carlos Aráoz Alvarado , Celia Escamilla-Rivera

The aim of this paper is to explore warm inflation in the background of $f(\mathcal{G})$ theory of gravity using scalar fields for the FRW universe model. We construct the field equations under slow-roll approximations and evaluate the…

广义相对论与量子宇宙学 · 物理学 2016-09-21 M. Sharif , Ayesha Ikram

According to the GEVAG (Generalized Entropy Varying-G) framework, any modification to the Bekenstein-Hawking area law would also lead to a varying-$G$ gravity theory in which the effective gravitational constant $G_\text{eff}$ becomes…

广义相对论与量子宇宙学 · 物理学 2026-03-26 Chen-Hao Wu , Yen Chin Ong

Swampland conjecture has been recently proposed to connect early time cosmological models with the string landscape, and then to understand if related scalar fields and potentials can come from some fundamental theory in the high energy…

广义相对论与量子宇宙学 · 物理学 2020-11-09 Micol Benetti , Salvatore Capozziello , Leila Lobato Graef

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…

天体物理学 · 物理学 2009-10-28 John D. Barrow , Paul Parsons

In this paper we present the techniques for computing cosmological bounces in polynomial $f(R)$ theories, whose order is more than two, for spatially flat FLRW spacetime. In these cases the conformally connected Einstein frame shows up…

广义相对论与量子宇宙学 · 物理学 2016-02-17 Kaushik Bhattacharya , Saikat Chakrabarty
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