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Related papers: Testing logarithmic corrections on $R^2$-exponenti…

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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 put forward novel extensions of Starobinsky inflation, involving a class of 'geometric' higher-curvature corrections that yield second-order Friedmann-Lema\^itre equations and second-order-in-time linearized equations around cosmological…

High Energy Physics - Theory · Physics 2021-05-26 Pablo A. Cano , Kwinten Fransen , Thomas Hertog

In this paper, we employ mimetic $f(R,T)$ gravity coupled with Lagrange multiplier and mimetic potential to yield viable inflationary cosmological solutions consistent with latest Planck and BICEP2/Keck Array data. We present here three…

General Relativity and Quantum Cosmology · Physics 2021-07-28 Snehasish Bhattacharjee

We include the single graviton loop contribution to the linearized Einstein equation. Explicit results are obtained for one loop corrections to the propagation of gravitational radiation. Although suppressed by a minuscule loop-counting…

General Relativity and Quantum Cosmology · Physics 2022-06-27 L. Tan , N. C. Tsamis , R. P. Woodard

We employ an unregulated computation the graviton self-energy from gravitons on de Sitter background to infer the renormalized result. This is used to quantum-correct the linearized Einstein equation. We solve this equation for the…

General Relativity and Quantum Cosmology · Physics 2022-07-11 L. Tan , N. C. Tsamis , R. P. Woodard

In this investigation, we perform an observational statistical analysis in the theory of $ f(R, L_m) $ gravity. The proposed theoretical model is based on the Ricci scalar's non-linear contribution. We use a distinct parameterization for…

General Relativity and Quantum Cosmology · Physics 2024-08-30 J. K. Singh , Shaily , Akanksha Singh , Harshna Balhara , Joao R. L. Santos

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

We investigate the cosmological production of gravitational waves in a nonsingular flat cosmology powered by a "running vacuum" energy density described by $\rho_{\Lambda}\equiv\rho_{\Lambda}(H)$, a phenomenological expression potentially…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-15 D. A. Tamayo , J. A. S. Lima , M. E. S. Alves , J. C. N. de Araujo

The full set of cosmological observables coming from linear scalar and tensor perturbations of loop quantum cosmology is computed in the presence of inverse-volume corrections. Background inflationary solutions are found at linear order in…

General Relativity and Quantum Cosmology · Physics 2011-03-28 Martin Bojowald , Gianluca Calcagni

The $R+R^2$, shortly named "$R^2$" ("Starobinsky") inflationary model, represents a fully consistent example of a one-parameter inflationary scenario. This model has a "graceful exit" from inflation and provides a mechanism for subsequent…

High Energy Physics - Theory · Physics 2016-11-28 Alexey S. Koshelev , Leonardo Modesto , Leslaw Rachwal , Alexei A. Starobinsky

Of many extended theories of gravity, $f(R,T)$ gravity has gained reasonable interest in recent times as it provides interesting results in cosmology. Logarithmic corrections in modified theories of gravity has been studied extensively. In…

General Relativity and Quantum Cosmology · Physics 2024-09-05 Biswajit Deb , Atri Deshamukhya

In recent years, modifications to General Relativity (GR) have been explored to address cosmological observations, particularly in the context of late-time cosmic acceleration. Among these, modifications based on the Teleparallel Equivalent…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-29 Saurabh Verma , Archana Dixit , Anirudh Pradhan , M. S. Barak

We study a new class of inflation model parametrized by the Hubble radius, such that $aH\propto \exp(-k\phi^n)$. These potentials are plateau-like, and reduce to the power-law potentials in the simplest case $n=2$. We investigate the range…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-20 Siri Chongchitnan

This review explores modified theories of gravity, particularly $f(R)$ gravity, as extensions to General Relativity (GR) that offer alternatives to dark energy for explaining cosmic acceleration. These models generalize the Einstein-Hilbert…

General Relativity and Quantum Cosmology · Physics 2025-03-05 Rafid H. Dejrah

We study the spectral index of curvature perturbations for inflationary models where the driving scalar field is coupled to a relativistic fluid through a friction term $\Gamma$. We find that only a very small friction term - $\Gamma \ll…

Astrophysics · Physics 2008-11-26 A. Cerioni , F. Finelli , A. Gruppuso

In this paper, we explore modified gravity in the framework of $f(R, \mathcal{L}_m)$ theories by reconstructing the function $f(\mathcal{L}_m)$, where $\mathcal{L}_m = \rho$ is the matter Lagrangian, under the assumption of a pressureless,…

General Relativity and Quantum Cosmology · Physics 2025-06-12 Y. Kalpana Devi , S. A. Narawade , B. Mishra

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

A computation of the inflationary observables n_{s} and r is made for `logamediate' inflation where the cosmological scale factor expands as $a=\exp (A(\ln t)^{\lambda})$, and is compared to their predicted values in the intermediate…

Astrophysics · Physics 2008-11-26 John D. Barrow , N. J. Nunes

A large class of quintessential inflationary models, recently proposed by Peebles and Vilenkin, leads to post-inflationary phases whose effective equation of state is stiffer than radiation. The expected gravitational waves logarithmic…

Astrophysics · Physics 2009-10-31 Massimo Giovannini

In this work, we study the $f(R)$ models of inflation in the context of gravity's rainbow theory. We choose three types of $f(R)$ models: $f(R)=R+\alpha (R/M)^{n},\,f(R)=R+\alpha R^{2}+\beta R^{2}\log(R/M^{2})$ and the Einstein-Hu-Sawicki…

General Relativity and Quantum Cosmology · Physics 2020-09-02 Areef Waeming , Phongpichit Channuie