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In this letter we study the behavior of non-minimally coupled Einstein-Gauss-Bonnet gravity theories with the constant-roll condition. Recalling the results of the striking GW170817 event, we demand that the velocity of the gravitational…

General Relativity and Quantum Cosmology · Physics 2020-11-10 V. K. Oikonomou , F. P. Fronimos

We study the inflationary phenomenology of a non-minimally coupled Einstein Gauss-Bonnet gravity theory, in the presence of a scalar potential, under the condition that the gravitational wave speed of the primordial gravitational waves is…

General Relativity and Quantum Cosmology · Physics 2020-08-26 S. D. Odintsov , V. K. Oikonomou , F. P. Fronimos

In this work we introduce a new theoretical framework for Einstein-Gauss-Bonnet theories of gravity, which results to particularly elegant, functionally simple and transparent gravitational equations of motion, slow-roll indices and the…

General Relativity and Quantum Cosmology · Physics 2020-07-28 S. D. Odintsov , V. K. Oikonomou , F. P. Fronimos

In this work we study the inflationary framework of Einstein-Gauss-Bonnet theories which produce a primordial gravitational wave speed that respects the constraint imposed by the GW170817 event, namely $\left| c_T^2 - 1 \right| < 6 \times…

General Relativity and Quantum Cosmology · Physics 2024-07-18 V. K. Oikonomou

We have explicitly demonstrated that scalar coupled Gauss-Bonnet gravity in four dimension can have non-trivial effects on the early inflationary stage of our universe. In particular, we have shown that the scalar coupled Gauss-Bonnet term…

General Relativity and Quantum Cosmology · Physics 2018-11-13 Sumanta Chakraborty , Tanmoy Paul , Soumitra SenGupta

In this work we shall introduce a theoretical framework comprised by a non-minimal coupled canonical scalar field, a non-minimal coupling to the Gauss-Bonnet invariant and a non-minimal kinetic coupling. This theoretical framework is…

General Relativity and Quantum Cosmology · Physics 2021-09-15 V. K. Oikonomou , F. P. Fronimos

We study the slow-roll single field inflation in the context of the consistent $D\to4$ Einstein-Gauss-Bonnet gravity that was recently proposed in \cite{Aoki:2020lig}. In addition to the standard attractor regime, we find a new attractor…

General Relativity and Quantum Cosmology · Physics 2021-05-03 Katsuki Aoki , Mohammad Ali Gorji , Shuntaro Mizuno , Shinji Mukohyama

We provide a refined and much more simplified Einstein-Gauss-Bonnet inflationary theoretical framework, which is compatible with the GW170817 observational constraints on the gravitational wave speed. As in previous works, the constraint…

General Relativity and Quantum Cosmology · Physics 2021-09-22 V. K. Oikonomou

In this work we study the GW170817-compatible Einstein-Gauss-Bonnet theories during the reheating and the end of inflationary era. Given the scalar field potential $V(\phi)$ which can have some intrinsic importance for the theory,…

General Relativity and Quantum Cosmology · Physics 2024-01-23 V. K. Oikonomou , Pyotr Tsyba , Olga Razina

In this paper we investigate the inflationary phenomenology of an Einstein-Gauss-Bonnet theory compatible with the GW170817 event, by imposing the constant-roll evolution on the scalar field. We develop the constant-roll GW170817-compatible…

General Relativity and Quantum Cosmology · Physics 2020-09-15 S. D. Odintsov , V. K. Oikonomou , F. P. Fronimos , S. A. Venikoudis

After the recent GW170817 event of the two neutron stars merging, many string corrected cosmological theories confronted the non-viability peril. This was due to the fact that most of these theories produce massive gravitons primordially.…

General Relativity and Quantum Cosmology · Physics 2021-02-03 V. K. Oikonomou , F. P. Fronimos

In this work we shall study Einstein Gauss-Bonnet theories and we investigate when these can have their gravitational wave speed equal to the speed of light, which is unity in natural units, thus becoming compatible with the striking event…

General Relativity and Quantum Cosmology · Physics 2019-10-02 S. D. Odintsov , V. K. Oikonomou

We investigate the non-Gaussianities of inflation driven by a single scalar field coupling non-minimally to the Einstein Gravity. We assume that the form of the scalar field is very general with an arbitrary sound speed. For convenience to…

High Energy Physics - Theory · Physics 2011-05-27 Taotao Qiu , Kwei-Chou Yang

In the present paper, we study the inflationary phenomenology of a $k$-inflation corrected Einstein-Gauss-Bonnet theory. Non-canonical kinetic terms are known for producing Jean instabilities or superluminal sound wave velocities in the…

General Relativity and Quantum Cosmology · Physics 2021-02-24 S. D. Odintsov , V. K. Oikonomou , F. P. Fronimos

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

Higgs inflation with a Gauss-Bonnet term is studied in the Einstein frame. Our model features two coupling functions, $\Omega^2(\phi)$ and $\omega(\phi)$, coupled to the Ricci scalar and Gauss-Bonnet combinations. We found a special…

General Relativity and Quantum Cosmology · Physics 2024-03-26 Seoktae Koh , Seong Chan Park , Gansukh Tumurtushaa

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

In this paper the focus is on inflationary dynamics in the context of Einstein Gauss-Bonnet gravitational theories. We investigate the implications of the slow-roll condition on the slow-roll indices and we investigate how the inflationary…

General Relativity and Quantum Cosmology · Physics 2018-09-26 S. D. Odintsov , V. K. Oikonomou

We study the inflationary phenomenology of a rescaled Einstein-Gauss-Bonnet gravity. In this framework, the gravitational constant of the Einstein-Hilbert term is rescaled due to effective terms active in the high curvature era. Basically,…

General Relativity and Quantum Cosmology · Physics 2025-03-25 V. K. Oikonomou , Ardit Gkioni , Iason Sdranis , Pyotr Tsyba , Olga Razina

We study two of the most theoretically promising models of inflation, namely the Natural inflation and the Mutated Hilltop inflation, in the Einstein-Gauss Bonnet(EGB) gravity framework. In this work, we try to explore these models in EGB…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-31 Mayukh R. Gangopadhyay , Hussain Ahmed Khan , Yogesh
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