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In this work we shall use a bottom-up approach for obtaining viable inflationary Einstein-Gauss-Bonnet models which are also compatible with the GW170817 event. Specifically, we shall use a recently developed theoretical framework in which…

General Relativity and Quantum Cosmology · Physics 2022-03-24 V. K. Oikonomou , P. D. Katzanis , Ilias C. Papadimitriou

In this work we investigate several Einstein-Gauss-Bonnet models that are compatible with the GW170817 event, the Atacama Cosmology Telescope data and the BICEP/Keck updated Planck constraints on the tensor-to-scalar ratio. We consider two…

General Relativity and Quantum Cosmology · Physics 2025-08-01 S. D. Odintsov , V. K. Oikonomou

During the inflationary epoch, we investigate the reconstruction of the background variables within the framework of Einstein-Gauss-Bonnet gravity, considering the scalar spectral index $n_s(N)$ and the tensor-to-scalar ratio $r(N)$, where…

General Relativity and Quantum Cosmology · Physics 2026-01-28 Ramón Herrera , Carlos Ríos

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

In this work we construct a bottom-up reconstruction technique for Loop Quantum Cosmology scalar-tensor theories, from the observational indices. Particularly, the reconstruction technique is based on fixing the functional form of the…

General Relativity and Quantum Cosmology · Physics 2018-05-02 Jaume de Haro , S. D. Odintsov , V. K. Oikonomou

We investigate the cosmological inflation for the Einstein-Hilbert action plus the Higgs potential function and the Gauss-Bonnet term coupled with the Higgs scalar field through a dilaton-like coupling. Then, using the…

General Relativity and Quantum Cosmology · Physics 2026-05-29 Zahra Ahghari , Mehrdad Farhoudi

In this paper, we analyze the early-time inflation in a scalar-tensor theory of gravity where the scalar field is minimally coupled with the Gauss-Bonnet four dimensional topological invariant. The theory belongs to a class of Horndeski…

General Relativity and Quantum Cosmology · Physics 2017-12-11 Lorenzo Sebastiani , Shynaray Myrzakul , Ratbay Myrzakulov

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 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

Recent results from the Atacama Cosmology Telescope (ACT), indicating a higher and more tightly constrained scalar spectral index, $n_s = 0.9743 \pm 0.0034$, place several inflationary models under tension, with quintessential inflation…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-17 Yogesh , Imtiyaz Ahmad Bhat , Mayukh R. Gangopadhyay , M. Sami

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 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

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

Recent analyses combining Atacama Cosmology Telescope (ACT) data with other cosmological datasets report a higher scalar spectral index $n_s$, creating tension with a wide range of inflationary models. Since a Gauss-Bonnet term with a…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-03 Yigan Zhu , Qing Gao , Yungui Gong , Zhu Yi

We consider inflationary models with the inflaton coupled to the Gauss-Bonnet term assuming a special relation $\delta_1=2\lambda\epsilon_1$ between the two slow-roll parameters $\delta_1$ and $\epsilon_1$. For the slow-roll inflation, the…

General Relativity and Quantum Cosmology · Physics 2018-10-19 Zhu Yi , Yungui Gong , Mudassar Sabir

We study inflationary models with a Gauss-Bonnet term to reconstruct the scalar field potentials and the Gauss-Bonnet coupling functions from the observable quantities. Using the observationally favored relations for both $n_s$ and $r$, we…

General Relativity and Quantum Cosmology · Physics 2017-06-14 Seoktae Koh , Bum-Hoon Lee , Gansukh Tumurtushaa

In this paper we study a class of quintessential Einstein Gauss-Bonnet models, focusing on their early and late-time phenomenology. With regard to the early-time phenomenology, we formalize the slow-roll evolution of these models and we…

General Relativity and Quantum Cosmology · Physics 2019-10-23 K. Kleidis , V. K. Oikonomou

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

We consider slow-roll inflation for a single scalar field with an arbitrary potential and an arbitrary nonminimal coupling to the Gauss-Bonnet term. By introducing a combined hierarchy of Hubble and Gauss-Bonnet flow functions, we…

High Energy Physics - Theory · Physics 2014-11-20 Zong-Kuan Guo , Dominik J. Schwarz

In this paper, we reconstruct viable inflationary models by starting from spectral index and tensor-to-scalar ratio from Planck observations. We analyze three different kinds of models: scalar field theories, fluid cosmology and…

General Relativity and Quantum Cosmology · Physics 2015-09-21 Ratbay Myrzakulov , Lorenzo Sebastiani , Sergio Zerbini
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