A refined Einstein–Gauss–Bonnet inflationary theoretical framework

Oikonomou, V. K.

doi:10.1088/1361-6382/ac2168

Cited by 83 publications

(41 citation statements)

References 65 publications

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“…In this paper it is demonstrated the phenomenology of the late-time Universe of a given scalar-tensor theory in the context of string-inspired gravity, see Ref. [47][48][49][50][51][52][53]. The theory involves a scalar field which is minimally coupled with the Ricci scalar and a function f (G) solely depending from the Gauss-Bonnet topological invariant G, representing higher curvature corrections and assists the accelerating expansion.…”

Section: Introductionmentioning

confidence: 99%

Late-time Cosmology of scalar field assisted $f(\mathcal{G})$ gravity

Venikoudis,

Fasoulakos,

Fronimos

2022

Preprint

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In this work we present the late-time behaviour of the Universe in the context of Einstein-Gauss-Bonnet gravitational theory. The theory involves a scalar field, which represents low-effective quantum corrections, assisted by a function f (G) solely depending from the Gauss-Bonnet topological invariant G. It is considered that the dark energy serves as the impact of all geometric terms, which are included in the gravitational action and the density of dark energy acts as a time dependent cosmological constant evolving with an infinitesimal rate and driving the Universe into an accelerating expansion. We examine two cosmological models of interest. The first involves a canonical scalar field in the presence of a scalar potential while the second, involves a scalar field which belongs to a generalized class of theories f (φ, X) namely the k-essence scalar field in the absence of scalar potential. As it is proved, the aforementioned models are in consistency with the latest Planck data and in relatively good agreement with the ΛCDM standard cosmological model. The absence of dark energy oscillations at the early stages of matter dominated era, which appear in alternative scenarios of cosmological dynamics in the context of modified f (R) gravitational theories, indicates an advantage of the theory for the interpretation of late-time phenomenology.

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Section: Introductionmentioning

confidence: 99%

Late-time Cosmology of scalar field assisted $f(\mathcal{G})$ gravity

Venikoudis,

Fasoulakos,

Fronimos

2022

Preprint

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“…2 model confronted with the latest Planck likelihood curves for N chosen in the range N =[50,60]. As it can be seen, the model has quite elegant viability characteristics comparable and almost identical with the standard R 2 model.…”

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confidence: 94%

$R^2$ Inflation Revisited and Dark Energy Corrections

Odintsov,

Oikonomou

2021

Preprint

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The vacuum R 2 model is known to generate a quasi-de Sitter evolution for inflation, using solely the slow-roll assumptions. Using standard reconstruction techniques, we demonstrate that the f (R) gravity which actually realizes the quasi-de Sitter evolution is not simply the R 2 model but a deformed R 2 model which contains extra terms in addition to the R 2 model. We analyze in detail the inflationary dynamics of the deformed R 2 model and we demonstrate that the predictions are quite close to the ones of the pure R 2 model, regardless the values of the free parameters. Basically the deformed R 2 model is also a single parameter inflationary model, exactly like the ordinary R 2 model. In contrast to the early-time era, where the deformed R 2 model is quite similar to the R 2 model, at late times, the phenomenological picture is different. The deformed R 2 model describes stronger gravity compared to the ordinary R 2 with an effectively smaller effective Planck mass. We propose the addition of an early dark energy term which does not affect at all the inflationary era, but takes over the control of the late-time dynamics at late times. We study in some detail the predicted dark energy era evolution, and we demonstrate that the dark energy corrected deformed R 2 model can describe a viable dark energy era, compatible with the Planck constraints on cosmological parameters. Furthermore the model is distinct from the Λ-Cold-Dark-Matter model, but shows a qualitatively similar behavior.

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“…When the spacetime dimension satisfies D ≥ 5, the GB term is no longer topological invariant and its influence will exit [41]. Recently, the GB term has been applied to the investigation of inflation after the GW170817 event [43][44][45][46]. It is reasonable consider branes in the GB gravity since the GB term has appeared in string theory.…”

Section: Introductionmentioning

confidence: 99%

Multi-kink brane in Gauss-Bonnet gravity

Xu¹,

Chen²,

Zhang³

et al. 2022

Preprint

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It is well known that the Gauss-Bonnet invariant is nontrivial in extra dimensional models. In this paper, we study the properties of thick branes generated by a bulk scalar field in the five-dimensional Einstein-Gauss-Bonnet Gravity. With the help of the superpotential method, we obtain a series of multi-kink brane solutions. We also analyze the linear stability of the brane system under tensor perturbations and prove that they are stable. The massless graviton is shown to be localized near the brane and hence the four-dimensional Newtonian potential can be recovered. By comparing the properties of these thick branes under different coupling parameters, we discuss the effect of the Gauss-Bonnet invariant on the thick branes.

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A refined Einstein–Gauss–Bonnet inflationary theoretical framework

Cited by 83 publications

References 65 publications

Late-time Cosmology of scalar field assisted $f(\mathcal{G})$ gravity

Late-time Cosmology of scalar field assisted $f(\mathcal{G})$ gravity

$R^2$ Inflation Revisited and Dark Energy Corrections

Multi-kink brane in Gauss-Bonnet gravity

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