Testing viable extensions of Einstein–Gauss–Bonnet gravity

Odintsov, Sergei D.; Sáez-Gómez, Diego; Sharov, G. S.

doi:10.1016/j.dark.2022.101100

Cited by 15 publications

(1 citation statement)

References 191 publications

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“…Many theories and cosmological models have been proposed to explain this phenomenon [3][4][5]. One of the actively developed is the Einstein-Gauss-Bonnet model of gravity (EGB) [6][7][8]. A distinctive feature of this model is the Gauss-Bonnet (GB) invariant in action [9,10].…”

Section: Introductionmentioning

confidence: 99%

The Early and Late Universe in the Modified Einstein-Maxwell-Gauss-Bonnet Model

Tsyba,

Rakhatov,

Razina

2024

Preprint

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This work investigates the Einstein-Gauss-Bonnet model with scalar and electromagnetic fields. The created model was reconstructed using a hybrid scale factor. The initial viability analysis of the model confirmed the compliance of the solutions with modern cosmological data. The equation of state parameter $\omega$, corresponds to the case of an accelerated expanding universe. In addition, an alternative approach utilizing $Om(z)$ diagnostics has been implemented. The values of the scalar field and its potential obtained during the solution correspond to the cases of "slow-roll" and chaotic inflation. The values of the slow-roll parameters, based on the coupling function $\xi(\phi)$ are obtained. Parameters correspond to the condition of the beginning of inflation. Based on the slow-roll parameters, the values of the spectral indices $n_S$, $n_T$, and the tensor-to-scalar ratio $r$ are obtained. The propagation speed of the acoustic ($c_A$) and tensor ($c_T$) perturbations have been determined. Subsequently, an examination of the post-inflationary phase in the universe's evolution was conducted. This analysis was predicated on the utilization of energy conditions. Furthermore, an extensive evaluation involving cosmographic parameters and statefinders diagnostics was executed. The application of the described methods has shown that the model is stable, viable, and can be used to study the early and late stages of the universe's evolution.

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Section: Introductionmentioning

confidence: 99%

The Early and Late Universe in the Modified Einstein-Maxwell-Gauss-Bonnet Model

Tsyba,

Rakhatov,

Razina

2024

Preprint

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Thermodynamics and Perturbative Analysis of Some Newly Developed F(R,Lm,T)$\mathcal {F}(R,L_m, T)$ Theories Under the Scenario of Conserved Energy‐momentum Tensor

Zubair

Waheed

Muneer

et al. 2023

Fortschritte der Physik

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The present work is devoted to explore some interesting cosmological features of a newly proposed theory of gravity namely theory, where R and T represent the Ricci scalar and trace of energy momentum‐tensor, respectively. First, a non‐equilibrium thermodynamical description is considered on the apparent horizon of the Friedmann's cosmos. The Friedmann equations are demonstrated to be equivalent to the first law of thermodynamics, i.e., , where refers to entropy production term. The constraint for validity of generalized second law of thermodynamics is also formulated and checked it for some simple well‐known forms of generic function . Next, the energy bounds for this framework and constraint the free variables by finding the validity regions for NEC and WEC are developed. Furthermore, some interesting cosmological solutions namely power law, ΛCDM, and de Sitter models in this theory are reconstructed. The reconstructed solutions are then examined by checking the validity of GSLT and energy bounds. Lastly, the stability of all reconstructed solutions by introducing suitable perturbations in the field equations is analyzed. It is concluded that obtained solutions are stable and cosmologically viable.

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Asymptotically AdS-Schwarzschild black hole in Pure-Lovelock theory in 3+1-dimensions

Mazharimousavi

2023

Annals of Physics

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Testing viable extensions of Einstein–Gauss–Bonnet gravity

Cited by 15 publications

References 191 publications

The Early and Late Universe in the Modified Einstein-Maxwell-Gauss-Bonnet Model

The Early and Late Universe in the Modified Einstein-Maxwell-Gauss-Bonnet Model

Thermodynamics and Perturbative Analysis of Some Newly Developed F(R,Lm,T)$\mathcal {F}(R,L_m, T)$ Theories Under the Scenario of Conserved Energy‐momentum Tensor

Asymptotically AdS-Schwarzschild black hole in Pure-Lovelock theory in 3+1-dimensions

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