Emergent Cosmology in 4D Einstein Gauss Bonnet Theory of Gravity

Abstract

In this paper, in an FLRW background and a perfect fluid equation of state, we explore the possibility of the realization of an emergent scenario in a 4D regularized extension of Einstein-Gauss-Bonnet gravity, with the field equations particularly expressed in terms of scalar-tensor degrees of freedom. By assuming non-zero spatial curvature ($k=\pm 1$), the stability of the Einstein static universe (ESU) and its subsequent exit into the standard inflationary system is tested through different approaches. In terms of dynamical systems, a spatially closed universe rather than an open universe shows appealing behaviour to exhibit a graceful transition from the Einstein static universe to standard cosmological history. We found that under linear homogeneous perturbations, for some constraints imposed on the model parameters, the Einstein static universe is stable under those perturbations. Moreover, it is noted that for a successful graceful transition, the equation of state $\omega$ must satisfy the conditions $-1<\omega <0$ and $\omega <-1$ for closed and open universes, respectively. Also, under density perturbations, the Einstein static universe is unstable if the fluid satisfies the strong energy condition but is stable if it violates it, for both closed and open universes. Furthermore, the Einstein static universe is seen to be stable under vector perturbations and tensor perturbations, regardless of whether the fluid obeys or violates the SEC.

12 pages, 2 figures, Accepted in Physica Scripta

References in corpus (22)

• Horndeski Gravity as $D\to 4$ Limit of Gauss-Bonnet
• On Taking the $D\to 4$ limit of Gauss-Bonnet Gravity: Theory and Solutions
• Derivation of Regularized Field Equations for the Einstein-Gauss-Bonnet Theory in Four Dimensions
• The 4D Einstein-Gauss-Bonnet Theory of Gravity: A Review
• Effective scalar-tensor description of regularized Lovelock gravity in four dimensions
• Stability of the Einstein static universe in modified Gauss-Bonnet gravity
• The Einstein static universe in Loop Quantum Cosmology
• Observational Constraints on the Regularized 4D Einstein-Gauss-Bonnet Theory of Gravity
• Einstein static universes are unstable in generic f(R) models
• Gravity with a generalized conformal scalar field: Theory and solutions
• On the stability of the Einstein Static Universe in Massive Gravity
• Emergent Universe from Energy-Momentum Squared Gravity
• Induced Matter Brane Gravity and Einstein Static Universe
• Inhomogeneous Perturbations and Stability Analysis of the Einstein Static Universe in f(R,T) Gravity
• Stability of the Einstein static Universe in Einstein-Cartan-Brans-Dicke gravity
• Emergent Universe Scenario, Bouncing and Cyclic Universes in Degenerate Massive Gravity
• Growth of matter density perturbations in 4D Einstein-Gauss-Bonnet gravity
• Cosmological Constraints on 4-Dimensional Einstein-Gauss-Bonnet Gravity
• On the initial singularity in Kantowski-Sachs spacetime
• Emergent scenario in mimetic gravity
• Einstein Static Universe and its Stability in Generalized Rastall Gravity
• Dynamical Wormholes in Higher Dimensions and the Emergent Universe

Cited by in corpus (3)

• Non-Singular Bouncing cosmology from Phantom Scalar-Gauss-Bonnet Coupling: Reconstruction with Observational Insights
• Avoiding Big Rip Singularities in Phantom Scalar Field theory with Gauss-Bonnet term
• Stability of the Einstein Static Universe in Zero-Point Length Cosmology with Topological Defects