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arXiv · 2405.09732

Dynamics of a higher-dimension Einstein-Scalar-Gauss-Bonnet cosmology

Alfredo D. Millano·Claudio Michea·Genly Leon·Andronikos Paliathanasis
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Abstract

We study the dynamics of the field equations in a five-dimensional spatially flat Friedmann-Lema\^itre-Robertson-Walker metric in the context of a Gauss-Bonnet-Scalar field theory where the quintessence scalar field is coupled to the Gauss-Bonnet scalar. Contrary to the four-dimensional Gauss-Bonnet theory, where the Gauss-Bonnet term does not contribute to the field equations, in this five-dimensional Einstein-Scalar-Gauss-Bonnet model, the Gauss-Bonnet term contributes to the field equations even when the coupling function is a constant. Additionally, we consider a more general coupling described by a power-law function. For the scalar field potential, we consider the exponential function. For each choice of the coupling function, we define a set of dimensionless variables and write the field equations into a system of ordinary differential equations. We perform a detailed analysis of the dynamics for both systems and classify the stability of the equilibrium points. We determine the presence of scaling and super-collapsing solutions using the cosmological deceleration parameter. This means that our models can explain the Universe's early and late-time acceleration phases. Consequently, this model can be used to study inflation or as a dark energy candidate.

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Alfredo D. Millano, Claudio Michea, Genly Leon, Andronikos Paliathanasis. 2024-05-15. Dynamics of a higher-dimension Einstein-Scalar-Gauss-Bonnet cosmology. https://doi.org/10.1016/j.dark.2024.101589

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