Scalar-Gauss-Bonnet model, the coincidence problem and the gravitational wave speed

Abstract

We introduce a dynamical dark energy model wherein quintessence interacts with both the Gauss-Bonnet invariant and dark matter. Initially, the Gauss-Bonnet invariant stabilizes the quintessence at a fixed point, resulting in a negligible density of dark energy. Subsequently, the conformal coupling to dark matter triggers the evolution of dark energy. This model proposes an explanation for the initial absence of dark energy in radiation era and its later emergence during the matter-dominated era, achieving a magnitude comparable to dark matter in the present epoch. In this scenario, the Gauss-Bonnet term does not directly influence late-time cosmic evolution. Our model aligns with the assumption that the speed of gravitational wave is infinitesimally close to the speed of light.

20 pages, 7 figures, major revision, accepted for publication in Physics Letters B

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Cited by in corpus (5)

• Quintessence in the Weyl-Gauss-Bonnet model
• Compact stars in Einstein-scalar-Gauss-Bonnet gravity: regular and divergent scalar field configurations
• Gauss-Bonnet-induced symmetry breaking/restoration during inflation
• Anisotropic Spacetimes in $f(G)$-gravity: Bianchi I, Bianchi III and Kantowski-Sachs Cosmologies
• Onset of dark energy from cosmological scalarization and gravitational wave speed