Brans-Dicke Theory as a Unified Model for Dark Matter - Dark Energy

Abstract

The Brans-Dicke (BD) theory of gravity is taken as a possible theory of k-essence coupled to gravity. It then has been realized that the BD scalar field does indeed play a role of a k-essence, but in a very unique way which distinguishes it from other k-essence fields studied in the literature. That is, first in the BD scalar field-dominated era when the contribution from this k-essence overwhelms those from other types of matter, the BD theory predicts the emergence of a yet-unknown {\it zero acceleration} epoch which is an intermediate stage acting as a ``crossing bridge'' between the decelerating matter-dominated era and the accelerating phase. Upon realizing this, next, closer study of the effects of this k-essence on the evolutionary behavior of the matter-dominated and the accelerating eras has been performed. The result of the study indicates that the BD scalar field appears to interpolate {\it smoothly} between these two late-time stages by speeding up the expansion rate of the matter-dominated era somewhat while slowing down that of the accelerating phase to some degree. Thus with the newly found BD scalar field-dominated era in between these two, the late-time of the universe evolution appears to be mixed sequence of the three stages.

25 pages, Mon. Not. R. Astron. Soc.(MNRAS), in press

Cited by in corpus (19)

• Instability of holographic dark energy models
• Instability of agegraphic dark energy models
• Is Local $H_0$ At Odds With Dark Energy EFT?
• Cosmic evolution and thermal stability of Barrow holographic dark energy in nonflat Friedmann-Robertson-Walker Universe
• Modified Brans-Dicke Theory in Arbitrary Dimensions
• Saez-Ballester gravity in Kantowski-Sachs Universe: a new reconstruction paradigm for Barrow Holographic Dark Energy
• Generalized interacting Barrow Holographic Dark Energy: cosmological predictions and thermodynamic considerations
• Friedmann cosmology with decaying vacuum density in Brans-Dicke theory
• Running vacuum in Brans-Dicke theory: a possible cure for the ${\sigma }_8$ and $H_0$ tensions
• Nucleation of vacuum bubbles in Brans-Dicke type theory
• Simplified Quartessence Cosmology
• Astrophysics in 2006
• Quantum Entropy-Driven Modifications to Holographic Dark Energy in $f(G,T)$ Gravity
• Cosmological Model with Cosmic transit behaviour in Brans-Dicke Theory
• Evolution of Generalized Brans-Dicke parameter within a Superbounce scenario
• Hairy black holes in dilatonic Einstein-Gauss-Bonnet theory
• Exploring Cosmological Implications of the Modified Raychaudhuri Equation in Non-Gravitating Vacuum Energy Theory
• Baryogenesis in Brans-Dicke theory
• Cosmological solutions in the Brans-Dicke theory via invariants of symmetry groups