Related papers: A note on the 3D Brans-Dicke theory
There has been substantial interest in obtaining a quantum-gravitational description of de Sitter space. However, any such attempts have encountered formidable obstacles, and new philosophical directions may be in order. One possibility,…
We consider a model where both dark energy and dark matter originate from the coupling of a scalar field with a non-conventional kinetic term to, both, a metric measure and a non-metric measure. An interacting dark energy/dark matter…
Exploring the recent expansion history of the universe promises insights into the cosmological model, the nature of dark energy, and potentially clues to high energy physics theories and gravitation. We examine the extent to which precision…
Properties of Braneworld models of dark energy are reviewed. Braneworld models admit the following interesting possibilities: (i) The effective equation of state can be w < -1 as well as w > -1. In the former case the expansion of the…
We reconsider constraints on Brans-Dicke theories arising from the requirement of successful Big Bang Nucleosynthesis. Such constraints typically arise by imposing that the universe be radiation-dominated at early times, and therefore…
The dominance of dark energy in the universe has necessitated the introduction of a repulsive gravity source to make q0 negative. The models for dark energy range from a simple lambda-term to quintessence, Chaplygin gas, etc. We look at the…
Inspired by recent developments in particle physics, the so-called brane world cosmology seems to provide an alternative explanation for the present dark energy problem. In this paper, we use the estimated age of high-$z$ objects to…
We consider a scalar field interaction with a cosmic string configuration in a flat 3-brane. The origin of this field is given by a compactification mechanism in the context of a 5-dimensional Brans-Dicke theory. We use the Cosmic Microwave…
We show that, in the context of the two-field measure theory, any k-essence model leads to the existence of a fluid made of non-relativistic matter and cosmological constant that would explain the dark matter and dark energy problem at the…
The spatially flat and isotropic cosmological model of Brans-Dicke theory with coupling parameter $\omega\neq-3/2$ is quantized by the approach of loop quantum cosmology. An interesting feature of this model is that, although the…
Using the covariant formalism developed in a companion paper (paper I), we derive observational constraint on the Brans-Dicke model in a flat FLRW universe with cosmological constant and cold dark matter. The CMB observations we use include…
The canonical cosmological model to explain the recent acceleration of the universe relies on a cosmological constant, and most dynamical dark energy and modified gravity model alternatives are based on scalar fields. Still, further…
We entertain the possibility that the phenomena typically attributed to dark matter may have a fundamentally emergent nature, rather than arising from new particle degrees of freedom. To illustrate this idea, we consider a field-theoretic…
The variational field equations of Brans-Dicke scalar-tensor theory of gravitation are presented in a Riemannian and non-Riemannian setting in the language of exterior differential forms over 4-dimensional spacetime. In Rosen coordinates,…
It has recently been proposed that the Universe might be accelerating as a consequence of extra dimensions with time varying size. We show that although these scenarios can lead to acceleration, they run into serious difficulty when taking…
The origin of dark energy remains to be one of the challenges of modern cosmology. We modify Jordan-Brans-Dicke theory using a vector field instead of a scalar field and theory becomes similar to a simple Einstein-aether theory. The time…
The LCDM model has been presented with a number of cosmic tensions in the face of precision cosmological data, suggesting the presence of a dynamical dark energy component. In this context, we investigate the cosmology arising from a…
In brane-world models with low tension, massive branons are natural candidates for dark matter. The phenomenology of these WIMP-like particles is completely determined by their mass, the brane tension and, in the case of effects due to…
In this manuscript, we present a novel dark energy model to study the nature of dark energy. Non-extensive Kaniadakis entropy and, timescale as infrared cutoff are the major tools of the current study. Age of the Universe will serve the…
By using the holographic hypothesis and Kaniadakis generalized entropy, which is based on relativistic statistical theory and modified Boltzmann-Gibbs entrory, we build Kaniadakis holographic dark energy (DE) model in the Brans-Dicke…