Related papers: Quintessence in a Brane World
We study the cosmological evolution of scalar fields that arise from a phase transition at some energy scale $\Lm_c$. We focus on negative power potentials given by $V=c\Lm_c^{4+n}\phi^{-n}$ and restrict the cosmological viable values of…
New constraints on the expansion rate of the Universe seem to favor evolving dark energy in the form of thawing quintessence models, i.e., models for which a canonical, minimally coupled scalar field has, at late times, begun to evolve away…
We examine dark energy models in which a quintessence or a phantom field, $\phi$, rolls near the vicinity of a local minimum or maximum, respectively, of its potential $V(\phi)$. Under the approximation that $(1/V)(dV/d\phi) \ll 1$,…
Braneworld models remain the most promising candidates to address several important questions in low-energy particle phenomenology and cosmology. The role of the moduli field(s) and its stabilization is an integral part of this question. In…
We revisit the idea of self-tuning the observed cosmological constant to a vanishing value and promote it to a selection criterion of brane-world models, in which our Universe is described by a 3-brane embedded in a 5d bulk. As a concrete…
Two co-dimensional thick brane-worlds are investigated in quite general terms for two intersecting scalar fields generating the extra dimension defect. In general, when one considers two co-dimensional thick brane-worlds, the warp factor is…
In this work we investigate the evolution of matter density perturbations for quintessence models with a self-interaction potential that is a combination of exponentials. One of the models is based on the Einstein theory of gravity, while…
Quintessence models have been widely examined in the context of scalar-Gauss-Bonnet gravity, a subclass of Horndeski's theory, and were proposed as viable candidates for Dark Energy. However, the relatively recent observational constraints…
Although quintessence cosmologies seem to explain the amount of cosmological constant today, the required conditions are severe. For example, an extremely slowly varying and light scalar field that rolls toward the vanishing vacuum energy…
Higher-dimensional braneworld models which contain both bulk and brane curvature terms in the action admit cosmological singularities of rather unusual form and nature. These `quiescent' singularities, which can occur both during the…
Within present constraints on the observed smooth energy and its equation of state parameter, it is important to find out whether the smooth energy is static (cosmological constant) or dynamic (quintessence). The most dynamical quintessence…
Combinations of recent cosmological observations, including Dark Energy Spectroscopic Instrument (DESI), show hints of a dynamical nature for dark energy. While the data suggest the possibility of the phantom crossing, it is worth…
In this work we investigate the evolution of matter density perturbations for two different quintessence models. One of them is based on the Einstein theory of gravity, while the other is based on the Brans-Dicke scalar tensor theory. We…
A model of an emergent universe is obtained in brane world. Here the bulk energy is in the form of cosmological constant, while the brane consists of the Chaplygin gas with the modified equation of state such as $p=A\rho-B/\rho$. Initially…
The time variation of the equation of state $w$ for quintessence scenario with a scalar field as dark energy is studied up to the third derivative ($d^3w/da^3$) with respect to the scale factor $a$, in order to predict the future…
In the study of three-brane cosmological models, an unusual law of cosmological expansion on the brane has been reported. According to this law, the energy density of matter on the brane quadratically enters the right-hand side of the new…
In this work we deal with the presence of braneworld solutions in a five-dimensional space-time with a single extra spatial dimension of infinite extent. The braneworld scenario is built under the presence of a single real scalar field, and…
The braneworld cosmology, in which our universe is imbedded as a hypersurface in a higher dimensional bulk, has the peculiar property that the inflationary consistency relation derived in a four-dimensional cosmology persists. This…
In this work we propose a simple general parametrization scheme of the Hubble parameter for the scalar field dark energy models. In our approach it is possible to incorporate both the quintessence and phantom scalar field in a single…
We study the dynamical equations for extra-dimensional dependence of a warp factor and a bulk scalar in 5d brane world scenarios with induced brane metric of constant curvature. These equations are similar to those for the time dependence…