Related papers: Enlarged quintessence cosmology
It is proposed that dark energy may become dominant over standard matter due to universe expansion (curvature decrease). Two models: non-linear gravity-matter system and modified gravity may provide the effective phantom or effective…
Dynamical vacuum energy or quintessence, a slowly varying and spatially inhomogeneous component of the energy density with negative pressure, is currently consistent with the observational data. One potential difficulty with the idea of…
Expansion dynamics of the Universe is one of the important subjects in modern cosmology. The dark energy equation of state determines this dynamics so that the Universe is in an accelerating phase. However, the dark matter can also affect…
Recent observations indicate that the universe's expansion has been accelerating of late. But recent theoretical work has highlighted the difficulty of squaring acceleration with the underlying assumptions of string theory, disfavoring most…
Cosmological hysteresis, has interesting and vivid implications in the scenario of a cyclic bouncy universe. This, purely thermodynamical in nature, is caused by the asymmetry in the equation of state parameter during expansion and…
In light of the recent observations of type Ia supernovae suggesting an accelerating expansion of the Universe, we wish in this paper to point out the possibility of using a complex scalar field as the quintessence to account for the…
We propose a model to describe the late-time cosmic acceleration in the context of the constant-roll model. By considering a coupling between massive neutrinos and the quintessence, the onset of evolution of the quintessence is related to…
In a recent Letter [Phys. Rev. Lett. 114 091301 (2105)] the cause of the acceleration of the present Universe has been identified with the shear viscosity of an imperfect relativistic fluid even in the absence of any bulk viscous…
D-dimensional cosmological model describing the evolution of a perfect fluid with negative pressure (x-fluid) and a fluid possessing both shear and bulk viscosity in n Ricci-flat spaces is investigated. The second equations of state are…
Growing neutrino quintessence solves the coincidence problem for dark energy by a growing cosmological value of the neutrino mass which emerges from a cosmon-neutrino interaction stronger than gravity. The cosmon-mediated attraction between…
A component of dark energy has been recently proposed to explain the current acceleration of the Universe. Unless some unknown symmetry in Nature prevents or suppresses it, such a field may interact with the pressureless component of dark…
We study models of quintessence consisting of a number of scalar fields coupled to several dark matter components. In the case of exponential potentials the scaling solutions can be described in terms of a single field. The corresponding…
Recent cosmological observations reveal that we are living in a flat accelerated expanding universe. In this work we have investigated the nature of the potential compatible with the power law expansion of the universe in a self interacting…
Recent studies of Type Ia Supernovae with redshifts up to about $z~\laq~1$ reveal evidence for a cosmic acceleration in the expansion of the Universe. The most straightforward explanation to account for this acceleration is a cosmological…
In this work we have investigated the possibility of having a late time accelerated phase of the universe, suggested by recent supernova observation, in the context of Brans Dicke (BD) theory with a symmetry breaking potential and a matter…
The kinematics and dynamic interpretation of the cosmological expansion is reviewed in a widely accessible manner with emphasis on the acceleration aspect. Virtually all the approaches that can in principle account for the accelerated…
Recent cosmological and astrophysical observations point out that the Universe is in accelerating expansion and filled up with non-luminous matter. In order to explain the observed large scale structures and this accelerating behavior one…
In this paper we give a physical explanation to the accelerated expansion of the Universe, alleviating the tension between the discrepancy of Hubble constant measurements. By the Euler Cauchy stress principle, we identify a controversy on…
The increase in mass of our observed expansive and isotropic relativistic Universe in the present relativistic cosmology is explained by the extensive assumption of the matter objects emerging on the horizon (of the most remote visibility).…
Exact solutions for a model with variable $G$, $\Lambda$ and bulk viscosity are obtained. Inflationary solutions with constant (de Sitter-type) and variable energy density are found. An expanding anisotropic universe is found to isotropize…