相关论文: Evolution of energy, momentum, and spin parameter …
The evolution of the dark energy parameter within the scope of a spatially homogeneous and isotropic Friedmann-Robertson-Walker (FRW) model filled with perfect fluid and dark energy components is studied by generalizing the recent results…
Recent observational evidences of accelerating phase of the universe strongly demand that the dominating matter in the universe is in the form of dark energy. In this work, we study the evolution of the apparent and event horizons for…
Decaying Dark Energy models modify the background evolution of the most common observables, such as the Hubble function, the luminosity distance and the Cosmic Microwave Background temperature-redshift scaling relation. We use the most…
We study pilgrim dark energy model by taking IR cut-offs as particle and event horizons as well as conformal age of the universe. We derive evolution equations for fractional energy density and equation of state parameters for pilgrim dark…
We discuss an interacting dark sector model featuring decaying vacuum energy and dark matter empowered by gravitationally induced matter creation. Motivated by quantum field theoretic considerations of vacuum decay and adiabatic particle…
We study the coupled dark energy model constructed from the general conformal transformation in which the coefficient of the conformal transformation depends on both the scalar field and its kinetic term. Under this conformal…
We study dark energy cosmological models, extensions of the standard model of particles, characterized by having an extra relativistic energy density at very early times, and that rapidly dilute after a phase transition occurs. These models…
The evolution of a flat, isotropic and homogeneous universe is studied. The background geometry in the early phases of the universe is conjectured to be filled with causal bulk viscous cosmological fluid and dark energy. The energy density…
In an expanding universe the vacuum energy density \rho_{\Lambda} is expected to be a dynamical quantity. In quantum field theory in curved space-time \rho_{\Lambda} should exhibit a slow evolution, determined by the expansion rate of the…
We solve analytically and numerically the generalized Einstein equations in scalar-tensor cosmologies to obtain the evolution of dark energy and matter linear perturbations. We compare our results with the corresponding results for…
The effective evolution of an inhomogeneous universe model in any theory of gravitation may be described in terms of spatially averaged variables. In Einstein's theory, restricting attention to scalar variables, this evolution can be…
We investigate in this paper the cosmological evolution of a dark energy model with two scalar fields where one of the scalar has canonical kinetic energy and another scalar has negative kinetic energy term. For such a system with…
Without relying on a spherical or ellipsoidal collapse model, we analytically derive the halo mass function and cuspy halo density (inner slope of -4/3) based on the mass and energy cascade theory in dark matter flow. The hierarchical halo…
We derive a model of dark energy which evolves with time via the scale factor. The equation of state $\omega=(1-2\alpha)/(1+2\alpha)$ is studied as a function of a parameter $\alpha$ introduced in this model. In addition to the recent…
We propose a new explanation for the origin of angular momentum in galaxies and their dark halos, in which the halos obtain their spin through the cumulative acquisition of angular momentum from satellite accretion. In our model, the…
We study the dynamics of expansion of the homogeneous isotropic Universe and the evolution of its components in the model with nonminimally coupled dynamical dark energy. Dark energy, like the other components of the Universe, is described…
We present the results of a series of N-body simulations in cosmologies where dark matter (DM) is coupled to dark energy (DE), so easing the cosmic coincidence problem. The dark-dark coupling introduces two novel effects in N-body dynamics:…
Recently, Valiviita et al. (2008) have reported a large-scale early-time instability in coupled dark energy and dark matter models. We take the same form of energy-momentum exchange and specialise to the case when the interaction rate is…
In order to depict the transition from deceleration to acceleration expansion of the universe we use a power-law expansion scale factor, $a\sim t^{n_0+bt^m}$, with $n_0$, $b$ and $m$ three parameters determined by $H_0$, $q_0$ and $z_T$.…
We formulate power-law holographic dark energy, which is a modified holographic dark energy model based on the extended entropy relation arising from the consideration of state mixing between the ground and the excited ones in the…