Mass Power Spectrum in a Universe Dominated by the Chaplygin Gas
نویسنده
چکیده
The mass power spectrum for a Universe dominated by the Chaplygin gas is evaluated numerically from scales of the order of the Hubble horizon to 100 Mpc. The results are compared with a pure baryonic Universe and a cosmological constant model. In all three cases, the spectrum increases with k, the wavenumber of the perturbations. The slope of the spectrum is higher for the baryonic model and smaller for the cosmological constant model, the Chaplygin gas interpolating these two models. The results are analyzed in terms of the sound velocity of the Chaplygin gas and the moment the Universe begins to accelerate. PACS number(s): 98.80.Bp, 98.65.Dx
منابع مشابه
Irreversible processes in a Universe modelled as a mixture of a Chaplygin gas and radiation
The evolution of a Universe modelled as a mixture of a Chaplygin gas and radiation is determined by taking into account irreversible processes. This mixture could interpolate periods of a radiation dominated, a matter dominated and a cosmological constant dominated Universe. The results of a Universe modelled by this mixture are compared with the results of a mixture whose constituents are radi...
متن کاملDensity Perturbations in an Universe Dominated by the Chaplygin Gas
We study the fate of density perturbations in an Universe dominate by the Chaplygin gas, which exhibit negative pressure. We show that it is possible to obtain the value for the density contrast observed in large scale structure of the Universe by fixing a free parameter in the equation of state of this gas. The negative character of pressure must be significant only very recently. PACS number(...
متن کاملPower spectrum in the Chaplygin gas model: tachyonic, fluid and scalar field representations
The Chaplygin gas model, characterized by an equation of state of the type p = − ρ emerges naturally from the Nambu-Goto action of string theory. This fluid representation can be recast under the form of a tachyonic field given by a Born-Infeld type Lagrangian. At the same time, the Chaplygin gas equation of state can be obtained from a self-interacting scalar field. We show that, from the poin...
متن کاملN ov 2 00 7 Interacting generalized Chaplygin gas model in non - flat universe
We employ the generalized Chaplygin gas of interacting dark energy to obtain the equation of state for the generalized Chaplygin gas energy density in non-flat universe. By choosing a negative value for B we see that w ef f Λ < −1, that corresponds to a universe dominated by phantom dark energy.
متن کاملNew Results in Chaplygin Gas Cosmology
We provide a rigorous derivation of the evolution equation in the context of Chaplygin gas cosmology, in which the relativistic formulation of Chaplygin matter is a crucial ingredient. This is in contrast to the existing literature where the non-relativistic form of the Chaplygin equation of state is naively used in the covariant Einsstein equation. Our results show that the Chaplygin model des...
متن کامل