On a class of scaling FRW cosmological models

Abstract

We study Friedmann-Robertson-Walker cosmological models with matter content composed of two perfect fluids ${\rho }_1$ and ${\rho }_2$, with barotropic pressure densities $p_1/{\rho }_1={\omega }_1=const$ and $p_2/{\rho }_2={\omega }_2=const$, where one of the energy densities is given by ${\rho }_1=C_1{a}^{\alpha }+C_2{a}^{\beta }$, with $C_1$, $C_2$, $\alpha$ and $\beta$ taking constant values. We solve the field equations by using the conservation equation without breaking it into two interacting parts with the help of a coupling interacting term $Q$. Nevertheless, with the found solution may be associated an interacting term $Q$, and then a number of cosmological interacting models studied in the literature correspond to particular cases of our cosmological model. Specifically those models having constant coupling parameters $\tilde{\alpha }$, $\tilde{\beta }$ and interacting terms given by $Q=\tilde{\alpha }H{\rho }_{{}_{DM}}$, $Q=\tilde{\alpha }H{\rho }_{{}_{DE}}$, $Q=\tilde{\alpha }H({\rho }_{{}_{DM}}+{\rho }_{{}_{DE}})$ and $Q=\tilde{\alpha }H{\rho }_{{}_{DM}}+\tilde{\beta }H{\rho }_{{}_{DE}}$, where ${\rho }_{{}_{DM}}$ and ${\rho }_{{}_{DE}}$ are the energy densities of dark matter and dark energy respectively. The studied set of solutions contains a class of cosmological models presenting a scaling behavior at early and at late times. On the other hand the two-fluid cosmological models considered in this paper also permit a three fluid interpretation which is also discussed. In this reinterpretation, for flat Friedmann-Robertson-Walker cosmologies, the requirement of positivity of energy densities of the dark matter and dark energy components allows the state parameter of dark energy to be in the range $-1.37\lesssim {\omega }_{{}_{DE}}<-1/3$.

17 pages, 10 figures

References in corpus (18)

• Dynamics of dark energy
• Improved Cosmological Constraints from New, Old and Combined Supernova Datasets
• Can dark energy evolve to the Phantom?
• Probing the Coupling between Dark Components of the Universe
• Dynamics of dark energy with a coupling to dark matter
• Consequences of dark matter-dark energy interaction on cosmological parameters derived from SNIa data
• Cosmologies with Energy Exchange
• Effects of the interaction between dark energy and dark matter on cosmological parameters
• Le Chatelier-Braun principle in cosmological physics
• Interacting Dark Energy and Dark Matter: observational Constraints from Cosmological Parameters
• Crossing of the phantom divide in modified gravity
• Dark Energy Model with Spinor Matter and Its Quintom Scenario
• Can a matter-dominated model with constant bulk viscosity drive the accelerated expansion of the universe?
• Interacting Dark Energy with Inhomogeneous Equation of State
• The Ups and Downs of Cyclic Universes
• Interacting cosmic fluids in power-law Friedmann-Robertson-Walker cosmological models
• Statefinder parameters in two dark energy models
• Tachyon field inspired dark energy and supernovae constraints

Cited by in corpus (1)

• Particle Production Scenario in an Algebraically Coupled Quintessence Field with a Dark Matter Fluid