Bulk viscosity, interaction and the viability of phantom solutions

Abstract

We study the dynamics of a bulk viscosity model in the Eckart approach for a spatially flat Friedmann-Robertson-Walker (FRW) universe. We have included radiation and dark energy, assumed as perfect fluids, and dark matter treated as an imperfect fluid having bulk viscosity. We also introduce an interaction term between the dark matter and dark energy components. Considering that the bulk viscosity is proportional to the dark matter energy density and imposing a complete cosmological dynamics, we find bounds on the bulk viscosity in order to reproduce a matter-dominated era (MDE). This constraint is independent of the interaction term. Some late time phantom solutions are mathematically possible. However, the constraint imposed by a MDE restricts the interaction parameter, in the phantom solutions, to a region consistent with a null value, eliminating the possibility of late time stable solutions with $w<-1$. From the different cases that we study, the only possible scenario, with bulk viscosity and interaction term, belongs to the quintessence region. In this latter case, we find bounds on the interaction parameter compatible with latest observational data.

8 pages, 5 figures

References in corpus (16)

• Dynamics of dark energy
• Dark Matter and Dark Energy Interactions: Theoretical Challenges, Cosmological Implications and Observational Signatures
• Indications of a late-time interaction in the dark sector
• Dynamics of interacting dark energy
• Does Bulk Viscosity Create a Viable Unified Dark Matter Model?
• Dark Interactions and Cosmological Fine-Tuning
• Can a matter-dominated model with constant bulk viscosity drive the accelerated expansion of the universe?
• Dissipation of dark matter
• Cosmological bounds on the equation of state of dark matter
• Constraints on dark-matter properties from large-scale structure
• Stability analysis for the background equations for inflation with dissipation and in a viscous radiation bath
• Structure formation in a $\Lambda$ $viscous$ CDM universe
• Nonlinear bulk viscosity and the stability of accelerated expansion in FRW spacetime
• Warm-Intermediate Inflationary Universe Model with Viscous Pressure in High Dissipative Regime
• No stable dissipative phantom scenario in the framework of a complete cosmological dynamics
• Dark matter perturbations and viscosity: a causal approach

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• Constraining Temporal Oscillations of Cosmological Parameters Using Type Ia Supernovae
• Phase space analysis of a FRW cosmology in the Maxwell$-$Cattaneo approach