Linear and non-Linear Instabilities in Unified Dark Energy Models

Abstract

We revisit the paradigm of unified dark energy discussing in detail the averaging problem in this type of scenarios, highlighting the need for a full non-linear treatment. We also address the question of if and how models with one or several dark fluids can be observationally distinguished. Simpler and physically clearer derivations of some key results, most notably on the relation between the generalized Chaplygin gas and the standard ($\Lambda$CDM) `concordance' model and on a Jeans-type small-scale instability of some coupled dark energy/dark matter models are presented.

6 pages, accepted for publication in Physical Review D

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Cited by in corpus (29)

• Interacting Dark Energy -- constraints and degeneracies
• The dark degeneracy and interacting cosmic components
• Revisiting Generalized Chaplygin Gas as a Unified Dark Matter and Dark Energy Model
• Shear and rotation in Chaplygin cosmology
• Nonlinear Chaplygin Gas Cosmologies
• Cosmological tachyon condensation
• Does Chaplygin gas have salvation?
• Unified Dark Fluid with Constant Adiabatic Sound Speed and Cosmic Constraints
• An entirely analytical cosmological model
• Non-linear dark energy clustering
• Clustering Properties of Dynamical Dark Energy Models
• Unified Dark Fluid with Constant Adiabatic Sound Speed: Including Entropic Perturbations
• Effective dark energy equation of state in interacting dark energy models
• Spherical `Top-Hat' Collapse in general Chaplygin gas dominated universes
• Lagrangian description of cosmic fluids: mapping dark energy into unified dark energy
• Power spectrum in the Chaplygin gas model: tachyonic, fluid and scalar field representations
• Constraints on the dark matter sound speed from galactic scales: the cases of the Modified and Extended Chaplygin Gas
• Scalar field-perfect fluid correspondence and nonlinear perturbation equations
• Stable Large-Scale Perturbations in Interacting Dark-Energy Model
• Spherical collapse for unified dark matter models
• Neutrino Dark Energy With More Than One Neutrino Species
• Is $w\ne -1$ evidence for a dynamical dark energy equation of state ?
• Spherical top-hat Collapse of a Viscous Unified Dark Fluid
• Relations between the modified Chaplygin gas and a scalar field
• Scalar and vector perturbations in a universe with nonlinear perfect fluid
• Assessing the viability of successful reconstruction of the dynamics of dark energy using varying fundamental couplings
• Interacting Dark Energy and Its Implications for Unified Dark Sector
• Dynamical friction shear and rotation in Chaplygin cosmology
• Halos of dark energy