Exploring the cosmological degeneracy between decaying dark matter model and viscous $\Lambda$CDM

Abstract

In the context of a homogeneous and isotropic universe, we consider the degeneracy condition at the background level between two scenarios in which processes out of equilibrium are possible; this consideration allows us to deviate from the perfect fluid description, and in this case bulk viscosity represents a viable candidate to describe entirely such effects. The cosmological model describing an unstable dark matter sector is mapped into a slight modification of the $\Lambda$CDM model characterized by a viscous dark matter sector; under this consideration our description does not depend on a specific formulation of viscous effects and these can be fully reconstructed and characterized by the parameter that determines the decay ratio of dark matter. However, in this new scenario the cosmic expansion is influenced by the viscous pressure and the dark energy sector given by the cosmological constant is translated into a dynamical one. As a consequence of our formulation, the test against observations of the model indicates consistency with quintessence dark energy, but the crossing of the phantom divide can be accessible.

13 pages, 6 figures. Published version in EPJC

References in corpus (31)

• The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: cosmological analysis of the DR12 galaxy sample
• The Case for a Positive Cosmological Lambda-term
• A 6% measurement of the Hubble parameter at $z\sim 0.45$: direct evidence of the epoch of cosmic re-acceleration
• The Pantheon+ Analysis: The Full Dataset and Light-Curve Release
• Everything You Always Wanted To Know About The Cosmological Constant Problem (But Were Afraid To Ask)
• Inhomogeneous Equation of State of the Universe: Phantom Era, Future Singularity and Crossing the Phantom Barrier
• Cosmological Non-Linearities as an Effective Fluid
• Dark Matter and Dark Energy Interactions: Theoretical Challenges, Cosmological Implications and Observational Signatures
• Gravitational Waves from Primordial Black Hole Mergers
• The Little Rip
• Viscous Little Rip Cosmology
• Constraints on the sum of the neutrino masses in dynamical dark energy models with $w(z)\ge -1$ are tighter than those obtained in $\Lambda$CDM
• A fresh look at linear cosmological constraints on a decaying dark matter component
• Late universe decaying dark matter can relieve the H_0 tension
• Converting non-relativistic dark matter to radiation
• Alleviating the $H_0$ and ${\sigma }_8$ anomalies with a decaying dark matter model
• Matter creation and cosmic acceleration
• Causality of the Einstein-Israel-Stewart Theory with Bulk Viscosity
• WMAP Constraints on Decaying Cold Dark Matter
• Decay of cosmological constant as Bose condensate evaporation
• Phantom behavior via cosmological creation of particles
• The Dark Matter equation of state through cosmic history
• Dark energy, matter creation and curvature
• Do observations prove that cosmological neutrinos are thermally distributed?
• Phantom dark energy as an effect of bulk viscosity
• An extensive investigation of the Generalised Dark Matter model
• Origin of Delta N_eff as a Result of an Interaction between Dark Radiation and Dark Matter
• The quantum realm of the "Little Sibling" of the Big Rip singularity
• Variable Cosmological Constant model: the reconstruction equations and constraints from current observational data
• Challenging matter creation models in the phantom divide
• Cosmic acceleration from first principles

Cited by in corpus (1)

• Thermodynamics of an universe with Decaying Cold Dark Matter