Novel approach toward the large-scale stable interacting dark-energy models and their astronomical bounds

Abstract

Stability analysis of interacting dark-energy models generally divides its parameters space into two regions, (i) w x ≥ −1 and ξ ≥ 0 and (ii) w x ≤ −1 and ξ ≤ 0, where w x is the dark-energy equation of state and ξ is the coupling strength of the interaction. Because of this separation, crucial information about the cosmology and phenomenology of these models may be lost. In a recent study, it has been shown that one can unify the two regions with a coupling function that depends on the dark-energy equation of state. In this work, we introduce a new coupling function that also unifies the two regions of the parameter space and generalizes the previous proposal. We analyze this scenario considering the equation of state of dark energy to be either constant or dynamical. We study the cosmology of such models and constrain both scenarios with the use of the latest astronomical data from both the background evolution as well as large-scale structures. Our analysis shows that a nonzero value of the coupling parameter ξ as well as the dark-energy equation of state other than −1 are allowed. However, within 1σ confidence level, ξ ¼ 0 and the darkenergy equation of state equal to −1 are compatible with the current data. In other words, the observational data allow a very small but nonzero deviation from the Λ cosmology; however, within the 1σ confidence region, the interacting models can mimic the Λ cosmology. In fact, we observe that the models both at the background and perturbative levels are very hard to distinguish from each other and from Λ cosmology as well. Finally, we offer a rigorous analysis on the current tension on H 0 , allowing different regions of the dark-energy equation of state, which shows that interacting dark-energy models reasonably solve the current tension on H 0 .

All-inclusive interacting dark sector cosmologies

“…It is important to mention that the division of the parameter space into (ξ < 0, w x < −1) or (ξ > 0, w x > −1) is motivated from the doom factor analysis [14]. Following the notation of [26,27,40], the doom factor d is defined as…”

“…We refer to Refs. [27,31,34,40,41] for details concerning the linear perturbation theory within these coupled cosmologies.…”

Dark calling dark: interaction in the dark sector in presence of neutrino properties after Planck CMB final release

“…It has been found that the presence of an interaction in the dark sector could successfully reconcile the long lasting cosmic coincidence problem [3,4,5,6,7]. Following this, a number of investigations in the context of interacting DE -DM models were performed by many investigators [8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43] (also see two review articles in this direction [44,45]). An interesting outcome from the interaction is that, it could naturally explain the phantom dark energy equation-ofstate [46,47,48,49].…”

Dawn of the dark: unified dark sectors and the EDGES Cosmic Dawn 21-cm signal

“…[48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63]). Although within most dark sector models the two dark components do not interact, an interesting class of cosmological models (usually referred to as coupled DE) feature interactions between DM and DE (see for example [64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96]). While we cannot do justice to the enormous literature on dark sector models, it is clear from the discussion so far that there is no shortage o...…”