More on the holographic Ricci dark energy model: smoothing Rips through interaction effects?

摘要

The background cosmological dynamics of the late Universe is analysed on theframework of a dark energy model described by an holographic Ricci dark energycomponent. Several kind of interactions between the dark energy and the darkmatter components are considered herein. We solve the background cosmologicaldynamics for the different choices of interactions with the aim to analyse notonly the current evolution of the universe but also its asymptotic behaviourand, in particular, possible future singularities removal. We show that in mostof the cases, the Big Rip singularity, a finger print of this model in absenceof an interaction between the dark sectors, is substituted by a de Sitter or aMinkowski state. Most importantly, we found two new {\textit{ future}} bouncingsolutions leading to two possible asymptotic behaviours, we named Little Bangand Little Sibling of the Big Bang. At a Little Bang, as the size of theuniverse shrinks to zero in an infinite cosmic time, the Hubble rate and itscosmic time derivative blow up. In addition, at a Little sibling of the BigBang, as the size of the universe shrinks to zero in an infinite cosmic time,the Hubble rate blows up but its cosmic time derivative is finite. These twoabrupt events can happen as well in the past.