Holographic Ricci DE as running vacuum with nonlinear interactions

TL;DR

This paper investigates a holographic Ricci dark energy model as a running vacuum with nonlinear dark sector interactions, constrained by observational data, revealing a transition from deceleration to acceleration and a quintessence-like behavior.

Contribution

It introduces three analytically feasible nonlinear interaction forms in the holographic Ricci dark energy model and constrains them with observational data, highlighting their distinct cosmic evolution features.

Findings

Model predicts transition from deceleration to acceleration.

Universe evolves from matter domination to stable de Sitter phase.

Model exhibits quintessence-like behavior, different from ΛCDM.

Abstract

The holographic Ricci dark energy can be treated as a running vacuum due to its analogy in the energy density, which is a combination of $H$ and $\dot H$, the model can predict either eternal acceleration or eternal deceleration. In the earlier works, we have shown that the presence of additive constant in the energy density or by considering possible interaction between dark sectors through a phenomenological term, the model can predict a transition from a prior decelerated to a late accelerated epoch. This paper analyses the cosmic evolution of holographic Ricci dark energy as a running vacuum with a nonlinear interaction between dark sectors in a flat FLRW universe. We consider three possible nonlinear interaction forms which give analytically feasible solutions. We have constrained the model using the Type1a Supernova(Pantheon)+CMB(Planck 2018)+BAO(SDSS) data and evaluated the best-estimated values of all the model parameters. We have analyzed the evolution of the Hubble parameter and deceleration parameter of all three cases. We perform state finder analysis of the model, which implies the quintessence nature of the model and found that it is distinguishably different from the standard $\Lambda$CDM model. The dynamical system analysis of all three cases confirms the evolution of the universe from an unstable prior matter-dominated era to a stable end de Sitter phase.