The approach of the three interacting fluids applied to the cosmological constant problem

TL;DR

This paper proposes a three-fluid cosmological model interacting to address the cosmological constant problem, fitting observational data and alleviating key cosmological issues like coincidence and age crises.

Contribution

It introduces a novel three-fluid interaction model that reproduces $\\Lambda$CDM behavior while providing insights into vacuum energy evolution and the cosmological constant problem.

Findings

Best-fit parameters: H_0=74.06 km/s/Mpc, q_0=-0.78, z_{acc}=0.75

Model aligns with observational data and alleviates coincidence and age problems

Statefinder analysis shows differences from standard $\\Lambda$CDM due to vacuum energy evolution

Abstract

We present a cosmological model constituted by three perfect fluids, cold dark matter, vacuum energy and radiation, which interacting with each other lead to an equivalent model of three self-preserved fluids that can be identified with the $ \Lambda$CDM model plus a warm dark matter component. The effective energy densities expressed in terms of the global density of energy, its derivatives and interactions, with parameters adjusted with the observational data allow to show the evolution of the vacuum energy. This supports the difference in 120 orders of magnitude of the so-called problem of the cosmological constant and at the same time the strict limits on its density parameter at early times. The best fits parameters of the model, $ H_0= 74.06 $km/sMpc and $q_0=-0.78$, $z_{acc}=0.75$ are concordant with the bibliography and also allow the so-called problems of coincidence and the crisis of age to be alleviated. A geometric analysis performed with statefinders shows the difference with the $\Lambda$CDM model because of the evolution of the effective vacuum density of energy.