On the equivalence of Lambda(t) and gravitationally induced particle production cosmologies

TL;DR

This paper demonstrates the theoretical equivalence between Lambda(t) cosmologies and gravitationally induced particle production models, showing they can produce similar dynamics and thermodynamics, and tests their observational viability with current data.

Contribution

It establishes a formal correspondence between Lambda(t) and particle production cosmologies, providing specific models and observational analysis to support their equivalence.

Findings

Both models can exhibit identical dynamic and thermodynamic behavior under certain conditions.

Current observational data can be fitted by both classes of models with comparable statistical support.

Particle production models can be interpreted as a unification of the dark sector in cosmology.

Abstract

The correspondence between cosmological models powered by a decaying vacuum energy density and gravitationally induced particle production is investigated. Although being physically different in the physics behind them we show that both classes of cosmologies under certain conditions can exhibit the same dynamic and thermodynamic behavior. Our method is applied to obtain three specific models that may be described either as Lambda(t)CDM or gravitationally induced particle creation cosmologies. In the point of view of particle production models, the later class of cosmologies can be interpreted as a kind of one-component unification of the dark sector. By using current type Ia supernovae data, recent estimates of the cosmic microwave background shift parameter and baryon acoustic oscillations measurements we also perform a statistical analysis to test the observational viability within the two equivalent classes of models and we obtain the best-fit of the free parameters. By adopting the Akaike information criterion we also determine the rank of the models considered here. Finally, the particle production cosmologies (and the associated decaying Lambda(t)-models) are modeled in the framework of field theory by a phenomenological scalar field model.