Gravitationally influenced particle creation models and late-time cosmic acceleration

TL;DR

This paper investigates gravitationally influenced adiabatic particle creation models as an alternative explanation for the universe's late-time acceleration, without relying on dark energy or modified gravity, and tests their observational and thermodynamic viability.

Contribution

It introduces generalized particle creation models, constrains them with supernova data, and establishes conditions for their thermodynamic and cosmographic viability.

Findings

Models resemble $\\Lambda$CDM at late times

Models satisfy the generalized second law of thermodynamics

Constraints consistent with observational data

Abstract

In this work we focus on the gravitationally influenced adiabatic particle creation process, a mechanism that does not need any dark energy or modified gravity models to explain the current accelerating phase of the universe. Introducing some particle creation models that generalize some previous models in the literature, we constrain the cosmological scenarios using the latest compilation of the Type Ia Supernovae data only, the first indicator of the accelerating universe. Aside from the observational constraints on the models, we examine the models using two model independent diagnoses, namely the cosmography and $Om$. Further, we establish the general conditions to test the thermodynamic viabilities of any particle creation model. Our analysis shows that at late-time, the models have close resemblance to that of the $\Lambda$CDM cosmology, and the models always satisfy the generalized second law of thermodynamics under certain conditions.