Do current observations support transient acceleration of our universe?

TL;DR

This paper investigates whether current observations support the possibility of the universe transitioning from acceleration to deceleration in the future, using matter creation theory, cosmography, and various models, but finds no strong evidence for such a transition.

Contribution

It introduces a cosmographic approach combined with matter creation theory to assess future deceleration, analyzing observational bounds across multiple models.

Findings

Future deceleration depends on model choice and data

No strong evidence currently supports future deceleration

Observational data are inconclusive about the universe's fate

Abstract

In the present article we have investigated a very natural question regarding the dynamics of the universe, namely, the possibility of its decelerating phase immediately after the present accelerating phase. To begin with, we have focused on the matter creation theory which is considered to be a viable alternative to dark energy and modified gravity models. Moreover, we have introduced the cosmographic approach which allows us to express the free parameters of a cosmological model in terms of the known cosmographic parameters. Assuming a generalized matter creation rate we have discussed the theoretical bounds on the model parameters allowing the future deceleration of the universe. Moreover, using the observational bounds on the cosmographic parameters obtained from the low redshifts observational probes, we have also examined the chance of a decelerating phase of the universe. Finally, considering a variety of known cosmological models and parametrizations, we have tested the same possibility. Our analysis shows that the chance of a future decelerating expansion of the universe is highly dependent on the choice of the cosmological models and parametrizations and also on the observational data. Even though the future decelerating expansion is allowed in some cosmological frameworks, but we do not see any strong evidence in favor of this. Perhaps, the future cosmological surveys could offer some more information regarding the fate of the universe.