Transient cosmic acceleration from interacting fluids

TL;DR

This paper explores a model where dark sector interactions cause a temporary cosmic acceleration, suggesting the universe's accelerated expansion might be a transient phase rather than eternal.

Contribution

It introduces a toy model with a time-dependent dark sector coupling that can produce transient acceleration, supported by statistical analysis of supernova data.

Findings

Transient acceleration can arise from dark sector interactions.

Supernova data supports the possibility of a temporary acceleration phase.

The model cancels the bare cosmological constant through interaction effects.

Abstract

Recent investigations seem to favor a cosmological dynamics according to which the accelerated expansion of the Universe may have already peaked and is now slowing down again \cite{sastaro}. As a consequence, the cosmic acceleration may be a transient phenomenon. We investigate a toy model that reproduces such a background behavior as the result of a time-dependent coupling in the dark sector which implies a cancelation of the "bare" cosmological constant. With the help of a statistical analysis of Supernova Type Ia (SNIa) data we demonstrate that for a certain parameter combination a transient accelerating phase emerges as a pure interaction effect.