Dark energy and the future fate of the Universe

TL;DR

This paper examines the potential for observing the universe's late-time inflation onset using various dark energy models, finding that current observations are insufficient to confirm inflation and estimating when it might become observable.

Contribution

It applies Hubble size and event horizon criteria to multiple dark energy models to predict the future observability of cosmic inflation onset.

Findings

Current observations cannot confirm inflation onset in tested models.

Estimated scale factors at inflation onset vary across models.

Different criteria yield different waiting times for inflation observability.

Abstract

We consider the possibility of observing the onset of the late time inflation of our patch of the Universe. The Hubble size criterion and the event horizon criterion are applied to several dark energy models to discuss the problem of future inflation of the Universe. We find that the acceleration has not lasted long enough to confirm the onset of inflation by present observations for the dark energy model with constant equation of state, the holographic dark energy model and the generalized Chaplygin gas (GCG) model. For the flat $\Lambda$CDM model with $\Omega_{m0}=0.3$, we find that if we use the Hubble size criterion, we need to wait until the $a_v$ which is the scale factor at the time when the onset of inflation is observed reaches 3.59 times of the scale factor $a_T$ when the Universe started acceleration, and we need to wait until $a_v=2.3 a_T$ to see the onset of inflation if we use the event horizon criterion. For the flat holographic dark energy model with $d=1$, we find that $a_v=3.46 a_T$ with the Hubble horizon and $a_v=2.34 a_T$ with the event horizon, respectively. For the flat GCG model with the best supernova fitting parameter $\alpha=1.2$, we find that $a_v=5.50 a_T$ with the Hubble horizon and $a_v=2.08 a_T$ with the event horizon, respectively.