Is the accelerated expansion evidence of a forthcoming change of signature on the brane?

TL;DR

This paper proposes that a change in the signature of the brane-world universe could explain sudden singularities and the observed accelerated expansion, suggesting a transition from Lorentzian to Euclidean signature without singularities.

Contribution

It introduces a model where signature change on branes accounts for sudden singularities, maintaining regularity in both brane and bulk, with energy conditions satisfied.

Findings

Signature change can mimic sudden singularities.

The universe's accelerated expansion may indicate a signature transition.

Energy conditions remain valid despite the signature change.

Abstract

We show that regular changes of signature on brane-worlds in AdS bulks may account for some types of the recently fashionable sudden singularities. Therefore, the possibility that the Universe seems to approach a future sudden singularity at an accelerated rate of expansion might simply be an indication that our braneworld is about to change from Lorentzian to Euclidean signature. Both the brane and the bulk remain fully regular everywhere. We present a model in which the weak and strong energy conditions hold on the brane, in contrast with the standard cosmologies leading to the analogous kinematical behaviour (that is, with a diverging Hubble factor).