dS${}_4$ universe emergent from Kerr-AdS${}_5$ spacetime: bubble nucleation catalyzed by a black hole

TL;DR

This paper explores how a four-dimensional de Sitter universe can emerge on a bubble in five-dimensional Kerr-AdS spacetime, analyzing the effects of black hole rotation on bubble nucleation and transition rates.

Contribution

It extends previous models by studying vacuum bubble nucleation in Kerr-AdS${}_5$ spacetime, incorporating black hole rotation effects on the emergence of a dS${}_4$ universe.

Findings

Black holes influence the bubble nucleation process.

A quasi-dS${}_4$ universe can form without violating swampland conjectures.

Black hole rotation affects the transition rate of bubble nucleation.

Abstract

The emergence of a four-dimensional de Sitter (dS${}_4$) universe on an expanding bubble in the five-dimensional anti-de Sitter (AdS${}_5$) background has been suggested as a possible cosmological scenario. It is motivated by the difficulties in the realization of a stable de Sitter vacua in string theory. The bubble can be nucleated in a meta-stable pure AdS${}_5$ spacetime, but it is known that a pure AdS spacetime is non-perturbatively unstable. It means that the pure AdS${}_5$ background is an idealized situation, and in realistic situations, non-linear perturbations in AdS may lead to the formation of black holes due to the gravitational turbulent instability. To investigate how the proposed scenario works in a more realistic situation, we here study the nucleation process of a vacuum bubble in the Kerr-AdS${}_5$ spacetime. Especially we investigate conditions sufficient to ensure the nucleation of a vacuum bubble with a rotating black hole and how the black hole affects the transition rate. We find that even in the Kerr-AdS${}_5$ spacetime, a quasi-dS${}_4$ expansion can be realized on the nucleated vacuum bubble without contradicting the de Sitter swampland conjectures.