Transdimensional Tunneling in the Multiverse

TL;DR

This paper explores topology-changing transitions between different vacua in a 6-dimensional Einstein-Maxwell theory, revealing mechanisms involving black hole and black brane nucleation that enable dimensional and topological shifts in the multiverse landscape.

Contribution

It introduces a detailed analysis of topology-changing transitions in a 6D Einstein-Maxwell landscape, identifying specific instantons and nucleation processes for different vacuum transitions.

Findings

Transitions occur via black hole pair nucleation for compactification changes.

Black brane nucleation mediates transitions between de Sitter and product vacua.

The spacetime structures resulting from brane nucleation are characterized.

Abstract

Topology-changing transitions between vacua of different effective dimensionality are studied in the context of a 6-dimensional Einstein-Maxwell theory. The landscape of this theory includes a $6d$ de Sitter vacuum ($dS_6$), a number of $dS_4 \times S_2$ and $AdS_4 \times S_2$ vacua, and a number of $AdS_2 \times S_4$ vacua. We find that compactification transitions $dS_6 \to AdS_2 \times S_4$ occur through the nucleation of electrically charged black hole pairs, and transitions from $dS_6$ to $dS_4 \times S_2$ and $AdS_4 \times S_2$ occur through the nucleation of magnetically charged spherical black branes. We identify the appropriate instantons and describe the spacetime structure resulting from brane nucleation.