APS Instability and the Topology of the Brane-World

TL;DR

This paper explores how the topology of the universe in brane-world cosmology might be constrained by instabilities in the bulk, particularly through the Adams-Polchinski-Silverstein conjecture, ruling out certain topologies.

Contribution

It links bulk instabilities to constraints on the universe's topology within the brane-world framework, based on the APS conjecture.

Findings

Many possible accelerating universe topologies are unstable.

Non-supersymmetric AdS orbifolds exhibit non-perturbative instabilities.

The APS conjecture supports topology constraints in brane-world cosmology.

Abstract

As is well known, classical General Relativity does not constrain the topology of the spatial sections of our Universe. However, the Brane-World approach to cosmology might be expected to do so, since in general any modification of the topology of the brane must be reflected in some modification of that of the bulk. Assuming the truth of the Adams-Polchinski-Silverstein conjecture on the instability of non-supersymmetric AdS orbifolds, evidence for which has recently been accumulating, we argue that indeed many possible topologies for accelerating universes can be ruled out because they lead to non-perturbative instabilities.