HoloSPLE: Nothing is certain in string compactifications

A bubble of nothing is a spacetime instability where a compact dimensioncollapses. After nucleation, it expands at the speed of light, leaving “nothing” behind. Weargue that the topological and dynamical mechanisms which could protect a compactificationagainst decay to nothing seem to be absent in string compactifications once supersymmetryis broken. The topological obstruction lies in a bordism group and, surprisingly, it candisappear even for a SUSY-compatible spin structure. As a proof of principle, we constructan explicit bubble of nothing for a T3 with completely periodic (SUSY-compatible) spinstructure in an Einstein dilaton Gauss-Bonnet theory, which arises in the low-energy limitof certain heterotic and type II flux compactifications. Without the topological protection,supersymmetric compactifications are purely stabilized by a Coleman-deLuccia mechanism,which relies on a certain local energy condition. This is violated in our example by thenonsupersymmetric GB term. In the presence of fluxes this energy condition gets modifiedand its violation might be related to the Weak Gravity Conjecture.

We expect that our techniques can be used to construct a plethora of new bubbles ofnothing in any setup where the low-energy bordism group vanishes, including type II compact-ifications onCY3, AdS flux compactifications on 5-manifolds, and M-theory on 7-manifolds.This lends further evidence to the conjecture that any non-supersymmetric vacuum of quan-tum gravity is ultimately unstable.

https://arxiv.org/pdf/2005.06494.pdf