Bubble instability of mIIA on $\mathrm{AdS}_4\times S^6$

TL;DR

This paper investigates the stability of non-supersymmetric AdS4 vacua in massive IIA supergravity compactified on a six-sphere, revealing a non-perturbative bubble instability associated with D2 brane nucleation.

Contribution

It introduces a new bubbling solution indicating a non-perturbative instability of the G2 invariant vacuum, extending to nearly-Kähler manifolds.

Findings

Identified a bubble of nothing instability in the G2 vacuum.

Extended the instability analysis to nearly-Kähler manifolds.

Demonstrated the instability involves D2 brane charge nucleation.

Abstract

We consider compactifications of massive IIA supergravity on a six-sphere. This setup is known to give rise to non-supersymmetric AdS$_4$ vacua preserving SO$(7)$ as well as G$_2$ residual symmetry. Both solutions have a round $S^6$ metric and are supported by the Romans' mass and internal $F_6$ flux. While the SO$(7)$ invariant vacuum is known to be perturbatively unstable, the G$_2$ invariant one has been found to have a fully stable Kaluza-Klein spectrum. Moreover, it has been shown to be protected against brane-jet instabilities. Motivated by these results, we study possible bubbling solutions connected to the G$_2$ vacuum, representing non-perturbative instabilities of the latter. We indeed find an instability channel represented by the nucleation of a bubble of nothing dressed up with a homogeneous D2 brane charge distribution in the internal space. Our solution generalizes to the case where $S^6$ is replaced by any six-dimensional nearly-K\"ahler manifold.