Membranes in AdS4 orientifold vacua and their Weak Gravity Conjecture

Abstract

Abstract We study type IIA orientifold compactifications with fluxes that give rise to perturbatively stable, non-supersymmetric AdS4 vacua with D6-brane gauge sectors. Non-perturbative instabilities can be mediated by D8-branes wrapped on the six internal dimensions X6, if they reduce to 4d membranes with a charge Q larger than its tension T. The mismatch Q ≠ T arises due to i) curvature corrections and ii) the BIon backreaction of D6-branes wrapping 3-cycles of X6. We give a simple expression for the second effect in toroidal orientifolds, and find that only pairs of 3-cycles at SU(2) angles contribute to it. They either contribute towards Q > T or Q < T depending on the 3-cycles separation, allowing to engineer 4d $$ \mathcal{N} $$ N = 0 vacua in tension with the Weak Gravity Conjecture for membranes.