Almost contact structures on manifolds with a $G_2$ structure

Abstract

We review the construction of almost contact metric (three-) structures on manifolds with a G2 structure. These are of interest for certain supersymmetric configurations in string and M-theory. We compute the torsion of the SU(3) structure associated to an ACMS and apply these computations to heterotic G2 systems and supersymmetry enhancement. We initiate the study of the space of ACM3Ss, which is an infinite dimensional space with a local product structure and interesting topological features. Tantalising links between ACM3Ss and associative and coassociative submanifolds are observed. ar X iv :2 10 1. 12 60 5v 1 [ he pth ] 2 9 Ja n 20 21