Flux backgrounds from Twist duality
Résumé
It is well known that a constant O(n,n,Z) transformation can relate different string backgrounds with n commuting isometries that have very different geometric and topological properties. Here we generalize this transformation by making the O(n,n) transformation coordinate dependent and construct discrete families of (flux) backgrounds on internal manifolds of different topologies. Our two principal examples include respectively the family of type IIB compactifications with D5 branes and O5 planes on six-dimensional nilmanifolds, and the heterotic torsional backgrounds.