Constructing nongeometric vacua in string theory

In this paper we investigate compactifications of the type II and heterotic string on four-dimensional spaces with nongeometric monodromies. We explicitly construct backgrounds which contain the Duality Twists discussed by Dabholkar and Hull [JHEP 0309 (2003) 054, hepth/0210209]. Similar constructions of nongeometric backgrounds have been discussed for type II strings by Hellerman, McGreevy, and Williams [hep-th/0208174]. We find that imposing such monodromies projects out many moduli from the resulting vacua and argue that these backgrounds are the spacetime realizations of interpolating asymmetric orbifolds. (C) 2004 Elsevier B.V. All rights reserved.