N=3warped compactifications

Orientifolds with three-form flux provide some of the simplest string examples of warped compactification. In this paper we show that some models of this type have the unusual feature of $D=4,$ $\mathcal{N}=3\mathrm{}$ spacetime supersymmetry. We discuss their construction and low energy physics. Although the local form of the moduli space is fully determined by supersymmetry, to find its global form requires a careful study of the Bogomol’nyi-Prasad-Sommerfield spectrum.