Generalized image orientifold compactifications and the Hitchin functionals Original Research Article

The four-dimensional image supergravity theories arising in compactifications of type IIA and type IIB on generalized orientifold backgrounds with background fluxes are discussed. The Kähler potentials are derived for reductions on image structure orientifolds and shown to consist of the logarithm of the two Hitchin functionals. These are functions of even and odd forms parameterizing the geometry of the internal manifold, the B-field and the dilaton. The superpotentials induced by background fluxes and the non-Calabi–Yau geometry are determined by a reduction of the type IIA and type IIB fermionic actions on image and generalized image manifolds. Mirror spaces of Calabi–Yau orientifolds with electric and part of the magnetic NS–NS fluxes are conjectured to be certain image structure manifolds. Evidence for this identification is provided by comparing the generalized type IIA and type IIB superpotentials.