Related papers: N=3 Warped Compactifications
S-folds are generalizations of orientifolds in type IIB string theory, such that the geometric identifications are accompanied by non-trivial S-duality transformations. They were recently used by Garcia-Etxebarria and Regalado to provide…
Invariance of the AdS_4 x CP^3 superstring under D=3 N=6 superconformal symmetry is discussed in the sector described by the OSp(4|6)/(SO(1,3) x U(3)) supercoset sigma-model action presented in the conformal basis for the osp(4|6)/(so(1,3)…
Several aspects concerning the physics of D-branes in Type II flux compactifications preserving minimal N=1 supersymmetry in four dimensions are considered. It is shown how these vacua are completely characterized in terms of properly…
We construct six- and four-dimensional toroidal compactifications of the Type I string with magnetic flux on the D-branes. The open strings in this background probe a noncommutative internal geometry. Phenomenologically appealing features…
We determine the spectrum of D-string bound states in various classes of generalized type I vacuum configurations with sixteen and eight supercharges. The precise matching of the BPS spectra confirms the duality between unconventional type…
We use F-theory to derive a general expression for the flux potential of type II compactifications with D7/D3 branes, including open string moduli and 2-form fluxes on the branes. Our main example is F-theory on K3 $\times$ K3 and its…
In the framework of orbifold compactifications of heterotic and type II orientifolds, we study effective N = 1 supergravity potentials arising from fluxes and gaugino condensates. These string solutions display a broad phenomenology which…
We study compact non-supersymmetric Z_N orbifolds in various dimensions. We compute the spectrum of several tachyonic type II and heterotic examples and partially classify tachyon-free heterotic models. We also discuss the relation to…
In Calabi-Yau fourfold compactifications of M-theory with flux, we investigate the possibility of partial supersymmetry breaking in the three-dimensional effective theory. To this end, we place the effective theory in the framework of…
We study type IIB orientifolds on T^{2d}/Z_N with supersymmetry broken by the compactification. We determine tadpole cancellation conditions including anti-branes and considering different actions for the parity Omega. Using these…
In this paper we compute the N=1 effective low energy action for a stack of N space-time filling D3-branes in generic type IIB Calabi-Yau orientifolds with non-trivial background fluxes by reducing the Dirac-Born-Infeld and Chern-Simons…
The characterization of a six- (or seven)-dimensional internal manifold with metric as having positive, zero or negative curvature is expected to be an important aspect of warped compactifications in supergravity. In this context, Douglas…
We outline a general geometric structure that underlies the N=1 superpotentials of a certain class of flux and brane configurations in type II string compactifications on Calabi-Yau threefolds. This ``holomorphic N=1 special geometry'' is…
We investigate a simple extra-dimensional model and its four-dimensional vacua. This model has a two-form flux and a positive cosmological constant, and the extra dimensions are compactified as the product of $N$ two-spheres. The theory is…
Compactifications of M-theory to two dimensional space-time on ${(K3\times \T^5)}/ \Z_2$ and ${(K3\times K3\times \S^1)}/ \Z_2$ orientifolds are presented. These orientifolds provide examples of anomaly free chiral supergravity models in…
We study the conditions an arbitrary flux configuration must fulfill in order to construct a 4d space-time of the type $AdS_2\times S^2$ from a type IIB supergravity flux compactification in which NS-NS fluxes are included. We present a…
We consider compactifications of type IIA superstring theory on mirror-folds obtained as K3 fibrations over two-tori with non-geometric monodromies involving mirror symmetries. At special points in the moduli space these are asymmetric…
We show that string/M theory compactifications to maximally symmetric space-times using manifolds whose scalar curvature is everywhere negative, must have significant warping, large stringy corrections, or both.
First we give a complex ball uniformization of the moduli space of 8 ordered points on the projective line by using the theory of periods of K3 surfaces. Next we give a projective model of this moduli space by using automorphic forms on a…
The compactification of the heterotic string on six-dimensional orbifolds is reviewed. Some important technical aspects of their construction are clarified and new parameters, called generalized discrete torsion, are introduced and related…