Related papers: Orientiholes
We discuss the consistency conditions of a novel orientifold projection of type IIB string theory on C^2/Z_N singularities, in which one mods out by the combined action of world-sheet parity and a geometric operation which exchanges the two…
We review the construction and phenomenology of intersecting brane worlds. The breaking of chiral and supersymmetry together with a reduction of gauge symmetry by introducing D-branes at generic angles into type I or type II string…
With model building applications in mind, we collect and develop basic techniques to analyze the landscape of D7-branes in type IIB compact Calabi-Yau orientifolds, in three different pictures: F-theory, the D7 worldvolume theory and…
Intersecting branes have been the subject of string model building for several years. This work introduces in detail the toroidal and Z_N-orientifolds, where the main discussion employs the picture of intersecting D6-branes. The derivation…
We study the dynamics of type I strings on Melvin backgrounds, with a single or multiple twisted two-planes. We construct two inequivalent types of orientifold models that correspond to (non-compact) irrational versions of Scherk-Schwarz…
Strominger and Vafa have used D-brane technology to identify and precisely count the degenerate quantum states responsible for the entropy of certain extremal, BPS-saturated black holes. Here we give a Type-II D-brane description of a class…
We consider six and four dimensional ${\cal N}=1$ supersymmetric orientifolds of Type IIB compactified on orbifolds. We give the conditions under which the perturbative world-sheet orientifold approach is adequate, and list the four…
We construct the non-extreme solutions of non-orthogonal intersecting D-branes. The solutions reduce to non-extreme black holes upon the toroidal compactification. We clarify the relation between two configurations with equal mass and…
We consider type IIB compactifications on a general 4D group manifold with different types of possible spacetime filling O-planes and the corresponding D-branes parallel to them. Once fluxes allowed by the associated orientifold projection…
Using a simple hypothesis about the degrees of freedom of intersecting branes we find a microscopic counting argument that reproduces the entropy of a class of BPS black holes of type IIA string theory on general Calabi Yau three folds.
Negative mass brane-like objects known as orientifolds are crucial in the construction of all presently understood realistic string compactifications and I review in general the link between negative energy objects and the existence of a…
We consider unoriented strings in the supersymmetric SL(2,R)/U(1) coset, which describes the two-dimensional Euclidean black hole, and its mirror dual N=2 Liouville theory. We analyze the orientifolds of these theories from several…
We show that the D-brane configurations for the five and four-dimensional black holes give the geometry of two and three-dimensional ones as well. The emergence of these lower dimensional black holes from the D-brane configurations for…
Starting from a peculiar orientifold projection proposed long ago by Angelantonj and Cardella, we elaborate on a novel perturbative scenario that involves only D-branes, together with the two types of orientifold planes ${\rm O}_{\pm}$ and…
Dualities between certain supersymmetric gauge field theories in three and four dimensions have been studied in considerable detail recently, by realizing them as geometric manipulations of configurations of extended objects in type II…
We demonstrate that M-theory compactifications on 7-manifolds of G_2 holonomy, which yield 4d N=1 supersymmetric systems, often admit at special loci in their moduli space a description as type IIA orientifolds. In this way, we are able to…
In this review we describe the general geometrical framework of brane world constructions in orientifolds of type IIA string theory with D6-branes wrapping 3-cycles in a Calabi-Yau 3-fold. These branes generically intersect in points on the…
It is pointed out that the energy of the bound states of D-branes and strings is determined by the central charge of the space-time supersymmetry. The universality which is seen at the black hole horizon appears also on the D-brane side:…
An orientifold of Type-IIB theory on a $K3$ realized as a $Z_2$ orbifold is constructed which corresponds to F-theory compactification on a Calabi-Yau orbifold with Hodge numbers $(51, 3)$. The T-dual of this model is analogous to an…
Equilibrium states of black holes can be modelled by isolated horizons. If the intrinsic geometry is spherical, they are called type I while if it is axi-symmetric, they are called type II. The detailed theory of geometry of quantum type I…