Related papers: Orientifold Precis
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 propose a conformal field theory description of a solitonic heterotic string in type $IIA$ superstring theory compactified on $K3$, generalizing previous work by J. Harvey, A. Strominger and A. Sen. In ten dimensions the construction…
We construct anomaly free non-supersymmetric large N gauge theories from orientifolds of Type IIB on C^3/G orbifolds. In particular, massless as well as tachyonic one-loop tadpoles are cancelled in these models. This is achieved by starting…
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…
Sigma model actions are constructed for the Type II superstring compactified to four and six dimensional curved backgrounds which can contain non-vanishing Ramond-Ramond fields. These actions are N=2 worldsheet superconformally invariant…
Type IIA string theory compactified on a Calabi-Yau threefold has a hypermultiplet moduli space whose metric is known to receive non-perturbative corrections from Euclidean D2-branes wrapped on 3-cycles. These corrections have been computed…
We consider the real topological string on certain non-compact toric Calabi-Yau three-folds X, in its physical realization describing an orientifold of type IIA on X with an O4-plane and a single D4-brane stuck on top. The orientifold can…
A geometrical approach in the non-symmetric connection framework is employed to examine the issue of higher order $\alpha'$ corrections to D=10 type IIB superstring backgrounds with a covariantly constant null Killing isometry and non-zero…
We construct, following \cite{mpgm14,mpgm17}, a massive M2-brane (supermembrane) as the limit of a genus two M2-brane that becomes a twice punctured Riemann surface with particular boundary conditions on the fields defined on the punctures.…
In this review article we study type IIB superstring compactifications in the presence of space-time filling D-branes while preserving N=1 supersymmetry in the effective four-dimensional theory. This amount of unbroken supersymmetry and the…
The cancellation of U(1)-gauge and U(1)-gravitational anomalies in certain D=4 N=1 Type IIB orientifolds is analyzed in detail, from a string theory point of view. We verify the proposal that these anomalies are cancelled by a Green-Schwarz…
We study a matrix model describing type IIB superstring in orbifold backgrounds. We particularly consider a {\bf C}^3/{\bf Z}_3 orbifold model whose six dimensional transverse space is orbifolded by {\bf Z}_3 discrete symmetry. This model…
We compute the two-point function for Z_N orbifold twist fields on the disk and RP2. We apply this to a computation of the O(g_s) correction to the Kahler potential for (the symmetric combination of) blow-up modes in type I string theory on…
We find the orbifold analog of the topological relation recently found by Freed and Witten which restricts the allowed D-brane configurations of Type II vacua with a topologically non-trivial flat $B$-field. The result relies in Douglas…
The supersymmetric action of type IIA D=10 superstring in N=2a, D=10 supergravity background can be derived by double dimensional reduction of the action of supermembrane coupled to D=11 supergravity. We demonstrate that the background…
We study superstrings with orientifold projections and with generalized open string boundary conditions (D-branes). We find two types of consistency condition, one related to the algebra of Chan-Paton factors and the other to cancellation…
We construct a covariant description of non-critical superstrings in even dimensions. We construct explicitly supersymmetric hybrid type variables in a linear dilaton background, and study an underlying N=2 twisted superconformal algebra…
In this dissertation, we study various aspects of type IIB string theory compactified on freely acting orbifolds. We focus particularly on asymmetric orbifolds, which are examples of non-geometric string compactifications and constitute an…
We outline the construction of type II superstring field theory leading to a geometric and algebraic BV master equation, analogous to Zwiebach's construction for the bosonic string. The construction uses the small Hilbert space. Elementary…
We construct the M-Theory lifts of type IIA orientifolds based on K3-fibred Calabi-Yau threefolds with compatible involutions. Such orientifolds are shown to lift to M-Theory on twisted connected sum $G_2$ manifolds. Beautifully, the two…