Related papers: Intersecting Branes, Defect Conformal Field Theori…

We study the relation between intersecting NS5-branes whose intersection is smoothed out and the deformed conifold in terms of the supergravity solution. We solve the condition of preserved supersymmetry on a metric inspired by the deformed…

The behaviour of supersymmetric D-branes under deformations of the closed string background is studied using world-sheet methods. We explain how lines of marginal stability and obstructions arise from this point of view. We also show why…

We construct the interaction terms between the world-volume fields of multiple M2-branes and the 3- and 6-form fields in the context of ABJM theory with U($N$)$\times$U($N$) gauge symmetry. A consistency check is made in the simplest case…

We study string theory propagating on R^6 times K3 by constructing orientifolds of Type IIB string theory compactified on the T^4/Z_N orbifold limits of the K3 surface. This generalises the Z_2 case studied previously. The orientifold…

Baryon number violation is discussed in gauge unified orbifold models of type II string theory with intersecting Dirichlet branes. We consider setups of D6-branes which extend along the flat Minkowski space-time directions and wrap around…

We show that the Gukov-Witten monodromy defects of supersymmetric Yang-Mills theory can be realized in perturbative string theory by considering an orbifold background of the Kanno-Tachikawa type and placing stacks of fractional D3-branes…

This thesis investigates correspondences between open and closed strings. This is done on the level of coupled open-closed moduli spaces and from a string field theoretic point of view. The construction of boundary string field theory on…

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, and point out their immediate phenomenological relevance. These…

We consider a D-brane probe in unstable string background associated with flux branes. The twist in spacetime metric reponsible for the supersymmetry breaking is shown to manifest itself in mixing of open Wilson lines with the phases of…

We review for non-experts possible phenomenological scenari in String Theory. In particular we focus on vacuum configurations with intersecting and/or magnetized unoriented D-branes. We will show how a TeV scale tension may be compatible…

Starting from the non-supersymmetric, tachyon-free orientifold of type 0 string theory, we construct four-dimensional brane world models with D6-branes intersecting at angles on internal tori. They support phenomenologically interesting…

This is an introductory review of the AdS/CFT correspondence and of the ideas that led to its formulation. We show how comparison of stacks of D3-branes with corresponding supergravity solutions leads to dualities between conformal large…

We consider freely acting orbifold compactifications, which interpolate in two possible decompactification limits between the supersymmetric type II string and the non-supersymmetric type 0 string. In particular we discuss how D-branes are…

D3 branes in the vicinity of an E6, E7, or E8 stack of 7-branes in flat space are known to host at low energy a famous class of strongly-coupled N = 2 superconformal field theories featuring exceptional global symmetry. What if, instead,…

We study the potential between a string and an anti-string source in M5-theory by using the adS/CFT duality conjecture. We find that the next to leading order corrections in a saddle point approximation renormalize the classical result.

We investigate orientifolds of type II string theory on K3 and Calabi-Yau 3-folds with intersecting D-branes wrapping special Lagrangian cycles. We determine quite generically the chiral massless spectrum in terms of topological invariants…

We study several classes of marginal deformations of the conformal field theory SU(2) x R. This theory describes the near-horizon region of a stack of parallel and coincident NS5-branes and is related holographically to little string…

Abelian gerbes and twisted bundles describe the topology of the NS-NS 3-form gauge field strength H. We review how they have been usefully applied to study and resolve global anomalies in open string theory. Abelian 2-gerbes and twisted…

We construct intersecting D5-brane orbifold models that yield the (non-supersymmetric) standard model up to vector-like matter and charged-singlet scalars. The models are constrained by the requirement that twisted tadpoles cancel, and that…

We derive the dynamics of M-brane intersections from the worldvolume action of one brane in the background supergravity solution of another one. In this way we obtain an effective action for the self-dual string boundary of an M2-brane in…