Related papers: D-brane non-perturbative effects and geometric def…

We give a world-sheet description of D-brane in terms of gluing conditions on T+T^*. Using the notion of generalized Kahler geometry we show that A- and B-types D-branes for the general N=(2,2) supersymmetric sigma model (including a…

We study D-branes in the null-brane background. Using the covariant formalism of the worldsheet theory, we construct the boundary states describing D-branes on the null-brane. From the cylinder amplitudes, we find that the D-branes with…

We analyze thoroughly the boundary conditions allowed in classical non-linear sigma models and derive from first principle the corresponding geometric objects, i.e. D-branes. In addition to giving classical D-branes an intrinsic and…

We study D0-branes in type IIA on $T^2$ with a background B-field turned on. We calculate explicitly how the background B-field modifies the D0-brane action. The effect of the B-field is to replace ordinary multiplication with a…

We consider the perturbation of giant gravitons in the background of dilatonic D-branes whose geometry is not of a conventional form of ${\rm AdS}_m \times {\rm S}^n$. We use the quadratic approximation to the brane action to investigate…

In this paper we find examples of moduli stabilization and runaway behavior which can be treated exactly. This is shown for supersymmetric field theories which can be realized on the world volume of D-branes. From a geometric point of view,…

We elucidate the structure of D terms in N=1 orientifold compactifications with fluxes. As a case study, we consider a simple orbifold of the type-IIA theory with D6-branes at angles, O6-planes and general NSNS, RR and Scherk-Schwarz…

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 consider non-perturbative six and four dimensional N=1 space-time supersymmetric orientifolds. Some states in such compactifications arise in ``twisted'' open string sectors which lack world-sheet description in terms of D-branes. Using…

We study non-supersymmetric SO(3)-invariant deformations of d=3, N=8 super Yang-Mills theory and their type IIA string theory dual. By adding both gaugino mass and scalar mass, dielectric D4-brane potential coincides with D5-brane potential…

We review the mechanism of gaugino condensation in the framework of the $d=10$ heterotic string and its $d=11$ extension of Horava and Witten. In particular we emphasize the relation between the gaugino condensate and the flux of the…

We analyse some physical consequences when supersymmetry is broken by a set of D-branes and/or orientifold planes in Type II string theories. Generically, there are global dilaton tadpoles at the disk level when the transverse space is…

There is a difficulty in defining the positions of the D-branes when the scalar fields on them are non-abelian. We show that we can use tachyon condensation to determine the position or the shape of D0-branes uniquely as a commutative…

We investigate the possibility of constructing a supergravity background dual to the quark-gluon plasma using D6-branes wrapping a three-cycle in the deformed conifold. The UV-completion of this setup is given by M-theory on a G2 holonomy…

This article discusses model-building scenarios including anti-D3-/D7-branes, in which supersymmetry is broken spontaneously, despite having no scale at which sparticles appear and standard supersymmetry is restored. If the branes are…

We focus on D-brane models in presence of closed string background fluxes. These fluxes modify the effective interactions on Dirichlet and Euclidean branes, in particular inducing fermionic masses. We show how they can create new…

We investigate the deformation of D-brane world-volumes in curved backgrounds. We calculate the leading corrections to the boundary conformal field theory involving the background fields, and in particular we study the correlation functions…

Recently, the first instance of a model of D-branes at Calabi-Yau singularities where supersymmetry is broken dynamically into stable vacua has been proposed. This construction was based on a system of $N$ regular and $M=1$ fractional…

Unstable, non-BPS D-branes in weakly coupled ten dimensional string theory have many mysterious properties. Among other things, it is not clear what sets their tension, what is their relation to the better understood BPS D-branes, and why…

We define noncommutative gerbes using the language of star products. Quantized twisted Poisson structures are discussed as an explicit realization in the sense of deformation quantization. Our motivation is the noncommutative description of…