Related papers: Interplay between Background Fluxes and Instanton …

One-loop corrections to the gauge coupling and the gauge kinetic function in certain classes of four-dimensional D-brane models are computed. It is described how to determine D-instanton corrections to the superpotential and the gauge…

We analyze certain brane bound states in M-theory and their descendants in type IIA string theory, all involving 3-form or 2-form background fluxes. Among them are configurations which represent NCYM, NCOS and ODp-theories in the scaling…

Sen has recently drawn attention to an exact time-dependent Boundary Conformal Field Theory with the space-time interpretation of brane creation and annihilation. An interesting limit of this BCFT is formally equivalent to an array of…

We obtain axionic charged primordial black holes on a vacuum created gravitational pair of $(3{\bar 3})$-brane by the Kalb-Ramond field on a $D_4$-brane in presence of a background open string metric. The new geometries on an emergent pair…

We study some configurations of brane probes which are partially wrapped on spheres transverse to a stack of non-threshold bound states. The latter are represented by the corresponding supergravity background. Two cases are studied:…

The Maldacena's proposal has established an intriguing connection between string theory in AdS spaces and gauge theory. In this paper we study the effects of adding D(-1)-branes to the system of D3- or (D1-D5)-branes and we give arguments…

It has been recently argued that inserting a probe anti-D3-brane in a flux background breaks supersymmetry spontaneously instead of explicitly, as previously thought. In this paper we argue that such spontaneous breaking of supersymmetry…

We explore the dynamics of magnetized nonsupersymmetric D5-brane configurations on Calabi-Yau orientifolds with fluxes. We show that supergravity D-terms capture supersymmetry breaking effects predicted by more abstract Pi-stability…

We analyze exactly the simplest minimal superstring theory, using its dual matrix model. Its target space is one dimensional (the Liouville direction), and the background fields include a linear dilaton, a possible tachyon condensate, and…

We review an approach for computing non-perturbative, exact superpotentials for Type II strings compactified on Calabi-Yau manifolds, with extra fluxes and D-branes on top. The method is based on an open string generalization of mirror…

We discuss the compactification of type I strings on a torus with additional background gauge flux on the D9-branes. The solutions to the cancellation of the RR tadpoles display various phenomenologically attractive features: supersymmetry…

We discuss D-branes from a conformal field theory point of view. In this approach, branes are described by boundary states providing sources for closed string modes, independently of classical notions. The boundary states must satisfy…

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…

In this note we study the possibility of obtaining dark energy solution in a D-brane scenario in a warped background that includes brane-position dependent corrections for the non-perturbative superpotential. The volume modulus is…

This thesis describes an attempt to write down covariant actions for coincident D-branes using so-called boundary fermions instead of matrices to describe the non-abelian fields. These fermions can be thought of as Chan-Paton degrees of…

We consider interactions of a NS open string with first important states of a NS closed string, i.e., a closed-string tachyon and a graviton, where both ends of the NS open string are attached on a D-brane, and a constant background B field…

We examine the solutions of world-volume action for a D3-brane being put near other D3-brane which is replaced by the background configuration of bulk space. It is shown that the BPS solutions are not affected by the D3-brane background,…

We present a stringy mechanism to generate Dirac neutrino masses by D-instantons in an experimentally relevant mass scale without fine-tuning. Within Type IIA string theory with intersecting D6-branes, we spell out specific conditions for…

We study conformal field theory correlation functions relevant for string diagrams with open strings that stretch between several parallel branes of different dimensions. In the framework of conformal field theory, they involve boundary…

A large class of D-branes in Calabi-Yau spaces can be constructed at the Gepner points using the techniques of boundary conformal field theory. In this note we develop methods that allow to compute open string amplitudes for such D-branes.…