Related papers: Fuzzy BIon

We discuss supersymmetry breaking via 3-form fluxes in chiral supersymmetric type IIB orientifold vacua with D3- and D7-branes. After a general discussion of possible choices of fluxes allowing for stabilizing of a part of the moduli, we…

Starting from the non-BPS D$(p+1)$-brane action we derive an effective action in $(p+1)$ space dimensions by studying the fluctuations of various bosonic fields around the time-like tachyonic kink solution (obtained by Wick rotation of the…

The low-energy effective action of type-I superstring theory in ten dimensions is obtained performing a truncation of type-IIB supergravity in a background where D9-branes are present. The open sector corresponds to the first order in the…

Non-commutative gauge theory on fuzzy sphere was obtained by Alekseev et al. as describing the low energy dynamics of a spherical D2-brane in S^3 with the background b-field. We identify a subset of solutions of this theory which are…

We use the Myers T-dual nonabelin Born-Infeld action to find some new nontrivial solutions for the branes in the background of D6-branes and Melvin magnetic tube field. In the D6-Branes background we can find both of the fuzzy sphere and…

We consider the equations of motion of the non-abelian 5-branes theory recently constructed in http://arxiv.org/abs/arXiv:1203.4224 and find exact string solutions both for uncompactified and compactified spacetime. Although one does not…

We propose that there is a unique expansion for the string theory S-matrix elements of tachyons that corresponds to non-abelian tachyon action. For those S-matrix elements which, in their expansion, there are the Feynman amplitudes…

In the first part of this work we consider an unstable non-BPS Dp-\bar{Dp}-brane pair in Type II superstring theory. Turning on a background NS-NS B-field (constant and nonzero along two spatial directions), we show that the tachyon…

In this thesis we discuss some nonperturbative and noncommutative aspects of string theory. We present low-energy background field solutions corresponding to various D-branes (and their bound states) and intersecting branes in flat and…

This thesis studies meta- and exactly stable supersymmetry breaking mechanisms in heterotic and type IIB string theories and constructs an F-theory Grand Unified Theory model for neutrino physics in which neutrino mass is determined by the…

Born-Infeld theory is the non-linear generalization of Maxwell electrodynamics. It naturally arises as the low-energy effective action of open strings, and it is also part of the world-volume effective action of D-branes. The N=1 and N=2…

We argue that the trace structure of the non-abelian Born-Infeld action can be fixed by demanding that the action be linearised by certain energy-minimising BPS-like configurations. It is shown how instantons in D4-branes, SU(2) monopoles…

We construct and explore BPS states that preserve 1/4 of supersymmetry in N=4 Yang-Mills theories. Such states are also realized as three-pronged strings ending on D3-branes. We correct the electric part of the BPS equation and relate its…

We present a class of BPS solutions of the IIB Matrix Theory which preserve 1/4 supersymmetry. The solutions desrcibe D-string configurations with left-moving oscillations. We demonstrate that the one-loop quantum effective action of Matrix…

We derive the general form of the moduli-space effective action for the long-range interaction of two BPS dyons in N=2 gauge theories. This action determines the bound state structure of various BPS and non-BPS states near marginal…

We give a confirmation of U-duality of type II superstring by discussing mass spectrum of the BPS states. We first evaluate the mass spectrum of BPS solitons with one kind of R-R charges. Our analysis is based on the 1-loop effective action…

We use dyonic brane configurations of type 0 string theory to study large N non-supersymmetric 4d gauge theories. The brane configurations define theories similar to the supersymmetric ones which arise in type II. We find the non-SUSY…

We reconstruct boundary superstring field theory via boundary states. After a minor modification of the fermionic two-form, all the equations needed for Batalin-Vilkovisky formulation are simply represented by closed string oscillators and…

We study realization of N=2 SUSY in N=2 abelian gauge theory with electric and magnetic $FI$ terms within a manifestly supersymmetric formulation. We find that after dualization of even one $FI$ term N=2 SUSY is realized in a partial…

We consider supersymmetric configurations in Type IIB supergravity obtained by the beackreaction of fundamental strings ending on a stack of D3-branes and smeared uniformly in the three spatial directions along the D3-branes. These…