Related papers: String Junctions and the BPS Spectrum of N=2 SU(2)…
As a novel application of string junctions, we provide evidence for the existence of stable non-BPS dyons with magnetic charge greater than 1 in (the semiclassical regime of) N=2 SU(2) Super-Yang-Mills theory. In addition, we find a new…
We show how BPS states of supersymmetric SU(2) Yang-Mills with matter -both massless and massive- are described as self-dual strings on a Riemann surface. This connection enables us to prove the stability and the strong coupling behaviour…
We investigate the massive states in F-theory compactification models, including BPS string junctions stretching between parallel 7-branes and KK modes. We obtain analytical results when there are two colliding bunches of 7-branes with a…
Type II strings in D=5 contain particle-like 1/8 supersymmetric BPS states. In this note we give a string-network representation of such states by considering (periodic) non-planar $(p,q,r)$-string networks of eight dimensional type II…
BPS states of N=2, D=4 Super Yang-Mills theories with ADE flavor symmetry arise as junctions joining a D3-brane to a set of 7-branes defining the enhanced flavor algebra. We show that the familiar BPS spectrum of SU(2) theories with N_f <=…
We study a BPS configuration in which four strings (of different type) meet at a point in $N = 2, D = 8$ supergravity, i.e., the low energy effective theory of $T^2$-compactified type II string theory. We demonstrate that the charge…
The N = 3 string models are special solutions of the type II perturbative string theories. We present explicit expressions for the helicity supertraces,which count the number of the perturbative BPS multiplets. Assuming the non-perturbative…
We construct $ 1/2 $ BPS 1-instanton states in the Hilbert space of $ 5d $ gauge theories. The states are local with the scale size $ \rho=0 $. With the degeneracy from the gauge orientation taken into account, the BPS spectrum consists of…
We consider the spectrum of BPS saturated states in $N = 2$ gauge theories in four dimensions. This spectrum may be discontinuous across real codimension one submanifolds of marginal stability in the moduli space of vacua. An example, which…
The BPS spectrum of string theory on AdS$_3\times {\rm S}^3 \times {\rm S}^3 \times {\rm S}^1$ is determined using a world-sheet description in terms of WZW models. It is found that the theory only has BPS states with $j^+ = j^-$ where…
We study BPS-saturated classical solutions for the world-sheet theory of a D-string in the presence of a point charge. These solutions are interpreted as describing planar 3-string junctions, which arise because the original D-string is…
We explicitly determine the global structure of the $SL(2,Z)$ bundle over the Coulomb branch of the moduli space of asymptotically free $N=2$ supersymmetric Yang-Mills theories with gauge group $SU(2)$ when massless hypermultiplets are…
We investigate the correspondence between existence/stability of BPS states in type II string theory compactified on a Calabi-Yau manifold and BPS solutions of four dimensional N=2 supergravity. Some paradoxes emerge, and we propose a…
We study the BPS spectrum of supersymmetric 5 dimensional field theories and their representations as string webs. It is found that a state of given charges exists when it has a representation as an irreducible string web. Its spin is…
We define the concept of Pi-stability, a generalization of mu-stability of vector bundles, and argue that it characterizes N=1 supersymmetric brane configurations and BPS states in very general string theory compactifications with N=2…
BPS states in N=4 supersymmetric SU(N) gauge theories in four dimensions can be represented as planar string networks with ends lying on D3-branes. We introduce several protected indices which capture information on the spectrum and various…
We review the recent developments in our understanding of non-BPS states and branes in string theory. The topics include 1) construction of unstable non-BPS D-branes in type IIA and type IIB string theories, 2) construction of stable…
I explain two applications of the relationship between four dimensional N=1 supersymmetric gauge theories, zero dimensional gauged matrix models, and geometric transitions in string theory. The first is related to the spectrum of BPS domain…
We study a three-dimensional gauge theory obtained from the dimensional reduction of a D4-brane worldvolume theory in the background of space-time moduli. An SL(3) symmetry in this theory, which acts on fields as well as coupling constants,…
We discuss BPS states preserving 1/4 supersymmetries of N=4 supersymmetric Yang-Mills theory as M2-branes holomorphically embedded and ending on M5-branes. We use techniques in electrodynamics to find the M2-brane configurations, and give…