Related papers: D1/D5 systems in ${\cal N}=4$ string theories

We study N=1 dualities in four dimensional supersymmetric gauge theories by D 6-branes wrapping around 3-cycles of Calabi-Yau threefolds in the type IIA string theory. We consider the models involving $SU(N_{c1})\times SU(N_{c2})$ product…

We consider the supersymmetry algebras of the 10 and 11 dimensional maximal supergravities. We construct expressions from which the topological charge structure of the algebras can be determined in supersymmetric curved backgrounds. These…

We develop both the gravity and field theory sides of the Karch-Randall conjecture that the near-horizon description of a certain D5-D3 brane configuration in string theory, realized as AdS_5 x S^5 bisected by an AdS_4 x S^2 "brane", is…

We investigate a class of N=4 quiver Chern-Simons theories and their gravity duals. We define the group of fractional D3-brane charges in a type IIB brane setup with taking account of D3-brane creation due to Hanany-Witten effect, and…

Correlators in symmetric orbifold CFTs are given by a finite sum of admissible branched covers of the 2d spacetime. We consider a Gross-Mende like limit where all operators have large twist, and show that the corresponding branched covers…

We construct several classes of exact supersymmetric supergravity solutions describing D4 branes polarized into NS5 branes and F-strings polarized into D2 branes. These setups belong to the same universality class as the perturbative…

We study the spectrum of stable BPS and non-BPS D-branes in Z_2 x Z_2 orientifolds for all choices of discrete torsion between the orbifold and orientifold generators. We compute the torsion K-theory charges in these D=4, N=1 orientifold…

The low-energy description of wrapped M5 branes in compactifications of M-theory on a Calabi-Yau threefold times a circle is given by a conformal field theory studied by Maldacena, Strominger and Witten and known as the MSW CFT. Taking the…

S-duality symmetry of type IIB string theory predicts the existence of a stable non-BPS state on an orbifold five plane of the type IIB theory if the orbifold group is generated by the simultaneous action of (-1)^{F_L} and the reversal of…

Using the relation between D-brane charges and K-theory, we study non-BPS D-branes and their behavior under T-duality. We point out that in general compactifications, D-brane charges are classified by relative K-theory groups. T-duality is…

We explore various aspects of implementing the full M-theory U-duality group E_{d+1}, and thus Lorentz invariance, in the finite N matrix theory (DLCQ of M-theory) on d-tori: (1) We generalize the analysis of U-duality orbits of BPS states…

We investigate behavior of brane backgrounds under poly-vector deformations in Type IIB and D=11 supergravities. We find that the standard bi-vector deformations add dissolved F1 string charge to a Dp-brane background, quadri-vector…

In the previous paper [hep-th/9904129], we constructed a general explicit BPS solution for (F, D3) non-threshold bound state. By using the SL(2,Z) symmetry of type IIB string theory, we here construct from (F, D3) a more general BPS…

In this thesis we discuss non-perturbative phenomena emerging in gauge and in string/supergravity theories. We compute the partition function of 5D minimal supersymmetric U(1) gauge theory with extra adjoint matter in general…

We study marginal deformations of ${\cal N}=2$, $d=4$ long linear quiver CFTs using the holographic description. We find a two-parameter family of AdS$_5$ solutions that generically break all of supersymmetry, but preserve ${\cal N}=1$ for…

I describe the main features of new intersecting D4- and D5-brane orbifold models that yield the non-supersymmetric standard model, up to vector-like matter and, in some cases, extra U(1) factors in the gauge group. There are six-stack…

We study the bulk effective theory of a class of orbifolds of the type IIB string with D5-branes, compactified to four dimensions. These constructions are connected, in a region of their moduli space, to some orbifolds of the type I and…

We consider system of Dp-branes in the presence of a nonzero B field with one leg along brane worldvolume and the other transverse to it. We study the corresponding supergravity solutions and show that the worldvolume theories decouple from…

We study different aspects of the construction of D=4, N=1 type IIB orientifolds based on toroidal Z_N and Z_M x Z_N, D=4 orbifolds. We find that tadpole cancellation conditions are in general more constraining than in six dimensions and…

We present a simple example of a supersymmetric attractor mechanism in the purely open string context of D-branes embedded in curved space-time. Our example involves a class of D3-branes embedded in the 2-charge D1-D5 background of type IIB…