A Comment on Fundamental Strings in M(atrix) Theory

We present a solution of M(atrix) theory describing type IIA fundamental string. Our construction is based on the central charge of the longitudinal membrane (= fundamental string), the BPS saturation condition and the relation between M(atrix) theory and supersymmetric Yang-Mills theory. The fundamental string corresponds to a photon in supersymmetric Yang-Mills theory.Comment: 11 pages + 2 uuencoded eps figures, LaTeX, errors corrected and arguments generalize

String junctions on backgrounds with a positively charged orientifold plane

By means of the heterotic/type IIB duality, we study properties of junctions on backgrounds with a positively charged orientifold seven-plane and D-branes, which are expected to give seven dimensional Sp(r) gauge theories. We give a modified BPS condition for the junctions and show that it reproduces the adjoint representation of the Sp(r) group.Comment: 16 pages + 3 eps figures, LaTeX, a reference adde

D-particle creation on an orientifold plane

We study the propagations of gravitational wave and D-particle on D6-brane and orientifold 6-plane backgrounds in the M-theory framework. In the case of orientifold plane, D-particle number is not conserved and gravitational wave can convert into D-particle. For the simplest case, we calculate its amplitude numerically.Comment: 10 pages + 3 eps figures, LaTeX, errors corrected and reference adde

Large N vector quantum mechanics and bubbling supertube solutions

We propose a large N vector quantum mechanics as the theory describing a D-particle probe in bubbling supertube solutions. We compute the effective action of this quantum mechanics and show that it coincides with the D-particle action in a certain decoupling limit, up to quadratic order in the velocity. The angular momentum of the D-particle, including the contribution of the Poynting vector, is reproduced as the vacuum expectation value of the SU(2)_R current.Comment: 17pages, PTPTeX; v2: added references; v3: changed TeX style, added references; v4: minor corrections, added referenc

Branes in type 0/type II duality

We derive relations between type 0 and type II D-brane configurations under the T-duality suggested by Bergman and Gaberdiel and confirm that the massless fields on D-branes are identical to those on the dual D-brane configurations. Furthermore, we discuss dualities of type 0 and type II NS5-branes and find that the dual of an unwrapped type 0 NS5-brane is a Kaluza-Klein monopole with non-supersymmetric blow up modes.Comment: 11 pages, 2 figures, explanations added, typos correcte

On String Junctions in Supersymmetric Gauge Theories

We study junctions consisting of confining strings in N=1 supersymmetric large N gauge theories by means of the gauge/gravity correspondence. We realize these junctions as D-brane configurations in infrared geometries of the Klebanov-Strassler (KS) and the Maldacena-Nunez (MN) solutions. After discussing kinematics associated with the balance of tensions, we compute the energies of baryon vertices numerically. In the KS background, baryon vertices give negative contributions to the energies. The results for the MN background strongly suggest that the energies of baryon vertices exactly vanish, as in the case of supersymmetric (p,q)-string junctions. We find that brane configurations in the MN background have a property similar to the holomorphy of the M-theory realization of (p,q)-string junctions. With the help of this property, we analytically prove the vanishing of the energies of baryon vertices in the MN background.Comment: 33 pages, 16 figures, LaTeX2e; references added, typos correcte

Baryon vertices in AdS black hole backgrounds

We numerically computed the energy of QCD string junctions in non-supersymmetric SU(N) gauge theories as the energy of brane configurations in the background of AdS black hole solutions, and extracted the contribution of baryon vertices. We obtain a negative vertex energy for the three- and four-dimensional Yang-Mills theories and a vanishing vertex energy for the five-dimensional theory.Comment: 12 pages, 2 eps figures, PTPTeX; V2: minor correction