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

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

A nonstandard construction of direct limit group actions

Manevitz and Weinberger proved that the existence of faithful $K$-Lipschitz $\mathbb{Z}/n\mathbb{Z}$-actions implies the existence of faithful $K$-Lipschitz $\mathbb{Q}/\mathbb{Z}$-actions. The $\mathbb{Q}/\mathbb{Z}$-actions were constructed from suitable actions of a sufficiently large hyperfinite cyclic group ${}^{\ast}\mathbb{Z}/\gamma{}^{\ast}\mathbb{Z}$ in the sense of nonstandard analysis. In this paper, we modify their construction, and prove that the existence of $\varepsilon$-faithful $K$-Lipschitz $G_{\lambda}$-actions implies the existence of $\varepsilon$-faithful $K$-Lipschitz $\varinjlim G_{\lambda}$-actions. In a similar way, we generalise Manevitz and Weinberger's result to injective direct limits of torsion groups

Orbifold Schur Index and IR formula

We discuss orbifold version of the Schur index defined as the supersymmetric partition function in S^3/Z_n x S^1. We first give a general formula for Lagrangian theories obtained by localization technique, and then suggest a generalization of the Cordova and Shao's IR formula. We confirm the generalized IR formula gives the correct answer for systems with free hypermultiplets if we tune the background fields so that they are invariant under the orbifold action. Unfortunately, we find disagreement for theories with dynamical vector multiplets.Comment: v3: 19 pages. References added, eq(34) corrected, and explanations improved. Version accepted for publication in PTE

Born-Infeld Action and Chern-Simons Term from Kaluza-Klein Monopole in M-theory

We investigate the zero modes of the Kaluza-Klein monopole in M-theory and show that the Born-Infeld action and the Chern-Simons term of a D6-brane are reproduced to quadratic order in the field strength of the U(1) field on the brane.Comment: 11 pages, LaTe

Baryon Mass and Phase Transitions in Large N Gauge Theory

We calculate the baryon mass in N=4 large $N$ gauge theory by means of AdS/CFT correspondence and show that it is a truly bound state, at least in some situations. We find that a phase transition occurs at a critical temperature. Furthermore, we find there are bound states of W-bosons in the Higgs phase, where the gauge group is broken to SU(N_1)xSU(N_2).Comment: 12 pages + 4 eps figure, PTPTeX style, grammatical errors corrected and Section 5 remove

String Junctions and Their Duals in Heterotic String Theory

We explicitly give the correspondence between spectra of heterotic string theory compactified on $T^2$ and string junctions in type IIB theory compactified on $S^2$.Comment: 13 pages + 4 eps figures, PTPTeX, typographical errors correcte