Solitonic d-5 brane and Vortex on the World-Sheet

We examine the behavior of the vortex defects, which are represented by the sine-Gordon potential, on the world-sheet when a solitonic d-5 brane is existing in the d-dimensional target space. The d-5 brane solution is obtained as an extension of 5-brane in 10d supergravity. It is shown that the vortices of any charge should be dissociated to the free gas when they approach to the brane. The meanings of this fact are addressed through the analysis of the renormalization group equations on the world sheet.Comment: 12 pages, Latex, no figur

2D Quantum Gravity Coupled to Renormalizable Matter Fields

We consider two-dimensional quantum gravity coupled to matter fields which are renormalizable, but not conformal invariant. Questions concerning the \b function and the effective action are addressed, and the effective action and the dressed renormalization group equations are determined for various matter potentials.Comment: 23 pages, Latex, NBI-HE-93-6

Holographic heavy-light mesons from non-Abelian DBI

In the context of gauge/gravity duals with flavor, we examine heavy-light mesons which involve a heavy and a light quark. For this purpose we embed two D7 brane probes at different positions into the gravity background. We establish the non-Abelian Dirac-Born-Infeld (DBI) action for these probes, in which the U(2) matrix describing the embedding is diagonal. The fluctuations of the brane probes correspond to the mesons. In particular, the off-diagonal elements of the U(2) fluctuation matrix correspond to the heavy-light mesons, while the diagonal elements correspond to the light-light and heavy-heavy mesons, respectively. The heavy-light mesons scale differently with the 't Hooft coupling than the mesons involving quarks of equal mass. The model describes both scalar and vector mesons. For different dilaton-deformed gravity backgrounds, we also calculate the Wilson loop energy, and compare with the meson masses.Comment: 21 pages, 7 figure