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We construct gauge invariant operators in non-commutative gauge theories which in the IR reduce to the usual operators of ordinary field theories (e.g. Tr F 2). We show that in the deep UV the two-point functions of these operators admit a universal exponential behavior which fit neatly with the dual supergravity results. We also consider the ratio between… (More)
We present a class of black string spacetimes which asymptote to maximally symmetric plane wave geometries. Our construction will rely on a solution generating technique, the null Melvin twist, which deforms an asymptotically flat black string spacetime to an asymptotically plane wave black string spacetime while preserving the event horizon.
We review a number of perturbative calculations describing the interactions of D-branes with massless elementary string states. The form factors for the scattering of closed strings off D-branes are closely related to the Veneziano amplitude. They show that, in interactions with strings, D-branes acquire many of their physical features: the effective size… (More)
We study the dynamics of D-branes in a smooth time-dependent background. The theory on the branes is a time-dependent noncommutative field theory. We find the metric and fluxes that determine the dual holographic closed string theory. This provides a concrete example of holography in a cosmological setting.
We consider a minimal scalar in the presence of a three-brane in ten dimensions. The linearized equation of motion, which is just the wave equation in the three-brane metric, can be solved in terms of associated Mathieu functions. An exact expression for the reflection and absorption probabilities can be obtained in terms of the characteristic exponent of… (More)
Recently it was suggested that a graviton in AdS 5 × S 5 with a large momentum along the sphere can blow up into a spherical D-brane in S 5. In this paper we show that the same graviton can also blow up into a spherical D-brane in AdS 5 with exactly the same quantum numbers (angular momentum and energy). These branes are BPS, preserving 16 of the 32… (More)
We consider the spectra of excitations around diagonal and intersecting D-brane configurations on tori. These configurations are described by constant curvature connections in a dual gauge theory description. The low-energy string fluctuation spectrum is reproduced exactly by the gauge theory in the case of vanishing field strength; however, this… (More)
We study dynamical aspects of large N QCD 4 via supergravity on Anti de Sitter black hole geometry. We compute the mass spectrum, the topological susceptibility and the gluon condensate and make a comparison to lattice simulations. We present analogous results for QCD 3 .
We study the non-commutative supersymmetric Yang-Mills theory at strong coupling using the AdS/CFT correspondence. The supergravity description and the UV/IR relation confirms the expectation that the non-commutativity affects the ultraviolet but not the infra-red of the Yang-Mills dynamics. We show that the supergravity solution dual to the non-commutative… (More)
Non-commutative supersymmetric Yang-Mills with rational Θ is dual to an ordinary supersymmetric Yang-Mills with a 't Hooft flux. It is believed that the simplest description is via the ordinary supersymmetric Yang-Mills. We claim, however, that the two descriptions form a hierarchy. The SYM description is the proper description in the ultra violet while the… (More)