We study D7 brane probes holomorphically embedded in the Klebanov-Strassler model. Analyzing the κ-symmetry condition for D7 branes wrapping a 4-cycle of a deformed conifold we find configurations that do not break N = 1 supersymmetry of the background. We compute the fluctuations of the probe around one of these configurations and obtain the spectrum of vector and scalar flavored mesons in the dual gauge theory. The spectrum is discrete and exhibits a mass gap.

Abstract:We study certain properties of the low energy regime of a theory which resembles four dimensional YM theory in the framework of a non-critical holographic gravity dual. We use for the latter the near extremal AdS 6 non-critical SUGRA. We extract the glueball spectra that associates with the fluctuations of the dilaton, one form and the graviton and compare the results to those of the critical near extremal D4 model and lattice simulations. We show an area law behavior for the Wilson loop and screening for the 't Hooft loop. The Luscher term is found to be − 3 24 π L . We derive the Regge trajectories of glueballs associated with the spinning folded string configurations.

A new holographic model of chiral symmetry breakingTo cite this article: Stanislav Kuperstein and Jacob Sonnenschein JHEP09 (2008) Abstract: A new family of models of flavour chiral symmetry breaking is proposed. The models are based on the embedding of a stack of D7 branes and a stack of anti-D7 branes in the conifold background. This family of gravity models is dual to a field theory with spontaneous breaking of conformal invariance and chiral flavour symmetry. We identify the corresponding Goldstone bosons and compute the spectra of massive scalar and vector mesons. The dual quiver gauge theory is also discussed. We further analyse a model where chiral symmetry is not broken.

In this paper we investigate the supergravity equations of motion associated with non-critical (d > 1) type II string theories that incorporate RR forms. Using a superpotential formalism we determine several classes of solutions. In particular we find analytic backgrounds with a structure of AdS p+2 × S d−p−2 and numerical solutions that asymptote a linear dilaton with a topology of R 1,d−3 × R × S 1 . The SUGRA solutions we have found can serve as anti holographic descriptions of gauge theories in a large N limit which is different than the one of the critical gauge/gravity duality. It is characterized by N → ∞ and g 2 Y M N ∼ 1. We have made the first steps in analyzing the corresponding gauge theory properties like Wilson loops and the glue-ball spectra.

We find a regular analytic 1st order deformation of the Klebanov-Strassler background. From the dual gauge theory point of view the deformation describes supersymmetry soft breaking gaugino mass terms. We calculate the difference in vacuum energies between the supersymmetric and the non-supersymmetric solutions and find that it matches the field theory prediction. We also discuss the breaking of the U (1) R symmetry and the space-time dependence of the gaugino bilinears two point function. Finally, we determine the Penrose limit of the non-supersymmetric background and write down the corresponding plane wave string theory. This string describes "annulons"-heavy hadrons with mass proportional to large global charge. Surprisingly the string spectrum has two fermionic zero modes. This implies that the sector in the non-supersymmetric gauge theory which is the dual of the annulons is supersymmetric.