119190458
Heating up the Baryonic Branch with U-duality: a unified picture of conifold black holes
We study different aspects of a U-duality recently presented by Maldacena and Martelli and apply it to non-extremal backgrounds. In particular, starting from new non-extremal wrapped D5 branes we generate new non-extremal generalizations of the Baryonic Branch of the Klebanov-Strassler solution. We also elaborate on different conceptual aspects of these U-dualities, like its action on (extremal and non-extremal) Dp branes, dual models for Yang-Mills-like theories, generic asymptotics and decoupling limit of the generated solutions.
15805106
String duals of two-dimensional (4,4) supersymmetric gauge theories
We study duals to field theories in two dimensions with = (4, 4) SUSY. The string backgrounds reproduce certain non-perturbative aspects of the dual field theory with a large number of colors Nc and a tunable number of flavors Nf. Different aspects of the two-dimensional field theory are discussed, among them the running of gauge couplings, the spectrum of mesons in Higgs and Coulomb branches, entanglement entropy and the non-relativistic version of our string backgrounds.
12143928
Unquenched flavors in the Klebanov-Witten model
Using AdS/CFT, we study the addition of an arbitrary number of backreacting flavors to the Klebanov-Witten theory, making many checks of consistency between our new Type IIB plus branes solution and expectations from field theory. We study generalizations of our method for adding flavors to all = 1 SCFTs that can be realized on D3-branes at the tip of a Calabi-Yau cone. Also, general guidelines suitable for the addition of massive flavor branes are developed.
118385203
Towards multi-scale dynamics on the baryonic branch of Klebanov-Strassler
We construct explicitly a new class of backgrounds in type-IIB supergravity which generalize the baryonic branch of Klebanov-Strassler. We apply a solution-generating technique that, starting from a large class of solutions of the wrapped-D5system, yields the new solutions, and then proceed to study in detail their properties, both in the IR and in the UV. We propose a simple intuitive field theory interpretation of the rotation procedure and of the meaning of our new solutions within the Papadopoulos-Tseytlin ansatz, in particular in relation to the duality cascade in the Klebanov-Strassler solution. The presence in the field theory of different VEVs for operators of dimensions 2, 3 and 6 suggests that this is an important step towards the construction of the string dual of a genuinely multi-scale (strongly coupled) dynamical model.
121982373
Fermionic current algebra in three dimensions
We consider the fermion-boson mapping in three dimensional space-time, in the Abelian case, from the current algebra point of view. It is shown that in a path-integral framework one can derive a general bosonization recipe leading, in the bosonic language, to the correct equal-time current commutators of the original free fermionic theory.
17311968
Backreacting flavors in the Klebanov-Strassler background
In this paper we present new analytic solutions of pure Type IIB supergravity plus D7-branes describing the addition of an arbitrary number of flavors to the Klebanov-Tseytlin and Klebanov-Strassler backgrounds. We provide a precise field theory dual and a detailed analysis of the duality cascade which describes its RG flow. Matchings of beta functions and anomalies between the field theory and the string setup are presented. We give an understanding of Seiberg duality as a large gauge transformation on the RR and NSNS potentials. We also analyze the UV behavior of the field theory that, as suggested by the string background, can be associated with a duality wall.
18292790
Fusion rules and four-point functions in the SL ( 2 , R ) WZNW model
We study the operator product expansion in the current algebra of SL(2, R). We incorporate the spectral flow symmetry into two alternative definitions proposed in the literature: i) an ansatz based on the requirement that the classical limit reproduces the tensor product of representations of SL(2, R) and ii) the analytic continuation from the operator product expansion in the Euclidean H 3 WZNW model. We show that both prescriptions lead to the same result for the operator product of the current algebra, although some ad-hoc assumptions of the former arise naturally as a consequence of the analytic continuation in the latter. We prove the closure of the operator algebra among the states leading to a unitary spectrum of string theory on AdS3. Using these fusion rules, we then discuss the factorization of four-point functions involving operators in various sectors of the SL(2, R) WZNW model and we verify that it satisfies the spectral flow selection rules. e-mail: w baron@iafe.uba.ar e-mail: carmen@iafe.uba.ar
122020140
Duality symmetries in string theory
The search for a unified theory of quantum gravity and gauge interactions leads naturally to string theory. This field of research has received a revival of interest after the discovery of duality symmetries in recent years. We present a self contained account of some non-perturbative aspects of string theory which have been recently understood. The spectrum and interactions of the five consistent superstring theories in ten dimensions are recollected and the fundamental principles underlying this initial stage in the construction of the theory are briefly reviewed. We next discuss some evidences that these apparently different superstrings are just different aspects of one unique theory. The key to this development is given by the non-perturbative duality symmetries which have modified and improved our understanding of string dynamics in many ways. In particular, by relating the fundamental objects of one theory to solitons of another theory, they have unraveled the presence of extended objects in the th...
121030693
Vacuum polarization in curved backgrounds deduced from Hadamard kernels
The point‐splitting method of regularization is applied to alternative Hadamard kernels, for scalar fields in curved backgrounds, in order to study the polarization term in the vacuum expectation value (VEV) of the energy‐momentum tensor. An ansatz to define this term is introduced and verified in several cases. The renormalized VEV of the energy‐momentum tensor of a scalar massive conformally coupled field in a Robertson–Walker universe is explicitly computed. Two terms appear, the polarization term, which coincides with the one computed using the above‐mentioned ansatz, and a creation of particle term.
14996531
Interaction of moving D-branes on orbifolds
We use the boundary state formalism to study the interaction of two moving identical D-branes in the Type II superstring theory compactified on orbifolds. By computing the velocity dependence of the amplitude in the limit of large separation we can identify the nature of the different forces between the branes. In particular, in the Z(3) orbifold case we find a boundary state which is coupled only to the N = 2 graviton multiplet containing just a graviton and a vector like in the extremal Reissner-Nordstrom configuration. We also discuss other cases including T-4/Z(2). (C) 1997 Elsevier Science B.V.
122296725
Intrinsic normal-ordered vertex operators from the multiloop N-tachyon amplitude
Abstract We construct vertex operators for arbitrary mass level states of the closed bosonic string. Starting from a generalization of the Koba-Nielsen amplitude which is suitable for an arbitrary genus Riemann surface, we read the vertex operators from the residues of the poles for the intermediate states. Since the original expression is metric independent and normal ordered without the need of inventing any regularization scheme, our vertex operators also possess these properties. We discuss their general features.