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.
122039305
Heterotic string covariant amplitudes and low-energy effective action
Abstract We compute the 3- and 4-point scattering amplitudes for gravitons, antisymmetric tensors, and gauge bosons in the heterotic string model using the covariant path integral formalism. From these amplitudes we deduce all the terms in the low-energy effective action involving cubic and quartic interactions of those fields, that are not affected by pole subtractions. We show that the spin connection should naturally contain torsion whose sign is unambiguously determined by the string amplitudes. The quartic interactions arising from the pure heterotic string part of the amplitudes (i.e. the pieces which are not contained in the SST-scattering amplitudes) are shown to vanish when the gauge field is embedded in the spin connection with torsion ( A μ → ω μ ). Some consequences for compactification are discussed.
124520602
Nondiagonal CP(m) cosets in string compactifications
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.
14066279
Glueballs of super Yang-Mills from wrapped branes
In this paper we study qualitative features of glueballs in = 1 SYM for models of wrapped branes in IIA and IIB backgrounds. The scalar mode, 0++ is found to be a mixture of the dilaton and the internal part of the metric. We carry out the numerical study of the IIB background. The potential found exhibits a mass gap and produces a discrete spectrum without any cut-off. We propose a regularization procedure needed to make these states normalizable.
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.
6639819
D6-branes and M theory geometrical transitions from gauged supergravity
We study the supergravity duals of supersymmetric theories arising in the world-volume of D6-branes wrapping holomorphic two-cycles and special lagrangian three-cycles within the framework of eight-dimensional gauged supergravity. When uplifted to 11d, our solutions represent M-theory on the background of, respectively, the small resolution of the conifold and a manifold with G2 holonomy. We further discuss on the flop and other possible geometrical transitions and its implications.
15316691
Supersymmetry and bosonization in three dimensions
Abstract We discuss on the possible existence of a supersymmetric invariance in purely fermionic planar systems and its relation to the fermion-boson mapping in three-dimensional quantum field theory. We consider, as a very simple example, the bosonization of free massive fermions and show that, under certain conditions on the masses, this model displays a supersymmetric-like invariance in the low energy regime. We construct the purely fermionic expression for the supercurrent and the non-linear supersymmetry transformation laws. We argue that the supersymmetry is absent in the limit of massless fermions where the bosonized theory is non-local.