43843434
Worldsheet instantons and (0,2) linear models
A bstractWe study the stability of heterotic compactifications described by (0,2) gauged linear sigma models with respect to worldsheet instanton corrections to the space-time superpotential following the work of Beasley and Witten [1]. We show that generic models elude the vanishing theorem proved there, and may not determine supersymmetric heterotic vacua. We then construct a subclass of linear models for which a vanishing theorem holds, generating an extensive list of consistent heterotic backgrounds.
54042308
Accidents in (0,2) Landau-Ginzburg theories
A bstractWe study the role of accidental symmetries in two-dimensional (0,2) superconformal field theories obtained by RG flow from (0,2) Landau-Ginzburg theories. These accidental symmetries are ubiquitous, and, unlike in the case of (2,2) theories, their identification is key to correctly identifying the IR fixed point and its properties. We develop a number of tools that help to identify such accidental symmetries in the context of (0,2) Landau-Ginzburg models and provide a conjecture for a toric structure of the SCFT moduli space in a large class of models. We also give a self-contained discussion of aspects of (0,2) conformal perturbation theory.
28988576
Hybrid conformal field theories
A bstractWe describe a class of (2,2) superconformal field theories obtained by fibering a Landau-Ginzburg orbifold CFT over a compact Kähler base manifold. While such models are naturally obtained as phases in a gauged linear sigma model, our construction is independent of such an embedding. We discuss the general properties of such theories and present a technique to study the massless spectrum of the associated heterotic compactification. We test the validity of our method by applying it to hybrid phases of linear models and comparing spectra among the phases.
118374856
Massless spectrum for hybrids CFTs
We describe a class of theories obtained by fibering a Landau-Ginburg orbifold over a compact Kaehler base. While such theories are often described as phases of some GLSM, our description is independent of such an embedding. We provide a method for computing the massless spectrum. This note is based on the longer paper arXiv:1307.7063.
13987648
Microscopic entropy of the most general four-dimensional BPS black hole
In a recent paper we have given the macroscopic and microscopic description of the generating solution of toroidally compactified string theory BPS black holes. In this note we compute its corresponding microscopic entropy. Since by definition the generating solution is the most general solution modulo U-duality transformations, this result accounts for the degeneracy of microstates determining the entropy of any regular BPS black holes of toroidally compactified string (or M) theory.
8372258
The Generating solution of regular N=8 BPS black holes
In this paper we construct the five-parameter generating solution of N = 8 BPS regular supergravity black holes as a five-parameter solution of the N = 2 STU model. Our solution has a simpler form with respect to previous constructions which have already appeared in the literature and moreover, through the embedding [SL(2)]3 SU(3,3) E7(7) discussed in previous papers, the action of the U-duality group is well defined. This allows us to reproduce via U-duality rotations any other solution, such as those corresponding to R-R black holes whose microscopic description is given by intersecting D-branes.
83740445
BPS three-brane solution on smooth ALE manifolds with flux.
In the present talk I review the construction of a new supersymmetric 3-brane solution of type IIB supergravity on an ALE transverse space in presence of a non trivial flux of the complex 2-form across the ALE cycles. After introducing the ansatz for the solution I will show how the supergravity field equations reduce to a differential equation of Heun type in the non-conformal warp factor H of the metric. Although our analysis is worked out purely at a macroscopic level comments will be made on the general features of the (non-conformal) gauge theory dual to this solution
119106510
Holographic correlators for general gauge mediation
A bstractWe use holographic techniques to compute two-point functions of operators belonging to a conserved current supermultiplet in theories which break supersymmetry at strong coupling. These are the relevant quantities one has to compute in models of gauge mediation to determine the soft spectrum in supersymmetric extensions of the Standard Model (SSM). Such holographic approach can be used for diverse gravitational backgrounds, but here we focus, for definiteness, on asymptotically AdS backgrounds. After presenting the general framework, we apply our formulas to two explicit examples which differ by the nature of the SSM gauginos, which have Dirac or Majorana masses, corresponding to models that respectively preserve or break R-symmetry.