Charting Class Sk{\cal S}_k Territory

We extend the investigation of the recently introduced class ${\cal S}_k$ of 4d $\mathcal{N}=1$ SCFTs, by considering a large family of quiver gauge theories within it, which we denote $\mathcal{S}^1_k$. These theories admit a realization in terms of $\mathbb{Z}_k$ orbifolds of Type IIA configurations of D4-branes stretched among relatively rotated sets of NS-branes. This fact permits a systematic investigation of the full family, which exhibits new features such as non-trivial anomalous dimensions differing from free field values and novel ways of gluing theories. We relate these ingredients to properties of compactification of the 6d (1,0) superconformal ${\cal T}_N^k$ theories on spheres with different kinds of punctures. We describe the structure of dualities in this class of theories upon exchange of punctures, including transformations that correspond to Seiberg dualities, and exploit the computation of the superconformal index to check the invariance of the theories under them.Comment: 44 pages, 24 figure

Is Content Publishing in BitTorrent Altruistic or Profit-Driven

BitTorrent is the most popular P2P content delivery application where individual users share various type of content with tens of thousands of other users. The growing popularity of BitTorrent is primarily due to the availability of valuable content without any cost for the consumers. However, apart from required resources, publishing (sharing) valuable (and often copyrighted) content has serious legal implications for user who publish the material (or publishers). This raises a question that whether (at least major) content publishers behave in an altruistic fashion or have other incentives such as financial. In this study, we identify the content publishers of more than 55k torrents in 2 major BitTorrent portals and examine their behavior. We demonstrate that a small fraction of publishers are responsible for 66% of published content and 75% of the downloads. Our investigations reveal that these major publishers respond to two different profiles. On one hand, antipiracy agencies and malicious publishers publish a large amount of fake files to protect copyrighted content and spread malware respectively. On the other hand, content publishing in BitTorrent is largely driven by companies with financial incentive. Therefore, if these companies lose their interest or are unable to publish content, BitTorrent traffic/portals may disappear or at least their associated traffic will significantly reduce

Multi-flux warped throats and cascading gauge theories

We describe duality cascades and their infrared behavior for systems of D3-branes at singularities given by complex cones over del Pezzo surfaces (and related examples), in the presence of fractional branes. From the gauge field theory viewpoint, we show that D3-branes probing the infrared theory have a quantum deformed moduli space, given by a complex deformation of the initial geometry to a simpler one. This implies that for the dual supergravity viewpoint, the gauge theory strong infrared dynamics smoothes out the naked singularities of the recently constructed warped throat solutions with 3-form fluxes, describing the cascading RG flow of the gauge theory. This behavior thus generalizes the Klebanov-Strassler deformation of the conifold. We describe several explicit examples, including models with several scales of strong gauge dynamics. In the regime of widely separated scales, the dual supergravity solutions should correspond to throats with several radial regions with different exponential warp factors. These rich throat geometries are expected to have interesting applications in compactification and model building. Along our studies, we also construct explicit duality cascades for gauge theories with irrational R-charges, obtained from D-branes probing complex cones over dP1 and dP2

Non-supersymmetric meta-stable vacua from brane configurations

We construct configurations of NS-, D4-, and D6-branes in type IIA string theory, realizing the recently discussed non-supersymmetric meta-stable minimum of 4d = 1 SU(Nc) super-Yang-Mills theories with massive flavors. We discuss their lift to M-theory and the mechanism of pseudo-moduli stabilization. We extend the construction to many other examples of meta-stable minima, including the SO/Sp theories, SU(Nc) with matter in two-index tensor representations, and to a chiral gauge theory

Reducción de contenido armónico usando un filtro activo de potencia tipo serie

Esta tesis se enmarca del estudio de la distorsión y mejora de la perturbación amónica en un sistema eléctrico y concretamente en el diseño y control. De los tres parámetros a definir en el diseño de un filtro activo de potencia tipo serie son: obtención de la señal de referencia del control, el método de control implementado y la etapa de potencia utilizada, esta tesis realiza un estudio completo de ellos así: o Se realiza la revisión bibliográfica como guía de solución usada a la implementación del filtro activo tipo serie y su algoritmo. o Se elabora un estudio de los diferentes tipos de perturbación hacia la compensación armónica para la implementación del filtro activo tipo serie. o Se presenta la formulación teórica p-q desarrollando la estrategia de control correspondiente a la misma según los objetivos de compensación establecidos. o Se centra en las formulaciones basadas en los sistemas rotativos: la transformación de Park o teoría d-q, se ha establecido la estrategia de control derivada de la formulación estudiada. Con esta ayuda se explicara detalladamente la estructura del filtro activo de potencia serie con la ventaja de profundizar un poco más en el diseño y de este modo ser guiado al implementarlo

Considerations in Determining the Cost of Measurement Uncertainty Associated with Dimensional Tolerances Verification

The verification of compliance with a design specification in manufacturing requires the use of metrological instruments to check if the magnitude associated with the design specification is or not according with tolerance range. Such instrumentation and their use during the measurement process, has associated an uncertainty of measurement whose value must be related to the value of tolerance tested. Most papers dealing jointly tolerance and measurement uncertainties are mainly focused on the establishment of a relationship uncertainty-tolerance without paying much attention to the impact from the standpoint of process cost. This paper analyzes the cost-measurement uncertainty, considering uncertainty as a productive factor in the process outcome. This is done starting from a cost-tolerance model associated with the process. By means of this model the existence of a measurement uncertainty is calculated in quantitative terms of cost and its impact on the process is analyzed

Fractional branes and dynamical supersymmetry breaking

We study the dynamics of fractional branes at toric singularities, including cones over del Pezzo surfaces and the recently constructed Yp,q theories. We find that generically the field theories on such fractional branes show dynamical supersymmetry breaking, due to the appearance of non-perturbative superpotentials. In special cases, one recovers the known cases of supersymmetric infrared behaviors, associated to SYM confinement (mapped to complex deformations of the dual geometries, in the gauge/string correspondence sense) or N = 2 fractional branes. In the supersymmetry breaking cases, when the dynamics of closed string moduli at the singularity is included, the theories show a runaway behavior (involving moduli such as FI terms or equivalently dibaryonic operators), rather than stable non-supersymmetric minima. We comment on the implications of this gauge theory behavior for the infrared smoothing of the dual warped throat solutions with 3-form fluxes, describing duality cascades ending in such field theories. We finally provide a description of the different fractional branes in the recently introduced brane tiling configurations