Inhomogenous loop quantum cosmology with matter

The linearly polarized Gowdy $T^3$ model with a massless scalar field with the same symmetries as the metric is quantized by applying a hybrid approach. The homogeneous geometry degrees of freedom are loop quantized, fact which leads to the resolution of the cosmological singularity, while a Fock quantization is employed for both matter and gravitational inhomogeneities. Owing to the inclusion of the massless scalar field this system allows us to modelize flat Friedmann-Robertson-Walker cosmologies filled with inhomogeneities propagating in one direction. It provides a perfect scenario to study the quantum back-reaction between the inhomogeneities and the polymeric homogeneous and isotropic background.Comment: 4 pages, Contribution to the proceedings of the Loops 11-Madrid conferenc

Inclusion of matter in inhomogeneous loop quantum cosmology

We study the hybrid quantization of the linearly polarized Gowdy $T^3$ model with a massless scalar field with the same symmetries as the metric. For simplicity, we quantize its restriction to the model with local rotational symmetry. Using this hybrid approach, the homogeneous degrees of freedom of the geometry are quantized \`a la loop, leading to the resolution of the cosmological singularity. A Fock quantization is employed both for the matter and the gravitational inhomogeneities. Owing to the inclusion of the massless scalar field this system allows us to modelize flat Friedmann-Robertson-Walker cosmologies filled with inhomogeneities propagating in one direction, providing a perfect scenario to study the quantum back-reaction of the inhomogeneities on the polymeric homogeneous and isotropic background.Comment: 4 pages. Contribution to the Proceedings of Spanish Relativity Meeting ERE2011, Madrid 201

Approximation methods in Loop Quantum Cosmology: From Gowdy cosmologies to inhomogeneous models in Friedmann-Robertson-Walker geometries

We develop approximation methods in the hybrid quantization of the Gowdy model with linear polarization and a massless scalar field, for the case of three-torus spatial topology. The loop quantization of the homogeneous gravitational sector of the Gowdy model (according to the improved dynamics prescription) and the presence of inhomogeneities lead to a very complicated Hamiltonian constraint. Therefore, the extraction of physical results calls for the introduction of well justified approximations. We first show how to approximate the homogeneous part of the Hamiltonian constraint, corresponding to Bianchi I geometries, as if it described a Friedmann-Robertson-Walker (FRW) model corrected with anisotropies. This approximation is valid in the high-energy sector of the FRW geometry (concerning its contribution to the constraint) and for anisotropy profiles that are sufficiently smooth. In addition, for certain families of states associated to regimes of physical interest, with negligible effects of the anisotropies and small inhomogeneities, one can approximate the Hamiltonian constraint of the inhomogeneous system by that of an FRW geometry with a relatively simple matter content, and then obtain its solutions.Comment: 20 pages, 3 figures. Minor changes, matches published versio

Irreducible Lie-Yamaguti algebras

Lie-Yamaguti algebras (or generalized Lie triple systems) are binary-ternary algebras intimately related to reductive homogeneous spaces. The Lie-Yamaguti algebras which are irreducible as modules over their Lie inner derivation algebra are the algebraic counterpart of the isotropy irreducible homogeneous spaces. These systems will be shown to split into three disjoint types: adjoint type, non-simple type and generic type. The systems of the first two types will be classified and most of them will be shown to be related to a Generalized Tits Construction of Lie algebras.Comment: 25 page

Introduction to Loop Quantum Cosmology

This is an introduction to loop quantum cosmology (LQC) reviewing mini- and midisuperspace models as well as homogeneous and inhomogeneous effective dynamics

Tool for acquisition of biometric signature samples

Signature Forgers es una aplicación para sistemas operativos Windows, desarrollada en C#, que entrena a falsificadores en la falsificación de firmas manuscritas. En la aplicación, los falsificadores tienen que superar 10 niveles de entrenamiento en los que se le mostrará distinta información de la firma original a falsificar. Durante dicho entrenamiento, la aplicación almacena datos relevantes de las firmas para su estudio posterior. Gracias a esta aplicación es posible estudiar el rendimiento y la habilidad de un falsificador, al medir la cantidad de conocimiento que éste obtiene de la firma en cada nivel. Las investigaciones en este campo ayudan a mejorar la seguridad de los distintos algoritmos de procesado, determinando cómo de difícil es engañar al sistema biométrico y, por tanto, cuál es su seguridad real.Ingeniería en Tecnologías de Telecomunicació

Una aproximación a la publicidad de cosméticos en las revistas femeninas editadas en España

Este trabajo analiza la publicidad gráfica de las marcas del creciente sector de la belleza y los cosméticos. Se estudian los anuncios aparecidos en su medio de preferencia: las revistas femeninas (editadas en España). A través de un análisis de contenido, mediante el registro de variables manifiestas, se ha estudiado la construcción comunicativa de estos mensajes visuales, en los que el recurso icónico primordial es la fotografía artística. El elemento central de la gráfica es una estructura que persigue representar los valores enunciados por la marca en el texto del anuncio y la composición nos guía desde la modelo, la persona que personifica dichos valores, hacia el producto.This work analyzes the graphic advertising of the brands of the growing sector of beauty and cosmetics. We study the advertising insertions appearing in their favorite medium: women's magazines (published in Spain). Through the analysis of content and recording manifest variables, we have studied the communicative construction of these visual messages, in which the iconic resource of artistic photography prevails. The main element of the graph is a structure that tries to represent the values enunciated by the brand in the advertisement claim and the composition leads us from the model, the person personifying those values, to the product.Aquest treball analitza la publicitat gràfica de les marques del creixent sector de la bellesa i els cosmètics. S'estudien els anuncis apareguts en el seu mitjà de preferència: les revistes femenines (editades a Espanya). A través d'una anàlisi de contingut, mitjançant el registre de variables manifestes, s'ha estudiat la construcció comunicativa d'aquests missatges visuals, en què el recurs icònic primordial és la fotografia artística. L'element central de la gràfica és una estructura que persegueix representar els valors enunciats per la marca al text de l'anunci i la composició ens guia des de la model, la persona que personifica aquests valors, cap al producte

Las gorras de paja de Bohoyo

En número dedicado a: La provincia de Ávil

Hybrid Quantum Cosmology: Combining Loop and Fock Quantizations

As a necessary step towards the extraction of realistic results from Loop Quantum Cosmology, we analyze the physical consequences of including inhomogeneities. We consider in detail the quantization of a gravitational model in vacuo which possesses local degrees of freedom, namely, the linearly polarized Gowdy cosmologies with the spatial topology of a three-torus. We carry out a hybrid quantization which combines loop and Fock techniques. We discuss the main aspects and results of this hybrid quantization, which include the resolution of the cosmological singularity, the polymeric quantization of the internal time, a rigorous definition of the quantum constraints and the construction of their solutions, the Hilbert structure of the physical states, and the recovery of a conventional Fock quantization for the inhomogeneities.Comment: 24 pages, published in International Journal of Modern Physics A, Special Issue: Proceedings of the Second Workshop on Quantum Gravity and Noncommutative Geometry (Lisbon, Portugal