2,810 research outputs found
Hybrid quantization of an inflationary model: The flat case
We present a complete quantization of an approximately homogeneous and
isotropic universe with small scalar perturbations. We consider the case in
which the matter content is a minimally coupled scalar field and the spatial
sections are flat and compact, with the topology of a three-torus. The
quantization is carried out along the lines that were put forward by the
authors in a previous work for spherical topology. The action of the system is
truncated at second order in perturbations. The local gauge freedom is fixed at
the classical level, although different gauges are discussed and shown to lead
to equivalent conclusions. Moreover, descriptions in terms of gauge-invariant
quantities are considered. The reduced system is proven to admit a symplectic
structure, and its dynamical evolution is dictated by a Hamiltonian constraint.
Then, the background geometry is polymerically quantized, while a Fock
representation is adopted for the inhomogeneities. The latter is selected by
uniqueness criteria adapted from quantum field theory in curved spacetimes,
which determine a specific scaling of the perturbations. In our hybrid
quantization, we promote the Hamiltonian constraint to an operator on the
kinematical Hilbert space. If the zero mode of the scalar field is interpreted
as a relational time, a suitable ansatz for the dependence of the physical
states on the polymeric degrees of freedom leads to a quantum wave equation for
the evolution of the perturbations. Alternatively, the solutions to the quantum
constraint can be characterized by their initial data on the minimum-volume
section of each superselection sector. The physical implications of this model
will be addressed in a future work, in order to check whether they are
compatible with observations.Comment: 20 pages, no figures. v2: minor changes, in particular, abstract
shortened, final discussion improve
Effective dynamics of scalar perturbations in a flat Friedmann-Robertson-Walker spacetime in Loop Quantum Cosmology
We study the evolution of a homogeneous and isotropic spacetime whose spatial
sections have three-torus topology, coupled to a massless scalar field with
small scalar perturbations within loop quantum cosmology. We consider a
proposal for the effective dynamics based on a previous hybrid quantization
completed by us. Consequently, we introduce a convenient gauge fixing and adopt
reduced canonical variables adapted to that hybrid quantum description.
Besides, we keep backreaction contributions on the background coming from terms
quadratic in the perturbations in the action of the system. We carry out a
numerical analysis assuming that the inhomogeneities were in a massless vacuum
state at distant past (where the initial data are set). At distant future, we
observe a statistical amplification of the modes amplitude in the infrared
region, as well as a phase synchronization arising from quantum gravity
phenomena. A description of the perturbations in terms of the Mukhanov-Sasaki
gauge invariants provides the same qualitative results. Finally, we analyze
some consequences of the backreaction in our effective description.Comment: 15 pages, 9 figures. Accepted for publication in Phys. Rev.
A complete hybrid quantization in inhomogeneous cosmology
A complete quantization of a homogeneous and isotropic spacetime with closed
spatial sections coupled to a massive scalar field is provided, within the
framework of Loop Quantum Cosmology. We identify solutions with their initial
data on the minimum volume section, and from this we construct the physical
Hilbert space. Moreover, a perturbative study allows us to introduce small
inhomogeneities. After gauge fixing, the inhomogeneous part of the system is
reduced to a linear field theory. We then adopt a standard Fock representation
to quantize these degrees of freedom. For the considered case of compact
spatial topology, the requirements of: i) invariance under the spatial
isometries, and ii) unitary implementation of the quantum dynamics, pick up a
unique Fock representation and a particular set of canonical fields (up to
unitary equivalence).Comment: 6 page
La sociedad civil desde la perspectiva metaestructural
The draft of this work lies in raising the definition of civil society from the perspective of the thinker Jacques Bidet. At first highlights the theme of modernity and thus of the existence of a metastructure that resides in a contractual relationship for both sides. At the same type of two types of rationality that run along modernity to give a picture metastructural. Civil society, therefore, from the perspective requires metastructural centricity, the interindividual and associativity. Finally, civil society from this perspective involves a dialectic of conflict that involves a dialectical relationship between the contractual terms of the speech alone can lead to a dialogue of all which is a kind of overdetermination of one ter
Migración de procesos de conversión en Perl a Aspire
Proyecto de Graduación (Bachillerato en IngenierÃa en Computación). Instituto Tecnológico de Costa Rica. Escuela de IngenierÃa en Computación, 2010.Este proyecto tiene como objetivo analizar una serie de procesos realizados para un cliente de la empresa Search Technologies. Estos procesos transforman documentos electrónicos a un formato más estructurado que permita su posterior indexación y publicación, ya sea tanto en lÃnea como fuera de lÃnea por medio de herramientas como Rocket NXT y Folio. Una vez analizados estos procesos, se han migrado a Aspire, una plataforma para procesamiento de documentos de alto rendimiento perteneciente a Search Technologies.
Los procesos escritos en Perl originalmente tienen como entrada documentos en formato
Microsoft Word 2003, PDF y HTML. Estos documentos deben ser convertidos a formato
HTML si no lo estuvieran y luego recibir una serie de transformaciones textuales mediante el uso de expresiones regulares, con el fin de que su posterior indexación y publicación pueda ser llevada a cabo satisfactoriamente. Este proceso es actualmente semiautomático, es decir, una parte del proceso debe ser realizada manualmente. Este proyecto fue capaz de automatizar el proceso en su totalidad y facilitar futuras implementaciones para otros clientes con necesidades similares.
La migración realizada consiste en la creación de pipelines de procesamiento en un ambiente de ejecución concurrente de muchos hilos y el uso extensivo de expresiones regulares. ______________________________________________________________
ABSTRACT
The goal of this project is to analyze a series of processes done for a particular client of
Search Technologies Company. Those processes transform electronic documents to a more
structured format that will allow them to be indexed and published online or offline using
Rocket NXT and Folio products. Once analyzed, those processes have been migrated to
Aspire, a high performance document processing framework property of Search
Technologies.
The processes originally written in Perl have as input Microsoft Word 2003 documents, PDF
and HTML files. Those documents must be converted to HTML format, if they were not yet,
and then passed through a series of text transformations using regular expressions, with the
intention of a later successful indexation and publication. This process is semiautomatic, i.e.,
part of the process is done manually. This project was capable of automate the process
entirely and facilitate future implementations for other clients with similar needs.
The migration consists of the creation of processing pipelines in a multithread concurrent
environment and the extensive use of regular expressions
Alternative method for information georeferencing coordinate system magna-sirgas
El posicionamiento preciso de puntos por sus siglas en ingles PPP, representa un método alternativo y de bajo costo que permite la georreferenciación de mojones o vértices de apoyo, que posteriormente, a partir de ellos, permitirán la captura de información con las precisiones suficientes para las necesidades de los trabajos de consultorÃa en generalN/AThe precise positioning of points for its acronym in English PPP represents an alternative and inexpensive allowing georeferenced landmarks or vertices of support, then from them, allow the capture of information with sufficient information for needs of consulting work in genera
(Tres problemas clásicos en Análisis Matemático)
Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Matemáticas, Departamento de Análisis Matemático y Matemática Aplicada, leÃda el 17-05-2021The title of this dissertation alludes to the study of three classical problems of mathematical analysis. All the results that have been obtained as the fruit of four years of hard work are related, wholly or partially to at least one of the following three fields:• Banach spaces of polynomials: This is a vast field as the educated reader knows well. In particular we have studied continuity properties of polynomials on Banach spaces and topological relationships among polynomial spaces.• Algebraic genericity and lineability: This is the study of the algebraic structure within certain sets in a linear space. We give an answer to a question posed by Gurariy in the early 2000’s and, as a matter of fact, we prove a generalizationto the question formulated by Gurariy. We also link the notion of algebraic genericity to the study of sequences of operators related to Taylor series. • The classical Bohr radius problem: We provide an estimated on the n-dimensional Bohr radius for the polydisk Dn that improves other previous estimates...El tÃtulo de esta tesis alude al estudio de tres problemas clásicos. Los resultados que se han obtenido, que son el fruto del arduo trabajo llevado a cabo durante los últimos cuatro años, están relacionados, total o parcialmente, con algunos de estos tres temas clásicos del Análisis Matemático: • Espacios de Banach de polinomios: Este es un tema muy extenso, como cualquier lector avezado entenderá enseguida. Siendo más concretos, estudiamos propiedades relacionadas con la continuidad de polinomios en espacios de Banach. También estudiamos la relación existente entre las topologÃas inducidas por diversas normas en un espacio de polinomios. • Genericidad Algebraica y lineabilidad: Este tema consiste en el estudio de las estructuras algebraicas contenidas en determinados conjuntos de un espacio vectorial o un álgebra. En este sentido, aportamos una solución completa a un problema planteado por V. Gurariy poco después del año 2000. De hecho, la solución proporcionada aquà es, en realidad, una generalización del problema original formulado por V. Gurariy. También investigamos problemas vinculados a la noción de genericidad algebraica en el contexto de sucesiones de operadores relacionados con series de Taylor. • El problema clásico del radio de Bohr: Como principal aportación a este problema, damos una acotación (inferior) del radio de Bohr n-dimensional para el polidisco Dn que mejora estimaciones previas...Fac. de Ciencias MatemáticasTRUEunpu
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