Wormholes and masses for Goldstone bosons

There exist non-trivial stationary points of the Euclidean action for an axion particle minimally coupled to Einstein gravity, dubbed wormholes. They explicitly break the continuos global shift symmetry of the axion in a non-perturbative way, and generate an effective potential that may compete with QCD depending on the value of the axion decay constant. In this paper, we explore both theoretical and phenomenological aspects of this issue. On the theory side, we address the problem of stability of the wormhole solutions, and we show that the spectrum of the quadratic action features only positive eigenvalues. On the phenomenological side, we discuss, beside the obvious application to the QCD axion, relevant consequences for models with ultralight dark matter, black hole superradiance, and the relaxation of the electroweak scale. We conclude discussing wormhole solutions for a generic coset and the potential they generate.Comment: 50 pages, 15 figures. v2: minor changes, refs adde

Complete confined bases for beam propagation in Cartesian coordinates

Complete bases that are useful for beam propagation problems and that present the distinct property of being spatially confined at the initial plane are proposed. These bases are constructed in terms of polynomials of Gaussians, in contrast with standard alternatives such as the Hermite-Gaussian basis that are given by a Gaussian times a polynomial. The property of spatial confinement implies that, for all basis elements, the spatial extent at the initial plane is roughly the same. This property leads to an optimal scaling parameter that is independent of truncation order for the fitting of a confined initial field. Given their form as combinations of Gaussians, the paraxial propagation of these basis elements can be modeled analytically.Comment: 6 pages, 4 figures, \c{opyright} 2017 Optical Society of America. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibite

Lorenz-Mie scattering of focused light via complex focus fields: an analytic treatment

The Lorenz-Mie scattering of a wide class of focused electromagnetic fields off spherical particles is studied. The focused fields in question are constructed through complex focal displacements, leading to closed-form expressions that can exhibit several interesting physical properties, such as orbital and/or spin angular momentum, spatially-varying polarization, and a controllable degree of focusing. These fields constitute complete bases that can be considered as nonparaxial extensions of the standard Laguerre-Gauss beams and the recently proposed polynomials-of-Gaussians beams. Their analytic form turns out to lead also to closed-form expressions for their multipolar expansion. Such expansion can be used to compute the field scattered by a spherical particle and the resulting forces and torques exerted on it, for any relative position between the field's focus and the particle.Comment: 11 pages, 7 figure

El neoliberalismo en los países andinos en proceso de cambio. Los casos de Ecuador, Venezuela y Bolivia

Metadados do trabalho de conclusão de curso: El neoliberalismo en los países andinos en proceso de cambio. Los casos de Ecuador, Venezuela y Bolivia, pela/o discente: Rodrigo Alonso Marichal, sob orientação: Nilson Araújo de Souza do Centro de Economia e Sociedade, curso de Ciências Econômicas - Economia, Integração e Desenvolvimento da Universidade Federal da Integração Latino-Americana (UNILA), no Repositório Institucional da Unila (RI-UNILA).El neoliberalismo en los países andinos en proceso de cambio. Los casos de Ecuador, Venezuela y Bolivi

Soliton fermionic number from the heat kernel expansion

Producción CientíficaWe consider different methods of calculating the (fractional) fermion number of solitons based on the heat kernel expansion. We derive a formula for the localized η function that provides a more systematic version of the derivative expansion for spectral asymmetry and compute the fermion number in amulti flavor extension of the Goldstone–Wilczek model. We also propose an improved expansion of the heat kernel that allows the tackling of the convergence issues and permits an automated computation of the coefficients.Juant de Castilla y León grant BU 229P18

Aplicación para racionalizar el uso del móvil

Este Trabajo de Fin de Grado agrupa una serie de tecnologías distintas para crear una aplicación Android que tiene como objetivo incentivar en el usuario la disminución de su uso del teléfono móvil. Esto es porque hoy en día estos dispositivos se utilizan, en mi opinión, de manera desmedida e innecesaria en la mayoría de los casos, y muchos usuarios tan solo necesitan y/o desean un pequeño aliciente para dejar de hacerlo. Si bien es cierto que el lector se podría plantear si la mejor alternativa para evitar el uso del móvil es una aplicación, lo cual es un tanto paradójico, mi respuesta ante eso es que es un mal necesario para lograr un bien superior. La aplicación pretende lograr estos objetivos a través de un acuario realizado en el motor de videojuegos Unity. El contenido de este acuario progresa en conformidad con el uso del dispositivo a través de una biblioteca de Android desarrollada en Java que accede al tiempo de uso de todas las demás aplicaciones. Esta información se procesa con un algoritmo cuya salida decide la medida en la que el acuario varía, tanto para bien, aumentando el tamaño de los peces, como para mal, disminuyéndolo. Los datos de un usuario serán persistentes ya que éste se autenticará en Google Play Juegos y se mantendrá constancia de sus pertenencias en una base de datos online y en tiempo real en Firebase, de Google. Todo lo anterior crea un entorno que permite poder compartir tu acuario con otras personas y crear competencia entre acuarios, en otras palabras, competencia en reducir el tiempo de uso de los aparatos Android

Chaotic Vibrations in a Buckled Beam Induced by a Galloping Phenomenon

Chaos theory has spectacularly evolved since the pioneering work by E. Lorenz on chaotic motion in a simple, deterministic system. Since then, the chaotic behavior of many other deterministic, low-dimensional systems in a large variety of fields has been developed. In the particular field of aeroelasticity of aircraft structures several reports of chaos have been documented. However, we are unaware of any report of chaotic systems of civil (non-aeronautical) use induced by an aeroelastic phenomenon. In this paper a well defined civil, aeroelastic system, susceptible to exhibit chaotic behavior is presented. The system consists of a buckled beam from which a second beam is suspended. This last beam (hereafter, galloping beam) has a square cross- section and can undergo transverse galloping. The system is subjected to an uniform wind flow and, as it will be shown in the paper, for wind velocities larger than a threshold value, the galloping beam begins to oscillate and induces, for a determined set of parameter values, a chaotic motion in the buckled bea