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Sample records for lorentz como ecuaciones

  1. Ecuaciones de diferencias mejoradas para ecuaciones diferenciales

    OpenAIRE

    Lick, Wilbert

    1985-01-01

    Se presenta en este artículo una resena sobre el uso del método integral para derivar ecuaciones de diferencias a partir de ecuaciones diferenciales. El método se aplica a varios tipos de ecuaciones diferenciales ordinarias correspondientes a problemas de valores de contorno y a problemas de valores iniciales, ilustrándose la utilidad del método con varios ejemplos sencillos. Peer Reviewed

  2. El conocimiento semántico en la representación de problemas de ecuaciones diferenciales como modelos matemáticos.

    Directory of Open Access Journals (Sweden)

    Rosa Virginia Hernández

    2016-12-01

    Full Text Available En este artículo se presenta la caracterización del conocimiento semántico evidenciado por un grupo de estudiantes en la representación externa a problemas de ecuaciones diferenciales lineales de segundo orden como modelos matemáticos. El trabajo fue cuantitativo de tipo exploratorio y descriptivo utilizando un cuestionario en la recolección de información. El soporte teórico que dio sentido al estudio fue el modelo de dos etapas propuesto por Mayer R. para la resolución de problemas matemáticos, el ciclo de modelación bajo la perspectiva cognitiva según Borromeo Ferri y la teoría de las representaciones de Goldin y Kaput. La investigación se centró específicamente en la fase de representación del modelo. Entre los principales hallazgos se destaca que cada participante hace su propia representación externa a conceptos como: sistema masa-resorte, peso, masa, punto de equilibrio, constante de elasticidad, punto de equilibrio, ley de Hooke, fuerza amortiguadora, fuerza externa, ley de Newton, entre otros. Se evidencian también dificultades en el tránsito del lenguaje natural al lenguaje matemático y la representación externa de cada una de los signos, símbolos o expresiones matemáticas inmersas en el problema de palabra, debido a que el resolutor tiene que construir un modelo mental de la situación real y plasmarlo en un modelo matemático. Lo anterior pone de manifiesto la importancia que tiene el conocimiento semántico en la etapa de traducción cuando se intentan resolver problemas como situaciones reales a modelar.

  3. Formulación variacional de ecuaciones diferenciales parciales

    Directory of Open Access Journals (Sweden)

    Luis J. Collantes

    2010-01-01

    Full Text Available En este trabajo se presenta una descripción del método variacional, el cual que se utiliza para el estudio cualitativo de ecuaciones diferenciales parciales: existencia, unicidad y regularidad de la solución. Se exhibe como ilustración el análisis de ecuaciones diferenciales parciales elípticas lineales de segundo orden, así como el estudio de una ecuación diferencial parcial hiperbólica no lineal de primer orden, en la cual se muestra la adaptabilidad del método.

  4. OFERTA Y DEMANDA: UN MODELO MATEMÁTICO CON ECUACIONES DIFERENCIALES

    OpenAIRE

    Hernán Alberto Escobar

    2010-01-01

    Se presentan inicialmente unas ideas relacionadas con los modelos matemáticos en general, para luego enfocarse en uno muy concreto: el que utiliza como insumo básico las ecuaciones diferenciales ordinarias (EDOs). Dado que el modelo de oferta y demanda, utiliza para su explicación matemática y económica, las ecuaciones diferenciales lineales, se lleva a cabo una explicación de cómo obtener una solución analítica y gráfica de dichas ecuaciones. Posteriormente, se explica con detalle los elemen...

  5. OFERTA Y DEMANDA: UN MODELO MATEMÁTICO CON ECUACIONES DIFERENCIALES

    Directory of Open Access Journals (Sweden)

    Hernán Alberto Escobar

    2010-07-01

    Full Text Available Se presentan inicialmente unas ideas relacionadas con los modelos matemáticos en general, para luego enfocarse en uno muy concreto: el que utiliza como insumo básico las ecuaciones diferenciales ordinarias (EDOs. Dado que el modelo de oferta y demanda, utiliza para su explicación matemática y económica, las ecuaciones diferenciales lineales, se lleva a cabo una explicación de cómo obtener una solución analítica y gráfica de dichas ecuaciones. Posteriormente, se explica con detalle los elementos básicos para definir con lenguaje de ecuaciones diferenciales los conceptos de oferta, demanda y el principio económico que los une, a través del planteamiento y solución de varios ejemplos de aplicación.

  6. Ecuaciones simultáneas con aplicaciones en Gretl

    OpenAIRE

    Regúlez Castillo, Marta

    2008-01-01

    Es un manual de utilidad tanto para alumnos de último año de licenciatura en especialidades de Cuantitativa, Macroeconomía, Economía del Trabajo, Economía Internacional, como para alumnos de master o doctorado con perfil cuantitativo. 1.El modelo de ecuaciones simultáneas. Forma estructural y forma reducida. 2.Identificación: Condiciones de orden y rango. 3.Estimación con información limitada. Estimación por MCO. Problemas en la forma estructural. Mínimos Cuadrados Indirectos (MC...

  7. Ecuaciones, teorías y ciencias que las usan

    Directory of Open Access Journals (Sweden)

    Rosa María Herrera

    2012-10-01

    Full Text Available Algunas ecuaciones resultan buenos modelos en problemas de la física alejados entre sí. Algunos modelos matemáticos suponen una abstracción subyacente en distintas teorías e incluso en diferentes ramas científicas. Algunas teorías nacen en cierto ambiente científico, perotrasladadas a otro resultan muy productivas e incluso crecen. Aquí se formulan algunos ejemplos de cada caso, se señala la estrategia de su construcción y se intenta indicar (explicar su valor como herramienta científica.

  8. Formulación variacional de ecuaciones diferenciales parciales

    Directory of Open Access Journals (Sweden)

    Luis J. Collantes

    2010-12-01

    Full Text Available En este trabajo se presenta una descripción del método variacional, el cual que se utiliza para el estudio cualitativo de ecuaciones diferenciales parciales: existencia, unicidad y regularidad de la solución. Se exhibe como ilustración el análisis de ecuaciones diferenciales parciales elípticas lineales de segundo orden, así como el estudio de una ecuación diferencial parcial hiperbólica no lineal de primer orden, en la cual se muestra la adaptabilidad del método. Abstract. This paper deals with the study of the variational method for partial differential equations concerning the existence, uniqueness and regularity of the solution. The aim of this work is to give a comprehensive description of the variational method, presenting examples from the simple second order linear elliptic partial differential equations to a most complex first order non-linear partial differential equation. Comments on the adaptability of this method to this kind of equations are given

  9. Sobre la aplicación del método de entropía en el estudio de soluciones globales en tiempo de ecuaciones diferenciales de evolución de tipo parabólico

    OpenAIRE

    Langoni, Laura

    2011-01-01

    Es un hecho conocido la creciente importancia y el amplio campo de aplicación que las ecuaciones en derivadas parciales tienen en la construcción de modelos matemáticos para la descripción de una gran variedad de problemas provenientes de diversas áreas del saber como, por ejemplo, la economía, la física, la biología. Muchos procesos de las ciencias aplicadas se pueden modelar matemáticamente por medio de ecuaciones de evolución. Estas ecuaciones, llamadas ecuaciones de estado, desc...

  10. Compactones, soluciones de ecuaciones no lineales con estructura tipo esferas duras

    Directory of Open Access Journals (Sweden)

    Máximo Agüero Granados

    2001-01-01

    Full Text Available Se estudian ciertas soluciones de ecuaciones no lineales que modelan procesos físicos, que tienen semejanzas con estructuras coherentes del tipo de esferas duras, modelo de partículas muy usado en varias ramas de la física. Estas soluciones compactas (gotas, kinks, etcétera. interactúan entre sí sólo a cortas distancias, porque no poseen colas infinitas como los solitones clásicos.

  11. Searching for Lorentz violation

    International Nuclear Information System (INIS)

    Allen, Roland E.; Yokoo, Seiichirou

    2004-01-01

    Astrophysical, terrestrial, and space-based searches for Lorentz violation are very briefly reviewed. Such searches are motivated by the fact that all superunified theories (and other theories that attempt to include quantum gravity) have some potential for observable violations of Lorentz invariance. Another motivation is the exquisite sensitivity of certain well-designed experiments and observations to particular forms of Lorentz violation. We also review some new predictions of a specific Lorentz-violating theory: If a fundamental energy m-bar c2 in this theory lies below the usual GZK cutoff E GZK , the cutoff is shifted to infinite energy; i.e., it no longer exists. On the other hand, if m-bar c2 lies above E GZK , there is a high-energy branch of the fermion dispersion relation which provides an alternative mechanism for super-GZK cosmic-ray protons

  12. El uso de manipulables para propiciar la comprensión del significado de ecuaciones lineales y cuadráticas, y de sistemas de ecuaciones lineales en la escuela secundaria

    OpenAIRE

    García, Paola; Vargas, Jorge

    2014-01-01

    El presente trabajo es una investigación en curso, en donde se pretende analizar el papel que juega la utilización de manipulables (balanzas concretas y balanzas simuladas utilizando GeoGebra) como recurso didáctico para propiciar la comprensión del significado de ecuaciones lineales, cuadráticas y sistemas de ecuaciones lineales en estudiantes de secundaria, de entre 13 y 15 años de edad, mediante una manipulación activa de dichos aparatos a través del contacto directo de estos con los estud...

  13. Ecuaciones diferenciales : teoría y práctica

    OpenAIRE

    Perelló, Miguel Ángel

    2002-01-01

    Ecuaciones diferenciales de primer orden. Ecuaciones y sistemas de orden superior. Series y transformada de Laplace. Teoría de la estabilidad. Ecuaciones en derivadas parciales. Introducción al cálculo variacional.

  14. Cálculo numérico y analítico de las ecuaciones de Karman-Prandtl para la estimación de coeficiente de fricción

    OpenAIRE

    Escobar Zamora, Iván

    2014-01-01

    El objetivo de este PFC es el desarollo, adaptación y aplicación de diferentes métodos numéricos para la resolución de las ecuaciones de Karman-Prandtl. Se realizará un estudio de los diferentes métodos numéricos para la resolución de ecuaciones y sistemas de ecuaciones diferenciales ordinarias, así como para la resolución de sistemas de ecuaciones no lineales. Se aplicarán dentro del campo de la Ingeniería Naval, en particular se buscará aproximar las ecuaciones de Karman-P...

  15. Threshold analyses and Lorentz violation

    International Nuclear Information System (INIS)

    Lehnert, Ralf

    2003-01-01

    In the context of threshold investigations of Lorentz violation, we discuss the fundamental principle of coordinate independence, the role of an effective dynamical framework, and the conditions of positivity and causality. Our analysis excludes a variety of previously considered Lorentz-breaking parameters and opens an avenue for viable dispersion-relation investigations of Lorentz violation

  16. Modelos en red para la resolución de sistemas de ecuaciones diferenciales acopladas : aplicación a problemas mecánicos

    OpenAIRE

    García Pérez, Mario

    2015-01-01

    La presente memoria aplica el método de simulación por redes a la búsqueda de soluciones numéricas de problemas formulados mediante ecuaciones diferenciales ordinarias o sistemas acoplados de estas ecuaciones, mediante el diseño de modelos en red y la subsiguiente simulación de estos modelos en un código de resolución de circuitos tal como Pspice u Orcad. La elaboración de este trabajo conlleva como objetivo inmediato la familiarización del alumno con conceptos no triviales de la teoría de...

  17. Algunos Aspectos de las ecuaciones autónomas

    OpenAIRE

    Rosales, José

    2006-01-01

    Se presentan teoremas básicos de ecuaciones diferenciales autónomas y algunos resultados interesantes sobre tales teoremas que permiten describir de manera efectiva ciertas propiedades de las órbitas de tales sistemas.

  18. Lorentz violation naturalness revisited

    Energy Technology Data Exchange (ETDEWEB)

    Belenchia, Alessio; Gambassi, Andrea; Liberati, Stefano [SISSA - International School for Advanced Studies, via Bonomea 265, 34136 Trieste (Italy); INFN, Sezione di Trieste, via Valerio 2, 34127 Trieste (Italy)

    2016-06-08

    We revisit here the naturalness problem of Lorentz invariance violations on a simple toy model of a scalar field coupled to a fermion field via a Yukawa interaction. We first review some well-known results concerning the low-energy percolation of Lorentz violation from high energies, presenting some details of the analysis not explicitly discussed in the literature and discussing some previously unnoticed subtleties. We then show how a separation between the scale of validity of the effective field theory and that one of Lorentz invariance violations can hinder this low-energy percolation. While such protection mechanism was previously considered in the literature, we provide here a simple illustration of how it works and of its general features. Finally, we consider a case in which dissipation is present, showing that the dissipative behaviour does not percolate generically to lower mass dimension operators albeit dispersion does. Moreover, we show that a scale separation can protect from unsuppressed low-energy percolation also in this case.

  19. SOBRE LAS ÓRBITAS PERIÓDICAS DE ECUACIONES DIFERENCIALES EN EL PLANO

    OpenAIRE

    Villaseñor Aguilar, Gabriel

    2012-01-01

    Las ecuaciones diferenciales, como es bien conocido, modelan una gran cantidad de situaciones de las matemáticas, física, ingeniería y demás ciencias aplicadas. En probabilidad y estadí́stica se obtiene razón de interés compuesto, en física el trabajo que se requiere en determinada condición de tiempo y espacio, crecimientos poblacionales, circuitos eléctricos, temperatura, etc. Una solución de una ecuación diferencial es una función que satisface la relación diferencial dada, a...

  20. Three questions on Lorentz violation

    Energy Technology Data Exchange (ETDEWEB)

    Iorio, Alfredo [Institute of Particle and Nuclear Physics, Charles University of Prague - V Holesovickach 2, 180 00 Prague 8 (Czech Republic); Department of Physics ' E. R. Caianiello' , University of Salerno and I.N.F.N. Naples, Gruppo Collegato di Salerno - Via Allende, 84081 Baronissi (Italy)

    2007-05-15

    We review the basics of the two most widely used approaches to Lorentz violation - the Standard Model Extension and Noncommutative Field Theory - and discuss in some detail the example of the modified spectrum of the synchrotron radiation. Motivated by touching upon such a fundamental issue as Lorentz symmetry, we ask three questions: What is behind the search for Lorentz violation? Is String Theory a physical theory? Is there an alternative to Supersymmetry?.

  1. Dynamics on Lorentz manifolds

    CERN Document Server

    Adams, Scot

    2001-01-01

    Within the general framework of the dynamics of "large" groups on geometric spaces, the focus is on the types of groups that can act in complicated ways on Lorentz manifolds, and on the structure of the resulting manifolds and actions. This particular area of dynamics is an active one, and not all the results are in their final form. However, at this point, a great deal can be said about the particular Lie groups that come up in this context. It is impressive that, even assuming very weak recurrence of the action, the list of possible groups is quite restricted. For the most complicated of the

  2. Método heurístico en el aprendizaje de ecuaciones diferenciales en estudiantes de ingenierías de la UNA - Puno - 2010

    OpenAIRE

    Condori Concha, Martín

    2012-01-01

    La presente investigación denominado "Método heurístico en el aprendizaje de ecuaciones diferenciales en estudiantes de ingenierías de la Universidad Nacional del Altiplano Puno" durante el primer semestre del 2009 que corresponde desde 21 de abril hasta 14 de Junio del 2010; tiene como objetivo de contribuir al proceso enseñanza-aprendizaje, la utilización del método heurístico en el aprendizaje de ecuaciones diferenciales en estudiantes de Ingenierías. La hipótesis con que se desarrolló la ...

  3. Physics of the Lorentz Group

    Science.gov (United States)

    Başkal, Sibel

    2015-11-01

    This book explains the Lorentz mathematical group in a language familiar to physicists. While the three-dimensional rotation group is one of the standard mathematical tools in physics, the Lorentz group of the four-dimensional Minkowski space is still very strange to most present-day physicists. It plays an essential role in understanding particles moving at close to light speed and is becoming the essential language for quantum optics, classical optics, and information science. The book is based on papers and books published by the authors on the representations of the Lorentz group based on harmonic oscillators and their applications to high-energy physics and to Wigner functions applicable to quantum optics. It also covers the two-by-two representations of the Lorentz group applicable to ray optics, including cavity, multilayer and lens optics, as well as representations of the Lorentz group applicable to Stokes parameters and the Poincaré sphere on polarization optics.

  4. Astroparticle tests of Lorentz symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, Jorge [Karlsruhe Institute of Technology, Karlsruhe (Germany)

    2016-07-01

    Lorentz symmetry is a cornerstone of modern physics. As the spacetime symmetry of special relativity, Lorentz invariance is a basic component of the standard model of particle physics and general relativity, which to date constitute our most successful descriptions of nature. Deviations from exact symmetry would radically change our view of the universe and current experiments allow us to test the validity of this assumption. In this talk, I describe effects of Lorentz violation in cosmic rays and gamma rays that can be studied in current observatories.

  5. Brane Lorentz symmetry from Lorentz breaking in the bulk

    Energy Technology Data Exchange (ETDEWEB)

    Bertolami, O [Departamento de Fisica, Instituto Superior Tecnico, Avenida Rovisco Pais 1, 1049-001 Lisbon (Portugal); Carvalho, C [Departamento de Fisica, Instituto Superior Tecnico, Avenida Rovisco Pais 1, 1049-001 Lisbon (Portugal)

    2007-05-15

    We propose the mechanism of spontaneous symmetry breaking of a bulk vector field as a way to generate the selection of bulk dimensions invisible to the standard model confined to the brane. By assigning a nonvanishing vacuum value to the vector field, a direction is singled out in the bulk vacuum, thus breaking the bulk Lorentz symmetry. We present the condition for induced Lorentz symmetry on the brane, as phenomenologically required.

  6. Propuesta de ecuaciones para predecir la composición corporal de ratas machos wistar

    Directory of Open Access Journals (Sweden)

    Marco Antonio Cossio-Bolaños

    2010-04-01

    Full Text Available Introducción: La evaluación de la composición corporal es importante, porque permite conocer el fraccionamiento del peso corporal en peso muscular, peso graso, peso residual y peso óseo, tanto en humanos, como en animales. Objetivos: Validar ecuaciones somáticas para predecir la composición corporal de un modelo tri-compartimental (peso graso, peso libre de grasa y peso residual de ratas machos wistar. Diseño: Estudio de tipo descriptivo de corte transversal. Institución: Facultad de Biología de la universidad estatal UNICAMP, Sao Paulo, Brasil. Material biológico: Ratas machos wistar. Métodos: Se estudió a 10 ratas machos wistar, con un promedio de edad de (X=98,00±10,40 días, se les evaluó el peso corporal (g. Enseguida fueron sacrificados y se procedió al fraccionamiento del peso graso (piel, peso libre de grasa (músculo y hueso y peso residual (PR (g. Los resultados fueron analizados por estadística descriptiva de media aritmética (X, desviación estándar (DE y correlación producto momento de Pearson (r. Para predecir los componentes, se aplicó regresiones estadísticas simples y múltiples, a partir del peso corporal (g y la edad (días como variables independientes. Por otro lado, para verificar la concordancia entre el método directo de disección in vitro con las ecuaciones de regresión, se utilizó el plotaje de Bland y Altman. Principales medidas de resultados: Validación de ecuaciones somáticas para predecir la composición corporal de ratas. Resultados: Se verificó altos coeficientes de correlación (r con el peso corporal y edad, los cuales dieron origen a ecuaciones que permitieron predecir el peso graso (PG = -31,6+(0,361*PT-(0,345*edad (R2=0,73 y peso libre de grasa (PLG = 19,9+(0,453*PT + (0,114*edad (R2=0,94. Sin embargo, el peso residual (PR fue obtenido por medio de una deducción matemática (PR=peso total-(PLG+PG. Así mismo, el plotaje de Bland y Altman permitió determinar alta concordancia

  7. Lorentz Covariance of Langevin Equation

    International Nuclear Information System (INIS)

    Koide, T.; Denicol, G.S.; Kodama, T.

    2008-01-01

    Relativistic covariance of a Langevin type equation is discussed. The requirement of Lorentz invariance generates an entanglement between the force and noise terms so that the noise itself should not be a covariant quantity. (author)

  8. Modelos de aplicación de ecuaciones diferenciales de primer orden con geogebra: actividades para resolver problemas de mezclas

    Directory of Open Access Journals (Sweden)

    Cesar Augusto Hernández-Suarez

    2016-09-01

    Full Text Available El objetivo del estudio es diseñar una actividad para abordar los problemas de mezclas en un curso de ecuaciones diferenciales que permita realizar cambios de representación en los registros gráfico, algebraico y lengua natural mediante la ayuda de software libre Geogebra, esperando así reducir la dificultad que presentan los estudiantes al momento de plantear la ecuación diferencial que modela un problema de mezclas. La actividad se fundamenta en dos marcos, el didáctico y el matemático, los cuales fueron elaborados con los aportes de distintas fuentes consultadas acerca del objeto de investigación. La selección de los participantes fue realizada mediante muestreo intencional y durante el desarrollo de este proceso se eligieron dieciocho (18 estudiantes de un programa académico de Ingeniería Civil de un curso de ecuaciones diferenciales. Se aplicó una encuesta a los estudiantes sobre los modelos de aplicación de ecuaciones diferenciales de primer orden para determinar el modelo a utilizar; los modelos con mayor porcentaje de elección fueron: Mezclas y ley de enfriamiento de Newton, razón por la cual se eligió el modelo de mezclas para el diseño de una actividad tipo test con 3 problemas que para ser resueltos con el Geogebra. Se analizan las respuestas dadas por los estudiantes al resolver una serie de problemas de aplicación de primer orden con el software libre Geogebra. Estos problemas permiten realizar traspasos del registro lenguaje natural al algebraico mediante representaciones ejecutables y preguntas que pretenden orientar al estudiante durante el desarrollo de la misma, con el fin de proporcionar herramientas para plantear la ecuación diferencial que se ajusta a los problemas planteados. Como resultados se obtiene una propuesta del uso del Geogebra como un recurso didáctico para favorecer la resolución de problemas de aplicación de ecuaciones diferenciales de primer orden (problemas de mezclas. Se puede concluir

  9. Estudio numérico de sistemas de ecuaciones no lineales difusas

    Directory of Open Access Journals (Sweden)

    Patricio Cumsille

    2010-01-01

    Full Text Available En este trabajo estudiamos la resolución numérica de sistemas de ecuaciones no lineales difusas. Más precisamente describimos, analizamos y simulamos métodos numéricos, tales como el método de Newton, con el fin de aproximar de forma eficiente las soluciones a dichos problemas. Una de las características principales de este tipo de problemas es que las téc- nicas analíticas estándares de soluciones no son adecuadas para resolverlos. Por esta razón, en este artículo nos centramos en el estudio de los resulta- dos conocidos para los métodos numéricos clásicos y en su adaptación a la resolución de problemas difusos. Resumen.

  10. Monodromía y ecuaciones fuchsianas en la obra de H. Poincaré

    Directory of Open Access Journals (Sweden)

    Aroca Hernández-Ros, José Manuel

    2004-08-01

    Full Text Available Las cinco memorias de Poincaré sobre funciones y grupos fuchsianos publicadas en Acta Mathematica entre 1882 y 1884 constituyen la culminación de la teoría geométrica de funciones y el origen de un gran número de problemas de la Matemática actual. La cuarta memoria, dedicada a los grupos de monodromía de las ecuaciones diferenciales lineales de tipo Fuchs, es la menos conocida pese a contener resultados interesantes tanto en torno al problema de Riemann-Hilbert como a la estructura de los espacios de moduli de curvas algebraicas. En esta nota, expuesta en un ciclo de conferencias sobre Poincaré en su sesquicentenario, organizado en la Real Academia de Ciencias, se exponen las conexiones de esta memoria con resultados recientes de la teoría de Galois diferencial.…

  11. Statistical mechanics and Lorentz violation

    International Nuclear Information System (INIS)

    Colladay, Don; McDonald, Patrick

    2004-01-01

    The theory of statistical mechanics is studied in the presence of Lorentz-violating background fields. The analysis is performed using the Standard-Model Extension (SME) together with a Jaynesian formulation of statistical inference. Conventional laws of thermodynamics are obtained in the presence of a perturbed hamiltonian that contains the Lorentz-violating terms. As an example, properties of the nonrelativistic ideal gas are calculated in detail. To lowest order in Lorentz violation, the scalar thermodynamic variables are only corrected by a rotationally invariant combination of parameters that mimics a (frame dependent) effective mass. Spin-couplings can induce a temperature-independent polarization in the classical gas that is not present in the conventional case. Precision measurements in the residual expectation values of the magnetic moment of Fermi gases in the limit of high temperature may provide interesting limits on these parameters

  12. Anomalous Lorentz and CPT violation

    Science.gov (United States)

    Klinkhamer, F. R.

    2018-01-01

    If there exists Lorentz and CPT violation in nature, then it is crucial to discover and understand the underlying mechanism. In this contribution, we discuss one such mechanism which relies on four-dimensional chiral gauge theories defined over a spacetime manifold with topology ℛ3 × S 1 and periodic spin structure for the compact dimension. It can be shown that the effective gauge-field action contains a local Chern-Simons-like term which violates Lorentz and CPT invariance. For arbitrary Abelian U(1) gauge fields with trivial holonomies in the compact direction, this anomalous Lorentz and CPT violation has recently been established perturbatively with a Pauli-Villars-type regularization and nonperturbatively with a lattice regularization based on Ginsparg-Wilson fermions.

  13. Transport properties of stochastic Lorentz models

    NARCIS (Netherlands)

    Beijeren, H. van

    Diffusion processes are considered for one-dimensional stochastic Lorentz models, consisting of randomly distributed fixed scatterers and one moving light particle. In waiting time Lorentz models the light particle makes instantaneous jumps between scatterers after a stochastically distributed

  14. Ecuaciones diferenciales y en diferencias aplicadas a los conceptos económicos y financieros || Differential and Difference Equations Applied to Economic and Financial Concepts

    Directory of Open Access Journals (Sweden)

    Tenorio Villalón, Ángel F.

    2013-01-01

    Full Text Available Este trabajo versa sobre la utilidad de las ecuaciones diferenciales y lasecuaciones en diferencias finitas para la resolución de distintos problemas en el ámbito de la economía y la empresa. En Economía es frecuente estudiar la evolución de los valores de una misma variable en distintos instantes temporales. Si la variable “tiempo" se considera como algo continuo, la evolución se estudia mediante ecuaciones diferenciales. Sin embargo, si el “tiempo" es tratado de manera discreta, se utilizan entonces ecuaciones en diferencias finitas.Concretamente, nuestro objetivo no solo es exponer la evolución que han sufrido las nociones de ecuaciones diferenciales y ecuaciones en diferencias finitas sino también dar una visión (no exhaustiva de sus múltiples aplicaciones a cuestiones relativas a fenómenos económicos y financieros. || This paper deals with the use of differential equations and finite difference methods for solving several problems in the field of Economics and Business Administration. Economics usually needs to study the evolution of the values which are taken by a given variable in different moments. If the time variable works in a continuous way, its evolution is studied by differential equations. Otherwise, time is a discrete variable and finite difference methods must be used. In addition, to expound the evolution of the notions of differential and difference equations, the goal of this paper is to show a general view (but not comprehensive of their many applications for explaining economical and financial phenomena.

  15. Estudio de un método basado en programación genética para la solución de Ecuaciones diferenciales ordinarias y parciales de dos variables

    OpenAIRE

    Ramírez Botero, Angélica María

    2014-01-01

    Este trabajo de tesis tiene como propósito, realizar un estudio desde el punto de vista matemático y computacional, sobre las ventajas y desventajas de usar un método basado en Programación Genética para resolver ecuaciones diferenciales ordinarias y ecuaciones diferenciales parciales en dos variables. En este estudio, se describe inicialmente las principales características del método exponiendo los fundamentos que soportan el desarrollo del algoritmo, desde su explicación conceptual hasta s...

  16. Herramienta para la enseñanza de las ecuaciones de Lagrange basada en la simulación de sistemas dinámicos

    OpenAIRE

    Bravo M., D. A.; Rengifo R., C. F.

    2014-01-01

    En este trabajo se propone una herramienta para la enseñanza de la mecánica clásica, modelando sistemas dinámicos con las ecuaciones de Lagrange, a partir de la simulación en Matlab ©. Este enfoque permite a los estudiantes de ingeniería y ciencias básicas, desarrollar competencias en programación, análisis numérico, con el uso de la física como herramienta fundamental para modelar y simular sistemas dinámicos complejos, como por ejemplo: robots industriales, robots bípedos y cualquier sistem...

  17. Lorentz covariant theory of gravitation

    International Nuclear Information System (INIS)

    Fagundes, H.V.

    1974-12-01

    An alternative method for the calculation of second order effects, like the secular shift of Mercury's perihelium is developed. This method uses the basic ideas of thirring combined with the more mathematical approach of Feyman. In the case of a static source, the treatment used is greatly simplified. Besides, Einstein-Infeld-Hoffmann's Lagrangian for a system of two particles and spin-orbit and spin-spin interactions of two particles with classical spin, ie, internal angular momentum in Moller's sense, are obtained from the Lorentz covariant theory

  18. Lorentz violations and Euclidean signature metrics

    International Nuclear Information System (INIS)

    Barbero G, J. Fernando; Villasenor, Eduardo J.S.

    2003-01-01

    We show that the families of effective actions considered by Jacobson et al. to study Lorentz invariance violations contain a class of models that represent pure general relativity with a Euclidean signature. We also point out that some members of this family of actions preserve Lorentz invariance in a generalized sense

  19. Virtualización de las ecuaciones diferenciales: Una experiencia nueva.

    Directory of Open Access Journals (Sweden)

    Guerrero Manzano, Mª del Mar

    2004-01-01

    Full Text Available En estos últimos años venimos asistiendo a una gran proliferación del uso de las nuevas tecnologías en la enseñanza universitaria. Teniendo en cuenta que su utilización no es fácil, pero que hoy es una realidad en la Universidad, y cada vez con mayor importancia, un grupo de profesores nos hemos planteado cómo virtualizar una parte de la materia que normalmente impartimos con la asignatura de Matemáticas en los estudios de Economía y Empresa. Las peculiaridades de esta asignatura y las características propias, la hacen especialmente complicada en la enseñanza presencial, por ello parece lógico que nos apoyemos en la enseñanza virtual de la misma. La opción escogida ha sido la de impartir la parte de dinámica económica (Ecuaciones Diferenciales de nuestra asignatura♣ en un campus virtual, compartido entre nueve universidades españolas (Grupo 9 de Universidades. Se van a poner de manifiesto los resultados de nuestra experiencia, indicando tanto las ventajas como los inconvenientes con los que nos hemos encontrado.

  20. Lorentz violation, gravitoelectromagnetic field and Bhabha scattering

    Science.gov (United States)

    Santos, A. F.; Khanna, Faqir C.

    2018-01-01

    Lorentz symmetry is a fundamental symmetry in the Standard Model (SM) and in General Relativity (GR). This symmetry holds true for all models at low energies. However, at energies near the Planck scale, it is conjectured that there may be a very small violation of Lorentz symmetry. The Standard Model Extension (SME) is a quantum field theory that includes a systematic description of Lorentz symmetry violations in all sectors of particle physics and gravity. In this paper, SME is considered to study the physical process of Bhabha Scattering in the Gravitoelectromagnetism (GEM) theory. GEM is an important formalism that is valid in a suitable approximation of general relativity. A new nonminimal coupling term that violates Lorentz symmetry is used in this paper. Differential cross-section for gravitational Bhabha scattering is calculated. The Lorentz violation contributions to this GEM scattering cross-section are small and are similar in magnitude to the case of the electromagnetic field.

  1. Differential field equations for the MHD waves and wave equation of Alfven; Las ecuaciones diferenciales de campo para las ondas MHD y la ecuacion de onda de Alfven

    Energy Technology Data Exchange (ETDEWEB)

    Fierros Palacios, Angel [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    2001-02-01

    In this work the complete set of differential field equations which describes the dynamic state of a continuos conducting media which flow in presence of a perturbed magnetic field is obtained. Then, the thermic equation of state, the wave equation and the conservation law of energy for the Alfven MHD waves are obtained. [Spanish] Es este trabajo se obtiene el conjunto completo de ecuaciones diferenciales de campo que describen el estado dinamico de un medio continuo conductor que se mueve en presencia de un campo magnetico externo perturbado. Asi, se obtiene la ecuacion termica de estado, la ecuacion de onda y la ley de la conservacion de la energia para las ondas de Alfven de la MHD.

  2. De un videojuego a las ecuaciones del tiro parabólico: una propuesta didáctica

    OpenAIRE

    Ruiz, Andrés; Oktaç, Asuman

    2014-01-01

    ¿Es posible partir de un videojuego para enseñar matemáticas o física? En el presente diseño de actividades didácticas se parte precisamente del conocimiento intuitivo que puede generar en el alumno el uso del videojuego “AngryBirds”, para darle significado y aplicación a lo que en él acontece, y que en escenarios escolares se estudia como la “función de posición” o bien, las ecuaciones del tiro parabólico. Se presenta una propuesta didáctica para el estudio del tiro parabólico a partir de un...

  3. Noncommutative gauge theory without Lorentz violation

    International Nuclear Information System (INIS)

    Carlson, Carl E.; Carone, Christopher D.; Zobin, Nahum

    2002-01-01

    The most popular noncommutative field theories are characterized by a matrix parameter θ μν that violates Lorentz invariance. We consider the simplest algebra in which the θ parameter is promoted to an operator and Lorentz invariance is preserved. This algebra arises through the contraction of a larger one for which explicit representations are already known. We formulate a star product and construct the gauge-invariant Lagrangian for Lorentz-conserving noncommutative QED. Three-photon vertices are absent in the theory, while a four-photon coupling exists and leads to a distinctive phenomenology

  4. A q-deformed Lorentz algebra

    International Nuclear Information System (INIS)

    Schmidke, W.B.; Wess, J.; Muenchen Univ.; Zumino, B.; Lawrence Berkeley Lab., CA

    1991-01-01

    We derive a q-deformed version of the Lorentz algebra by deformating the algebra SL(2, C). The method is based on linear representations of the algebra on the complex quantum spinor space. We find that the generators usually identified with SL q (2, C) generate SU q (2) only. Four additional generators are added which generate Lorentz boosts. The full algebra of all seven generators and their coproduct is presented. We show that in the limit q→1 the generators are those of the classical Lorentz algebra plus an additional U(1). Thus we have a deformation of SL(2, C)xU(1). (orig.)

  5. Constraining Lorentz Violation in Electroweak Physics

    Science.gov (United States)

    Lehnert, Ralf

    2018-01-01

    For practical reasons, the majority of past Lorentz tests has involved stable or quasistable particles, such as photons, neutrinos, electrons, protons, and neutrons. Similar efforts in the electroweak sector have only recently taken shape. Within this context, Lorentz-violation searches in the Standard-Model Extension’s Z-Boson sector will be discussed. It is argued that existing precision data on polarized electron-electron scattering can be employed to extract the first conservative two-sided limits on Lorentz breakdown in this sector at the level of 10-7.

  6. Lorentz violations in multifractal spacetimes

    Energy Technology Data Exchange (ETDEWEB)

    Calcagni, Gianluca [Instituto de Estructura de la Materia, CSIC, Madrid (Spain)

    2017-05-15

    Using the recent observation of gravitational waves (GW) produced by a black-hole merger, we place a lower bound on the energy above which a multifractal spacetime would display an anomalous geometry and, in particular, violations of Lorentz invariance. In the so-called multifractional theory with q-derivatives, we show that the deformation of dispersion relations is much stronger than in generic quantum-gravity approaches (including loop quantum gravity) and, contrary to the latter, present observations on GWs can place very strong bounds on the characteristic scales at which spacetime deviates from standard Minkowski. The energy at which multifractal effects should become apparent is E{sub *} > 10{sup 14} GeV (thus improving previous bounds by 12 orders of magnitude) when the exponents in the measure are fixed to their central value 1 / 2. We also estimate, for the first time, the effect of logarithmic oscillations in the measure (corresponding to a discrete spacetime structure) and find that they do not change much the bounds obtained in their absence, unless the amplitude of the oscillations is fine tuned. This feature, unavailable in known quantum-gravity scenarios, may help the theory to avoid being ruled out by gamma-ray burst (GRB) observations, for which E{sub *} > 10{sup 17} GeV or greater. (orig.)

  7. Lorentz violation. Motivation and new constraints

    International Nuclear Information System (INIS)

    Liberati, S.; Maccione, L.

    2009-09-01

    We review the main theoretical motivations and observational constraints on Planck scale sup-pressed violations of Lorentz invariance. After introducing the problems related to the phenomenological study of quantum gravitational effects, we discuss the main theoretical frameworks within which possible departures from Lorentz invariance can be described. In particular, we focus on the framework of Effective Field Theory, describing several possible ways of including Lorentz violation therein and discussing their theoretical viability. We review the main low energy effects that are expected in this framework. We discuss the current observational constraints on such a framework, focusing on those achievable through high-energy astrophysics observations. In this context we present a summary of the most recent and strongest constraints on QED with Lorentz violating non-renormalizable operators. Finally, we discuss the present status of the field and its future perspectives. (orig.)

  8. Testing Lorentz invariance of dark matter

    CERN Document Server

    Blas, Diego; Sibiryakov, Sergey

    2012-01-01

    We study the possibility to constrain deviations from Lorentz invariance in dark matter (DM) with cosmological observations. Breaking of Lorentz invariance generically introduces new light gravitational degrees of freedom, which we represent through a dynamical timelike vector field. If DM does not obey Lorentz invariance, it couples to this vector field. We find that this coupling affects the inertial mass of small DM halos which no longer satisfy the equivalence principle. For large enough lumps of DM we identify a (chameleon) mechanism that restores the inertial mass to its standard value. As a consequence, the dynamics of gravitational clustering are modified. Two prominent effects are a scale dependent enhancement in the growth of large scale structure and a scale dependent bias between DM and baryon density perturbations. The comparison with the measured linear matter power spectrum in principle allows to bound the departure from Lorentz invariance of DM at the per cent level.

  9. Testing Lorentz invariance of dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Blas, Diego [Theory Group, Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Ivanov, Mikhail M.; Sibiryakov, Sergey, E-mail: diego.blas@cern.ch, E-mail: mm.ivanov@physics.msu.ru, E-mail: sibir@inr.ac.ru [Faculty of Physics, Moscow State University, Vorobjevy Gory, 119991 Moscow (Russian Federation)

    2012-10-01

    We study the possibility to constrain deviations from Lorentz invariance in dark matter (DM) with cosmological observations. Breaking of Lorentz invariance generically introduces new light gravitational degrees of freedom, which we represent through a dynamical timelike vector field. If DM does not obey Lorentz invariance, it couples to this vector field. We find that this coupling affects the inertial mass of small DM halos which no longer satisfy the equivalence principle. For large enough lumps of DM we identify a (chameleon) mechanism that restores the inertial mass to its standard value. As a consequence, the dynamics of gravitational clustering are modified. Two prominent effects are a scale dependent enhancement in the growth of large scale structure and a scale dependent bias between DM and baryon density perturbations. The comparison with the measured linear matter power spectrum in principle allows to bound the departure from Lorentz invariance of DM at the per cent level.

  10. Lorentz violation. Motivation and new constraints

    Energy Technology Data Exchange (ETDEWEB)

    Liberati, S. [Scuola Internazionale Superiore di Studi Avanzati SISSA, Trieste (Italy); Istituto Nazionale di Fisica Nucleare INFN, Sezione di Trieste (Italy); Maccione, L. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2009-09-15

    We review the main theoretical motivations and observational constraints on Planck scale sup-pressed violations of Lorentz invariance. After introducing the problems related to the phenomenological study of quantum gravitational effects, we discuss the main theoretical frameworks within which possible departures from Lorentz invariance can be described. In particular, we focus on the framework of Effective Field Theory, describing several possible ways of including Lorentz violation therein and discussing their theoretical viability. We review the main low energy effects that are expected in this framework. We discuss the current observational constraints on such a framework, focusing on those achievable through high-energy astrophysics observations. In this context we present a summary of the most recent and strongest constraints on QED with Lorentz violating non-renormalizable operators. Finally, we discuss the present status of the field and its future perspectives. (orig.)

  11. Constrained Gauge Fields from Spontaneous Lorentz Violation

    CERN Document Server

    Chkareuli, J L; Jejelava, J G; Nielsen, H B

    2008-01-01

    Spontaneous Lorentz violation realized through a nonlinear vector field constraint of the type $A_{\\mu}^{2}=M^{2}$ ($M$ is the proposed scale for Lorentz violation) is shown to generate massless vector Goldstone bosons, gauging the starting global internal symmetries in arbitrary relativistically invariant theories. The gauge invariance appears in essence as a necessary condition for these bosons not to be superfluously restricted in degrees of freedom, apart from the constraint due to which the true vacuum in a theory is chosen by the Lorentz violation. In the Abelian symmetry case the only possible theory proves to be QED with a massless vector Goldstone boson naturally associated with the photon, while the non-Abelian symmetry case results in a conventional Yang-Mills theory. These theories, both Abelian and non-Abelian, look essentially nonlinear and contain particular Lorentz (and $CPT$) violating couplings when expressed in terms of the pure Goldstone vector modes. However, they do not lead to physical ...

  12. Constrained gauge fields from spontaneous Lorentz violation

    DEFF Research Database (Denmark)

    Chkareuli, J. L.; Froggatt, C. D.; Jejelava, J. G.

    2008-01-01

    Spontaneous Lorentz violation realized through a nonlinear vector field constraint of the type AµAµ=M2 (M is the proposed scale for Lorentz violation) is shown to generate massless vector Goldstone bosons, gauging the starting global internal symmetries in arbitrary relativistically invariant...... theories. The gauge invariance appears in essence as a necessary condition for these bosons not to be superfluously restricted in degrees of freedom, apart from the constraint due to which the true vacuum in a theory is chosen by the Lorentz violation. In the Abelian symmetry case the only possible theory...... couplings when expressed in terms of the pure Goldstone vector modes. However, they do not lead to physical Lorentz violation due to the simultaneously generated gauge invariance. Udgivelsesdato: June 11...

  13. The Scientific Correspondence of H A Lorentz

    CERN Document Server

    Kox, AJ

    2008-01-01

    Presents a selection of more than 400 letters from and to the Dutch physicist and Nobel Prize winner Hendrik Antoon Lorentz (1853-1928), covering the period from 1883 until a few months before his death.

  14. New bounds on isotropic Lorentz violation

    International Nuclear Information System (INIS)

    Carone, Christopher D.; Sher, Marc; Vanderhaeghen, Marc

    2006-01-01

    Violations of Lorentz invariance that appear via operators of dimension four or less are completely parametrized in the Standard Model Extension (SME). In the pure photonic sector of the SME, there are 19 dimensionless, Lorentz-violating parameters. Eighteen of these have experimental upper bounds ranging between 10 -11 and 10 -32 ; the remaining parameter, k-tilde tr , is isotropic and has a much weaker bound of order 10 -4 . In this Brief Report, we point out that k-tilde tr gives a significant contribution to the anomalous magnetic moment of the electron and find a new upper bound of order 10 -8 . With reasonable assumptions, we further show that this bound may be improved to 10 -14 by considering the renormalization of other Lorentz-violating parameters that are more tightly constrained. Using similar renormalization arguments, we also estimate bounds on Lorentz-violating parameters in the pure gluonic sector of QCD

  15. k-essence explains a Lorentz violation experiment

    International Nuclear Information System (INIS)

    Li Miao; Pang Yi; Wang Yi

    2009-01-01

    Recently, a state of the art experiment shows evidence for Lorentz violation in the gravitational sector. To explain this experiment, we investigate a spontaneous Lorentz violation scenario with a generalized scalar field. We find that when the scalar field is nonminimally coupled to gravity, the Lorentz violation induces a deformation in the Newtonian potential along the direction of Lorentz violation.

  16. Lorentz Transformation from Symmetry of Reference Principle

    International Nuclear Information System (INIS)

    Petre, M.; Dima, M.; Dima, A.; Petre, C.; Precup, I.

    2010-01-01

    The Lorentz Transformation is traditionally derived requiring the Principle of Relativity and light-speed universality. While the latter can be relaxed, the Principle of Relativity is seen as core to the transformation. The present letter relaxes both statements to the weaker, Symmetry of Reference Principle. Thus the resulting Lorentz transformation and its consequences (time dilatation, length contraction) are, in turn, effects of how we manage space and time.

  17. Ecuaciones constitutivas de la fluencia en caliente de aceros microaleados

    Directory of Open Access Journals (Sweden)

    Cabrera, J. M.

    1998-05-01

    Full Text Available Over centuries, the hot forming has been employed to provide shape to metáis. Nowadays, the deformation at high temperatures gives also the required final mechanical properties. From this point of view, the obtention of a constitutive equation describing the hot flow behaviour of microalloyed steels in particular is a very important task. The main difficulty in modelling the high temperature flow arises from the simultaneity of two opposite phenomena, namely, work hardening and dynamic softening due to recovery and recrystallization. In this is work a review of constitutive equations (including the effect of the chemical composition describing the flow behaviour of microalloyed steels deformed under high temperature conditions.

    Durante siglos el conformado en caliente se ha utilizado para proporcionar a los metales la forma deseada. Hoy en día la deformación en caliente no sólo genera la geometría deseada sino las características mecánicas requeridas. Así, la obtención de una ecuación constitutiva para la fluencia en caliente de un acero en particular, es una tarea ineludible para efectuar simulaciones por ordenador de procesos industriales. La complicación de la modelización de la fluencia a alta temperatura proviene de la simultaneidad de dos fenómenos contrapuestos durante la deformación, a saber, endurecimiento por deformación y ablandamiento por recuperación de la estructura. Este último a su vez puede constar de restauración y recristalización dinámicas. En este trabajo se revisan y plantean las ecuaciones constitutivas que describen las curvas de fluencia bajo condiciones de deformación en caliente, y se presenta una aplicación de las mismas a aceros microaleados.

  18. Ecuaciones en derivadas parciales con condiciones de contorno no lineales aplicaciones a la dinámica de tumores

    OpenAIRE

    Morales Rodrigo, Cristian

    2009-01-01

    Esta tesis presenta tres partes: En la primera haremos un estudio teórico general de las ecuaciones elípticas en derivadas parciales con condiciones de contorno no lineales. Posteriormente, en la segunda, haremos un estudio teórico de ecuaciones elíptica

  19. Lorentz violation and black-hole thermodynamics

    International Nuclear Information System (INIS)

    Betschart, G.; Kant, E.; Klinkhamer, F.R.

    2009-01-01

    We consider nonstandard photons from nonbirefringent modified Maxwell theory and discuss their propagation in a fixed Schwarzschild spacetime background. This particular modification of Maxwell theory is Lorentz-violating and allows for maximal photon velocities differing from the causal speed c of the asymptotic background spacetime. In the limit of geometrical optics, light rays from modified Maxwell theory are found to propagate along null geodesics in an effective metric. We observe that not every Lorentz-violating theory with multiple maximal velocities different from the causal speed c modifies the notion of the event horizon, contrary to naive expectations. This result implies that not every Lorentz-violating theory with multiple maximal velocities necessarily leads to a contradiction with the generalized second law of thermodynamics.

  20. Improved test of Lorentz invariance in electrodynamics

    International Nuclear Information System (INIS)

    Wolf, Peter; Bize, Sebastien; Clairon, Andre; Santarelli, Giorgio; Tobar, Michael E.; Luiten, Andre N.

    2004-01-01

    We report new results of a test of Lorentz invariance based on the comparison of a cryogenic sapphire microwave resonator and a hydrogen-maser. The experimental results are shown together with an extensive analysis of systematic effects. Previously, this experiment has set the most stringent constraint on Kennedy-Thorndike type violations of Lorentz invariance. In this work we present new data and interpret our results in the general Lorentz violating extension of the standard model of particle physics (SME). Within the photon sector of the SME, our experiment is sensitive to seven SME parameters. We marginally improve present limits on four of these, and by a factor seven to ten on the other three

  1. Spontaneous Lorentz breaking at high energies

    International Nuclear Information System (INIS)

    Cheng, H.-C.; Luty, Markus A.; Mukohyama, Shinji; Thaler, Jesse

    2006-01-01

    Theories that spontaneously break Lorentz invariance also violate diffeomorphism symmetries, implying the existence of extra degrees of freedom and modifications of gravity. In the minimal model ('ghost condensation') with only a single extra degree of freedom at low energies, the scale of Lorentz violation cannot be larger than about M ∼ 100GeV due to an infrared instability in the gravity sector. We show that Lorentz symmetry can be broken at much higher scales in a non-minimal theory with additional degrees of freedom, in particular if Lorentz symmetry is broken by the vacuum expectation value of a vector field. This theory can be constructed by gauging ghost condensation, giving a systematic effective field theory description that allows us to estimate the size of all physical effects. We show that nonlinear effects become important for gravitational fields with strength Φ 1/2 ∼> g, where g is the gauge coupling, and we argue that the nonlinear dynamics is free from singularities. We then analyze the phenomenology of the model, including nonlinear dynamics and velocity-dependent effects. The strongest bounds on the gravitational sector come from either black hole accretion or direction-dependent gravitational forces, and imply that the scale of spontaneous Lorentz breaking is M ∼ 12 GeV, g 2 10 15 GeV). If the Lorentz breaking sector couples directly to matter, there is a spin-dependent inverse-square law force, which has a different angular dependence from the force mediated by the ghost condensate, providing a distinctive signature for this class of models

  2. Einstein-Yang-Mills-Lorentz black holes

    Energy Technology Data Exchange (ETDEWEB)

    Cembranos, Jose A.R.; Gigante Valcarcel, Jorge [Universidad Complutense de Madrid, Departamento de Fisica Teorica I, Madrid (Spain)

    2017-12-15

    Different black hole solutions of the coupled Einstein-Yang-Mills equations have been well known for a long time. They have attracted much attention from mathematicians and physicists since their discovery. In this work, we analyze black holes associated with the gauge Lorentz group. In particular, we study solutions which identify the gauge connection with the spin connection. This ansatz allows one to find exact solutions to the complete system of equations. By using this procedure, we show the equivalence between the Yang-Mills-Lorentz model in curved space-time and a particular set of extended gravitational theories. (orig.)

  3. The Lorentz integral transform and its inversion

    International Nuclear Information System (INIS)

    Barnea, N.; Efros, V.D.; Leidemann, W.; Orlandini, G.

    2010-01-01

    The Lorentz integral transform method is briefly reviewed. The issue of the inversion of the transform, and in particular its ill-posedness, is addressed. It is pointed out that the mathematical term ill-posed is misleading and merely due to a historical misconception. In this connection standard regularization procedures for the solution of the integral transform problem are presented. In particular a recent one is considered in detail and critical comments on it are provided. In addition a general remark concerning the concept of the Lorentz integral transform as a method with a controlled resolution is made. (author)

  4. Vortices in superconductors from Lorentz violation

    International Nuclear Information System (INIS)

    Belich, H.; Orlando, M.T.D.; Costa-Soares, T.; Helayel-Neto, J.A.

    2004-01-01

    We start from a Lorentz non-invariant Abelian-Higgs model in 1+3 dimensions, and carry out its dimensional reduction to D = 1 + 2. The planar model resulting thereof is composed by a Maxwell-Chern-Simons-Proca gauge sector, a massive scalar sector, and a mixing term (involving the fixed background, v μ ) that realizes Lorentz violation for the reduced model. Vortex type solutions of the planar model are investigated in a superconducting environment . Our vortex solutions are electrically charged and exhibit a screened electric field. (author)

  5. Nonlinear Lorentz-invariant theory of gravitation

    International Nuclear Information System (INIS)

    Petry, W.

    1976-01-01

    A nonlinear Lorentz-invariant theory of gravitation and a Lorentz-invariant Hamiltonian for a particle with spin in the gravitational field are developed. The equations of motions are studied. The theory is applied to the three well known tests of General Relativity. In the special case of the red shift of spectral lines and of the deflection of light, the theory gives the same results as the General Theory of Relativity, whereas in the case of the perihelion of the Mercury, the theory gives 40,3'', in good agreement with experimental results of Dicke. (author)

  6. Self-duality in generalized Lorentz superspaces

    International Nuclear Information System (INIS)

    Devchand, C.; Nuyts, J.

    1996-12-01

    We extend the notion of self-duality to spaces built from a set of representations of the Lorentz group with bosonic or fermionic behaviour, not having the traditional spin-one upper-bound of super Minkowski space. The generalized derivative vector fields on such superspace are assumed to form a superalgebra. Introducing corresponding gauge potentials and hence covariant derivatives and curvatures, we define generalized self-duality as the Lorentz covariant vanishing of certain irreducible parts of the curvatures. (author). 4 refs

  7. Lorentz-violating electrodynamics and the cosmic microwave background.

    Science.gov (United States)

    Kostelecký, V Alan; Mewes, Matthew

    2007-07-06

    Possible Lorentz-violating effects in the cosmic microwave background are studied. We provide a systematic classification of renormalizable and nonrenormalizable operators for Lorentz violation in electrodynamics and use polarimetric observations to search for the associated violations.

  8. Lorentz covariant canonical symplectic algorithms for dynamics of charged particles

    Science.gov (United States)

    Wang, Yulei; Liu, Jian; Qin, Hong

    2016-12-01

    In this paper, the Lorentz covariance of algorithms is introduced. Under Lorentz transformation, both the form and performance of a Lorentz covariant algorithm are invariant. To acquire the advantages of symplectic algorithms and Lorentz covariance, a general procedure for constructing Lorentz covariant canonical symplectic algorithms (LCCSAs) is provided, based on which an explicit LCCSA for dynamics of relativistic charged particles is built. LCCSA possesses Lorentz invariance as well as long-term numerical accuracy and stability, due to the preservation of a discrete symplectic structure and the Lorentz symmetry of the system. For situations with time-dependent electromagnetic fields, which are difficult to handle in traditional construction procedures of symplectic algorithms, LCCSA provides a perfect explicit canonical symplectic solution by implementing the discretization in 4-spacetime. We also show that LCCSA has built-in energy-based adaptive time steps, which can optimize the computation performance when the Lorentz factor varies.

  9. Test of CPT and Lorentz invariance from muonium spectroscopy

    NARCIS (Netherlands)

    Hughes, V. W.; Perdekamp, M. Grosse; Kawall, D.; Liu, W.; Jungmann, K.; Putlitz, G. zu

    2001-01-01

    Following a suggestion of Kostelecky et al. we have evaluated a test of CPT and Lorentz invariance from the microwave spectroscopy of muonium. Hamiltonian terms beyond the standard model violating CPT and Lorentz invariance would contribute frequency shifts $\\delta\

  10. Classroom Experiment to Verify the Lorentz Force

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 8; Issue 3. Classroom Experiment to Verify the Lorentz Force. Somnath Basu Anindita Bose Sumit Kumar Sinha Pankaj Vishe S Chatterjee. Classroom Volume 8 Issue 3 March 2003 pp 81-86 ...

  11. Spacetime-varying couplings and Lorentz violation

    International Nuclear Information System (INIS)

    Kostelecky, V. Alan; Lehnert, Ralf; Perry, Malcolm J.

    2003-01-01

    Spacetime-varying coupling constants can be associated with violations of local Lorentz invariance and CPT symmetry. An analytical supergravity cosmology with a time-varying fine-structure constant provides an explicit example. Estimates are made for some experimental constraints

  12. Lorentz Spengler's descriptions of chitons (Mollusca: Polyplacophora)

    NARCIS (Netherlands)

    Kaas, P.; Knudsen, J.

    1992-01-01

    The present paper deals with an important Danish paper on the Polyplacophora, published in 1797 by Lorentz Spengler: Udförlig Beskrivelse over det mangeskallede Konkylie-Slaegt, af Linnaeus kaldet Chiton; med endeel nye Arter og Varieteter. -Skrivter af Naturhistorie-Selskabet, 4e Bind, Ie Hefte,

  13. Characterisation of Embeddings in Lorentz Spaces

    Czech Academy of Sciences Publication Activity Database

    Gogatishvili, Amiran; Johansson, M.; Okpoti, C.A.; Persson, L. E.

    2007-01-01

    Roč. 76, č. 1 (2007), s. 69-92 ISSN 0004-9727 R&D Projects: GA ČR GA201/05/2033 Institutional research plan: CEZ:AV0Z10190503 Keywords : non-increasing rearrangement * Lorentz spaces * weights Subject RIV: BA - General Mathematics Impact factor: 0.297, year: 2007

  14. The Lorentz Theory of Electrons and Einstein's Theory of Relativity

    Science.gov (United States)

    Goldberg, Stanley

    1969-01-01

    Traces the development of Lorentz's theory of electrons as applied to the problem of the electrodynamics of moving bodies. Presents evidence that the principle of relativity did not play an important role in Lorentz's theory, and that though Lorentz eventually acknowledged Einstein's work, he was unwilling to completely embrace the Einstein…

  15. Los modelos de ecuaciones estructurales y su aplicación en el Índice Europeo de Satisfacción del Cliente

    Directory of Open Access Journals (Sweden)

    Mercedes Casas Guillén

    2002-01-01

    Full Text Available Las empresas elaboran planes estratégicos que requieren conocer el grado de satisfacción que sus productos y servicios provocan en los clientes, esto ha llevado a las instituciones de los países desarrollados a elaborar indicadores estadísticos que midan la satisfacción. La elaboración del Índice Europeo de Satisfacción del Cliente (ECSI tiene su origen en la necesidad de disponer de información periódica, desglosada y comparable, relativa a la calidad de los diferentes sectores económicos europeos, desde la perspectiva de la satisfacción del cliente en las empresas de servicios. El ECSI se construye a partir de un modelo de ecuaciones estructurales que relaciona los componentes de la satisfacción. Las diferentes variables del modelo estructural subyacente en el ECSI, toman como variable principal o resultado, la componente satisfacción, y consideran además, la imagen, las expectativas del cliente, la calidad percibida “hardware” y “software”, el valor percibido y la fidelización del cliente. La estimación de los parámetros del modelo se realiza empleando ecuaciones lineales simultáneas (Partial Least Squares. PLS.

  16. Solución de ecuaciones cuadráticas a partir de los elementos de Euclides

    OpenAIRE

    Sánchez, Diana; Montes, Carlos; Luque, Carlos Julio

    2005-01-01

    Se presenta una manera de solucionar ecuaciones cuadráticas a partir de las proposiciones 5 y 6 del libro II de los Elementos de Euclides. Se estudian estas proposiciones, su demostración y aplicación en la solución de las ecuaciones cuadráticas resaltando su valor didáctico. Se presenta además la solución de algunas de las ecuaciones cuadráticas que distinguía Al-Kharizmi, quien utilizaba, al igual que Euclides, la aplicación de áreas en su resolución.

  17. EL USO DE MANIPULABLES PARA PROPICIAR LA COMPRENSIÓN DEL SIGNIFICADO DE ECUACIONES LINEALES EN LA ESCUELA SECUNDARIA

    Directory of Open Access Journals (Sweden)

    Paola Tonanzy García Mendívil

    2016-06-01

    Full Text Available En el siguiente artículo se presenta una propuesta de enseñanza donde se utiliza la balanza como un recurso didáctico para el aprendizaje de las ecuaciones lineales. El objetivo del estudio fue el de propiciar la comprensión del concepto de ecuación lineal con una incógnita y de ecuación lineal con dos variables con estudiantes de primer grado de secundaria, mediante el uso de manipulables. Este estudio considera como referente teórico el enfoque cognitivo basado en los registros de representación semiótica de Raymond Duval y las actividades diseñadas promueven la articulación de los registros de representación: verbal, tabular, gráfico y algebraico. La metodología de trabajo fue por el estudio de casos, por la naturaleza del trabajo los casos a estudiar fueron parejas de estudiantes. Con el uso de la balanza como instrumento de enlace se logró la conversión directa y recíproca entre los registros de representación algebraico y gráfico. Con base al análisis de resultados se encontró que la balanza constituyó un valioso recurso para lograr incidir positivamente en el aprendizaje de la noción de ecuación lineal con una incógnita y de dos variables.

  18. BPS Lorentz-violating vortex solutions

    International Nuclear Information System (INIS)

    Casana, Rodolfo; Ferreira Junior, Manoel M.; Hora, E. da

    2011-01-01

    In this work, we deal with the construction of static Bogomol'nyi-Prasad-Sommerfield (BPS) rotationally symmetric configurations on the dimensional CPT-even Lorentz-breaking photonic sector of the Standard Model Extension (SME). The main objective of this presentation is to show the possibility of obtaining such BPS solutions, even in the presence of a Lorentz-violating background. A secondary objective is to analyze the effects of this background on such topologically non-trivial BPS configurations. In order to obtain these results, we deal with some specific components of Lorentz-violating field, handling with the static Euler-Lagrange equation of motion to gauge field, from which we fix temporal gauge (absence of electric field) as a proper gauge choice. Also, considering this equation, we consistently determine an interesting configuration (discarding non-interesting ones) to the Lorentz-breaking sector. Using this configuration and the standard rotationally symmetric vortex Ansatz (which describes the behaviors of Higgs and gauge fields via two profile functions, g(r) and a(r), respectively), we construct a rotationally symmetric expression to the energy density of the system. To obtain BPS solutions, we rewrite this expression in order to have static vortex solutions satisfying a set of first order differential equations (BPS ones). The existence of such solutions is strongly constrained by a relation between some parameters of the model, including the Lorentz-breaking one. Naturally, we show that the total energy of these BPS solutions is proportional to their magnetic flux, which is quantized according to their winding number. Using suitable boundary conditions (near the origin and asymptotically), we numerically integrate the BPS equations (by means of the shooting method). By this way, we obtain solutions for some physical quantities (Higgs field, magnetic field and energy density) for several values of the Lorentz-violating parameters. From these

  19. Neutrality of the lorentz transformations in SRT

    International Nuclear Information System (INIS)

    Hamdan, N.; Baza, S.

    2005-01-01

    The special theory of Relativity (SRT), gives us two results, the dilation of time and the contraction of the Length, which have been refuted by many scientists. The solution to these kinematical effects has driven researchers to develop new methods. One of these methods is using the physical law equations and apply the principle of relativity to them. With this approach, we reformulated the SRT in a simple manner which has dynamical applications without using the Lorentz transformations (LT) and its kinematical effects. We obtained the results which require the invariant of Maxwell's field equations under the LT in a way different to that of Einsterin. In the present paper, we get the LT from the Lorentz force. In contrast to Einstein's LT with its kinematical effects, the LT produced in this paper is simply a neutral transformation. Containing no physical significance, i.e. LT and its kinematical effects do not explain any physical phenomenon. (author)

  20. Sixth Meeting on CPT and Lorentz Symmetry

    CERN Document Server

    CPT and Lorentz Symmetry

    2014-01-01

    This book contains the Proceedings of the Sixth Meeting on CPT and Lorentz Symmetry, held at Indiana University in Bloomington on June 17–21, 2013. The Meeting focused on tests of these fundamental symmetries and on related theoretical issues, including scenarios for possible violations. Topics covered at the meeting include searches for CPT and Lorentz violations involving: accelerator and collider experiments; atomic, nuclear, and particle decays; birefringence, dispersion, and anisotropy in cosmological sources; clock-comparison measurements; electromagnetic resonant cavities and lasers; tests of the equivalence principle; gauge and Higgs particles; high-energy astrophysical observations; laboratory tests of gravity; matter interferometry; neutrino oscillations and propagation; oscillations and decays of neutral mesons; particle–antiparticle comparisons; post-newtonian gravity in the solar system and beyond; second- and third-generation particles; space-based missions; spectroscopy of hydrogen and ant...

  1. Hiding Lorentz invariance violation with MOND

    International Nuclear Information System (INIS)

    Sanders, R. H.

    2011-01-01

    Horava-Lifshitz gravity is an attempt to construct a renormalizable theory of gravity by breaking the Lorentz invariance of the gravitational action at high energies. The underlying principle is that Lorentz invariance is an approximate symmetry and its violation by gravitational phenomena is somehow hidden to present limits of observational precision. Here I point out that a simple modification of the low-energy limit of Horava-Lifshitz gravity in its nonprojectable form can effectively camouflage the presence of a preferred frame in regions where the Newtonian gravitational field gradient is higher than cH 0 ; this modification results in the phenomenology of modified Newtonian dynamics (MOND) at lower accelerations. As a relativistic theory of MOND, this modified Horava-Lifshitz theory presents several advantages over its predecessors.

  2. Lorentz violation and generalized uncertainty principle

    Science.gov (United States)

    Lambiase, Gaetano; Scardigli, Fabio

    2018-04-01

    Investigations on possible violation of Lorentz invariance have been widely pursued in the last decades, both from theoretical and experimental sides. A comprehensive framework to formulate the problem is the standard model extension (SME) proposed by A. Kostelecky, where violation of Lorentz invariance is encoded into specific coefficients. Here we present a procedure to link the deformation parameter β of the generalized uncertainty principle to the SME coefficients of the gravity sector. The idea is to compute the Hawking temperature of a black hole in two different ways. The first way involves the deformation parameter β , and therefore we get a deformed Hawking temperature containing the parameter β . The second way involves a deformed Schwarzschild metric containing the Lorentz violating terms s¯μ ν of the gravity sector of the SME. The comparison between the two different techniques yields a relation between β and s¯μ ν. In this way bounds on β transferred from s¯μ ν are improved by many orders of magnitude when compared with those derived in other gravitational frameworks. Also the opposite possibility of bounds transferred from β to s¯μ ν is briefly discussed.

  3. EINSTEIN EQUATIONS FOR TETRAD FIELDS ECUACIONES DE EINSTEIN PARA CAMPOS TETRADOS

    Directory of Open Access Journals (Sweden)

    Héctor Torres-Silva

    2008-11-01

    Full Text Available Every metric tensor can be expressed by the inner product of tetrad fields. We prove that Einstein's equations for these fields have the same form as the stress-energy tensor of electromagnetism if the total external current . Using the Evans' unified field theory, we show that the true unification of gravity and electromagnetism is with source-free Maxwell equations.Todo tensor métrico puede ser expresado por el producto interno de campos tetrados. Se prueba que las ecuaciones de Einstein para esos campos tienen la misma forma que el tensor electromagnético de momento-energía si la corriente externa total es igual a cero. Usando la teoría de campo unificado de Evans se muestra que la verdadera unificación de la gravedad y el electromagnetismo es con las ecuaciones de Maxwell sin fuentes.

  4. Poincaré, creador de los métodos todavía modernos en las ecuaciones diferenciales y en la mecánica celeste

    Directory of Open Access Journals (Sweden)

    Delshams i Valdés, Amadeu

    2004-08-01

    Full Text Available Con motivo del sesquicentenario del nacimiento de Henri Poincaré, resulta impresionante comprobar la influencia actual de su obra, así como el gran adelanto de sus métodos e ideas respecto a las de los científicos coetáneos. En esta conferencia se repasan algunas de sus contribuciones principales a las ecuaciones diferenciales y ala mecánica celeste, y se discute el papel central que tuvo en éstas su memoria sobre el problema de tres cuerpos presentada en 1889 a un concurso para conmemorar el sexagésimo aniversario del Rey Óscar II de Suecia y Noruega.…

  5. MAXWELL EQUATIONS FOR A GENERALISED LAGRANGIAN FUNCTIONAL ECUACIONES DE MAXWELL PARA UNA FUNCIONAL DE LAGRANGE GENERALIZADA

    Directory of Open Access Journals (Sweden)

    Héctor Torres-Silva

    2008-11-01

    Full Text Available This work deals with the problem of the construction of the Lagrange functional for an electromagnetic field. The generalised Maxwell equations for an electromagnetic field in free space are introduced. The main idea relies on the change of Lagrange function under the integral action. Usually, the Lagrange functional which describes the electromagnetic field is built with the quadrate of the electromagnetic field tensor . Such a quadrate term is the reason, from a mathematical point of view, for the linear form of the Maxwell equations in free space. The author does not make this assumption and nonlinear Maxwell equations are obtained. New material parameters of free space are established. The equations obtained are quite similar to the well-known Maxwell equations. The energy tensor of the electromagnetic field from a chiral approach to the Born Infeld Lagrangian is discussed in connection with the cosmological constant.Se aborda el problema de la construcción de la funcional de Lagrange de un campo electromagnético. Se introducen las ecuaciones generalizadas de Maxwell de un campo electromagnético en el espacio libre. La idea principal se basa en el cambio de función de Lagrange en virtud de la acción integral. Por lo general, la funcional de lagrange, que describe el campo electromagnético, se construye con el cuadrado del tensor de campo electromagnético. Ese término cuadrático es la razón, desde un punto de vista matemático, de la forma lineal de las ecuaciones de Maxwell en el espacio libre. Se obtienen las ecuaciones no lineales de Maxwell sin considerar esta suposición. Las ecuaciones de Maxwell obtenidas son bastante similares a las conocidas ecuaciones de Maxwell. Se analiza el tensor de energía del campo electromagnético en un enfoque quiral de la Lagrangiana de Born Infeld en relación con la constante cosmológica.

  6. Concerning the equivalence of Lorentz's and Einstein's theories

    International Nuclear Information System (INIS)

    Clube, S.V.M.

    1978-01-01

    A clear distinction is drawn between derivations of the Lorentz transformations by Lorentz and Einstein. The choice as to which derivation is correct is still open to experimental test. Possible reasons are given for preferring the Lorentz derivation in terms of a material aether, and the role of covariance in physical theory is considered to be heuristic rather than fundamental. The existence of a material aether also permits one to question the fundamental role of fields in modern theory

  7. Are the invariance principles really truly Lorentz covariant?

    International Nuclear Information System (INIS)

    Arunasalam, V.

    1994-02-01

    It is shown that some sections of the invariance (or symmetry) principles such as the space reversal symmetry (or parity P) and time reversal symmetry T (of elementary particle and condensed matter physics, etc.) are not really truly Lorentz covariant. Indeed, I find that the Dirac-Wigner sense of Lorentz invariance is not in full compliance with the Einstein-Minkowski reguirements of the Lorentz covariance of all physical laws (i.e., the world space Mach principle)

  8. Lorentz Violation, Möller Scattering, and Finite Temperature

    Directory of Open Access Journals (Sweden)

    Alesandro F. Santos

    2018-01-01

    Full Text Available Lorentz and CPT symmetries may be violated in new physics that emerges at very high energy scale, that is, at the Planck scale. The differential cross section of the Möller scattering due to Lorentz violation at finite temperature is calculated. Lorentz-violating effects emerge from an interaction vertex due to a CPT-odd nonminimal coupling in the covariant derivative. The finite temperature effects are determined using the Thermo Field Dynamics (TFD formalism.

  9. A new General Lorentz Transformation model

    International Nuclear Information System (INIS)

    Novakovic, Branko; Novakovic, Alen; Novakovic, Dario

    2000-01-01

    A new general structure of Lorentz Transformations, in the form of General Lorentz Transformation model (GLT-model), has been derived. This structure includes both Lorentz-Einstein and Galilean Transformations as its particular (special) realizations. Since the free parameters of GLT-model have been identified in a gravitational field, GLT-model can be employed both in Special and General Relativity. Consequently, the possibilities of an unification of Einstein's Special and General Theories of Relativity, as well as an unification of electromagnetic and gravitational fields are opened. If GLT-model is correct then there exist four new observation phenomena (a length and time neutrality, and a length dilation and a time contraction). Besides, the well-known phenomena (a length contraction, and a time dilation) are also the constituents of GLT-model. It means that there is a symmetry in GLT-model, where the center of this symmetry is represented by a length and a time neutrality. A time and a length neutrality in a gravitational field can be realized if the velocity of a moving system is equal to the free fall velocity. A time and a length neutrality include an observation of a particle mass neutrality. A special consideration has been devoted to a correlation between GLT-model and a limitation on particle velocities in order to investigate the possibility of a travel time reduction. It is found out that an observation of a particle speed faster then c=299 792 458 m/s, is possible in a gravitational field, if certain conditions are fulfilled

  10. Testing Lorentz invariance in β decay

    Directory of Open Access Journals (Sweden)

    Sytema A.

    2014-03-01

    Experimentally we exploit the Gamow-Teller transition of polarized 20Na, where we can test the dependence of the β-decay rate on the spin orientation of 20Na. The polarization degree is measured using the β asymmetry, while the decay rate is measured by the γ yield. A change in the γ rate, when reversing the spin, implies Lorentz invariance violation. The decay rate should depend on sidereal time and the polarization direction relative to the rotation axis of the earth. The method of the measurement will be presented, together with the first results.

  11. Lorentz invariance with an invariant energy scale.

    Science.gov (United States)

    Magueijo, João; Smolin, Lee

    2002-05-13

    We propose a modification of special relativity in which a physical energy, which may be the Planck energy, joins the speed of light as an invariant, in spite of a complete relativity of inertial frames and agreement with Einstein's theory at low energies. This is accomplished by a nonlinear modification of the action of the Lorentz group on momentum space, generated by adding a dilatation to each boost in such a way that the Planck energy remains invariant. The associated algebra has unmodified structure constants. We also discuss the resulting modifications of field theory and suggest a modification of the equivalence principle which determines how the new theory is embedded in general relativity.

  12. Mixed Lorentz boosted $Z^{0}'s$

    CERN Document Server

    Kjaer, N J

    2001-01-01

    A novel technique is proposed to study systematic errors on jet reconstruction in W physics measurements at LEP2 with high statistical precision. The method is based on the emulation of W pair events using Mixed Lorentz Boosted Z0 events. The scope and merits of the method and its statistical accuracy are discussed in the context of the DELPHI W mass measurement in the fully hadronic channel. The numbers presented are preliminary in the sense that they do not constitute the final DELPHI systematic errors.

  13. Effective potential in Lorentz-breaking field theory models

    Energy Technology Data Exchange (ETDEWEB)

    Baeta Scarpelli, A.P. [Centro Federal de Educacao Tecnologica, Nova Gameleira Belo Horizonte, MG (Brazil); Setor Tecnico-Cientifico, Departamento de Policia Federal, Belo Horizonte, MG (Brazil); Brito, L.C.T. [Universidade Federal de Lavras, Departamento de Fisica, Lavras, MG (Brazil); Felipe, J.C.C. [Universidade Federal de Lavras, Departamento de Fisica, Lavras, MG (Brazil); Universidade Federal dos Vales do Jequitinhonha e Mucuri, Instituto de Engenharia, Ciencia e Tecnologia, Veredas, Janauba, MG (Brazil); Nascimento, J.R.; Petrov, A.Yu. [Universidade Federal da Paraiba, Departamento de Fisica, Joao Pessoa, Paraiba (Brazil)

    2017-12-15

    We calculate explicitly the one-loop effective potential in different Lorentz-breaking field theory models. First, we consider a Yukawa-like theory and some examples of Lorentz-violating extensions of scalar QED. We observe, for the extended QED models, that the resulting effective potential converges to the known result in the limit in which Lorentz symmetry is restored. Besides, the one-loop corrections to the effective potential in all the cases we study depend on the background tensors responsible for the Lorentz-symmetry violation. This has consequences for physical quantities like, for example, in the induced mass due to the Coleman-Weinberg mechanism. (orig.)

  14. Consistent Lorentz violation in flat and curved space

    International Nuclear Information System (INIS)

    Dvali, Gia; Pujolas, Oriol; Redi, Michele

    2007-01-01

    Motivated by the severity of the bounds on Lorentz violation in the presence of ordinary gravity, we study frameworks in which Lorentz violation does not affect the spacetime geometry. We show that there are at least two inequivalent classes of spontaneous Lorentz breaking that even in the presence of gravity result in Minkowski space. The first one generically corresponds to the condensation of tensor fields with tachyonic mass, which in turn is related to ghost condensation. In the second class, realized by the Dvali-Gabadadze-Porrati model or theories of massive gravitons, spontaneous Lorentz breaking is induced by the expectation value of sources. The generalization to de Sitter space is also discussed

  15. Studies on representation of the Lorentz group and gauge theory

    International Nuclear Information System (INIS)

    Hanitriarivo, R.

    2002-01-01

    This work is focused on studies about the representation of the Lorentz group and gauge theory. The mathematical tools required for the different studies are presented, as well as for the representation of the Lorentz group and for the gauge theory. Representation of the Lorentz group gives the possible types of fields and wave functions that describe particles: fermions are described by spinors and bosons are described by scalar or vector. Each of these entities (spinors, scalars, vectors) are characterized by their behavior under the action of Lorentz transformations.Gauge theory is used to describe the interactions between particles. [fr

  16. Effective potential in Lorentz-breaking field theory models

    International Nuclear Information System (INIS)

    Baeta Scarpelli, A.P.; Brito, L.C.T.; Felipe, J.C.C.; Nascimento, J.R.; Petrov, A.Yu.

    2017-01-01

    We calculate explicitly the one-loop effective potential in different Lorentz-breaking field theory models. First, we consider a Yukawa-like theory and some examples of Lorentz-violating extensions of scalar QED. We observe, for the extended QED models, that the resulting effective potential converges to the known result in the limit in which Lorentz symmetry is restored. Besides, the one-loop corrections to the effective potential in all the cases we study depend on the background tensors responsible for the Lorentz-symmetry violation. This has consequences for physical quantities like, for example, in the induced mass due to the Coleman-Weinberg mechanism. (orig.)

  17. Some impacts of Lorentz violation on cosmology

    International Nuclear Information System (INIS)

    Arianto; Zen, Freddy P.; Gunara, Bobby E.; Triyanta; Supardi

    2007-01-01

    The impact of Lorentz violation on the dynamics of a scalar field is investigated. In particular, we study the dynamics of a scalar field in the scalar-vector-tensor theory where the vector field is constrained to be unity and time like. By taking a generic form of the scalar field action, a generalized dynamical equation for the scalar-vector-tensor theory of gravity is obtained to describe the cosmological solutions. We present a class of exact solutions for an ordinary scalar field or phantom field corresponding to a power law coupling vector and the Hubble parameter. As the results, we find a constant equation of state in de Sitter space-time and power law expansion with the quadratic of coupling vector, while a dynamic equation of state is obtained for n > 2. Then, we consider the inflationary scenario based on the Lorentz violating scalar-vector-tensor theory of gravity with general power-law coupling vector and two typical potentials: inverse power-law and power-law potentials. In fact, both the coupling vector and the potential models affect the dynamics of the inflationary solutions. Finally, we use the dynamical system formalism to study the attractor behavior of a cosmological model containing a scalar field endowed with a quadratic coupling vector and a chaotic potential

  18. Quantizations of D = 3 Lorentz symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Lukierski, J. [University of Wroclaw, Institute for Theoretical Physics, Wroclaw (Poland); Tolstoy, V.N. [University of Wroclaw, Institute for Theoretical Physics, Wroclaw (Poland); Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow (Russian Federation)

    2017-04-15

    Using the isomorphism o(3; C) ≅ sl(2; C) we develop a new simple algebraic technique for complete classification of quantum deformations (the classical r-matrices) for real forms o(3) and o(2,1) of the complex Lie algebra o(3; C) in terms of real forms of sl(2; C): su(2), su(1,1) and sl(2; R). We prove that the D = 3 Lorentz symmetry o(2,1) ≅ su(1,1) ≅ sl(2; R) has three different Hopf-algebraic quantum deformations, which are expressed in the simplest way by two standard su(1,1) and sl(2; R) q-analogs and by simple Jordanian sl(2; R) twist deformation. These quantizations are presented in terms of the quantum Cartan-Weyl generators for the quantized algebras su(1,1) and sl(2; R) as well as in terms of quantum Cartesian generators for the quantized algebra o(2,1). Finally, some applications of the deformed D = 3 Lorentz symmetry are mentioned. (orig.)

  19. Cosmological constraints on Lorentz violating dark energy

    CERN Document Server

    Audren, B; Lesgourgues, J; Sibiryakov, S

    2013-01-01

    The role of Lorentz invariance as a fundamental symmetry of nature has been lately reconsidered in different approaches to quantum gravity. It is thus natural to study whether other puzzles of physics may be solved within these proposals. This may be the case for the cosmological constant problem. Indeed, it has been shown that breaking Lorentz invariance provides Lagrangians that can drive the current acceleration of the universe without experiencing large corrections from ultraviolet physics. In this work, we focus on the simplest model of this type, called ThetaCDM, and study its cosmological implications in detail. At the background level, this model cannot be distinguished from LambdaCDM. The differences appear at the level of perturbations. We show that in ThetaCDM, the spectrum of CMB anisotropies and matter fluctuations may be affected by a rescaling of the gravitational constant in the Poisson equation, by the presence of extra contributions to the anisotropic stress, and finally by the existence of ...

  20. Cosmological constraints on Lorentz violating dark energy

    Energy Technology Data Exchange (ETDEWEB)

    Audren, B.; Lesgourgues, J. [FSB/ITP/LPPC, École Polytechnique Fédérale de Lausanne, CH-1015, Lausanne (Switzerland); Blas, D. [Theory Group, Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Sibiryakov, S., E-mail: Benjamin.Audren@epfl.ch, E-mail: Diego.Blas@cern.ch, E-mail: Julien.Lesgourgues@cern.ch, E-mail: Sergey.Sibiryakov@cern.ch [Institute for Nuclear Research of the Russian Academy of Sciences, 60th October Anniversary Prospect, 7a, 117312 Moscow (Russian Federation)

    2013-08-01

    The role of Lorentz invariance as a fundamental symmetry of nature has been lately reconsidered in different approaches to quantum gravity. It is thus natural to study whether other puzzles of physics may be solved within these proposals. This may be the case for the cosmological constant problem. Indeed, it has been shown that breaking Lorentz invariance provides Lagrangians that can drive the current acceleration of the universe without experiencing large corrections from ultraviolet physics. In this work, we focus on the simplest model of this type, called ΘCDM, and study its cosmological implications in detail. At the background level, this model cannot be distinguished from ΛCDM. The differences appear at the level of perturbations. We show that in ΘCDM, the spectrum of CMB anisotropies and matter fluctuations may be affected by a rescaling of the gravitational constant in the Poisson equation, by the presence of extra contributions to the anisotropic stress, and finally by the existence of extra clustering degrees of freedom. To explore these modifications accurately, we modify the Boltzmann code class. We then use the parameter inference code Monte Python to confront ΘCDM with data from WMAP-7, SPT and WiggleZ. We obtain strong bounds on the parameters accounting for deviations from ΛCDM. In particular, we find that the discrepancy between the gravitational constants appearing in the Poisson and Friedmann equations is constrained at the level of 1.8%.

  1. Introduction to Ives' 'Derivation of the Lorentz transformations'

    International Nuclear Information System (INIS)

    Ruderfer, M.

    1979-01-01

    Lorentz ether theory is elevated on a par with special relativity by Ives' derivation of the Lorentz transformations. The two theories combined then demand the physical existence of a relativistic ether. This is supported by the still unfolding hierarchy of matter. Cogent implications for physical theory follow. (Auth.)

  2. Vortex deformation and reduction of the Lorentz force

    International Nuclear Information System (INIS)

    Vuorio, M.

    1977-01-01

    A vortex of an extreme II-type superconductor is considered in the presence of a transport current. The equivalence of Magnus and Lorentz forces in a static vortex is discussed and the effect of vortex deformation is included in calculating corrections to the conventional expression of the Lorentz force. (author)

  3. Lorentz Invariant Spectrum of Minimal Chiral Schwinger Model

    Science.gov (United States)

    Kim, Yong-Wan; Kim, Seung-Kook; Kim, Won-Tae; Park, Young-Jai; Kim, Kee Yong; Kim, Yongduk

    We study the Lorentz transformation of the minimal chiral Schwinger model in terms of the alternative action. We automatically obtain a chiral constraint, which is equivalent to the frame constraint introduced by McCabe, in order to solve the frame problem in phase space. As a result we obtain the Lorentz invariant spectrum in any moving frame by choosing a frame parameter.

  4. Ecuaciones diferenciales estocásticas y casos de aplicación en finanzas

    OpenAIRE

    Marín Sánchez, Freddy H.

    2007-01-01

    El cálculo estocástico tiene muchas aplicaciones en las áreas de Biología, Sociología, Demografía, Economía y Finanzas. Por otro lado, las series de tiempo son una herramienta estadística muy utilizada en el estudio de series financieras y económicas. Estas dos herramientas pueden emplearse conjuntamente para estudiar la dinámica de precios de algunos commodities con características especiales. En este trabajo se presentan de manera formal los elementos matemáticos de las Ecuaciones Diferenci...

  5. Ecuaciones constitutivas avanzadas para describir el comportamiento termoviscoplástico de metales FCC

    OpenAIRE

    Pereira Valadés, Daniel

    2011-01-01

    En este proyecto de fin de carrera se ha llevado a cabo el estudio y proposición de ecuaciones constitutivas avanzadas que permitan describir con exactitud el comportamiento termoviscoplástico de metales FCC. Este estudio es de vital importancia para entender el proceso que tiene lugar en estos metales bajo condiciones de carga dinámicas, siempre en deformación plástica. La utilidad del estudio reside en la gran cantidad de procesos industriales que se llevan a cabo con este tipo de solicitac...

  6. Sobre la convergencia de un método secante para ecuaciones matriciales no lineales

    Directory of Open Access Journals (Sweden)

    Mauricio Macías C.

    2014-12-01

    Full Text Available En este artículo desarrollamos una teoría general de convergencia de un método secante para resolver ecuaciones matriciales no lineales. Además, presentamos condiciones suficientes para que este método proporcione un algoritmo local y superlinealmente convergente. Abstract. In this paper we develop a general theory of convergence of a secant method to solve nonlinear matrix equations. In addition, we give sufficient conditions in order to this method provide a local and superlinearly convergent algorithm.

  7. Lorentz violation, gravitoelectromagnetism and Bhabha scattering at finite temperature

    Science.gov (United States)

    Santos, A. F.; Khanna, Faqir C.

    2018-04-01

    Gravitoelectromagnetism (GEM) is an approach for the gravitation field that is described using the formulation and terminology similar to that of electromagnetism. The Lorentz violation is considered in the formulation of GEM that is covariant in its form. In practice, such a small violation of the Lorentz symmetry may be expected in a unified theory at very high energy. In this paper, a non-minimal coupling term, which exhibits Lorentz violation, is added as a new term in the covariant form. The differential cross-section for Bhabha scattering in the GEM framework at finite temperature is calculated that includes Lorentz violation. The Thermo Field Dynamics (TFD) formalism is used to calculate the total differential cross-section at finite temperature. The contribution due to Lorentz violation is isolated from the total cross-section. It is found to be small in magnitude.

  8. Modelling Planck-scale Lorentz violation via analogue models

    International Nuclear Information System (INIS)

    Weinfurtner, Silke; Liberati, Stefano; Visser, Matt

    2006-01-01

    Astrophysical tests of Planck-suppressed Lorentz violations had been extensively studied in recent years and very stringent constraints have been obtained within the framework of effective field theory. There are however still some unresolved theoretical issues, in particular regarding the so called 'naturalness problem' - which arises when postulating that Planck suppressed Lorentz violations arise only from operators with mass dimension greater than four in the Lagrangian. In the work presented here we shall try to address this problem by looking at a condensed-matter analogue of the Lorentz violations considered in quantum gravity phenomenology. specifically, we investigate the class of two-component BECs subject to laserinduced transitions between the two components, and we show that this model is an example for Lorentz invariance violation due to ultraviolet physics. We shall show that such a model can be considered to be an explicit example high-energy Lorentz violations where the 'naturalness problem' does not arise

  9. Bumpy black holes from spontaneous Lorentz violation

    International Nuclear Information System (INIS)

    Dubovsky, Sergei; Tinyakov, Peter; Zaldarriaga, Matias

    2007-01-01

    We consider black holes in Lorentz violating theories of massive gravity. We argue that in these theories black hole solutions are no longer universal and exhibit a large number of hairs. If they exist, these hairs probe the singularity inside the black hole providing a window into quantum gravity. The existence of these hairs can be tested by future gravitational wave observatories. We generically expect that the effects we discuss will be larger for the more massive black holes. In the simplest models the strength of the hairs is controlled by the same parameter that sets the mass of the graviton (tensor modes). Then the upper limit on this mass coming from the inferred gravitational radiation emitted by binary pulsars implies that hairs are likely to be suppressed for almost the entire mass range of the super-massive black holes in the centers of galaxies

  10. Lorentz Violation in Warped Extra Dimensions

    International Nuclear Information System (INIS)

    Rizzo, Thomas G.

    2011-01-01

    Higher dimensional theories which address some of the problematic issues of the Standard Model(SM) naturally involve some form of D = 4 + n-dimensional Lorentz invariance violation (LIV). In such models the fundamental physics which leads to, e.g., field localization, orbifolding, the existence of brane terms and the compactification process all can introduce LIV in the higher dimensional theory while still preserving 4-d Lorentz invariance. In this paper, attempting to capture some of this physics, we extend our previous analysis of LIV in 5-d UED-type models to those with 5- d warped extra dimensions. To be specific, we employ the 5-d analog of the SM Extension of Kostelecky et al. which incorporates a complete set of operators arising from spontaneous LIV. We show that while the response of the bulk scalar, fermion and gauge fields to the addition of LIV operators in warped models is qualitatively similar to what happens in the flat 5-d UED case, the gravity sector of these models reacts very differently than in flat space. Specifically, we show that LIV in this warped case leads to a non-zero bulk mass for the 5-d graviton and so the would-be zero mode, which we identify as the usual 4-d graviton, must necessarily become massive. The origin of this mass term is the simultaneous existence of the constant non-zero AdS 5 curvature and the loss of general co-ordinate invariance via LIV in the 5-d theory. Thus warped 5-d models with LIV in the gravity sector are not phenomenologically viable.

  11. Constructos y variables del ambiente virtual de aprendizaje, desde la perspectiva del modelo de ecuaciones estructurales

    Directory of Open Access Journals (Sweden)

    Alfredo Ángel Ramírez\\u2013Carbajal

    2016-01-01

    Full Text Available Este artículo presenta el diseño y los resultados de un proyecto de investigación. Se inicia con la contextualización en el área educativa y enseguida se describe una aproximación a la revisión de la literatura sobre el ambiente virtual de aprendizaje y el modelo de ecuaciones estructurales. En la fundamentación, se explican las teorías de la acción razonada, la del modelo de aceptación de la tecnología, la del modelo de éxito de los sistemas de información y la del modelo de ecuaciones estructurales. Mediante el método, se logra recopilar 1175 artículos de distintas revistas científicas. A partir de estos y con la aplicación de una serie de criterios se identifica una muestra representativa de 421. Los resultados dan cuenta de los constructos, las variables y el tipo de teorías aplicadas en los ambientes virtuales investigados. Por último, la discusión y las conclusiones están referidas a las asociaciones entre los elementos de los modelos publicados por sus autores.

  12. ECUACIONES PARA ESTIMAR EL PODER CALORÍFICO DE LA MADERA DE CUATRO ESPECIES DE ÁRBOLES

    OpenAIRE

    Dimas Agostinho-Da Silva; Braulio Otomar-Caron; Carlos R. Sanquetta; Alexandre Behling; Denise Scmidt; Rogério Bamberg; Elder Eloy; Ana Paula Dalla-Corte

    2014-01-01

    El objetivo de este trabajo fue ajustar ecuaciones de regresión que expresen el poder calorífico superior (PCS) de la madera de cuatro especies forestales: Acacia mearnsii De Willd., Eu - calyptus grandis Hill, Mimosa scabrella Benth. y Ateleia glazioviana Baill. El procedimiento de selección de variables hacia atrás se utilizó para generar ecuaciones de PCS en función de los contenidos de material volátil (CMV), ceniza (CC), carbono fijo (CCF) y materia orgánica (CMO). Las muestras se recole...

  13. Contração de Lorentz, lei de Gauss e lei de Ampère

    Directory of Open Access Journals (Sweden)

    Ortiz Olivia

    2003-01-01

    Full Text Available Mostramos como obter a expressão para a contração de Lorentz dos comprimentos, a partir das leis de Gauss e Ampère, sem qualquer conhecimento da teoria da relatividade especial de Einstein. Mostramos em seguida que tal resultado é consistente com a transformação relativística dos campos elétrico e magnético.

  14. Dificultades en el aprendizaje de problemas que se modelan con ecuaciones lineales: El caso de estudiantes de octavo nivel de un colegio de Heredia

    Directory of Open Access Journals (Sweden)

    Gilberto Chavarría Arroyo

    2014-07-01

    Full Text Available Se presentan los resultados de una investigación, cuyo propósito fue analizar las dificultades de estudiantes de octavo año, al aprender el tema de resolución de problemas algebraicos modelados mediante ecuaciones lineales con una incógnita. Los protagonistas fueron estudiantes con bajo rendimiento en matemática de un colegio de Heredia. La investigación se desarrolló desde el paradigma naturalista y se utilizó el estudio de caso como método, mediante un enfoque cualitativo. Se aplicaron técnicas como observaciones de clase, cuestionario a estudiantes, entrevistas no estructuradas a la docente y entrevista clínica a los educandos. Entre los datos más relevantes se destacaron las principales causas de las dificultades de los estudiantes al aprender a resolver problemas algebraicos: aspectos afectivos, deficiencia en conocimientos previos, poca comprensión relacional, fatiga, distracción, deficiencias en la lectura y mal manejo de terminología.

  15. Factoring the dispersion relation in the presence of Lorentz violation

    International Nuclear Information System (INIS)

    Colladay, Don; McDonald, Patrick; Mullins, David

    2010-01-01

    We produce an explicit formula for the dispersion relation for the Dirac equation in the standard model extension in the presence of Lorentz violation. Our expression is obtained using novel techniques which exploit the algebra of quaternions. The dispersion relation is found to conveniently factor in two special cases that each involve a mutually exclusive set of nonvanishing Lorentz-violating parameters. This suggests that a useful approach to studies of Lorentz-violating models is to split the parameter space into two separate pieces, each of which yields a simple, tractable dispersion relation that can be used for analysis.

  16. Rotation associated with product of two Lorentz transformations

    International Nuclear Information System (INIS)

    Van Wyk, C.B.

    1984-01-01

    In the usual presentation of the Lorentz transformation there is an almost complete absence of the use of products of these transformations. One of the reasons for this appears to be the large amount of calculation involved when multi-plying the 4X4 matrices of the vector representation of the Lorentz transformation. In the article this problem is partly cleared up by using the coordinate free two-component spinor representation of rotations and Lorentz transformations. It is also shown that the theory derived in the article can be applied to Thomas precission in a very simple and direct way

  17. Strong binary pulsar constraints on Lorentz violation in gravity.

    Science.gov (United States)

    Yagi, Kent; Blas, Diego; Yunes, Nicolás; Barausse, Enrico

    2014-04-25

    Binary pulsars are excellent laboratories to test the building blocks of Einstein's theory of general relativity. One of these is Lorentz symmetry, which states that physical phenomena appear the same for all inertially moving observers. We study the effect of violations of Lorentz symmetry in the orbital evolution of binary pulsars and find that it induces a much more rapid decay of the binary's orbital period due to the emission of dipolar radiation. The absence of such behavior in recent observations allows us to place the most stringent constraints on Lorentz violation in gravity, thus verifying one of the cornerstones of Einstein's theory much more accurately than any previous gravitational observation.

  18. Generalizations of teleparallel gravity and local Lorentz symmetry

    International Nuclear Information System (INIS)

    Sotiriou, Thomas P.; Barrow, John D.; Li Baojiu

    2011-01-01

    We analyze the relation between teleparallelism and local Lorentz invariance. We show that generic modifications of the teleparallel equivalent to general relativity will not respect local Lorentz symmetry. We clarify the reasons for this and explain why the situation is different in general relativity. We give a prescription for constructing teleparallel equivalents for known theories. We also explicitly consider a recently proposed class of generalized teleparallel theories, called f(T) theories of gravity, and show why restoring local Lorentz symmetry in such theories cannot lead to sensible dynamics, even if one gives up teleparallelism.

  19. Strong Binary Pulsar Constraints on Lorentz Violation in Gravity

    CERN Document Server

    Yagi, Kent; Yunes, Nicolas; Barausse, Enrico

    2014-01-01

    Binary pulsars are excellent laboratories to test the building blocks of Einstein's theory of General Relativity. One of these is Lorentz symmetry which states that physical phenomena appear the same for all inertially moving observers. We study the effect of violations of Lorentz symmetry in the orbital evolution of binary pulsars and find that it induces a much more rapid decay of the binary's orbital period due to the emission of dipolar radiation. The absence of such behavior in recent observations allows us to place the most stringent constraints on Lorentz violation in gravity, thus verifying one of the cornerstones of Einstein's theory much more accurately than any previous gravitational observation.

  20. Uniformly bounded representations of the Lorentz groups

    International Nuclear Information System (INIS)

    Brega, A.O.

    1982-01-01

    For the Lorentz group G = SO/sub e/(n + 1, 1)(ngreater than or equal to 2) the author constructs a family of uniformly bounded representations by means of analytically continuing a certain normalization of the unitary principal series. The method the author uses relies on an analysis of various operators under a Mellin transform and extends earlier work of E.N. Wilson. In a series of papers Kunze and Stein initiated the theory of uniformly bounded representations of semisimple Lie groups; the starting point is the unitary principal series T(sigma,s) obtained in a certain subgroup M of G and a purely imaginary number s. From there Kunze and Stein constructed families of representations R(sigma,s) depending analytically on a parameter s in a domain D of C containing the imaginary axis which are unitarily equilvalent to T(sigma,s) for s contained in the set of imaginary numbers and whose operator norms are uniformly bounded for each s in D. In the case of the Lorentz groups SO/sub e/(n + 1, 1)(ngreater than or equal to2) and the trivial representation 1 of M, E.N. Wilson obtained such a family R(1,s) for the domain D = [s contained in the set of C: absolute value Re(s) Vertical Bar2]. For this domain D and for any representation sigma of M the author provides a family R(sigma,s) of uniformly bounded representations analytically continuing T(sigma,s), thereby generalizing Wilson's work. The author has also investigated certain symmetry properties of the representations R(sigma,s) under the action of the Weyl group. The trivial representation is Weyl group invariant and the family R(1,s) obtained by Wilson satisfies R(1,s) = R(1,-s) reflecting this. Obtained was the analogous result R(sigma,s) = R(sigma,-s) for some well known representations sigma that are Weyl group invariant. This involves the explicit computation of certain constants arising in the Fourier transforms of intertwining operators

  1. Lorentz invariance violation in modified gravity

    International Nuclear Information System (INIS)

    Brax, Philippe

    2012-01-01

    We consider an environmentally dependent violation of Lorentz invariance in scalar-tensor models of modified gravity where General Relativity is retrieved locally thanks to a screening mechanism. We find that fermions have a modified dispersion relation and would go faster than light in an anisotropic and space-dependent way along the scalar field lines of force. Phenomenologically, these models are tightly restricted by the amount of Cerenkov radiation emitted by the superluminal particles, a constraint which is only satisfied by chameleons. Measuring the speed of neutrinos emitted radially from the surface of the earth and observed on the other side of the earth would probe the scalar field profile of modified gravity models in dense environments. We argue that the test of the equivalence principle provided by the Lunar ranging experiment implies that a deviation from the speed of light, for natural values of the coupling scale between the scalar field and fermions, would be below detectable levels, unless gravity is modified by camouflaged chameleons where the field normalisation is environmentally dependent.

  2. ICECUBE NEUTRINOS AND LORENTZ INVARIANCE VIOLATION

    Energy Technology Data Exchange (ETDEWEB)

    Amelino-Camelia, Giovanni [Dipartimento di Fisica, Sapienza Università di Roma and INFN, Sez. Roma1, P.le A. Moro 2, I-00185 Roma (Italy); Guetta, D. [Osservatorio astronomico di Roma, v. Frascati 33, I-00040 Monte Porzio Catone (Italy); Piran, Tsvi [The Racah Institute for Physics, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel)

    2015-06-20

    The IceCube neutrino telescope has found so far no evidence of gamma-ray burst (GRB) neutrinos. We here notice that these results assume the same travel times from source to telescope for neutrinos and photons, an assumption that is challenged by some much-studied pictures of spacetime quantization. We briefly review previous results suggesting that limits on quantum-spacetime effects obtained for photons might not be applicable to neutrinos, and we then observe that the outcome of GRB-neutrino searches could depend strongly on whether one allows for neutrinos to be affected by the minute effects of Lorentz invariance violation (LIV) predicted by some relevant quantum-spacetime models. We discuss some relevant issues using as an illustrative example three neutrinos that were detected by IceCube in good spatial coincidence with GRBs, but hours before the corresponding gamma rays. In general, this could happen if the earlier arrival reflects quantum-spacetime-induced LIV, but, as we stress, some consistency criteria must be enforced in order to properly test such a hypothesis. Our analysis sets the stage for future GRB-neutrino searches that could systematically test the possibility of quantum-spacetime-induced LIV.

  3. Lorentz invariance violation in modified gravity

    Energy Technology Data Exchange (ETDEWEB)

    Brax, Philippe, E-mail: philippe.brax@cea.fr [Institut de Physique Theorique, CEA, IPhT, CNRS, URA 2306, F-91191Gif/Yvette Cedex (France)

    2012-06-06

    We consider an environmentally dependent violation of Lorentz invariance in scalar-tensor models of modified gravity where General Relativity is retrieved locally thanks to a screening mechanism. We find that fermions have a modified dispersion relation and would go faster than light in an anisotropic and space-dependent way along the scalar field lines of force. Phenomenologically, these models are tightly restricted by the amount of Cerenkov radiation emitted by the superluminal particles, a constraint which is only satisfied by chameleons. Measuring the speed of neutrinos emitted radially from the surface of the earth and observed on the other side of the earth would probe the scalar field profile of modified gravity models in dense environments. We argue that the test of the equivalence principle provided by the Lunar ranging experiment implies that a deviation from the speed of light, for natural values of the coupling scale between the scalar field and fermions, would be below detectable levels, unless gravity is modified by camouflaged chameleons where the field normalisation is environmentally dependent.

  4. Direct Lorentz force compensation flowmeter for electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Vasilyan, S., E-mail: suren.vasilyan@tu-ilmenau.de; Froehlich, Th. [Institute of Process Measurement and Sensor Technology, Ilmenau University of Technology, 98684 Ilmenau (Germany)

    2014-12-01

    A simplified method of contactless Lorentz force (LF) measurements for flow meters on electrolytes is described and realized. Modification and comparative representation are discussed against recently well-developed methods. Based on the catapult effect, that current carrying conductor experiences a repulsive force in a magnetic field, we demonstrate force measurement method of LF velocimetry applications by commonly known “electromagnetic force” compensation principle. Measurement approach through zero point stability is considered to minimize mechanical influences and avoid gravimetric uncertainties. Here, the current carrying wires are static fixed in the vicinity of magnet system at zero point stable position, while occurring deflection of magnets by electrolyte flow is compensated by external applied current within wires. Measurements performed by developed servo-system which drives control loop by means of optical position sensor for simplified (i) single wire and (ii) coil-like extended compensation schemes. Guided by experiments on electrolyte flow, we demonstrate the applicability of adopted principle for conductivities ranging from 2 to 20 S/m. Further improvements are discussed in agreement with the parameters of demonstration setup, straightforward theory, and experimental results. We argue that this method is potentially suitable for: (a) applications with higher conductivity like molten metal (order of 10{sup 6 }S/m) assuming spatial configuration of setup and (b) for lower range of conductivity (below 1 S/m) while this is strongly subject to stiffness of system and noise mainly mechanical and thermal radiations.

  5. Traveling solitons in Lorentz and CPT breaking systems

    International Nuclear Information System (INIS)

    Souza Dutra, A. de; Correa, R. A. C.

    2011-01-01

    In this work we present a class of traveling solitons in Lorentz and CPT breaking systems. In the case of Lorentz violating scenarios, as far as we know, only static solitonic configurations were analyzed up to now in the literature. Here it is shown that it is possible to construct some traveling solitons which cannot be mapped into static configurations by means of Lorentz boosts due to explicit breaking. In fact, the traveling solutions cannot be reached from the static ones by using something similar to a Lorentz boost in those cases. Furthermore, in the model studied, a complete set of exact solutions is obtained. The solutions present a critical behavior controlled by the choice of an arbitrary integration constant.

  6. Dynamics and control of Lorentz-augmented spacecraft relative motion

    CERN Document Server

    Yan, Ye; Yang, Yueneng

    2017-01-01

    This book develops a dynamical model of the orbital motion of Lorentz spacecraft in both unperturbed and J2-perturbed environments. It explicitly discusses three kinds of typical space missions involving relative orbital control: spacecraft hovering, rendezvous, and formation flying. Subsequently, it puts forward designs for both open-loop and closed-loop control schemes propelled or augmented by the geomagnetic Lorentz force. These control schemes are entirely novel and represent a significantly departure from previous approaches.

  7. Lorentz and CPT violation in QED revisited: A missing analysis

    Energy Technology Data Exchange (ETDEWEB)

    Del Cima, Oswaldo M., E-mail: wadodelcima@if.uff.b [Universidade Federal Fluminense (UFF), Polo Universitario de Rio das Ostras, Rua Recife s/n, 28890-000, Rio das Ostras, RJ (Brazil); Fonseca, Jakson M., E-mail: jakson.fonseca@ufv.b [Universidade Federal de Vicosa (UFV), Departamento de Fisica, Avenida Peter Henry Rolfs s/n, 36570-000, Vicosa, MG (Brazil); Franco, Daniel H.T., E-mail: daniel.franco@ufv.b [Universidade Federal de Vicosa (UFV), Departamento de Fisica, Avenida Peter Henry Rolfs s/n, 36570-000, Vicosa, MG (Brazil); Piguet, Olivier, E-mail: opiguet@pq.cnpq.b [Universidade Federal do Espirito Santo (UFES), Departamento de Fisica, Campus Universitario de Goiabeiras, 29060-900, Vitoria, ES (Brazil)

    2010-05-03

    We investigate the breakdown of Lorentz symmetry in QED by a CPT violating interaction term consisting of the coupling of an axial fermion current with a constant vector field b, in the framework of algebraic renormalization - a regularization-independent method. We show, to all orders in perturbation theory, that a CPT-odd and Lorentz violating Chern-Simons-like term, definitively, is not radiatively induced by the axial coupling of the fermions with the constant vector b.

  8. Lorentz and CPT violation in QED revisited: A missing analysis

    International Nuclear Information System (INIS)

    Del Cima, Oswaldo M.; Fonseca, Jakson M.; Franco, Daniel H.T.; Piguet, Olivier

    2010-01-01

    We investigate the breakdown of Lorentz symmetry in QED by a CPT violating interaction term consisting of the coupling of an axial fermion current with a constant vector field b, in the framework of algebraic renormalization - a regularization-independent method. We show, to all orders in perturbation theory, that a CPT-odd and Lorentz violating Chern-Simons-like term, definitively, is not radiatively induced by the axial coupling of the fermions with the constant vector b.

  9. Measurement of the Lorentz-FitzGerald body contraction

    Science.gov (United States)

    Rafelski, Johann

    2018-02-01

    A complete foundational discussion of acceleration in the context of Special Relativity (SR) is presented. Acceleration allows the measurement of a Lorentz-FitzGerald body contraction created. It is argued that in the back scattering of a probing laser beam from a relativistic flying electron cloud mirror generated by an ultra-intense laser pulse, a first measurement of a Lorentz-FitzGerald body contraction is feasible.

  10. Non-Abelian Gauge Theory in the Lorentz Violating Background

    Science.gov (United States)

    Ganai, Prince A.; Shah, Mushtaq B.; Syed, Masood; Ahmad, Owais

    2018-03-01

    In this paper, we will discuss a simple non-Abelian gauge theory in the broken Lorentz spacetime background. We will study the partial breaking of Lorentz symmetry down to its sub-group. We will use the formalism of very special relativity for analysing this non-Abelian gauge theory. Moreover, we will discuss the quantisation of this theory using the BRST symmetry. Also, we will analyse this theory in the maximal Abelian gauge.

  11. The BTZ black hole as a Lorentz-flat geometry

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, Pedro D., E-mail: alvarez@physics.ox.ac.uk [Rudolf Peierls Centre for Theoretical Physics, University of Oxford (United Kingdom); Pais, Pablo, E-mail: pais@cecs.cl [Centro de Estudios Científicos (CECs), Av. Arturo Prat 514, Valdivia (Chile); Universidad Andrés Bello, Av. República 440, Santiago (Chile); Rodríguez, Eduardo, E-mail: eduarodriguezsal@unal.edu.co [Departamento de Matemática y Física Aplicadas, Universidad Católica de la Santísima Concepción, Concepción (Chile); Salgado-Rebolledo, Patricio, E-mail: pasalgado@udec.cl [Centro de Estudios Científicos (CECs), Av. Arturo Prat 514, Valdivia (Chile); Departamento de Física, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Physique Théorique et Mathématique, Université Libre de Bruxelles and International Solvay Institutes, Campus Plaine C.P. 231, B-1050 Bruxelles (Belgium); Zanelli, Jorge, E-mail: z@cecs.cl [Centro de Estudios Científicos (CECs), Av. Arturo Prat 514, Valdivia (Chile); Universidad Andrés Bello, Av. República 440, Santiago (Chile)

    2014-11-10

    It is shown that 2+1 dimensional anti-de Sitter spacetimes are Lorentz-flat. This means, in particular, that any simply-connected patch of the BTZ black hole solution can be endowed with a Lorentz connection that is locally pure gauge. The result can be naturally extended to a wider class of black hole geometries and point particles in three-dimensional spacetime.

  12. Quantum-gravity phenomenology, Lorentz symmetry, and the SME

    International Nuclear Information System (INIS)

    Lehnert, Ralf

    2007-01-01

    Violations of spacetime symmetries have recently been identified as promising signatures for physics underlying the Standard Model. The present talk gives an overview over various topics in this field: The motivations for spacetime-symmetry research, including some mechanisms for Lorentz breaking, are reviewed. An effective field theory called the Standard-Model Extension (SME) for the description of the resulting low-energy effects is introduced, and some experimental tests of Lorentz and CPT invariance are discussed

  13. Modelos dinámicos y ecuaciones diferenciales en gestión de empresas

    OpenAIRE

    Reyes-Ortiz, Giovanni-Efrain

    2012-01-01

    El objetivo fundamental de este estudio es abordar la aplicación de los modelos de Maclaurin-Taylor y de ecuaciones diferenciales en la dirección y gestión de unidades de producción. Entre los aspectos más importantes de los procesos de planeación y evaluación de actividades se encuentra la identificación de funciones de producción y de costos. Cuando estos procesos están en función de la proyección o identificación de tendencias se puede requerir la utilización de los model...

  14. Ejemplos y definiciones de ecuaciones: una ventana hacia el conocimiento conceptual de estudiantes de secundaria

    Directory of Open Access Journals (Sweden)

    Elena Fernández Millán

    2018-04-01

    Full Text Available En este estudio utilizamos la generación de ejemplos y la definición de conceptos por estudiantes para indagar en el conocimiento conceptual implícito y explícito del concepto ecuación que han adquirido en la Educación Secundaria. Los estudiantes mostraron facilidad para generar ejemplos de ecuaciones y determinar diferencias entre ellos, dando evidencias de su conocimiento conceptual implícito. En cuanto al explícito, manifestaron dificultades para definir el concepto ecuación. Generar ejemplos les ayudó a identificar elementos comunes, generalizar y expresar verbalmente, aunque con ciertas limitaciones, lo que para ellos es una ecuación.

  15. Hendrik Antoon Lorentz: his role in physics and society

    Science.gov (United States)

    Berends, Frits

    2009-04-01

    Hendrik Antoon Lorentz (1853-1928) was appointed in 1878 to a chair of theoretical physics at the University of Leiden, one of the first of such chairs in the world. A few years later Heike Kamerlingh Onnes became his experimental colleague, after vehement discussions in the faculty. Lorentz strongly supported Kamerlingh Onnes then, and proved subsequently to be an ideal colleague. With Lorentz's electron theory the classical theory of electromagnetism obtained its final form, at the time often called the Maxwell-Lorentz theory. In this theory the Zeeman effect could be explained: the first glimpse of the electron. The Nobel Prize followed in 1902. The Lorentz transformation, established in 1904, preceded the special theory of relativity. Later on, Lorentz played a much admired role in the debate on the new developments in physics, in particular as chairman of a series of Solvay conferences. Gradually his stature outside of physics grew, both nationally as chairman of the Zuiderzee committee and internationally as president of the International Commission on Intellectual Cooperation of the League of Nations. At his funeral the overwhelming tribute was the recognition of his unique greatness. Einstein said about him 'He meant more to me personally than anyone else I have met on my life's journey'.

  16. Hendrik Antoon Lorentz: his role in physics and society

    Energy Technology Data Exchange (ETDEWEB)

    Berends, Frits [Emeritus Theoretical Physics, Leiden University (Netherlands)

    2009-04-22

    Hendrik Antoon Lorentz (1853-1928) was appointed in 1878 to a chair of theoretical physics at the University of Leiden, one of the first of such chairs in the world. A few years later Heike Kamerlingh Onnes became his experimental colleague, after vehement discussions in the faculty. Lorentz strongly supported Kamerlingh Onnes then, and proved subsequently to be an ideal colleague. With Lorentz's electron theory the classical theory of electromagnetism obtained its final form, at the time often called the Maxwell-Lorentz theory. In this theory the Zeeman effect could be explained: the first glimpse of the electron. The Nobel Prize followed in 1902. The Lorentz transformation, established in 1904, preceded the special theory of relativity. Later on, Lorentz played a much admired role in the debate on the new developments in physics, in particular as chairman of a series of Solvay conferences. Gradually his stature outside of physics grew, both nationally as chairman of the Zuiderzee committee and internationally as president of the International Commission on Intellectual Cooperation of the League of Nations. At his funeral the overwhelming tribute was the recognition of his unique greatness. Einstein said about him 'He meant more to me personally than anyone else I have met on my life's journey'.

  17. Hendrik Antoon Lorentz: his role in physics and society

    International Nuclear Information System (INIS)

    Berends, Frits

    2009-01-01

    Hendrik Antoon Lorentz (1853-1928) was appointed in 1878 to a chair of theoretical physics at the University of Leiden, one of the first of such chairs in the world. A few years later Heike Kamerlingh Onnes became his experimental colleague, after vehement discussions in the faculty. Lorentz strongly supported Kamerlingh Onnes then, and proved subsequently to be an ideal colleague. With Lorentz's electron theory the classical theory of electromagnetism obtained its final form, at the time often called the Maxwell-Lorentz theory. In this theory the Zeeman effect could be explained: the first glimpse of the electron. The Nobel Prize followed in 1902. The Lorentz transformation, established in 1904, preceded the special theory of relativity. Later on, Lorentz played a much admired role in the debate on the new developments in physics, in particular as chairman of a series of Solvay conferences. Gradually his stature outside of physics grew, both nationally as chairman of the Zuiderzee committee and internationally as president of the International Commission on Intellectual Cooperation of the League of Nations. At his funeral the overwhelming tribute was the recognition of his unique greatness. Einstein said about him 'He meant more to me personally than anyone else I have met on my life's journey'.

  18. The Lorentz-Dirac equation in light of quantum theory

    International Nuclear Information System (INIS)

    Nikishov, A.I.

    1996-01-01

    To high accuracy, an electron in ultrarelativistic motion 'sees' an external field in its rest frame as a crossed field (E=H, E·H=0). In this case, quantum expressions allow the introduction of a local intensity of the radiation, which determines the radiative term of the force of radiative reaction. For γ=(1-v2)-1/2>> 1 this term is much larger than the mass term, i.e., the term with xd3do. Under these conditions, the reduced Lorentz-Dirac equation, which is obtained from the full Lorentz-Dirac equation by eliminating the terms xd3do and xe on the right side using the equation of motion without taking into account the force of radiative reaction, is equivalent to good accuracy to the original Lorentz-Dirac equation. Exact solutions to the reduced Lorentz-Dirac equation are obtained for a constant field and the field of a plane wave. For γ∼1 a local expression for the radiative term cannot be obtained quantitatively from the quantum expressions. In this case the mass (Lorentz-Dirac) terms in the original and reduced Lorentz-Dirac equations are not small compared to the radiative term. The predictions of these equations, which depend appreciably on the mass terms, are therefore less reliable

  19. Solución de redes de flujo para gases usando el modelo de balance de nodos y el método de linealización de ecuaciones

    Directory of Open Access Journals (Sweden)

    Paulo César Narváez

    1999-09-01

    Full Text Available El dimensionamiento de redes de distribución de gases es un problema complejo, tanto por la diversidad de los fenómenos que se presentan, como por la variación de las propiedades de los fluidos, en especial, la densidad por efecto de los cambios en la presión a lo largo de la red. Este trabajo presenta un modelo para su simulación a partir de la deducción de la ecuación general de flujo en estado estable e isotérmico, su inclusión en el modelo de balance de nodos y la solución de este por el método de linealización de ecuaciones. Adicionalmente, se hace un resumen de las ecuaciones empíricas más usadas para el cálculo de la caída de presión para gases fluyendo en tuberías y un ejemplo que ilustra la aplicación del modelo y el método desarrollado.

  20. LORENTZ PHASE IMAGING AND IN-SITU LORENTZ MICROSCOPY OF PATTERNED CO-ARRAYS

    International Nuclear Information System (INIS)

    VOLKOV, V.V.; ZHU, Y.

    2003-01-01

    Understanding magnetic structures and properties of patterned and ordinary magnetic films at nanometer length-scale is the area of immense technological and fundamental scientific importance. The key feature to such success is the ability to achieve visual quantitative information on domain configurations with a maximum ''magnetic'' resolution. Several methods have been developed to meet these demands (Kerr and Faraday effects, differential phase contrast microscopy, magnetic force microscopy, SEMPA etc.). In particular, the modern off-axis electron holography allows retrieval of the electron-wave phase shifts down to 2π/N (with typical N = 10-20, approaching in the limit N ∼ 100) in TEM equipped with field emission gun, which is already successfully employed for studies of magnetic materials at nanometer scale. However, it remains technically demanding, sensitive to noise and needs highly coherent electron sources. As possible alternative we developed a new method of Lorentz phase microscopy [1,2] based on the Fourier solution [3] of magnetic transport-of-intensity (MTIE) equation. This approach has certain advantages, since it is less sensitive to noise and does not need high coherence of the source required by the holography. In addition, it can be realized in any TEM without basic hardware changes. Our approach considers the electron-wave refraction in magnetic materials (magnetic refraction) and became possible due to general progress in understanding of noninterferometric phase retrieval [4-6] dealing with optical refraction. This approach can also be treated as further development of Fresnel microscopy, used so far for imaging of in-situ magnetization process in magnetic materials studied by TEM. Figs. 1-3 show some examples of what kind information can be retrieved from the conventional Fresnel images using the new approach. Most of these results can be compared with electron-holographic data. Using this approach we can shed more light on fine details of

  1. Ecuaciones para la evaluación de la composición corporal en niños y adolescentes

    Directory of Open Access Journals (Sweden)

    Cristian Curilem-Gatica

    2016-01-01

    Full Text Available Resumen: El uso del índice de masa corporal (IMC es el más masivo a nivel mundial y a pesar de existir recomendaciones para su interpretación en relación al sexo, edad y raza, normalmente se estandariza su entendimiento, aumentando el error en el resultado y en la clasificación del estado nutricional. El uso de la composición corporal entrega información de mayor relevancia que el IMC, siendo la masa grasa y la masa muscular las principales. Esta comunicación presenta una revisión de las ecuaciones existentes y propone aquellas más simples y con menor error de estimación para ser usadas como una herramienta que reemplace o complemente al IMC, favoreciendo una mejor comprensión e interpretación del estado nutricional y nivel de actividad física.

  2. PREVALENCIA DE LA ENFERMEDAD RENAL CRÓNICA DETERMINADA MEDIANTE LA APLICACIÓN DE ECUACIONES PREDICTIVAS EN PERSONAS HIPERTENSAS ATENDIDAS EN ATENCION PRIMARIA

    Directory of Open Access Journals (Sweden)

    Rafael Gómez Navarro

    2009-01-01

    Full Text Available Fundamento: La enfermedad renal crónica (ERC constituye un importante problema de salud en las sociedades desarrolladas vinculado al progresivo envejecimiento de la población y a la elevada prevalencia de patologías como la hipertensión arterial (HTA y la diabetes mellitus. Los objetivos de este trabajo son: estudiar la función renal (FR en las personas hipertensas mediante ecuaciones predictivas y creatinina plasmática (Crp. Conocer el porcentaje de personas con enfermedad renal crónica (ERC que presentan valores normales de Crp. Analizar los factores que colaboran en el deterioro de su FR. Metodos: Estudio descriptivo transversal de las personas con hipertensión arterial (HTA. Se determinó Crp y tensión arterial (TA. Se calculó el filtrado glomerular mediante las fórmulas de Cockroft-Gault y MDRD. Se registraron los años de evolución de la HTA. Se realizó estudio descriptivo de las variables estudiadas y se analizó la posible dependencia entre algunas mediante regresión lineal múltiple.. Resultados: Se estudió un total de 52 pacientes (57,7% mujeres. Edad media 72,4 ± 10,8. Un 32,6% (Cockcroft-Gault o un 21,5% (MDRD cumplían criterio de ERC. Predomina la ERC en las mujeres. El 21,4% (Cockcroft-Gault y 9,5% (MDRD de pacientes con ERC tenían valores normales de Crp. No encontramos dependencia lineal entre las cifras de TA y la FR. El cumplimiento de los objetivos de TA no supone un menor desarrollo de ERC. En los varones encontramos dependencia lineal entre la FR (MDRD y los años de evolución de la HTA. Conclusiones: La ERC es una patología frecuente en las personas hipertensas. La utilización sistemática de ecuaciones predictivas facilita la detección de ERC oculta en pacientes con Crp normal.

  3. In-depth Study on Cylinder Wake Controlled by Lorentz Force

    International Nuclear Information System (INIS)

    Zhang Hui; Fan Bao-Chun; Chen Zhi-Hua

    2011-01-01

    The underlying mechanisms of the electromagnetic control of cylinder wake are investigated and discussed. The effects of Lorentz force are found to be composed of two parts, one is its direct action on the cylinder (the wall Lorentz force) and the other is applied to the fluid (called the field Lorentz force) near the cylinder surface. Our results show that the wall Lorentz force can generate thrust and reduce the drag; the field Lorentz force increases the drag. However, the cylinder drag is dominated by the wall Lorentz force. In addition, the field Lorentz force above the upper surface decreases the lift, while the upper wall Lorentz force increases it. The total lift is dominated by the upper wall Lorentz force. (fundamental areas of phenomenology(including applications))

  4. Lorentz Violation of the Photon Sector in Field Theory Models

    Directory of Open Access Journals (Sweden)

    Lingli Zhou

    2014-01-01

    Full Text Available We compare the Lorentz violation terms of the pure photon sector between two field theory models, namely, the minimal standard model extension (SME and the standard model supplement (SMS. From the requirement of the identity of the intersection for the two models, we find that the free photon sector of the SMS can be a subset of the photon sector of the minimal SME. We not only obtain some relations between the SME parameters but also get some constraints on the SMS parameters from the SME parameters. The CPT-odd coefficients (kAFα of the SME are predicted to be zero. There are 15 degrees of freedom in the Lorentz violation matrix Δαβ of free photons of the SMS related with the same number of degrees of freedom in the tensor coefficients (kFαβμν, which are independent from each other in the minimal SME but are interrelated in the intersection of the SMS and the minimal SME. With the related degrees of freedom, we obtain the conservative constraints (2σ on the elements of the photon Lorentz violation matrix. The detailed structure of the photon Lorentz violation matrix suggests some applications to the Lorentz violation experiments for photons.

  5. On the ether-like Lorentz-breaking actions

    International Nuclear Information System (INIS)

    Petrov, A.Yu; Nascimento, J.R.; Gomes, M.; Silva, A. J. da

    2011-01-01

    We demonstrate the generation of the CPT-even, ether-like Lorentz-breaking actions for the scalar and electro-magnetic fields via their appropriate Lorentz-breaking coupling to spinor fields in three, four and five space-time dimensions. Besides, we show that the ether-like terms for the spinor field also can be generated as a consequence of the same couplings. The key result which will be presented here is the finiteness of the ether-like term for the electromagnetic field not only in three and five space-time dimensions where it is natural due to known effects of the dimensional regularization but also in four space-time dimensions. Moreover, we present the calculation of the last result within different calculational schemes and conclude that the result for the four-dimensional ether-like term for the electromagnetic field essentially depending on the calculation scheme, similarly to the result for the Carroll-Field-Jackiw (CFJ) term which probably signalizes a possibility for arising of a new anomaly. Also we discuss the dispersion relations in the theories with ether-like Lorentz-breaking terms which allows to discuss the consistency of the Lorentz-breaking modified theories for different (space-like or time-like) Lorentz-breaking vectors and find the tree-level effective (Breit) potential for fermion scattering and the one-loop effective potential corresponding to the action of the scalar field. (author)

  6. Lorentz-violating alternative to the Higgs mechanism?

    International Nuclear Information System (INIS)

    Alexandre, Jean; Mavromatos, Nick E.

    2011-01-01

    We consider a four-dimensional field-theory model with two massless fermions, coupled to an Abelian vector field without flavor mixing, and to another Abelian vector field with flavor mixing. Both Abelian vectors have a Lorentz-violating kinetic term, introducing a Lorentz-violation mass scale M, from which fermions and the flavor-mixing vector get their dynamical masses, whereas the vector coupled without flavor mixing remains massless. When the two coupling constants have similar values in order of magnitude, a mass hierarchy pattern emerges, in which one fermion is very light compared to the other, while the vector mass is of the order of the heavy fermion mass. The work presented here may be considered as a Lorentz-symmetry-violating alternative to the Higgs mechanism, in the sense that no scalar particle (fundamental or composite) is necessary for the generation of the vector-meson mass. However, the model is not realistic given that, as a result of Lorentz violation, the maximal (light-cone) speed seen by the fermions is smaller than that of the massless gauge boson (which equals the speed of light in vacuo) by an amount which is unacceptably large to be compatible with the current tests of Lorentz invariance, unless the gauge couplings assume unnaturally small values. Possible ways out of this phenomenological drawback are briefly discussed, postponing a detailed construction of more realistic models for future work.

  7. Lorentz-violating theories in the standard model extension

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira Junior, Manoel Messias [Universidade Federal do Maranhao (UFMA), Sao Luis, MA (Brazil)

    2012-07-01

    Full text: Lorentz-violating theories have been an issue of permanent interest in the latest years. Many of these investigations are developed under the theoretical framework of the Standard Model Extension (SME), a broad extension of the minimal Standard Model embracing Lorentz-violating (LV) terms, generated as vacuum expectation values of tensor quantities, in all sectors of interaction. In this talk, we comment on some general properties of the SME, concerning mainly the gauge and fermion sectors, focusing in new phenomena induced by Lorentz violation. The LV terms are usually separated in accordance with the behavior under discrete symmetries, being classified as CPT-odd or CPT-even, parity-even or parity-odd. We follow this classification scheme discussing some features and new properties of the CPT-even and CPT-odd parts of the gauge and fermion sectors. We finalize presenting some upper bounds imposed on the corresponding LV coefficients. (author)

  8. Lorentz violation and black-hole thermodynamics: Compton scattering process

    International Nuclear Information System (INIS)

    Kant, E.; Klinkhamer, F.R.; Schreck, M.

    2009-01-01

    A Lorentz-noninvariant modification of quantum electrodynamics (QED) is considered, which has photons described by the nonbirefringent sector of modified Maxwell theory and electrons described by the standard Dirac theory. These photons and electrons are taken to propagate and interact in a Schwarzschild spacetime background. For appropriate Lorentz-violating parameters, the photons have an effective horizon lying outside the Schwarzschild horizon. A particular type of Compton scattering event, taking place between these two horizons (in the photonic ergoregion) and ultimately decreasing the mass of the black hole, is found to have a nonzero probability. These events perhaps allow for a violation of the generalized second law of thermodynamics in the Lorentz-noninvariant theory considered.

  9. Special Relativity in Week One: 3) Introducing the Lorentz Contraction

    Science.gov (United States)

    Huggins, Elisha

    2011-05-01

    This is the third of four articles on teaching special relativity in the first week of an introductory physics course.1,2 With Einstein's second postulate that the speed of light is the same to all observers, we could use the light pulse clock to introduce time dilation. But we had difficulty introducing the Lorentz contraction until we saw the movie "Time Dilation, an Experiment with Mu-Mesons" by David Frisch and James Smith.3,4 The movie demonstrates that time dilation and the Lorentz contraction are essentially two sides of the same coin. Here we take the muon's point of view for a more intuitive understanding of the Lorentz contraction, and use the results of the movie to provide an insight into the way we interpret experimental results involving special relativity.

  10. Comment on 'Lorentz transformations with arbitrary line of motion'

    International Nuclear Information System (INIS)

    Tjiang, Paulus C; Sutanto, Sylvia H

    2007-01-01

    A short comment regarding the derivation of Lorentz transformation proposed by Iyer and Prabhu (2007 Eur. J. Phys. 11 183-90) is given. It is shown that the proposed derivation is similar to that appearing in the standard textbooks of classical mechanics, electrodynamics and the theory of relativity. In fact, those textbooks also provide an elegant form of the Lorentz matrix for the (3+1)-dimensional case, which Iyer and Prabhu claim to be difficult to attain because of its algebraic complexity. We also provide the derivation of the (3+1)-dimensional version of the Lorentz matrix using a method analogous to that proposed by Iyer and Prabhu, and show that the result is completely equivalent to the (3+1)-dimensional version appearing in the textbooks. (letters and comments)

  11. Convexity and concavity constants in Lorentz and Marcinkiewicz spaces

    Science.gov (United States)

    Kaminska, Anna; Parrish, Anca M.

    2008-07-01

    We provide here the formulas for the q-convexity and q-concavity constants for function and sequence Lorentz spaces associated to either decreasing or increasing weights. It yields also the formula for the q-convexity constants in function and sequence Marcinkiewicz spaces. In this paper we extent and enhance the results from [G.J.O. Jameson, The q-concavity constants of Lorentz sequence spaces and related inequalities, Math. Z. 227 (1998) 129-142] and [A. Kaminska, A.M. Parrish, The q-concavity and q-convexity constants in Lorentz spaces, in: Banach Spaces and Their Applications in Analysis, Conference in Honor of Nigel Kalton, May 2006, Walter de Gruyter, Berlin, 2007, pp. 357-373].

  12. Detecting Lorentz Violations with Gravitational Waves From Black Hole Binaries

    Science.gov (United States)

    Sotiriou, Thomas P.

    2018-01-01

    Gravitational wave observations have been used to test Lorentz symmetry by looking for dispersive effects that are caused by higher order corrections to the dispersion relation. In this Letter I argue on general grounds that, when such corrections are present, there will also be a scalar excitation. Hence, a smoking-gun observation of Lorentz symmetry breaking would be the direct detection of scalar waves that travel at a speed other than the speed of the standard gravitational wave polarizations or the speed of light. Interestingly, in known Lorentz-breaking gravity theories the difference between the speeds of scalar and tensor waves is virtually unconstrained, whereas the difference between the latter and the speed of light is already severely constrained by the coincident detection of gravitational waves and gamma rays from a binary neutron star merger.

  13. Uso de representaciones geométricas para resolver ecuaciones cuadráticas a través del método griego: experimento de enseñanza

    OpenAIRE

    Acuña, Jairo; Bustos, Geraldine; Cuervo, Miguel Ángel; Pulido, Karen Lulieth

    2012-01-01

    Presentamos los resultados obtenidos de una actividad realizada en el marco de un experimento de enseñanza desarrollado en grado noveno de una institución educativa de la ciudad de Bogotá. Dicho experimento fue realizado por cuatro estudiantes de Licenciatura en Educación Básica con Énfasis en Matemáticas. En esta investigación se usa el álgebra geométrica como recurso didáctico para comprender la solución de ecuaciones cuadráticas de la forma a través del método griego. Describimos una de...

  14. Polinomios y resolución de ecuaciones en Educación Secundaria Obligatoria y Bachillerato

    OpenAIRE

    Niévares García, Elisa

    2013-01-01

    Análisis de los conceptos de polinomios y resolución de ecuaciones, de dónde provienen y cómo son tratados en el currículo de Educación Secundaria Obligatoria y Bachillerato. Matemática Aplicada Máster en Profesor de Educación Secundaria Obligatoria y Bachillerato, Formación Profesional y Enseñanzas de Idiomas

  15. Uso de ecuaciones estructurales en áreas de manufactura y mejora continua. El caso de plantas de manufactura

    Directory of Open Access Journals (Sweden)

    Carlos Monge

    2016-03-01

    Full Text Available El uso de la modelación mediante ecuaciones estructurales ha sido empleado de manera amplia en las áreas de las ciencias del comportamiento, mercadotecnia, preferencias del consumidor y servicio al cliente. Sin embargo, existe poca bibliografía que muestre su uso en áreas de manufactura, calidad o mejora continua. El presente artículo presenta la aplicación exitosa, estadísticamente significativa y relevante de ecuaciones estructurales en una investigación realizada en plantas de manufactura de Apodaca, México. En ese estudio se analizan aspectos de manufactura y mejora continua y su impacto en la eficiencia operacional de las plantas, y se presentan los resultados de la aplicación en las áreas mencionadas, sugiriendo que las ecuaciones estructurales pueden ser utilizadas  en distintas áreas con la misma eficacia y confiabilidad que otras técnicas estadísticas de análisis multivariado.

  16. Synchronizing and controlling hyperchaos in complex Lorentz-Haken systems

    Energy Technology Data Exchange (ETDEWEB)

    Jinqing, Fang [Academia Sinica, Beijing, BJ (China). Inst. of Atomic Energy

    1995-03-01

    Synchronizing hyperchaos is realized by the drive-response relationship in the complex Lorentz-Haken system and its higher-order cascading systems for the first time. Controlling hyperchaos is achieved by the intermittent proportional feedback to all of the drive (master) system variables. The complex Lorentz-Haken system describes the detuned single-mode laser and is taken as a typical example of hyperchaotic synchronization to clarify our ideas and results. The ideas and concepts could be extended to some nonlinear dynamical systems and have prospects for potential applications, for example. to laser, electronics, plasma, cryptography, communication, chemical and biological systems and so on. (8 figs., 2 tabs.).

  17. Synchronizing and controlling hyperchaos in complex Lorentz-Haken systems

    International Nuclear Information System (INIS)

    Fang Jinqing

    1995-03-01

    Synchronizing hyperchaos is realized by the drive-response relationship in the complex Lorentz-Haken system and its higher-order cascading systems for the first time. Controlling hyperchaos is achieved by the intermittent proportional feedback to all of the drive (master) system variables. The complex Lorentz-Haken system describes the detuned single-mode laser and is taken as a typical example of hyperchaotic synchronization to clarify our ideas and results. The ideas and concepts could be extended to some nonlinear dynamical systems and have prospects for potential applications, for example. to laser, electronics, plasma, cryptography, communication, chemical and biological systems and so on. (8 figs., 2 tabs.)

  18. Lorentz and CPT violation in the Standard-Model Extension

    Energy Technology Data Exchange (ETDEWEB)

    Lehnert, Ralf, E-mail: ralehner@indiana.edu [Indiana University Center for Spacetime Symmetries (United States)

    2013-03-15

    Lorentz and CPT invariance are among the symmetries that can be investigated with ultrahigh precision in subatomic physics. Being spacetime symmetries, Lorentz and CPT invariance can be violated by minuscule amounts in many theoretical approaches to underlying physics that involve novel spacetime concepts, such as quantized versions of gravity. Regardless of the underlying mechanism, the low-energy effects of such violations are expected to be governed by effective field theory. This talk provides a survey of this idea and includes an overview of experimental efforts in the field.

  19. Lorentz and Poincaré invariance 100 years of relativity

    CERN Document Server

    Hsu Jong Ping

    2001-01-01

    This collection of papers provides a broad view of the development of Lorentz and Poincaré invariance and spacetime symmetry throughout the past 100 years. The issues explored in these papers include: (1) formulations of relativity theories in which the speed of light is not a universal constant but which are consistent with the four-dimensional symmetry of the Lorentz and Poincaré groups and with experimental results, (2) analyses and discussions by Reichenbach concerning the concepts of simultaneity and physical time from a philosophical point of view, and (3) results achieved by the union o

  20. MODELACIÓN DE ECUACIONES ESTRUCTURALES PARA LA EVALUACIÓN FORMATIVA DE LOS PROGRAMAS EDUCATIVOS

    Directory of Open Access Journals (Sweden)

    Aida Rodríguez Hernández

    2007-09-01

    Full Text Available

    En la Universidad de Quintana Roo, México, buscando un sistema de evaluación de la calidad enfocado a orientar de modo dinámico las acciones hacia las metas de calidad deseadas en las carreras de ingeniería, se ha experimentado un modelo que permite monitorear el impacto que tienen las acciones y los recursos empleados, indicando cuáles procesos requieren atención prioritaria. La metodología de análisis se basa principalmente en la modelación de ecuaciones estructurales, con los objetivos de analizar si el modelo se ajusta a los datos colectados y cuáles factores están correctamente representados. Los resultados indican qué factores están pobremente medidos y las interrelaciones existentes.

  1. Four-dimensional aether-like Lorentz-breaking QED revisited and problem of ambiguities

    Energy Technology Data Exchange (ETDEWEB)

    Baeta Scarpelli, A.P. [Setor Tecnico-Cientifico, Departamento de Policia Federal, Rua Hugo D' Antola, 95, Lapa, Sao Paulo (Brazil); Mariz, T. [Universidade Federal de Alagoas, Instituto de Fisica, Maceio, Alagoas (Brazil); Nascimento, J.R.; Petrov, A.Yu. [Universidade Federal da Paraiba, Departamento de Fisica, Caixa Postal 5008, Joao Pessoa, Paraiba (Brazil)

    2013-08-15

    In this paper, we consider the perturbative generation of the CPT-even aether-like Lorentz-breaking term in the extended Lorentz-breaking QED within different approaches and discuss its ambiguities. (orig.)

  2. Four-dimensional aether-like Lorentz-breaking QED revisited and problem of ambiguities

    International Nuclear Information System (INIS)

    Baeta Scarpelli, A.P.; Mariz, T.; Nascimento, J.R.; Petrov, A.Yu.

    2013-01-01

    In this paper, we consider the perturbative generation of the CPT-even aether-like Lorentz-breaking term in the extended Lorentz-breaking QED within different approaches and discuss its ambiguities. (orig.)

  3. Direct observation of rectified motion of vortices by Lorentz microscopy

    Indian Academy of Sciences (India)

    We have investigated the vortex dynamics for the `ratchet' operation in a niobium superconductor via a direct imaging of Lorentz microscopy. We directly observe one-directional selective motion of field-gradient-driven vortices along fabricated channels. This results from the rectification of vortices in a spatially asymmetric ...

  4. Studying Lorentz-violating electromagnetic waves in confined media

    International Nuclear Information System (INIS)

    Viana, Davidson R.; Gomes, Andre H.; Fonseca, Jakson M.; Moura-Melo, Winder A.

    2009-01-01

    Full text. Planck energy scale is still far beyond current possibilities. A question of interest is whether the Lorentz symmetry remains valid at these extremely high energies, whose answer certainly would be useful whenever building grand unified theories, in which general relativity is consistently accommodated. Here, we study a reminiscent of this possible symmetry violation, incorporated in the body of the so-called Standard Model Extension (SME). More precisely, we deal with the pure (Abelian) gauge sector, so that we have a modified classical electromagnetism in (3+1) dimensions, whose Lagrangian include a term proportional to a (constant) background tensor that breaks the Lorentz symmetry, but respecting CPT. Our attention is devoted to the wave-like solutions constrained to propagate inside confined media, like waveguides and resonant cavities. Our preliminary findings indicate that Lorentz-breaking implies in modifications of the standard results which are proportional to the (very small) violating parameters, but could be largely enhanced by diminishing the size of the confined media. Under study is the case of a toroidal cavity where the electromagnetic field should respect the additional requirement of being single-valued in the (toroidal) angular variable. Perhaps, such an extra feature combined with the usual boundary conditions could lead us to large effects of this violation, somewhat similar to those predicted for CPT- and Lorentz-odd electromagnetic waves constrained to propagate along a hollow conductor waveguide. (author)

  5. On Einstein's kinematics and his derivation of Lorentz transformation equations

    International Nuclear Information System (INIS)

    Gulati, Shobha; Gulati, S.P.

    1981-01-01

    Recently the present authors have claimed that Einstein's historic derivation of 1905 of Lorentz transformation equations is a 'howler' - a correct result achieved through some incorrect steps. In the present contribution, this howler is fully resolved. Incidently, Einstein's kinematical considerations are found to be void of any new definitional elements or conventionality as unjustifiably claimed by Einstein and some other scientists. (author)

  6. Lorentz- and CPT-symmetry studies in subatomic physics

    Energy Technology Data Exchange (ETDEWEB)

    Lehnert, Ralf, E-mail: ralehner@indiana.edu [Leibniz Universität Hannover (Germany)

    2016-12-15

    Subatomic systems provide an exquisite test bench for spacetime symmetries. This work motivates such measurements, reviews the effective field theory test framework for the description of Lorentz and CPT violation, and employs this framework to study the phenomenology of spacetime-symmetry breaking in various subatomic systems.

  7. On the Lorentz degree of a product of polynomials

    KAUST Repository

    Ait-Haddou, Rachid

    2015-01-01

    In this note, we negatively answer two questions of T. Erdélyi (1991, 2010) on possible lower bounds on the Lorentz degree of product of two polynomials. We show that the correctness of one question for degree two polynomials is a direct consequence of a result of Barnard et al. (1991) on polynomials with nonnegative coefficients.

  8. The scientific correspondence of H. A. Lorentz: Volume I

    NARCIS (Netherlands)

    Kox, A.J.

    2008-01-01

    This book presents a selection of 434 carefully annotated letters from and to the Dutch physicist and Nobel Prize winner Hendrik Antoon Lorentz (1853-1928), covering the period from 1883 until a few months before his death in February 1928. Most of these letters are of a scientific nature, with the

  9. Structural aspects of Lorentz-violating quantum field theory

    Science.gov (United States)

    Cambiaso, M.; Lehnert, R.; Potting, R.

    2018-01-01

    In the last couple of decades the Standard Model Extension has emerged as a fruitful framework to analyze the empirical and theoretical extent of the validity of cornerstones of modern particle physics, namely, of Special Relativity and of the discrete symmetries C, P and T (or some combinations of these). The Standard Model Extension allows to contrast high-precision experimental tests with posited alterations representing minute Lorentz and/or CPT violations. To date no violation of these symmetry principles has been observed in experiments, mostly prompted by the Standard-Model Extension. From the latter, bounds on the extent of departures from Lorentz and CPT symmetries can be obtained with ever increasing accuracy. These analyses have been mostly focused on tree-level processes. In this presentation I would like to comment on structural aspects of perturbative Lorentz violating quantum field theory. I will show that some insight coming from radiative corrections demands a careful reassessment of perturbation theory. Specifically I will argue that both the standard renormalization procedure as well as the Lehmann-Symanzik-Zimmermann reduction formalism need to be adapted given that the asymptotic single-particle states can receive quantum corrections from Lorentz-violating operators that are not present in the original Lagrangian.

  10. A Lorentz-Violating Alternative to Higgs Mechanism?

    CERN Document Server

    Alexandre, Jean

    2011-01-01

    We consider a four-dimensional field-theory model with two massless fermions, coupled to an Abelian vector field without flavour mixing, and to another Abelian vector field with flavour mixing. Both Abelian vectors have a Lorentz-violating kinetic term, introducing a Lorentz-violation mass scale $M$, from which fermions and the flavour-mixing vector get their dynamical masses, whereas the vector coupled without flavour mixing remains massless. When the two coupling constants have similar values in order of magnitude, a mass hierarchy pattern emerges, in which one fermion is very light compared to the other, whilst the vector mass is larger than the mass of the heavy fermion. The work presented here may be considered as a Lorentz-symmetry-Violating alternative to the Higgs mechanism, in the sense that no scalar particle (fundamental or composite) is necessary for the generation of the vector-meson mass. However, the model is not realistic given that, as a result of Lorentz Violation, the maximal (light-cone) s...

  11. Lorentz force actuation of a heated atomic force microscope cantilever.

    Science.gov (United States)

    Lee, Byeonghee; Prater, Craig B; King, William P

    2012-02-10

    We report Lorentz force-induced actuation of a silicon microcantilever having an integrated resistive heater. Oscillating current through the cantilever interacts with the magnetic field around a NdFeB permanent magnet and induces a Lorentz force that deflects the cantilever. The same current induces cantilever heating. With AC currents as low as 0.2 mA, the cantilever can be oscillated as much as 80 nm at resonance with a DC temperature rise of less than 5 °C. By comparison, the AC temperature variation leads to a thermomechanical oscillation that is about 1000 times smaller than the Lorentz deflection at the cantilever resonance. The cantilever position in the nonuniform magnetic field affects the Lorentz force-induced deflection, with the magnetic field parallel to the cantilever having the largest effect on cantilever actuation. We demonstrate how the cantilever actuation can be used for imaging, and for measuring the local material softening temperature by sensing the contact resonance shift.

  12. Anomalous current in periodic Lorentz gases with infinite horizon

    Energy Technology Data Exchange (ETDEWEB)

    Dolgopyat, Dmitrii I [University of Maryland, College Park (United States); Chernov, Nikolai I [University of Alabama at Birmingham, Birmingham, Alabama (United States)

    2009-08-31

    Electric current is studied in a two-dimensional periodic Lorentz gas in the presence of a weak homogeneous electric field. When the horizon is finite, that is, free flights between collisions are bounded, the resulting current J is proportional to the voltage difference E, that is, J=1/2 D*E+o(||E||), where D* is the diffusion matrix of a Lorentz particle moving freely without an electric field (see a mathematical proof). This formula agrees with Ohm's classical law and the Einstein relation. Here the more difficult model with an infinite horizon is investigated. It is found that infinite corridors between scatterers allow the particles (electrons) to move faster, resulting in an abnormal current (causing 'superconductivity'). More precisely, the current is now given by J=1/2 DE| log||E|| | + O(||E||), where D is the 'superdiffusion' matrix of a Lorentz particle moving freely without an electric field. This means that Ohm's law fails in this regime, but the Einstein relation (suitably interpreted) still holds. New results are also obtained for the infinite-horizon Lorentz gas without external fields, complementing recent studies by Szasz and Varju. Bibliography: 31 titles.

  13. Anomalous current in periodic Lorentz gases with infinite horizon

    International Nuclear Information System (INIS)

    Dolgopyat, Dmitrii I; Chernov, Nikolai I

    2009-01-01

    Electric current is studied in a two-dimensional periodic Lorentz gas in the presence of a weak homogeneous electric field. When the horizon is finite, that is, free flights between collisions are bounded, the resulting current J is proportional to the voltage difference E, that is, J=1/2 D*E+o(||E||), where D* is the diffusion matrix of a Lorentz particle moving freely without an electric field (see a mathematical proof). This formula agrees with Ohm's classical law and the Einstein relation. Here the more difficult model with an infinite horizon is investigated. It is found that infinite corridors between scatterers allow the particles (electrons) to move faster, resulting in an abnormal current (causing 'superconductivity'). More precisely, the current is now given by J=1/2 DE| log||E|| | + O(||E||), where D is the 'superdiffusion' matrix of a Lorentz particle moving freely without an electric field. This means that Ohm's law fails in this regime, but the Einstein relation (suitably interpreted) still holds. New results are also obtained for the infinite-horizon Lorentz gas without external fields, complementing recent studies by Szasz and Varju. Bibliography: 31 titles.

  14. On the Lorentz degree of a product of polynomials

    KAUST Repository

    Ait-Haddou, Rachid

    2015-01-01

    In this note, we negatively answer two questions of T. Erdélyi (1991, 2010) on possible lower bounds on the Lorentz degree of product of two polynomials. We show that the correctness of one question for degree two polynomials is a direct consequence

  15. A note on Lorentz transformation and pseudo-rapidity distributions

    International Nuclear Information System (INIS)

    Hama, Y.

    1980-07-01

    It is shown that although rapidity and pseudo-rapidity are almost equivalent variables, their difference may in pratice become quite remarkable. Non Lorentz invariance of pseudo-rapidity distributions may cause appearance of strange effects at first sight, such as deformation of a perfectly symmetric particle distribution into an asymmetric one when going to another frame. (Author) [pt

  16. Adaptive compensation of Lorentz force detuning in superconducting RF cavities

    Energy Technology Data Exchange (ETDEWEB)

    Pischalnikov, Yuriy [Fermilab; Schappert, Warren [Fermilab

    2011-11-01

    The Lorentz force can dynamically detune pulsed Superconducting RF cavities and considerable additional RF power can be required to maintain the accelerating gradient if no effort is made to compensate. Fermilab has developed an adaptive compensation system for cavities in the Horizontal Test Stand, in the SRF Accelerator Test Facility, and for the proposed Project X.

  17. Prospects for Lorentz and CPT tests with hydrogen and antihydrogen

    CERN Document Server

    Becker, Tobias Frederic

    2017-01-01

    As a summer student for 13 weeks in the ASACUSA-CUSP collaboration, under the supervision of Chloé Malbrunot, my project consisted in a first part on the theoretical treatment of Lorentz and CPT violation in hydrogen & antihydrogen in the framework of the Standard Model Extension SME and in second part on experimental measurements on a hydrogen beam.

  18. What Governs Lorentz Factors of Jet Components in Blazars? Xinwu ...

    Indian Academy of Sciences (India)

    Abstract. We use a sample of radio-loud Active Galactic Nuclei. (AGNs) with measured black hole masses to explore the jet formation mechanisms in these sources. We find a significant correlation between black hole mass and the bulk Lorentz factor of the jet components for this sample, while no significant correlation is ...

  19. What Governs Lorentz Factors of Jet Components in Blazars?

    Indian Academy of Sciences (India)

    We use a sample of radio-loud Active Galactic Nuclei (AGNs) with measured black hole masses to explore the jet formation mechanisms in these sources. We find a significant correlation between black hole mass and the bulk Lorentz factor of the jet components for this sample, while no significant correlation is present ...

  20. Helicity and evanescent waves. [Energy transport velocity, helicity, Lorentz transformation

    Energy Technology Data Exchange (ETDEWEB)

    Agudin, J L; Platzeck, A M [La Plata Univ. Nacional (Argentina); Albano, J R [Instituto de Astronomia y Fisica del Espacio, Buenos Aires, Argentina

    1978-02-20

    It is shown that the projection of the angular momentum of a circularly polarized electromagnetic evanescent wave along the mean velocity of energy transport (=helicity) can be reverted by a Lorentz transformation, in spite of the fact that this velocity is c.

  1. Black holes in Lorentz-violating gravity theories

    International Nuclear Information System (INIS)

    Barausse, Enrico; Sotiriou, Thomas P

    2013-01-01

    Lorentz symmetry and the notion of light cones play a central role in the definition of horizons and the existence of black holes. Current observations provide strong indications that astrophysical black holes do exist in Nature. Here we explore what happens to the notion of a black hole in gravity theories where local Lorentz symmetry is violated, and discuss the relevant astrophysical implications. Einstein-aether theory and Hořava gravity are used as the theoretical background for addressing this question. We review earlier results about static, spherically symmetric black holes, which demonstrate that in Lorentz-violating theories there can be a new type of horizon and, hence, a new notion of black hole. We also present both known and new results on slowly rotating black holes in these theories, which provide insights on how generic these new horizons are. Finally, we discuss the differences between black holes in Lorentz-violating theories and in General Relativity, and assess to what extent they can be probed with present and future observations. (paper)

  2. Special Relativity in Week One: 3) Introducing the Lorentz Contraction

    Science.gov (United States)

    Huggins, Elisha

    2011-01-01

    This is the third of four articles on teaching special relativity in the first week of an introductory physics course. With Einstein's second postulate that the speed of light is the same to all observers, we could use the light pulse clock to introduce time dilation. But we had difficulty introducing the Lorentz contraction until we saw the movie…

  3. Cosmic rays and the search for a Lorentz Invariance Violation

    International Nuclear Information System (INIS)

    Bietenholz, Wolfgang

    2008-11-01

    This is an introductory review about the on-going search for a signal of Lorentz Invariance Violation (LIV) in cosmic rays. We first summarise basic aspects of cosmic rays, focusing on rays of ultra high energy (UHECRs). We discuss the Greisen-Zatsepin-Kuz'min (GZK) energy cutoff for cosmic protons, which is predicted due to photopion production in the Cosmic Microwave Background (CMB). This is a process of modest energy in the proton rest frame. It can be investigated to a high precision in the laboratory, if Lorentz transformations apply even at factors γ ∝ O(10 11 ). For heavier nuclei the energy attenuation is even faster due to photo-disintegration, again if this process is Lorentz invariant. Hence the viability of Lorentz symmetry up to tremendous γ-factors - far beyond accelerator tests - is a central issue. Next we comment on conceptual aspects of Lorentz Invariance and the possibility of its spontaneous breaking. This could lead to slightly particle dependent ''Maximal Attainable Velocities''. We discuss their effect in decays, Cerenkov radiation, the GZK cutoff and neutrino oscillation in cosmic rays. We also review the search for LIV in cosmic γ-rays. For multi TeV γ-rays we possibly encounter another puzzle related to the transparency of the CMB, similar to the GZK cutoff, due to electron/positron creation and subsequent inverse Compton scattering. The photons emitted in a Gamma Ray Burst occur at lower energies, but their very long path provides access to information not far from the Planck scale. We discuss conceivable non-linear photon dispersions based on non-commutative geometry or effective approaches. No LIV has been observed so far. However, even extremely tiny LIV effects could change the predictions for cosmic ray physics drastically. An Appendix is devoted to the recent hypothesis by the Pierre Auger Collaboration, which identifies nearby Active Galactic Nuclei - or objects next to them - as probable UHECR sources. (orig.)

  4. Comparación entre las ecuaciones CKD-EPI y MDRD para la estimación del filtrado glomerular en pacientes con enfermedad renal crónica

    Directory of Open Access Journals (Sweden)

    Guillermo J. Rosa-Diez

    2011-08-01

    Full Text Available La ecuación MDRD para la estimación del índice de filtrado glomerular (IFG, es la estrategia más utilizada para evaluar pacientes con enfermedad renal crónica (ERC. Sin embargo, puede subestimar el IFG con el riesgo de asignar al paciente a estadios más avanzados de ERC. La nueva ecuación CKD-EPI, mejoraría la exactitud y precisión de las estimaciones. Sus autores sugieren que reemplace a la anterior. No habiendo comparaciones de estas ecuaciones aplicadas en un gran número de pacientes en nuestro país, nuestro objetivo fue realizarla en una amplia cohorte de pacientes. Se evaluó la concordancia de asignación en estadios de ERC entre ambas ecuaciones, tomando como referencia los datos surgidos de MDRD. Se calculó la media de las diferencias de los IFG obtenidos empleando ambas ecuaciones y se aplicó el análisis estadístico de Bland-Altman. Se estudió una cohorte de 9 319 pacientes con una media de creatinina sérica de 1.60 ± 1.03 mg/dl, 67% de sexo femenino y edad media 58 ± 20 años. En el grupo total, CKD-EPI presentó una media de IFG 0.61 ml/min/1.73 m² mayor que MDRD (p: NS. En los estadios 2 y 3A las medias del IFG fueron respectivamente 6.95 ± 4.76 y 3.21 ± 3.31, y la concordancia de 81 y 74%. El porcentaje de pacientes con un IFG menor de 60 ml/min/1.73 m², se redujo de 76.3% (MDRD a 70.1% (CKD-EPI. Por lo tanto, la nueva ecuación CKD-EPI disminuye el número de pacientes con IFG debajo de 60 ml/min/1.73 m² y asigna estadios de IFG más elevado a un número mayor de pacientes.

  5. Crimen y disuasión. Evidencia desde un modelo de ecuaciones simultáneas para las regiones de Chile

    Directory of Open Access Journals (Sweden)

    Jorge Rivera

    2004-01-01

    Full Text Available En este trabajo se desarrolla y estima un modelo de ecuaciones simultáneas que explica la criminalidad en Chile por regiones en el periodo 1988-2000 para varias categorías de delitos. El modelo desarrollado innova al abordar diversos problemas de endogeneidad presentes en la determinación del crimen. Los resultados obtenidos indican que: i los diversos tipos de delitos analizados tienen determinantes socioeconómicos heterogéneos; ii las fuentes y oportunidades de ingreso legal e ilegal, incluido el desempleo, afectan la comisión de varios delitos; iii existe una doble causalidad separable entre la eficiencia policial y la criminalidad, congruente con la hipótesis de “congestión” del esfuerzo policial; iv aumentos en la dotación policial presentan dos efectos contrapuestos en la tasa de criminalidad, por medio de la disuasión de crimen y la mayor propensión a denunciar delitos por parte de los afectados, y v la asignación local de recursos policiales es endógena a la criminalidad observada en periodos previos. Estos resultados sugieren que el adecuado estudio de los determinantes de la criminalidad y la elaboración de políticas públicas para combatirla requieren forzosamente un enfoque que permita abordar y separar los diversos y complejos efectos que forman parte en la determinación del crimen, como los examinados en este trabajo.

  6. Algoritmos paralelos y distribuidos para resolver ecuaciones matriciales de Lyapunov en problemas de reducción de modelos.

    OpenAIRE

    CLAVER IBORRA, JOSE MANUEL

    2011-01-01

    La reducción de modelos para problemas de control de gran tamaño es actualmente uno de los temas fundamentales en teoría de sistemas y control. Entre diversas técnicas existentes, los métodos de truncamiento de estados son los que permiten una mayor precisión en la representación del sistema reducido. Muchos de estos métodos necesitan resolver una o más ecuaciones de Lyapunov (habitualmente acopladas), requiriéndose en ocasiones el factor de Cholesky de su solución. En esta tesis se pesentan ...

  7. Modelación matemática en la resolución de sistemas de ecuaciones lineales

    OpenAIRE

    López, Jorge Iván; Flores, Ángel

    2012-01-01

    El presente trabajo se enfoca a realizar un estudio del impacto que tiene la Modelación Matemática en el aprendizaje de sistemas de ecuaciones lineales dentro del contexto de enseñanza Aprender Matemática, Haciendo Matemática. Este modelo de enseñanza se fundamenta en el marco teórico de Vygotsky y se busca que el alumno desarrolle una Cultura Básica a partir de dos aspectos fundamentales: Competencias: las cuales comprenden: el desarrollo de un pensamiento matemático, la capacidad de resolve...

  8. How (not) to teach Lorentz covariance of the Dirac equation

    International Nuclear Information System (INIS)

    Nikolić, Hrvoje

    2014-01-01

    In the textbook proofs of the Lorentz covariance of the Dirac equation, one treats the wave function as a spinor and gamma matrices as scalars, leading to a quite complicated formalism with several pedagogic drawbacks. As an alternative, I propose to teach the Dirac equation and its Lorentz covariance by using a much simpler, but physically equivalent formalism, in which these drawbacks do not appear. In this alternative formalism, the wave function transforms as a scalar and gamma matrices as components of a vector, such that the standard physically relevant bilinear combinations do not change their transformation properties. The alternative formalism allows also a natural construction of some additional non-standard bilinear combinations with well-defined transformation properties. (paper)

  9. Testing Lorentz invariance of dark matter with satellite galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Bettoni, Dario [Institut für Theoretische Physik, Ruprecht-Karls-Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg (Germany); Nusser, Adi [Physics Department and the Asher Space Science Institute—Technion, Haifa 32000 (Israel); Blas, Diego; Sibiryakov, Sergey, E-mail: d.bettoni@thphys.uni-heidelberg.de, E-mail: adi@physics.technion.ac.il, E-mail: diego.blas@cern.ch, E-mail: sergey.sibiryakov@cern.ch [Theoretical Physics Department, CERN, CH-1211 Geneva 23 (Switzerland)

    2017-05-01

    We develop the framework for testing Lorentz invariance in the dark matter sector using galactic dynamics. We consider a Lorentz violating (LV) vector field acting on the dark matter component of a satellite galaxy orbiting in a host halo. We introduce a numerical model for the dynamics of satellites in a galactic halo and for a galaxy in a rich cluster to explore observational consequences of such an LV field. The orbital motion of a satellite excites a time dependent LV force which greatly affects its internal dynamics. Our analysis points out key observational signatures which serve as probes of LV forces. These include modifications to the line of sight velocity dispersion, mass profiles and shapes of satellites. With future data and a more detailed modeling these signatures can be exploited to constrain a new region of the parameter space describing the LV in the dark matter sector.

  10. Linear negative magnetoresistance in two-dimensional Lorentz gases

    Science.gov (United States)

    Schluck, J.; Hund, M.; Heckenthaler, T.; Heinzel, T.; Siboni, N. H.; Horbach, J.; Pierz, K.; Schumacher, H. W.; Kazazis, D.; Gennser, U.; Mailly, D.

    2018-03-01

    Two-dimensional Lorentz gases formed by obstacles in the shape of circles, squares, and retroreflectors are reported to show a pronounced linear negative magnetoresistance at small magnetic fields. For circular obstacles at low number densities, our results agree with the predictions of a model based on classical retroreflection. In extension to the existing theoretical models, we find that the normalized magnetoresistance slope depends on the obstacle shape and increases as the number density of the obstacles is increased. The peaks are furthermore suppressed by in-plane magnetic fields as well as by elevated temperatures. These results suggest that classical retroreflection can form a significant contribution to the magnetoresistivity of two-dimensional Lorentz gases, while contributions from weak localization cannot be excluded, in particular for large obstacle densities.

  11. Lorentz covariance ‘almost’ implies electromagnetism and more

    International Nuclear Information System (INIS)

    Sobouti, Y

    2015-01-01

    Beginning from two simple assumptions, (i) the speed of light is a universal constant, or its equivalent, the spacetime intervals are Lorentz invariant, and (ii) there are mutually interacting particles, with a covariant ‘source-field’ equation, one arrives at a class of field equations of which the standard electromagnetism (EM) and electrodynamics are special cases. The formalism, depending on how one formulates the source-field equation, allows one to speculate magnetic monopoles, massive photons, nonlinear EMs, and more. (paper)

  12. Unified derivation of the Galileo and the Lorentz transformations

    International Nuclear Information System (INIS)

    Sardelis, D.A.

    1982-01-01

    By using the principle of relativity together with the general assumptions of space-time homogeneity and space isotropy underlying the principle of inertia, a most general transformation is constructed connecting any two inertial frames. The Galileo and the Lorentz transformations are then deduced by constraining these general inertial transformations through the corresponding two physical principles: the (classical) principle of acceleration invariance and the (relativistic) principle that all interactions propagate with the same finite and invariant speed. (author)

  13. Control of weakly conductive fluids by near wall Lorentz forces

    Energy Technology Data Exchange (ETDEWEB)

    Hinze, M. [Technische Univ. Dresden (Germany). Inst. fuer Numerische Mathematik

    2007-07-01

    In this work optimal and model-predictive control approaches for control of weakly conductive fluids are developed. The flow around the circular cylinder at low Reynolds numbers serves as prototyping application. Control by near-wall Lorentz forces gains either to suppress the formation of the von Karman Vortex Street, or to reduce the drag. Besides a concise mathematical modelling numerical examples are presented which highlight the scope of the presented control approaches. (orig.)

  14. Characterization of associate spaces of weighted Lorentz spaces with applications

    Czech Academy of Sciences Publication Activity Database

    Gogatishvili, Amiran; Pick, L.; Soudský, F.

    2014-01-01

    Roč. 224, č. 1 (2014), s. 1-23 ISSN 0039-3223 R&D Projects: GA ČR GA13-14743S Institutional support: RVO:67985840 Keywords : weighted Lorentz spaces * weighted inequalities * non-increasing rearragement * Banach function space Subject RIV: BA - General Mathematics Impact factor: 0.610, year: 2014 http://journals.impan.gov.pl/sm/Inf/224-1-1.html

  15. Heat conduction in caricature models of the Lorentz gas

    International Nuclear Information System (INIS)

    Kramli, A.; Simanyi, N.; Szasz, D.

    1987-01-01

    Heat transport coefficients are calculated for various random walks with internal states (the Markov partition of the Sinai billiard connects these walks with the Lorentz gas among a periodic configuration of scatterers). Models with reflecting or absorbing barriers and also those without or with local thermal equilibrium are investigated. The method is unified and is based on the Keldysh expansion of the resolvent of a matrix polynomial

  16. Embeddings of Lorentz-type spaces involving weighted integral means

    Czech Academy of Sciences Publication Activity Database

    Gogatishvili, Amiran; Křepela, M.; Pick, L.; Soudský, F.

    2017-01-01

    Roč. 273, č. 9 (2017), s. 2939-2980 ISSN 0022-1236 R&D Projects: GA ČR GA13-14743S Institutional support: RVO:67985840 Keywords : classical Lorentz spaces * embeddings * iterated operators Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 1.254, year: 2016 http://www.sciencedirect.com/science/article/pii/S0022123617302252

  17. Prospects for testing Lorentz and CPT symmetry with antiprotons

    Science.gov (United States)

    Vargas, Arnaldo J.

    2018-03-01

    A brief overview of the prospects of testing Lorentz and CPT symmetry with antimatter experiments is presented. The models discussed are applicable to atomic spectroscopy experiments, Penning-trap experiments and gravitational tests. Comments about the sensitivity of the most recent antimatter experiments to the models reviewed here are included. This article is part of the Theo Murphy meeting issue `Antiproton physics in the ELENA era'.

  18. Prospects for testing Lorentz and CPT symmetry with antiprotons.

    Science.gov (United States)

    Vargas, Arnaldo J

    2018-03-28

    A brief overview of the prospects of testing Lorentz and CPT symmetry with antimatter experiments is presented. The models discussed are applicable to atomic spectroscopy experiments, Penning-trap experiments and gravitational tests. Comments about the sensitivity of the most recent antimatter experiments to the models reviewed here are included.This article is part of the Theo Murphy meeting issue 'Antiproton physics in the ELENA era'. © 2018 The Author(s).

  19. Comment on self-inverse form of the Lorentz transformation

    International Nuclear Information System (INIS)

    Cook, R.J.

    1979-01-01

    It has been shown that the kinematic relations between two iertial reference frames in relative motion can be made symmetric by an appropriate orientation of the coordinate axes of the two frames. It follows from this symmetry and the principle of relativity that the transformation matrix, A, from one frame to the other, and its inverse, A -1 , are equal. This result, along with a limiting-velocity postulate, was used in a derivation of the Lorentz transformation. The present note points out that only two transformation laws are compatible with the symmetry condition A = A -1 . One of these is the Lorentz transformation and the other violates causality. Thus, if the limiting-velocity postulate is replaced by the requirement that causality be satisfied in all inertial frames, one arrives at a derivation of the Lorentz transformation based entirely on concepts which were known and widely accepted long before the advent of special relativity: the homogeneity and isotropy of space in all inertial frames, the principle of relativity, and the principle of causality

  20. Remote sub-wavelength focusing of ultrasonically activated Lorentz current

    Science.gov (United States)

    Rekhi, Angad S.; Arbabian, Amin

    2017-04-01

    We propose the use of a combination of ultrasonic and magnetic fields in conductive media for the creation of RF electrical current via the Lorentz force, in order to achieve current generation with extreme sub-wavelength resolution at large depth. We demonstrate the modeling, generation, and measurement of Lorentz current in a conductive solution and show that this current can be localized at a distance of 13 cm from the ultrasonic source to a region about three orders of magnitude smaller than the corresponding wavelength of electromagnetic waves at the same operation frequency. Our results exhibit greater depth, tighter localization, and closer agreement with prediction than previous work on the measurement of Lorentz current in a solution of homogeneous conductivity. The proposed method of RF current excitation overcomes the trade-off between focusing and propagation that is fundamental in the use of RF electromagnetic excitation alone and has the potential to improve localization and depth of operation for RF current-based biomedical applications.

  1. Estudio comparativo de flujo de fluido a través de una placa de orificio usando las ecuaciones de Stokes y de Navier-Stokes

    Directory of Open Access Journals (Sweden)

    Miryam Lucía Guerra-Mazo

    2016-05-01

    Full Text Available Presenta los resultados de la comparación entre las ecuaciones de Stokes y de Navier-Stokes para la simulación del flujo de agua líquida, a condiciones atmosféricas, a través de una placa orificio concéntrica. A partir de los datos experimentales que fueron tomados en el banco de fluidos, se evaluaron las simulaciones de ambas ecuaciones, usando el software libre Freefem++cs, que se basa en el método de los elementos finitos; las variables evaluadas son velocidad y presión en un intervalo de tiempo. Al analizar los resultados obtenidos con las simulaciones y comparar con los datos experimentales se encontró que las ecuaciones de Navier-Stokes representan mejor el sistema que la ecuación de Stokes.

  2. Cosmic rays and the search for a Lorentz Invariance Violation

    Energy Technology Data Exchange (ETDEWEB)

    Bietenholz, Wolfgang, E-mail: wolbi@nucleares.unam.mx

    2011-08-15

    This is an introductory review about the ongoing search for a signal of Lorentz Invariance Violation (LIV) in cosmic rays. We first summarise basic aspects of cosmic rays, focusing on rays of ultrahigh energy (UHECRs). We discuss the Greisen-Zatsepin-Kuz'min (GZK) energy cutoff for cosmic protons, which is predicted due to photopion production in the Cosmic Microwave Background (CMB). This is a process of modest energy in the proton rest frame. It can be investigated to a high precision in the laboratory, if Lorentz transformations apply even at factors {gamma}{approx}O(10{sup 11}). For heavier nuclei, the energy attenuation is even faster due to photo-disintegration, again if this process is Lorentz invariant. Hence the viability of Lorentz symmetry up to tremendous {gamma}-factors-far beyond accelerator tests-is a central issue. Next, we comment on conceptual aspects of Lorentz Invariance and the possibility of its spontaneous breaking. This could lead to slightly particle dependent 'Maximal Attainable Velocities'. We discuss their effect in decays, Cerenkov radiation, the GZK cutoff and neutrino oscillation in cosmic rays. We also review the search for LIV in cosmic {gamma}-rays. For multi-TeV {gamma}-rays, we encounter another possible puzzle related to the transparency of the CMB, similar to the GZK cutoff, due to electron/positron creation and subsequent inverse Compton scattering. The photons emitted in a Gamma Ray Burst occur at lower energies, but their very long path provides access to information not that far from the Planck scale. We discuss conceivable nonlinear photon dispersions based on non-commutative geometry or effective approaches. No LIV has been observed so far. However, even extremely tiny LIV effects could change the predictions for cosmic ray physics drastically. An Appendix is devoted to the recent results by the Pierre Auger Collaboration, in particular the hypothesis that nearby Active Galactic Nuclei-or objects next to

  3. Cosmic rays and the search for a Lorentz Invariance Violation

    Energy Technology Data Exchange (ETDEWEB)

    Bietenholz, Wolfgang [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC

    2008-11-15

    This is an introductory review about the on-going search for a signal of Lorentz Invariance Violation (LIV) in cosmic rays. We first summarise basic aspects of cosmic rays, focusing on rays of ultra high energy (UHECRs). We discuss the Greisen-Zatsepin-Kuz'min (GZK) energy cutoff for cosmic protons, which is predicted due to photopion production in the Cosmic Microwave Background (CMB). This is a process of modest energy in the proton rest frame. It can be investigated to a high precision in the laboratory, if Lorentz transformations apply even at factors {gamma} {proportional_to} O(10{sup 11}). For heavier nuclei the energy attenuation is even faster due to photo-disintegration, again if this process is Lorentz invariant. Hence the viability of Lorentz symmetry up to tremendous {gamma}-factors - far beyond accelerator tests - is a central issue. Next we comment on conceptual aspects of Lorentz Invariance and the possibility of its spontaneous breaking. This could lead to slightly particle dependent ''Maximal Attainable Velocities''. We discuss their effect in decays, Cerenkov radiation, the GZK cutoff and neutrino oscillation in cosmic rays. We also review the search for LIV in cosmic {gamma}-rays. For multi TeV {gamma}-rays we possibly encounter another puzzle related to the transparency of the CMB, similar to the GZK cutoff, due to electron/positron creation and subsequent inverse Compton scattering. The photons emitted in a Gamma Ray Burst occur at lower energies, but their very long path provides access to information not far from the Planck scale. We discuss conceivable non-linear photon dispersions based on non-commutative geometry or effective approaches. No LIV has been observed so far. However, even extremely tiny LIV effects could change the predictions for cosmic ray physics drastically. An Appendix is devoted to the recent hypothesis by the Pierre Auger Collaboration, which identifies nearby Active Galactic Nuclei - or objects

  4. Vectorización de algoritmos generales de convergencia fuerte para la solución de ecuaciones diferenciales estocásticas (SDE)

    OpenAIRE

    Quiñones Botero, Carlos Eduardo

    2007-01-01

    La teoría de las Ecuaciones Diferenciales Estocásticas (SDE) ha sido desarrollada en el último medio siglo, pero no se ha creado una librería para la solución numérica de este tipo de ecuaciones. A pesar de que actualmente existen métodos numéricos de alta eficiencia para la solución de las SDE y de que existen aplicaciones académicas e industriales en donde se utilizan, no se ha desarrollado una librería de fuente abierta que implemente vectorizadamente los mejores algoritmos disponibles act...

  5. Desarrollo de ecuaciones alométricas de biomasa para la regeneración de cuatro especies en Durango, México

    OpenAIRE

    Favian Flores Medina; Daniel José Vega-Nieva; José Javier Corral-Rivas; Juan Gabriel Álvarez-González; Ana Daria Ruiz-González; Carlos Antonio López-Sanchez; Artemio Carillo Parra

    2018-01-01

    El objetivo del trabajo consistió en el desarrollo de ecuaciones alométricas para estimar la biomasa aérea por fracciones de grosor de la regeneración de Arbutus arizonica, Juniperus deppeana, Quercus sideroxyla y Pinus cooperi en la Unidad de Manejo Forestal (Umafor 1008) en el estado de Durango. Se utilizaron datos provenientes de 114 individuos (25, 29, 30 y 30, respectivamente), colectados mediante un muestreo destructivo para ajustar los modelos. La aditividad de las ecuaciones de estima...

  6. Investigations on the Effects of Vortex-Induced Vibration with Different Distributions of Lorentz Forces

    Directory of Open Access Journals (Sweden)

    Hui Zhang

    2017-01-01

    Full Text Available The control of vortex-induced vibration (VIV in shear flow with different distributions of Lorentz force is numerically investigated based on the stream function–vorticity equations in the exponential-polar coordinates exerted on moving cylinder for Re = 150. The cylinder motion equation coupled with the fluid, including the mathematical expressions of the lift force coefficient C l , is derived. The initial and boundary conditions as well as the hydrodynamic forces on the surface of cylinder are also formulated. The Lorentz force applied to suppress the VIV has no relationship with the flow field, and involves two categories, i.e., the field Lorentz force and the wall Lorentz force. With the application of symmetrical Lorentz forces, the symmetric field Lorentz force can amplify the drag, suppress the flow separation, decrease the lift fluctuation, and then suppress the VIV while the wall Lorentz force decreases the drag only. With the application of asymmetrical Lorentz forces, besides the above-mentioned effects, the field Lorentz force can increase additional lift induced by shear flow, whereas the wall Lorentz force can counteract the additional lift, which is dominated on the total effect.

  7. Vacuum solutions of a gravity model with vector-induced spontaneous Lorentz symmetry breaking

    International Nuclear Information System (INIS)

    Bertolami, O.; Paramos, J.

    2005-01-01

    We study the vacuum solutions of a gravity model where Lorentz symmetry is spontaneously broken once a vector field acquires a vacuum expectation value. Results are presented for the purely radial Lorentz symmetry breaking (LSB), radial/temporal LSB and axial/temporal LSB. The purely radial LSB result corresponds to new black hole solutions. When possible, parametrized post-Newtonian parameters are computed and observational boundaries used to constrain the Lorentz symmetry breaking scale

  8. Gravitation as a Plastic Distortion of the Lorentz Vacuum

    CERN Document Server

    Fernández, Virginia Velma

    2010-01-01

    Addressing graduate students and researchers in theoretical physics and mathematics, this book presents a new formulation of the theory of gravity. In the new approach the gravitational field has the same ontology as the electromagnetic, strong, and weak fields. In other words it is a physical field living in Minkowski spacetime. Some necessary new mathematical concepts are introduced and carefully explained. Then they are used to describe the deformation of geometries, the key to describing the gravitational field as a plastic deformation of the Lorentz vacuum. It emerges after further analysis that the theory provides trustworthy energy-momentum and angular momentum conservation laws, a feature that is normally lacking in General Relativity.

  9. Lorentz Invariance Violation and Modified Hawking Fermions Tunneling Radiation

    Directory of Open Access Journals (Sweden)

    Shu-Zheng Yang

    2016-01-01

    Full Text Available Recently the modified Dirac equation with Lorentz invariance violation has been proposed, which would be helpful to resolve some issues in quantum gravity theory and high energy physics. In this paper, the modified Dirac equation has been generalized in curved spacetime, and then fermion tunneling of black holes is researched under this correctional Dirac field theory. We also use semiclassical approximation method to get correctional Hamilton-Jacobi equation, so that the correctional Hawking temperature and correctional black hole’s entropy are derived.

  10. Tests of CPT, Lorentz invariance and the WEP with antihydrogen

    International Nuclear Information System (INIS)

    Holzscheiter, M.H.

    1999-01-01

    Antihydrogen atoms, produced near rest, trapped in a magnetic well, and cooled to the lowest possible temperature (kinetic energy) could provide an extremely powerful tool for the search of violations of CPT and Lorentz invariance. Equally well, such a system could be used for searches of violations of the Weak Equivalence Principle (WEP) at high precision. The author describes his plans to form a significant number of cold, trapped antihydrogen atoms for comparative precision spectroscopy of hydrogen and antihydrogen and comment on possible first experiments

  11. Vacuum Cherenkov radiation for Lorentz-violating fermions

    Science.gov (United States)

    Schreck, M.

    2017-11-01

    The current work focuses on the process of vacuum Cherenkov radiation for Lorentz-violating fermions that are described by the minimal standard-model extension (SME). To date, most considerations of this important hypothetical process have been restricted to Lorentz-violating photons, as the necessary theoretical tools for the SME fermion sector have not been available. With their development in a very recent paper, we are now in a position to compute the decay rates based on a modified Dirac theory. Two realizations of the Cherenkov process are studied. In the first scenario, the spin projection of the incoming fermion is assumed to be conserved, and in the second, the spin projection is allowed to flip. The first type of process is shown to be still forbidden for the dimensionful a and b coefficients where there are strong indications that it is energetically disallowed for the H coefficients, as well. However, it is rendered possible for the dimensionless c , d , e , f , and g coefficients. For large initial fermion energies, the decay rates for the c and d coefficients were found to grow linearly with momentum and to be linearly suppressed by the smallness of the Lorentz-violating coefficient where for the e , f , and g coefficients this suppression is even quadratic. The decay rates vanish in the vicinity of the threshold, as expected. The decay including a fermion spin-flip plays a role for the spin-nondegenerate operators and it was found to occur for the dimensionful b and H coefficients as well as for the dimensionless d and g . The characteristics of this process differ much from the properties of the spin-conserving one, e.g., there is no threshold. Based on experimental data of ultra-high-energy cosmic rays, new constraints on Lorentz violation in the quark sector are obtained from the thresholds. However, it does not seem to be possible to derive bounds from the spin-flip decays. This work reveals the usefulness of the quantum field theoretic methods

  12. Constraining spacetime nonmetricity with Lorentz-violation methods

    Science.gov (United States)

    Xiao, Zhi; Lehnert, Ralf; Snow, W. M.; Xu, Rui

    2018-01-01

    In this report, we will give the first constraints on in-matter nonmetricity. We will show how the effective-field-theory (EFT) toolbox developed for the study of Lorentz violation (LV) can be employed for investigations of the “effective LV” background caused by nonmetricity, a geometric object extending the notion of a Riemannian manifold. The idea is to probe for the effects of spacetime nonmetricity sourced by liquid 4He with polarized slow neutrons. We present the first constraints on isotropic and parity-odd nonmetricity components. Further constraints on anisotropic nonmetricity components within this EFT framework may be feasible with proper experimental techniques in the near future.

  13. Testing Lorentz invariance emergence in Ising Model using lattice Monte Carlo simulations

    CERN Document Server

    Stojku, Stefan

    2017-01-01

    All measurements performed so far at the observable energy scales show no violation of Lorentz invariance. However, it is yet impossible to check experimentally whether this symmetry holds at high energies such as the Planck scale. Recently, theories of gravitation with Lorentz violation, known as Horava-Lifshitz gravity [1, 2] have gained significant attention by treating Lorentz symmetry as an emergent phenomenon. A Lif-shitz type theory assumes an anisotropic scaling between space and time weighted by some critical exponent. In order for these theories to be viable candidates for quantum gravity description of the nature, Lorentz symmetry needs to be recovered at low energies.

  14. Two-dimensional Lorentz-Weyl anomaly and gravitational Chern-Simons theory

    International Nuclear Information System (INIS)

    Chamseddine, A.H.; Froehlich, J.

    1992-01-01

    Two-dimensional chiral fermions and bosons, more generally conformal blocks of two-dimensional conformal field theories, exhibit Weyl-, Lorentz- and mixed Lorentz-Weyl anomalies. A novel way of computing these anomalies for a system of chiral bosons of arbitrary conformal spin j is sketched. It is shown that the Lorentz- and mixed Lorentz-Weyl anomalies of these theories can be cancelled by the anomalies of a three-dimensional classical Chern-Simons action for the spin connection, expressed in terms of the dreibein field. Some tentative applications of this result to string theory are indicated. (orig.)

  15. A new perspective on relativistic transformation: formulation of the differential Lorentz transformation based on first principles

    International Nuclear Information System (INIS)

    Huang, Young-Sea

    2010-01-01

    The differential Lorentz transformation is formulated solely from the principle of relativity and the invariance of the speed of light. The differential Lorentz transformation transforms physical quantities, instead of space-time coordinates, to keep laws of nature form-invariant among inertial frames. The new relativistic transformation fulfills the principle of relativity, whereas the usual Lorentz transformation of space-time coordinates does not. Furthermore, the new relativistic transformation is compatible with quantum mechanics. The formulation herein provides theoretical foundations for the differential Lorentz transformation as the fundamental relativistic transformation.

  16. Lorentz covariant tempered distributions in two-dimensional space-time

    International Nuclear Information System (INIS)

    Zinov'ev, Yu.M.

    1989-01-01

    The problem of describing Lorentz covariant distributions without any spectral condition has hitherto remained unsolved even for two-dimensional space-time. Attempts to solve this problem have already been made. Zharinov obtained an integral representation for the Laplace transform of Lorentz invariant distributions with support in the product of two-dimensional future light cones. However, this integral representation does not make it possible to obtain a complete description of the corresponding Lorentz invariant distributions. In this paper the author gives a complete description of Lorentz covariant distributions for two-dimensional space-time. No spectral conditions is assumed

  17. Analysis and solution of algebraic-differential equations of the steam generation processes; Analisis y resolucion de ecuaciones algebraico-diferenciales de los procesos de generacion de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Herrera, Juan Anibal

    1996-10-01

    organizacion eficiente para obtener su solucion. 3.- Se aplicaron dos herramientas computacionales que ayudan a rastrear los posibles errores en los codigos de los modelos matematicos. Estas herramientas fueron: a) Analizador sintactico para modelos de simulacion (ASMOS).- Esta herramienta detecta los errores en la asignacion y referencia de variables. b) Analizador estructural para modelos de simulacion (AEMOS).- Esta herramienta tiene como funcion principal obtener la matriz de dependencias, la cual relaciona las ecuaciones y las variables de un modelo. Durante esta etapa se sugirieron mejoras a estas herramientas. 4.- Se realizaron pruebas a los modelos matematicos en forma individual, primero en estado estable y despues en estado dinamico. Estas pruebas sirvieron para: a) Validar los modelos matematicos. b) Analizar el comportamiento de las variables de los modelos matematicos con diferentes parametros, condiciones de operacion y condiciones de inicio y arranque. 5.- Por ultimo, se realizo el acoplamiento entre los equipos analizados hasta formar una red de equipos que represente el ciclo caldera-sobrecalentador y se realizaron pruebas en estado estable y en estado dinamico. Estas pruebas sirvieron para: a) Observar el comportamiento de las variables cuando son acoplados dos o mas equipos. b) Observar las caracteristicas que puede presentar el metodo de integracion numerico al resolver la red de equipos y analizar los resultados numericos obtenidos. En este trabajo se logro analizar y adaptar los modelos matematicos en su forma individual para permitir que los equipos puedan operar a diferentes condiciones de operacion, cambiar sus geometrias y obtener diferentes conexiones con otros equipos, y a partir de esto, se construyo una red de equipos que represente el ciclo caldera-sobrecalentador y se selecciono un metodo numerico para resolver la red de equipos en estado estable y dinamico.

  18. Algunos problemas provenientes de la Teoría de Rayos Aplicada a las Ecuaciones de Onda Sísmica

    Directory of Open Access Journals (Sweden)

    Carlos César Piedrahita Escobar

    2013-11-01

    Full Text Available La parte inicial de este artículo revisa la aplicación de la teoría de rayos en las ecuaciones de onda sísmicas, en particular, la propagación de ondas P. La parte final del artículo se centra en un par de problemas que se generan a partir del análisis utilizando teoría de rayos. Estos problemas posee un interés académico en su formulación matemática, además tienen un interés práctico para el  área de la Geofísica de Exploración y/o Producción.

  19. Desarrollo de ecuaciones alométricas de biomasa para la regeneración de cuatro especies en Durango, México

    Directory of Open Access Journals (Sweden)

    Favian Flores Medina

    2018-03-01

    Full Text Available El objetivo del trabajo consistió en el desarrollo de ecuaciones alométricas para estimar la biomasa aérea por fracciones de grosor de la regeneración de Arbutus arizonica, Juniperus deppeana, Quercus sideroxyla y Pinus cooperi en la Unidad de Manejo Forestal (Umafor 1008 en el estado de Durango. Se utilizaron datos provenientes de 114 individuos (25, 29, 30 y 30, respectivamente, colectados mediante un muestreo destructivo para ajustar los modelos. La aditividad de las ecuaciones de estimación de biomasa se aseguró mediante el ajuste simultáneo de todas las ecuaciones, con el procedimiento estadístico denominado 3SLS (Three-Stage Least Squares. Los modelos desarrollados permiten estimar la biomasa en peso seco de los componentes, peso total, hojas, ramillas ( 2.51 cm. Las ecuaciones alométricas con mejor ajuste correspondieron al peso total, con valores de coeficiente de determinación ajustado de 0.97, 0.94, 0.95 y 0.97 para Arbutus, Juniperus, Quercus y Pinus cooperi, respectivamente. En general las ecuaciones mostraron un ajuste satisfactorio en cada una de las fracciones; con ellas se podrán hacer estimaciones no destructivas de la biomasa por categoría de grosor de la regeneración de las cuatro especies estudiadas, lo que mejorará las predicciones de biomasa y almacén de carbono por fracciones en los bosques con presencia de los cuatro taxa estudiados.

  20. Consistency relation for the Lorentz invariant single-field inflation

    International Nuclear Information System (INIS)

    Huang, Qing-Guo

    2010-01-01

    In this paper we compute the sizes of equilateral and orthogonal shape bispectrum for the general Lorentz invariant single-field inflation. The stability of field theory implies a non-negative square of sound speed which leads to a consistency relation between the sizes of orthogonal and equilateral shape bispectrum, namely f NL orth. ≤ −0.054f NL equil. . In particular, for the single-field Dirac-Born-Infeld (DBI) inflation, the consistency relation becomes f NL orth. = 0.070f NL equil. ≤ 0. These consistency relations are also valid in the mixed scenario where the quantum fluctuations of some other light scalar fields contribute to a part of total curvature perturbation on the super-horizon scale and may generate a local form bispectrum. A distinguishing prediction of the mixed scenario is τ NL loc. > ((6/5)f NL loc. ) 2 . Comparing these consistency relations to WMAP 7yr data, there is still a big room for the Lorentz invariant inflation, but DBI inflation has been disfavored at more than 68% CL

  1. A perfectly conducting surface in electrodynamics with Lorentz symmetry breaking

    Science.gov (United States)

    Borges, L. H. C.; Barone, F. A.

    2017-10-01

    In this paper we consider a model which exhibits explicit Lorentz symmetry breaking due to the presence of a single background vector v^{μ } coupled to the gauge field. We investigate such a theory in the vicinity of a perfectly conducting plate for different configurations of v^{μ }. First we consider no restrictions on the components of the background vector and we treat it perturbatively up to second order. Next, we treat v^{μ } exactly for two special cases: the first one is when it has only components parallel to the plate, and the second one when it has a single component perpendicular to the plate. For all these configurations, the propagator for the gauge field and the interaction force between the plate and a point-like electric charge are computed. Surprisingly, it is shown that the image method is valid in our model and we argue that it is a non-trivial result. We show there arises a torque on the mirror with respect to its positioning in the background field when it interacts with a point-like charge. It is a new effect with no counterpart in theories with Lorentz symmetry in the presence of a perfect mirror.

  2. Possible cosmogenic neutrino constraints on Planck-scale Lorentz violation

    International Nuclear Information System (INIS)

    Mattingly, David M.; Maccione, Luca; Galaverni, Matteo; Liberati, Stefano; Sigl, Günter

    2010-01-01

    We study, within an effective field theory framework, O(E 2 M Pl 2 ) Planck-scale suppressed Lorentz invariance violation (LV) effects in the neutrino sector, whose size we parameterize by a dimensionless parameter η ν . We find deviations from predictions of Lorentz invariant physics in the cosmogenic neutrino spectrum. For positive O(1) coefficients no neutrino will survive above 10 19 eV. The existence of this cutoff generates a bump in the neutrino spectrum at energies of 10 17 eV. Although at present no constraint can be cast, as current experiments do not have enough sensitivity to detect ultra-high-energy neutrinos, we show that experiments in construction or being planned have the potential to cast limits as strong as η ν ∼ −4 on the neutrino LV parameter, depending on how LV is distributed among neutrino mass states. Constraints on η ν < 0 can in principle be obtained with this strategy, but they require a more detailed modeling of how LV affects the neutrino sector

  3. Spontaneous Lorentz and diffeomorphism violation, massive modes, and gravity

    International Nuclear Information System (INIS)

    Bluhm, Robert; Fung Shuhong; Kostelecky, V. Alan

    2008-01-01

    Theories with spontaneous local Lorentz and diffeomorphism violation contain massless Nambu-Goldstone modes, which arise as field excitations in the minimum of the symmetry-breaking potential. If the shape of the potential also allows excitations above the minimum, then an alternative gravitational Higgs mechanism can occur in which massive modes involving the metric appear. The origin and basic properties of the massive modes are addressed in the general context involving an arbitrary tensor vacuum value. Special attention is given to the case of bumblebee models, which are gravitationally coupled vector theories with spontaneous local Lorentz and diffeomorphism violation. Mode expansions are presented in both local and spacetime frames, revealing the Nambu-Goldstone and massive modes via decomposition of the metric and bumblebee fields, and the associated symmetry properties and gauge fixing are discussed. The class of bumblebee models with kinetic terms of the Maxwell form is used as a focus for more detailed study. The nature of the associated conservation laws and the interpretation as a candidate alternative to Einstein-Maxwell theory are investigated. Explicit examples involving smooth and Lagrange-multiplier potentials are studied to illustrate features of the massive modes, including their origin, nature, dispersion laws, and effects on gravitational interactions. In the weak static limit, the massive mode and Lagrange-multiplier fields are found to modify the Newton and Coulomb potentials. The nature and implications of these modifications are examined.

  4. Possible cosmogenic neutrino constraints on Planck-scale Lorentz violation

    Energy Technology Data Exchange (ETDEWEB)

    Mattingly, David M. [New Hamshire Univ., Durham, NH (United States); Maccione, Luca [DESY Hamburg (Germany). Theory Group; Galaverni, Matteo [INAF-IASF Bologna (Italy); Liberati, Stefano [INFN, Trieste (Italy); SISSA, Trieste (Italy); Sigl, Guenter [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik

    2009-11-15

    We study, within an effective field theory framework, O(E{sup 2}/M{sup 2}{sub Pl}) Planck-scale suppressed Lorentz invariance violation (LV) effects in the neutrino sector, whose size we parameterize by a dimensionless parameter {eta}{sub {nu}}. We find deviations from predictions of Lorentz invariant physics in the cosmogenic neutrino spectrum. For positive O(1) coefficients no neutrino will survive above 10{sup 19} eV. The existence of this cutoff generates a bump in the neutrino spectrum at energies of 10{sup 17} eV. Although at present no constraint can be cast, as current experiments do not have enough sensitivity to detect ultra-high-energy neutrinos, we show that experiments in construction or being planned have the potential to cast limits as strong as {eta}{sub {nu}}

  5. K-theory for discrete subgroups of the Lorentz groups

    International Nuclear Information System (INIS)

    Schwalbe, D.A.

    1986-01-01

    In the thesis, a conjecture on the structure of the topological K theory groups associated to an action of a discrete group on a manifold is verified in the special case when the group is a closed discrete subgroup of a Lorentz group. The K theory is the topological K theory of the reduced crossed product C algebra arising from the action of a countable discrete group acting by diffeomorphisms on a smooth, Hausdorf, and second and countable manifold. The proof uses the geometric K theory of Baum and Connes. In this situation, they have developed a geometrically realized K theory which they conjecture to be isomorphic to the analytic K theory. Work of Kasparov is used to show the geometric K groups and the analytic K groups are isomorphic for actions of the Lorentz groups on a manifold. Work of Marc Rieffel on Morita equivalence of C/sup */ algebras, shows the analytic K theory for a closed discrete subgroup of a Lie group acting on a manifold is isomorphic to the K theory of the Lie group itself, acting on an induced manifold

  6. A perfectly conducting surface in electrodynamics with Lorentz symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Borges, L.H.C. [UNESP, Campus de Guaratingueta, DFQ, Guaratingueta, SP (Brazil); Barone, F.A. [IFQ, Universidade Federal de Itajuba, Itajuba, MG (Brazil)

    2017-10-15

    In this paper we consider a model which exhibits explicit Lorentz symmetry breaking due to the presence of a single background vector v{sup μ} coupled to the gauge field. We investigate such a theory in the vicinity of a perfectly conducting plate for different configurations of v{sup μ}. First we consider no restrictions on the components of the background vector and we treat it perturbatively up to second order. Next, we treat v{sup μ} exactly for two special cases: the first one is when it has only components parallel to the plate, and the second one when it has a single component perpendicular to the plate. For all these configurations, the propagator for the gauge field and the interaction force between the plate and a point-like electric charge are computed. Surprisingly, it is shown that the image method is valid in our model and we argue that it is a non-trivial result. We show there arises a torque on the mirror with respect to its positioning in the background field when it interacts with a point-like charge. It is a new effect with no counterpart in theories with Lorentz symmetry in the presence of a perfect mirror. (orig.)

  7. Non-dissipative electromagnetic media with two Lorentz null cones

    International Nuclear Information System (INIS)

    Dahl, Matias F.

    2013-01-01

    We study Maxwell’s equations on a 4-manifold where the electromagnetic medium is modeled by an antisymmetric (2/2 )-tensor with 21 real coefficients. In this setting the Fresnel surface is a fourth-order polynomial surface that describes the dynamical response of the medium in the geometric optics limit. For example, in an isotropic medium the Fresnel surface is a Lorentz null cone. The contribution of this paper is the pointwise description of all electromagnetic medium tensors κ with real coefficients that satisfy the following three conditions: (i)medium κ is invertible, (ii)medium κ is skewon-free, or non-dissipative, (iii)the Fresnel surface of κ is the union of two distinct Lorentz null cones. We show that there are only three classes of media with these properties and give explicit expressions in local coordinates for each class. - Highlights: ► We find two new electromagnetic media classes for which the Fresnel surface decomposes into two light cones. ► In a suitable setting we classify all electromagnetic media where this is the case. ► We find an electromagnetic medium tensor with three different signal speeds in one direction. ► The work is related to [5], which classifies all media with one light cone (in a suitable setting).

  8. Como reescribir funciones aleatorias multivariadas como univariadas para hacer cokrigeage. La teoría

    Directory of Open Access Journals (Sweden)

    Adrian Martínez-Vargas

    2010-03-01

    Full Text Available En el año 2005 Martínez-Vargas formuló un sistema de cokrigeage puro heterotópico para estimar una función aleatoria regionalizada (RF Z*(x definida como la combinación lineal de n RF's univariadas Zi(x, cuyos coeficientes 1i(x son indicatrices de un set disyuntivo de categorías i. Aparentemente este modelo se contradice pues asume que las covarianzas cruzadas existen en un mismo punto, a pesar de su carácter puramente heterotópico. Para evadir dicha contradicción se redefinió el set de RF Zi(x como una única RF Z(x,i, siendo los puntos (x,i y (x,j no coincidentes si i y j no son iguales. La heterotopía fue simplemente considerada como una omisión de la RF Z(x,. en los datos y en los puntos a estimar, no impuesta por el modelo; entonces el resultado es simplemente un caso particular del cokrigeage clásico. Con esta notación se reescribió el sistema de cokrigeage clásico como el sistema de krigeage de la RF univariada Z(x,i, asumiendo que esta posee un drift definido como m(x,i,j, donde los miembros fl(x,i,j de m(x,i,j pueden ser linealmente dependientes o independientes. Bajo esta notación el sistema de krigeage se reduce a un sistema univariado, la existencia de más de una variable o la presencia de heterotropía no impone la necesidad de manipulaciones extras para definir el sistema de ecuaciones de krigeage, incrementándose la eficiencia computacional.

  9. The energy-momentum spectrum in local field theories with broken Lorentz-symmetry

    International Nuclear Information System (INIS)

    Borchers, H.J.; Buchholz, D.

    1984-05-01

    Assuming locality of the observables and positivity of the energy it is shown that the joint spectrum of the energy-momentum operators has a Lorentz-invariant lower boundary in all superselection sectors. This result is of interest if the Lorentz-symmetry is (spontaneously) broken, such as in the charged sectors of quantum electrodynamics. (orig.)

  10. Propagation of a radial phased-locked Lorentz beam array in turbulent atmosphere.

    Science.gov (United States)

    Zhou, Guoquan

    2011-11-21

    A radial phased-locked (PL) Lorentz beam array provides an appropriate theoretical model to describe a coherent diode laser array, which is an efficient radiation source for high-power beaming use. The propagation of a radial PL Lorentz beam array in turbulent atmosphere is investigated. Based on the extended Huygens-Fresnel integral and some mathematical techniques, analytical formulae for the average intensity and the effective beam size of a radial PL Lorentz beam array are derived in turbulent atmosphere. The average intensity distribution and the spreading properties of a radial PL Lorentz beam array in turbulent atmosphere are numerically calculated. The influences of the beam parameters and the structure constant of the atmospheric turbulence on the propagation of a radial PL Lorentz beam array in turbulent atmosphere are discussed in detail. © 2011 Optical Society of America

  11. RESTAURACIÓN DIGITAL DE IMÁGENES MEDIANTE ECUACIONES DIFERENCIALES PARCIALES

    OpenAIRE

    Triana, Juan Gabriel; Romero, Liliana Constanza; Roldán, Diego Gerardo

    2013-01-01

    La restauración digital de imágenes, definida como el arte de mejorar la calidad de las imágenes, ha logrado un amplio desarrollo en los últimos años, alcanzando un alto nivel de popularidad, desde que se utilizaron métodos matemáticos y computacionales para restaurar las imágenes distorsionadas, enviadas por el telescopio Hubble; sin embargo, las imágenes no siempre son afectadas de manera total, algunas sufren pérdida de información en algunas regiones, otras simplemente son afectadas por e...

  12. Sistemas homogéneos de ecuaciones diofánticas. Resolución y aplicación al ajuste automático de reacciones químicas

    Directory of Open Access Journals (Sweden)

    Recuero, Alfonso

    1984-06-01

    Full Text Available An algorithm to solve systems of linear homogeneous diophantine equations is given here. Subsequently, as an example of application, a method of heuristic search for the best solution is described; this fulfils certain conditions within an infinite space of solutions of various dimensions. Finally, an application of the algorithm and of the process of heuristic search for the best solution in adjusting chemical reactions is described. The listing in BASIC of the program of application mentioned is included, for the HP-75 portable computer.

    Se presenta un algoritmo de resolución de sistemas de ecuaciones diofánticas lineales y homogéneas. Seguidamente y como ejemplo de aplicación se describe un método de búsqueda heurística de una solución óptima que cumpla unas ciertas condiciones dentro de un espacio infinito de soluciones de varias dimensiones. Por último se describe la aplicación del algoritmo y del procedimiento de búsqueda heurística para el caso de ajuste de reacciones químicas. Se incluye el listado en BASIC del programa para el ordenador HP-75.

  13. Extended hamiltonian formalism and Lorentz-violating lagrangians

    Directory of Open Access Journals (Sweden)

    Don Colladay

    2017-09-01

    Full Text Available A new perspective on the classical mechanical formulation of particle trajectories in Lorentz-violating theories is presented. Using the extended hamiltonian formalism, a Legendre Transformation between the associated covariant lagrangian and hamiltonian varieties is constructed. This approach enables calculation of trajectories using Hamilton's equations in momentum space and the Euler–Lagrange equations in velocity space away from certain singular points that arise in the theory. Singular points are naturally de-singularized by requiring the trajectories to be smooth functions of both velocity and momentum variables. In addition, it is possible to identify specific sheets of the dispersion relations that correspond to specific solutions for the lagrangian. Examples corresponding to bipartite Finsler functions are computed in detail. A direct connection between the lagrangians and the field-theoretic solutions to the Dirac equation is also established for a special case.

  14. Lorentz transformations, sideways shift and massless spinning particles

    Energy Technology Data Exchange (ETDEWEB)

    Bolonek-Lasoń, K. [Department of Statistical Methods, Faculty of Economics and Sociology (Poland); Kosiński, P. [Department of Computer Science, Faculty of Physics and Applied Informatics, University of Łódź, Pomorska 149/153, 90-236 Łódź (Poland); Maślanka, P., E-mail: pmaslan@uni.lodz.pl [Department of Computer Science, Faculty of Physics and Applied Informatics, University of Łódź, Pomorska 149/153, 90-236 Łódź (Poland)

    2017-06-10

    Recently (Stone et al. (2015) ) the influence of the so called “Wigner translations” (more generally-Lorentz transformations) on circularly polarized Gaussian packets (providing the solution to Maxwell equations in paraxial approximation) has been studied. It appears that, within this approximation, the Wigner translations have an effect of shifting the wave packet trajectory parallel to itself by an amount proportional to the photon helicity. It has been suggested that this shift may result from specific properties of the algebra of Poincare generators for massless particles. In the present letter we describe the general relation between transformation properties of electromagnetic field on quantum and classical levels. It allows for a straightforward derivation of the helicity-dependent transformation rules. We present also an elementary derivation of the formula for sideways shift based on classical Maxwell theory. Some comments are made concerning the generalization to higher helicities and the relation to the coordinate operator defined long time ago by Pryce.

  15. Application of the Lorentz-transform technique to meson photoproduction

    International Nuclear Information System (INIS)

    Reiss, C.; Leidemann, W.; Orlandini, G.; Tomusiak, E.L.

    2003-01-01

    We show that the Lorentz integral transform (LIT) technique which has been successfully applied to photoreactions in light nuclei can also be applied to photoreactions involving particle production. A simple model where results are easily calculable in the traditional fashion is used to test the technique. Specifically, we compute inclusive π + photoproduction from deuterium for photon energies less than 200 MeV using a Yamaguchi model for the NN interaction. It is demonstrated that, although the response functions for inclusive meson production do not have favourable asymptotic behavior, one can nonetheless extract them by inversion of the transform. The implication is that one can treat realistic problems of photo-meson production, including all final-state interactions, by means of the LIT technique. (orig.)

  16. Violations of Lorentz invariance in the neutrino sector after OPERA

    Energy Technology Data Exchange (ETDEWEB)

    Maccione, Luca [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Liberati, Stefano [Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste (Italy); INFN, Sezione de Trieste (Italy); Mattingly, David M. [New Hampshire Univ., Durham (United States). Dept. of Physics

    2011-10-15

    The OPERA collaboration has recently reported that neutrinos travel faster than light. We review the theoretical situation of constraints on violations of Lorentz invariance, focusing in particular on the compatibility between the OPERA results with both previous constraints and recently obtained ones. We generalize to higher order operators the recent constraint provided by the absence of neutrino energy loss, via electron-positron pair production at OPERA energies, and show that no modi ed in vacuo dispersion relation within an effective field theory context is compatible with OPERA results. We conclude that the OPERA result is incompatible with current observations, at least without resorting to models beyond effective field theory, possibly with local environmental effects. (orig.)

  17. Longitudinal Lorentz force on a subwavelength-diameter optical fiber

    International Nuclear Information System (INIS)

    Yu Huakang; Fang Wei; Gu Fuxing; Yang Zongyin; Tong Limin; Qiu Min

    2011-01-01

    We analyze the longitudinal Lorentz forces that a propagating continuous-wave light exerts on a subwavelength-diameter optical fiber. Our theoretical results show that, during the propagating process, the guided light exerts no net time-averaged force on the fiber. Via numerical simulation, we find a significant overall pull force of 0.4 pN/mW acting on a 450-nm-diam fiber tip at a wavelength of 980 nm due to the scattering of the end face and a calculated force distribution reveals the feature of a near-field accumulation. Our results may be helpful to the configuration of optomechanical components or devices based on these fibers.

  18. Diffusion in lattice Lorentz gases with mixtures of point scatterers

    International Nuclear Information System (INIS)

    Acedo, L.; Santos, A.

    1994-01-01

    Monte Carlo simulations are carried out to evaluate the diffusion coefficient in some lattice Lorentz gases with mixtures of point scatterers in the limit of a low concentration of scatterers. Two models on a square lattice are considered: (a) right and left stochastic rotators plus pure reflectors and (b) right and left stochastic mirrors plus pure reflectors. The simulation data are compared with the repeated ring approximation (RRA). The agreement is excellent for models in the absence of pure reflectors, suggesting that the RRA gives the correct diffusion coefficient for those cases. As the fraction x B of reflectors increases, the diffusion coefficient decreases and seems to vanish at x B c congruent 0.8 (percolation threshold) with a critical exponent μ congruent 2 (stochastic model) or μ congruent 3 (deterministic rotator model)

  19. Lorentz violating p-form gauge theories in superspace

    Energy Technology Data Exchange (ETDEWEB)

    Upadhyay, Sudhaker [Indian Institute of Technology Kharagpur, Centre for Theoretical Studies, Kharagpur (India); Shah, Mushtaq B.; Ganai, Prince A. [National Institute of Technology, Department of Physics, Srinagar, Kashmir (India)

    2017-03-15

    Very special relativity (VSR) keeps the main features of special relativity but breaks rotational invariance due to an intrinsic preferred direction. We study the VSR-modified extended BRST and anti-BRST symmetry of the Batalin-Vilkovisky (BV) actions corresponding to the p = 1, 2, 3-form gauge theories. Within the VSR framework, we discuss the extended BRST invariant and extended BRST and anti-BRST invariant superspace formulations for these BV actions. Here we observe that the VSR-modified extended BRST invariant BV actions corresponding to the p = 1, 2, 3-form gauge theories can be written in a manifestly covariant manner in a superspace with one Grassmann coordinate. Moreover, two Grassmann coordinates are required to describe the VSR-modified extended BRST and extended anti-BRST invariant BV actions in a superspace. These results are consistent with the Lorentz-invariant (special relativity) formulation. (orig.)

  20. Lorentz Invariance Violation effects on UHECR propagation: A geometrized approach

    Science.gov (United States)

    Torri, Marco Danilo Claudio; Bertini, Stefano; Giammarchi, Marco; Miramonti, Lino

    2018-06-01

    We explore the possibility to geometrize the interaction of massive fermions with the quantum structure of space-time, trying to create a theoretical background, in order to explain what some recent experimental results seem to implicate on the propagation of Ultra High Energy Cosmic Rays (UHECR). We will investigate part of the phenomenological implications of this approach on the predicted effect of the UHECR suppression, in fact recent evidences seem to involve the modification of the GZK cut-off phenomenon. The search for an effective theory, which can explain this physical effect, is based on Lorentz Invariance Violation (LIV), which is introduced via Modified Dispersion Relations (MDRs). Furthermore we illustrate that this perspective implies a more general geometry of space-time than the usual Riemannian one, indicating, for example, the opportunity to resort to Finsler theory.

  1. Lorentz transformations, sideways shift and massless spinning particles

    Science.gov (United States)

    Bolonek-Lasoń, K.; Kosiński, P.; Maślanka, P.

    2017-06-01

    Recently (Stone et al. (2015) [16]) the influence of the so called ;Wigner translations; (more generally-Lorentz transformations) on circularly polarized Gaussian packets (providing the solution to Maxwell equations in paraxial approximation) has been studied. It appears that, within this approximation, the Wigner translations have an effect of shifting the wave packet trajectory parallel to itself by an amount proportional to the photon helicity. It has been suggested that this shift may result from specific properties of the algebra of Poincare generators for massless particles. In the present letter we describe the general relation between transformation properties of electromagnetic field on quantum and classical levels. It allows for a straightforward derivation of the helicity-dependent transformation rules. We present also an elementary derivation of the formula for sideways shift based on classical Maxwell theory. Some comments are made concerning the generalization to higher helicities and the relation to the coordinate operator defined long time ago by Pryce.

  2. A heuristic derivation of Minkowski distance and Lorentz transformation

    International Nuclear Information System (INIS)

    Hassani, Sadri

    2008-01-01

    Students learn new abstract concepts best when these concepts are connected through a well-designed analogy, to familiar ideas. Since the concept of the relativistic spacetime distance is highly abstract, it would be desirable to connect it to the familiar Euclidean distance, but present the latter in such a way that it makes a transparent contact with the former. Starting with some intuitive and 'obvious' assumptions concerning distance in one dimension, we 'derive' the two-dimensional Euclidean distance between two points in terms of their coordinates. Then, assuming the invariance of this distance, we deduce the (familiar) two-dimensional orthogonal coordinate transformation. We present the derivation in such a way that the transition to spacetime becomes 'self-evident.' Thus, following exactly the same procedure, we derive the Minkowskian distance and the corresponding transformation that respects the invariance of that distance, i.e., the Lorentz transformation

  3. Modified Einstein and Finsler Like Theories on Tangent Lorentz Bundles

    CERN Document Server

    Stavrinos, Panayiotis; Vacaru, Sergiu I.

    2014-01-01

    We study modifications of general relativity, GR, with nonlinear dispersion relations which can be geometrized on tangent Lorentz bundles. Such modified gravity theories, MGTs, can be modeled by gravitational Lagrange density functionals $f(\\mathbf{R},\\mathbf{T},F)$ with generalized/ modified scalar curvature $\\mathbf{R}$, trace of matter field tensors $\\mathbf{T}$ and modified Finsler like generating function $F$. In particular, there are defined extensions of GR with extra dimensional "velocity/ momentum" coordinates. For four dimensional models, we prove that it is possible to decouple and integrate in very general forms the gravitational fields for $f(\\mathbf{R},\\mathbf{T},F)$--modified gravity using nonholonomic 2+2 splitting and nonholonomic Finsler like variables $F$. We study the modified motion and Newtonian limits of massive test particles on nonlinear geodesics approximated with effective extra forces orthogonal to the four-velocity. We compute the constraints on the magnitude of extra-acceleration...

  4. Piezoelectric Tuner Compensation of Lorentz Detuning in Superconducting Cavities

    International Nuclear Information System (INIS)

    Jean Delayen; Davis, G.

    2003-01-01

    Pulsed operation of superconducting cavities can induce large variations of the resonant frequency through excitation of the mechanical modes by the radiation pressure. The phase and amplitude control system must be able to accommodate this frequency variation; this can be accomplished by increasing the capability of the rf power source. Alternatively, a piezo electric tuner can be activated at the same repetition rate as the rf to counteract the effect of the radiation pressure. We have demonstrated such a system on the prototype medium beta SNS cryomodule with a reduction of the dynamic Lorentz detuning during the rf pulse by a factor of 3. Piezo electric tuners can also be used to reduce the level of microphonics in low-current cw accelerators. We have measured the amplitude and phase of the transfer function of the piezo control system (from input voltage to cavity frequency) up to several kHz

  5. Discharge switch driving by Lorentz force and its characteristics

    International Nuclear Information System (INIS)

    Inoue, Kunikazu; Hasegawa, Mitsuo; Ueno, Isao

    1999-01-01

    Our newly developed 'Rotary-Arc mode Discharge Switch' have featured longer life expectancy and lower inductance-wise by extremely minimizing the insulation deterioration and consumable main electrode through installation of permanent magnet, simplified construction and careful attention on the demagnetization. Resultantly, highly efficient and larger capacitive discharge switch have been available at such economical cost. In addition, by having derived an experimental formula for the driving speed of the arc, the required design parameters of the discharge switch have been determined, and then it has been well noted that any affections of electro-magnetic Lorentz force toward the starting characteristics have been negligible small. All these have made it possible to materialize such discharge switch which will satisfy the required conditions. (author)

  6. Violations of Lorentz invariance in the neutrino sector after OPERA

    International Nuclear Information System (INIS)

    Maccione, Luca; Liberati, Stefano; Mattingly, David M.

    2011-10-01

    The OPERA collaboration has recently reported that neutrinos travel faster than light. We review the theoretical situation of constraints on violations of Lorentz invariance, focusing in particular on the compatibility between the OPERA results with both previous constraints and recently obtained ones. We generalize to higher order operators the recent constraint provided by the absence of neutrino energy loss, via electron-positron pair production at OPERA energies, and show that no modi ed in vacuo dispersion relation within an effective field theory context is compatible with OPERA results. We conclude that the OPERA result is incompatible with current observations, at least without resorting to models beyond effective field theory, possibly with local environmental effects. (orig.)

  7. Constraints and stability in vector theories with spontaneous Lorentz violation

    International Nuclear Information System (INIS)

    Bluhm, Robert; Gagne, Nolan L.; Potting, Robertus; Vrublevskis, Arturs

    2008-01-01

    Vector theories with spontaneous Lorentz violation, known as bumblebee models, are examined in flat spacetime using a Hamiltonian constraint analysis. In some of these models, Nambu-Goldstone modes appear with properties similar to photons in electromagnetism. However, depending on the form of the theory, additional modes and constraints can appear that have no counterparts in electromagnetism. An examination of these constraints and additional degrees of freedom, including their nonlinear effects, is made for a variety of models with different kinetic and potential terms, and the results are compared with electromagnetism. The Hamiltonian constraint analysis also permits an investigation of the stability of these models. For certain bumblebee theories with a timelike vector, suitable restrictions of the initial-value solutions are identified that yield ghost-free models with a positive Hamiltonian. In each case, the restricted phase space is found to match that of electromagnetism in a nonlinear gauge

  8. Extended hamiltonian formalism and Lorentz-violating lagrangians

    Science.gov (United States)

    Colladay, Don

    2017-09-01

    A new perspective on the classical mechanical formulation of particle trajectories in Lorentz-violating theories is presented. Using the extended hamiltonian formalism, a Legendre Transformation between the associated covariant lagrangian and hamiltonian varieties is constructed. This approach enables calculation of trajectories using Hamilton's equations in momentum space and the Euler-Lagrange equations in velocity space away from certain singular points that arise in the theory. Singular points are naturally de-singularized by requiring the trajectories to be smooth functions of both velocity and momentum variables. In addition, it is possible to identify specific sheets of the dispersion relations that correspond to specific solutions for the lagrangian. Examples corresponding to bipartite Finsler functions are computed in detail. A direct connection between the lagrangians and the field-theoretic solutions to the Dirac equation is also established for a special case.

  9. Lorentz invariance and the rotor Doppler shift experiments

    International Nuclear Information System (INIS)

    Rodrigues Junior, W.A.; Tiomno, J.

    1984-01-01

    It is shown that 'Rotor Doppler shift Experiments' provide a way to distinguish Einstein's Special Relativity (SR) from Lorentz's Aether Theory (LAT). Misconceptions in previous papers involving the Doppler shift experiments are examined. The theoretical and experimental data available on rotor Doppler shift experiments are analysed. Two models of SR violating theories are used to predict the output of a recently proposed experiment by Torr and Kolen. The first one corresponds to (strict) LAT and the other to an extended form of LAT Contrary to the first, the second theory leads to results in agreement with the preliminary experimental data of Torr et al indicating a breakdown both of SR and strict LAT. (Author) [pt

  10. Lorentz invariance and the rotor Doppler shift experiments

    International Nuclear Information System (INIS)

    Rodrigues Junior, W.A.; Tiomno, J.

    1984-01-01

    It is shown that 'Rotor Doppler shift Experiments' provide a way to distinguish Einstein's Special Relativity (SR) from Lorentz's Aether Theory (LAT). Misconceptions in previous papers involving the Doppler shift experiments are examined. The theoretical and experimental data available on rotor Doppler shift experiments are analysed. Two models of SR violating theories are used to predict the output of a recently proposed experiment by Torr and Kolen. The first one corresponds to (strict) LAT and the other to an extended form of LAT. Contrary to the first, the second theory leads to results in agreement with the preliminary experimental data of Torr et al indicating a breakdown both of SR and strict LAT. (Author) [pt

  11. Tests of Lorentz invariance using a microwave resonator

    International Nuclear Information System (INIS)

    Wolf, Peter; Bize, Sebastien; Clairon, Andre; Santarelli, Giorgio; Luiten, Andre N.; Tobar, Michael E.

    2003-01-01

    The frequencies of a cryogenic sapphire oscillator and a hydrogen maser are compared to set new constraints on a possible violation of Lorentz invariance. We determine the variation of the oscillator frequency as a function of its orientation (Michelson-Morley test) and of its velocity (Kennedy-Thorndike test) with respect to a preferred frame candidate. We constrain the corresponding parameters of the Mansouri and Sexl test theory to δ-β+1/2=(1.5±4.2)x10 -9 and β-α-1=(-3.1±6.9)x10 -7 which is of the same order as the best previous result for the former and represents a 30-fold improvement for the latter

  12. Validation of Hiriart equation to compute steam production by the lip pressure method; Validacion de la ecuacion de Hiriart para calculo de gasto de vapor por el metodo de presion de labio

    Energy Technology Data Exchange (ETDEWEB)

    Flores Armenta, Magaly [Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad, Morelia (Mexico)

    1996-09-01

    Mainly in new geothermal wells, it is necessary to evaluate the production in a very fast, simple and not expensive way, to know the convenience to install surface equipment, such as silencers and separators, to drive the steam to the commercial gathering system. In practice, one of the most known methods is the lip pressure one, which requires a simple set of installations. The objective of this paper is to validate the steam flow rate calculated by the lip pressure method, with respect to the ASME method. The ASME method is known for its accuracy, and is done by measuring the steam and liquid after a high pressure separator, by an orifice plate of known diameter and a triangular weir. Results of the validation show up the feasibility of application of the lip pressure method by using a simple adjustment equation. Percentage of mistake results less than 1%, without any notable influence of the production enthalpy. That equation to be applied in a general case, is as follows: Q{nu} =(20642)(F*P*D{sup 2}/{radical}h-2000). For the particular case of the Los Azufres geothermal field, the equation is: Q{nu}= 810*P*D{sup 2} [Espanol] En los pozos geotermicos, principalmente en los nuevos, es necesario evaluar su produccion de manera rapida, sencilla y economica, para determinar la conveniencia de instalar equipo superficial, como separadores, silenciadores, etc., que permita la integracion del vapor al sistema comercial de generacion electrica. Para fines practicos uno de los metodos mas conocidos es el de presion de labio, que solo requiere un arreglo sencillo de instalaciones superficiales. En este documento se validan y ajustan los calculos de produccion de vapor por ese metodo de presion de labio, con respecto a las mediciones exactas efectuadas con el metodo ASME. Este ultimo es reconocido internacionalmente por su precision, y se lleva a cabo separando la mezcla obtenida en superficie en un recipiente a presion para medir el vapor a traves de una placa de orificio

  13. Influencia de curso pre cálculo en ecuaciones diferenciales y desarrollo de pensamiento variacional

    Directory of Open Access Journals (Sweden)

    Mawency Vergel Ortega

    2018-01-01

    Full Text Available La investigación sigue un enfoque cuantitativo con apoyo del enfoque cualitativo, descriptivo, diseño cuasi experimental. En esta investigación se plantearon los objetivos: estudiar si mejoran las competencias en pensamiento variacional y didácticas de los estudiantes con la utilización de curso precálculo utilizando plataforma virtual respecto a enseñanza tradicional; examinar la influencia en desarrollo del pensamiento matemático y su enseñanza; así como analizar qué tipología de alumnos obtiene mejores resultados en relación a su nivel de competencia digital. Se han obtenido los siguientes avances: el grupo experimental ha obtenido una mejora estadísticamente significativa de sus competencias interpretativas y de pensamiento matemático respecto al grupo control.

  14. TRACCIÓN DE EQUIPOS AGRÍCOLAS CON ECUACIONES MICKLETHWAITE, BEKKER, JANOSI-HANOMOTO Y BRIXIUS EVALUADOS CON VISUAL BASIC

    Directory of Open Access Journals (Sweden)

    Américo José Hossne García

    2017-06-01

    Full Text Available La determinación de la tracción de los tractores agrícolas acredita su empleo eficiente, por ejemplo en: disminución del tiempo oportuno de operación, reducción de daños físicos y terramecánicos, adecuadas característica ingenieriles, tipo y número de neumáticos tractivos y reducción de los costos. El objetivo de este trabajo fue la utilización de las ecuaciones de Micklethwaite, Bekker, Janosi-Hanomoto, y Brixius adaptadas al campo agrícola analizadas con el lenguaje de programación Visual Basic. En la metodología se utilizaron los procedimientos de aplicación de las ecuaciones, las relaciones algebraicas y procedimientos programáticos en Visual Basic 6, diagrama de flujo y el análisis en la tracción sencilla, doble, aperos de tiro y montados; todos, con transferencia de peso y análisis de inestabilidad. El programa desarrollado con sus códigos proporciona una interfaz de usuario intuitiva mediante la vinculación de bases de datos con especificaciones del equipo agrícola, características del neumático, datos del suelo, datos del apero y los coeficientes de las ecuaciones para predecir el rendimiento de un tractor y modelo seleccionados. El programa demostró ser accesible, con mecanismos de uso sin instalación, eficiente y versátil. Las ecuaciones se emplearon con un número de parámetros representativos del área, que pueden ser reemplazados o ampliados y aplicables al agro involucrando la humedad del suelo.

  15. Validación por hidrodensitometría de ecuaciones de pliegues cutáneos utilizadas para estimar la composición corporal en mujeres

    Directory of Open Access Journals (Sweden)

    Juan Carlos Aristizábal

    2008-09-01

    Full Text Available Introducción. Las ecuaciones de pliegues cutáneos son ampliamente utilizadas para estimar la composición corporal; sin embargo, en nuestra población no se han validado contra un método de referencia. Objetivo. Validar por hidrodensitometría las ecuaciones de Durning/Womersley, Jackson/Pollock y Ramírez/Torun en mujeres de 18 a 40 años. Materiales y métodos. Se comparó el porcentaje de grasa de 52 mujeres obtenido por hidrodensitometría, medición simultánea del peso bajo el agua (báscula Chatillon y del volumen pulmonar residual (espirómetro VMAX 22 Sensormedics, con el estimado por las ecuaciones de pliegues cutáneos (calibrador Harpenden de Durning/Womersley, Jackson/Pollock y Ramírez/Torun. Para el análisis estadístico se utilizaron la t de Student pareada, los coeficientes de correlación de Pearson e intraclase, y el método de Bland-Altman. Resultados. El porcentaje de grasa obtenido por hidrodensitometría (29,6±5,8 presentó diferencias (p Conclusión. Las ecuaciones de pliegues cutáneos presentaron pobre validez en la predicción del porcentaje de grasa, con diferencias significativas con la hidrodensitometría, una baja concordancia y unos amplios límites de ésta, lo cual, sugiere que sus resultados no son comparables ni intercambiables con este método.

  16. Construcción y estudio de códigos adaptativos de linealización local para ecuaciones diferenciales ordinarias

    Directory of Open Access Journals (Sweden)

    Alina Sotolongo Aguiar

    2014-04-01

    Full Text Available El propósito de este trabajo es construir códigos adaptativos del método de Linealización Local para Ecuaciones Diferenciales Ordinarias (EDO y analizar su comportamiento numérico. Además, se estudia el efecto que sobre las propiedades de los códigos produce la variación en la precisión de las aproximaciones de Padé utilizadas.

  17. Precipitación de sulfuros metálicos a partir de licor residual ácido: modelos y ecuaciones cinéticas

    Directory of Open Access Journals (Sweden)

    Miguel Garrido-Rodríguez

    2013-03-01

    Full Text Available Con el fin de complementar el estudio termodinámico de la precipitación de sulfuros metálicos en licor residual ácido, la presente investigación tuvo el propósito de obtener los modelos y las ecuaciones cinéticas. Se utilizó para ello la metodología propuesta por Dobrojotov & Rodríguez, la cual, a partir del método gráfico, permite determinar los exponentes empíricos y las ecuaciones y modelos cinéticos que caracterizan de forma particular la influencia de diferentes variables sobre la velocidad del proceso de precipitación y rigen el comportamiento de las distintas especies metálicas. Los modelos y ecuaciones obtenidas establecen la dependencia entre la velocidad del proceso de precipitación de sulfuros en el licor residual ácido de la tecnología de lixiviación ácida a presión y las variables temperatura, velocidad de agitación y concentración de agente precipitante (hidrogenosulfuro de sodio para las especies metálicas cobre, zinc, cobalto y níquel

  18. Diffusion limit of Lévy-Lorentz gas is Brownian motion

    Science.gov (United States)

    Magdziarz, Marcin; Szczotka, Wladyslaw

    2018-07-01

    In this paper we analyze asymptotic behaviour of a stochastic process called Lévy-Lorentz gas. This process is aspecial kind of continuous-time random walk in which walker moves in the fixed environment composed of scattering points. Upon each collision the walker performs a flight to the nearest scattering point. This type of dynamics is observed in Lévy glasses or long quenched polymers. We show that the diffusion limit of Lévy-Lorentz gas with finite mean distance between scattering centers is the standard Brownian motion. Thus, for long times the behaviour of the Lévy-Lorentz gas is close to the diffusive regime.

  19. The flight of the bumblebee: solutions from a vector-induced spontaneous Lorentz symmetry breaking model

    International Nuclear Information System (INIS)

    Bertolami, Orfeu; Paramos, Jorge

    2006-01-01

    The vacuum solutions arising from a spontaneous breaking of Lorentz symmetry due to the acquisition of a vacuum expectation value by a vector field are derived. These include the purely radial Lorentz symmetry breaking (LSB), radial/temporal LSB and axial/temporal LSB scenarios. It is found that the purely radial LSB case gives rise to new black hole solutions. Whenever possible. Parametrized Post-Newtonian (PPN) parameters are computed and compared to observational bounds, in order to constrain the Lorentz symmetry breaking scale

  20. Traces of Lorentz symmetry breaking in a hydrogen atom at ground state

    Science.gov (United States)

    Borges, L. H. C.; Barone, F. A.

    2016-02-01

    Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the hydrogen atom are investigated. We use standard Rayleigh-Schrödinger perturbation theory in order to obtain the corrections to the ground state energy and the wave function. It is shown that an induced four-pole moment arises, due to the Lorentz symmetry breaking. The model considered is the one studied in Borges et al. (Eur Phys J C 74:2937, 2014), where the Lorentz symmetry is broken in the electromagnetic sector.

  1. Traces of Lorentz symmetry breaking in a hydrogen atom at ground state

    Energy Technology Data Exchange (ETDEWEB)

    Borges, L.H.C. [Universidade Federal do ABC, Centro de Ciencias Naturais e Humanas, Santo Andre, SP (Brazil); Barone, F.A. [IFQ-Universidade Federal de Itajuba, Itajuba, MG (Brazil)

    2016-02-15

    Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the hydrogen atom are investigated. We use standard Rayleigh-Schroedinger perturbation theory in order to obtain the corrections to the ground state energy and the wave function. It is shown that an induced four-pole moment arises, due to the Lorentz symmetry breaking. The model considered is the one studied in Borges et al. (Eur Phys J C 74:2937, 2014), where the Lorentz symmetry is broken in the electromagnetic sector. (orig.)

  2. Traces of Lorentz symmetry breaking in a hydrogen atom at ground state

    International Nuclear Information System (INIS)

    Borges, L.H.C.; Barone, F.A.

    2016-01-01

    Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the hydrogen atom are investigated. We use standard Rayleigh-Schroedinger perturbation theory in order to obtain the corrections to the ground state energy and the wave function. It is shown that an induced four-pole moment arises, due to the Lorentz symmetry breaking. The model considered is the one studied in Borges et al. (Eur Phys J C 74:2937, 2014), where the Lorentz symmetry is broken in the electromagnetic sector. (orig.)

  3. First test of Lorentz violation with a reactor-based antineutrino experiment

    International Nuclear Information System (INIS)

    Abe, Y.; Ishitsuka, M.; Konno, T.; Kuze, M.; Aberle, C.; Buck, C.; Hartmann, F.X.; Haser, J.; Kaether, F.; Lindner, M.; Reinhold, B.; Schwetz, T.; Wagner, S.; Watanabe, H.; Anjos, J.C. dos; Gama, R.; Lima, H.P.-Jr.; Pepe, I.M.; Bergevin, M.; Felde, J.; Maesano, C.N.; Bernstein, A.; Bowden, N.S.; Dazeley, S.; Erickson, A.; Keefer, G.; Bezerra, T.J.C.; Furuta, H.; Suekane, F.; Bezrukhov, L.; Lubsandorzhiev, B.K.; Yanovitch, E.; Blucher, E.; Conover, E.; Crum, K.; Strait, M.; Worcester, M.; Busenitz, J.; Goon, J.TM.; Habib, S.; Ostrovskiy, I.; Reichenbacher, J.; Stancu, I.; Sun, Y.; Cabrera, A.; Franco, D.; Kryn, D.; Obolensky, M.; Roncin, R.; Tonazzo, A.; Caden, E.; Damon, E.; Lane, C.E.; Maricic, J.; Miletic, T.; Milincic, R.; Perasso, S.; Smith, E.; Camilleri, L.; Carr, R.; Franke, A.J.; Shaevitz, M.H.; Toups, M.; Cerrada, M.; Crespo-Anadon, J.I.; Gil-Botella, I.; Lopez-Castano, J.M.; Novella, P.; Palomares, C.; Santorelli, R.; Chang, P.J.; Horton-Smith, G.A.; McKee, D.; Shrestha, D.; Chimenti, P.; Classen, T.; Collin, A.P.; Cucoanes, A.; Durand, V.; Fechner, M.; Fischer, V.; Hayakawa, T.; Lasserre, T.; Letourneau, A.; Lhuillier, D.; Mention, G.; Mueller, Th.A.; Perrin, P.; Sida, J.L.; Sinev, V.; Veyssiere, C.

    2012-01-01

    We present a search for Lorentz violation with 8249 candidate electron antineutrino events taken by the Double Chooz experiment in 227.9 live days of running. This analysis, featuring a search for a sidereal time dependence of the events, is the first test of Lorentz invariance using a reactor-based antineutrino source. No sidereal variation is present in the data and the disappearance results are consistent with sidereal time independent oscillations. Under the Standard-Model Extension, we set the first limits on 14 Lorentz violating coefficients associated with transitions between electron and tau flavor, and set two competitive limits associated with transitions between electron and muon flavor. (authors)

  4. Spontaneous Lorentz violation and the long-range gravitational preferred-frame effect

    International Nuclear Information System (INIS)

    Graesser, Michael L.; Jenkins, Alejandro; Wise, Mark B.

    2005-01-01

    Lorentz-violating operators involving Standard Model fields are tightly constrained by experimental data. However, bounds are more model-independent for Lorentz violation appearing in purely gravitational couplings. The spontaneous breaking of Lorentz invariance by the vacuum expectation value of a vector field selects a universal rest frame. This affects the propagation of the graviton, leading to a modification of Newton's law of gravity. We compute the size of the long-range preferred-frame effect in terms of the coefficients of the two-derivative operators in the low-energy effective theory that involves only the graviton and the Goldstone bosons

  5. Influencia de la altitud en la composición química de los aceites de oliva vírgenes de Andalucía. Ecuaciones matemáticas de clasificación

    Directory of Open Access Journals (Sweden)

    Ferreiro, L.

    1992-06-01

    Full Text Available The changes of chemical composition due to climatic influence, in virgin olive oil, is a research subject which has been scarcely developed. This paper studies this relation with Andalusian oils by altitude as an indirect parameter related to climate of their olive grow zones. It was found that sterols and some triterpenic alcohols and hydrocarbons show changes in relation with altitude. The oils were classified into two groups of altitude, valley and mountains, by mean of discriminant and regression analysis procedures. The rules were verified with samples harvested in 1988 and 1989. It was found a significative predictive power (more than 90% when the variety is Picual.

    La influencia del clima en la composición química del aceite de oliva virgen es un campo de investigación que ha sido escasamente estudiado. En el presente trabajo se expone el estudio de esta relación, realizado para Andalucía, a través de un parámetro indirecto como es la altitud de las zonas de cultivo. Se ha encontrado que parámetros como los esteroles, y algunos alcoholes e hidrocarburos triterpénicos presentan variaciones sensibles en función de la altitud. Estas variaciones han servido para diferenciar los aceites procedentes de olivares de valle de los procedentes de montaña, utilizando técnicas de análisis discriminante y de regresión. Las ecuaciones obtenidas se han verificado con aceites de las cosechas de 1988 y 1989, encontrándose una significativa capacidad predictiva (más del 90% cuando la variedad del olivar es una constante.

  6. ECUACIONES ALOMÉTRICAS PARA ESTIMAR BIOMASA Y CARBONO EN Quercus magnoliaefolia

    Directory of Open Access Journals (Sweden)

    Jesús D. Gómez-Díaz

    2011-01-01

    Full Text Available En el ejido El Zapote de la Reserva de la Biosfera "Sierra de Huautla", estado de Morelos, México, se seleccionaron doce árboles de Quercus magnoliaefolia Née y se determinó su biomasa en la parte aérea. El modelo alométrico quedó expresado como: B = 0.0345 * DAP2.9334 en donde B es la biomasa (kg y DAP es el diámetro a la altura del pecho (cm, con un coeficiente de determinación (R2= 0.98; P<0.001. Adicionalmente, se estimó la biomasa mediante una regresión lineal múltiple que consideró el área basal (AB, la densidad específica de la madera (DEM y la altura de los árboles (H. Una alta proporción de la varianza de la biomasa fue explicada solamente por el área basal. La DEM y H no incrementaron significativamente la precisión de los modelos. El porcentaje promedio de carbono en los árboles de Q. magnoliaefolia fue de 47.14 con valores de 46.29 % para el fuste, 46.83 % para las ramas y 48.31 % para el follaje. La proporción promedio de los componentes de la especie estudiada fue de 2.5 % para el fuste, 27.8 % para las ramas y 9.6 % para el follaje.

  7. Cosmological evolution of interacting dark energy in Lorentz violation

    International Nuclear Information System (INIS)

    Zen, Freddy P.; Gunara, Bobby E.; Triyanta; Arianto; Purwanto, A.

    2009-01-01

    The cosmological evolution of an interacting scalar-field model in which the scalar field interacts with dark matter, radiation, and baryons via Lorentz violation is investigated. We propose a model of interaction through the effective coupling, anti β. Using dynamical system analysis, we study the linear dynamics of an interacting model and show that the dynamics of critical points are completely controlled by two parameters. Some results can be mentioned as follows. Firstly, the sequence of radiation, the dark matter, and the scalar-field dark energy exist and baryons are subdominant. Secondly, the model also allows for the possibility of having a universe in the phantom phase with constant potential. Thirdly, the effective gravitational constant varies with respect to time through anti β. In particular, we consider the simple case where anti β has a quadratic form and has a good agreement with the modified ΛCDM and quintessence models. Finally, we also calculate the first post-Newtonian parameters for our model. (orig.)

  8. On the Lorentz invariance of bit-string geometry

    International Nuclear Information System (INIS)

    Noyes, H.P.

    1995-09-01

    We construct the class of integer-sided triangles and tetrahedra that respectively correspond to two or three discriminately independent bit-strings. In order to specify integer coordinates in this space, we take one vertex of a regular tetrahedron whose common edge length is an even integer as the origin of a line of integer length to the open-quotes pointclose quotes and three integer distances to this open-quotes pointclose quotes from the three remaining vertices of the reference tetrahedron. This - usually chiral - integer coordinate description of bit-string geometry is possible because three discriminately independent bit-strings generate four more; the Hamming measures of these seven strings always allow this geometrical interpretation. On another occasion we intend to prove the rotational invariance of this coordinate description. By identifying the corners of these figures with the positions of recording counters whose clocks are synchronized using the Einstein convention, we define velocities in this space. This suggests that it may be possible to define boosts and discrete Lorentz transformations in a space of integer coordinates. We relate this description to our previous work on measurement accuracy and the discrete ordered calculus of Etter and Kauffman (DOC)

  9. Lorentz transformations, sideways shift and massless spinning particles

    Directory of Open Access Journals (Sweden)

    K. Bolonek-Lasoń

    2017-06-01

    Full Text Available Recently (Stone et al. (2015 [16] the influence of the so called “Wigner translations” (more generally-Lorentz transformations on circularly polarized Gaussian packets (providing the solution to Maxwell equations in paraxial approximation has been studied. It appears that, within this approximation, the Wigner translations have an effect of shifting the wave packet trajectory parallel to itself by an amount proportional to the photon helicity. It has been suggested that this shift may result from specific properties of the algebra of Poincare generators for massless particles. In the present letter we describe the general relation between transformation properties of electromagnetic field on quantum and classical levels. It allows for a straightforward derivation of the helicity-dependent transformation rules. We present also an elementary derivation of the formula for sideways shift based on classical Maxwell theory. Some comments are made concerning the generalization to higher helicities and the relation to the coordinate operator defined long time ago by Pryce.

  10. Iterative reconstruction of magnetic induction using Lorentz transmission electron tomography

    International Nuclear Information System (INIS)

    Phatak, C.; Gürsoy, D.

    2015-01-01

    Intense ongoing research on complex nanomagnetic structures requires a fundamental understanding of the 3D magnetization and the stray fields around the nano-objects. 3D visualization of such fields offers the best way to achieve this. Lorentz transmission electron microscopy provides a suitable combination of high resolution and ability to quantitatively visualize the magnetization vectors using phase retrieval methods. In this paper, we present a formalism to represent the magnetic phase shift of electrons as a Radon transform of the magnetic induction of the sample. Using this formalism, we then present the application of common tomographic methods particularly the iterative methods, to reconstruct the 3D components of the vector field. We present an analysis of the effect of missing wedge and the limited angular sampling as well as reconstruction of complex 3D magnetization in a nanowire using simulations. - Highlights: • We present a formalism to represent electron-optical magnetic phase shift as a Radon transform of the 3D magnetic induction of the nano-object. • We have analyzed four different tomographic reconstruction methods for vectorial data reconstruction. • Reconstruction methods were tested for varying experimental limitations such as limited tilt range and limited angular sampling. • The analysis showed that Gridrec and SIRT methods performed better with lower errors than other reconstruction methods

  11. Charged Lifshitz black hole and probed Lorentz-violation fermions from holography

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Cheng-Jian, E-mail: rocengeng@hotmail.com [Department of Physics, Nanchang University, Nanchang, 330031 (China); Center for Relativistic Astrophysics and High Energy Physics, Nanchang University, Nanchang 330031 (China); Kuang, Xiao-Mei, E-mail: xmeikuang@gmail.com [Instituto de Física, Pontificia Universidad Católica de Valparaíso, Casilla 4059, Valparaíso (Chile); Shu, Fu-Wen, E-mail: shufuwen@ncu.edu.cn [Department of Physics, Nanchang University, Nanchang, 330031 (China); Center for Relativistic Astrophysics and High Energy Physics, Nanchang University, Nanchang 330031 (China)

    2017-06-10

    We analytically obtain a new charged Lifshitz solution by adding a non-relativistic Maxwell field in Hořava–Lifshitz gravity. The black hole exhibits an anisotropic scaling between space and time (Lifshitz scaling) in the UV limit, while in the IR limit, the Lorentz invariance is approximately recovered. We introduce the probed Lorentz-violation fermions into the background and holographically investigate the spectral properties of the dual fermionic operator. The Lorentz-violation of the fermions will enhance the peak and correspond larger fermi momentum, which compensates the non-relativistic bulk effect of the dynamical exponent (z). For a fixed z, when the Lorentz-violation of fermions increases to a critical value, the behavior of the low energy excitation goes from a non-Fermi liquid type to a Fermi liquid type, which implies a kind of phase transition.

  12. Propagation of partially coherent Lorentz-Gauss vortex beam through oceanic turbulence.

    Science.gov (United States)

    Liu, Dajun; Yin, Hongming; Wang, Guiqiu; Wang, Yaochuan

    2017-11-01

    The partially coherent Lorentz-Gauss vortex beam generated by a Schell-model source has been introduced. Based on the extended Huygens-Fresnel principle, the cross-spectral density function of a partially coherent Lorentz-Gauss vortex beam propagating in oceanic turbulence is derived. The influences of coherence length, topological charge M, and oceanic turbulence on the spreading properties and position of the coherence vortex for a partially coherent Lorentz-Gauss vortex beam are analyzed in detail. The results show that a partially coherent Lorentz-Gauss vortex beam propagating in stronger oceanic turbulence will evolve into a Gaussian-like beam more rapidly as the propagation distance increases, and the number of coherent vortices will change.

  13. Low regularity solutions of the Chern-Simons-Higgs equations in the Lorentz gauge

    Directory of Open Access Journals (Sweden)

    Nikolaos Bournaveas

    2009-09-01

    Full Text Available We prove local well-posedness for the 2+1-dimensional Chern-Simons-Higgs equations in the Lorentz gauge with initial data of low regularity. Our result improves earlier results by Huh [10, 11].

  14. Generation of higher derivatives operators and electromagnetic wave propagation in a Lorentz-violation scenario

    Energy Technology Data Exchange (ETDEWEB)

    Borges, L.H.C., E-mail: luizhenriqueunifei@yahoo.com.br [Universidade Federal do ABC, Centro de Ciências Naturais e Humanas, Av. dos Estados, 5001, Santo André, SP, 09210-580 (Brazil); Dias, A.G., E-mail: alex.dias@ufabc.edu.br [Universidade Federal do ABC, Centro de Ciências Naturais e Humanas, Av. dos Estados, 5001, Santo André, SP, 09210-580 (Brazil); Ferrari, A.F., E-mail: alysson.ferrari@ufabc.edu.br [Universidade Federal do ABC, Centro de Ciências Naturais e Humanas, Av. dos Estados, 5001, Santo André, SP, 09210-580 (Brazil); Nascimento, J.R., E-mail: jroberto@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, João Pessoa, Paraíba, 58051-970 (Brazil); Petrov, A.Yu., E-mail: petrov@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, João Pessoa, Paraíba, 58051-970 (Brazil)

    2016-05-10

    We study the perturbative generation of higher-derivative Lorentz violating operators as quantum corrections to the photon effective action, originated from a specific Lorentz violation background, which has already been studied in connection with the physics of light pseudoscalars. We calculate the complete one loop effective action of the photon field through the proper-time method, using the zeta function regularization. This result can be used as a starting point to study possible effects of the Lorentz violating background we are considering in photon physics. As an example, we focus on the lowest order corrections and investigate whether they could influence the propagation of electromagnetic waves through the vacuum. We show, however, that no effects of the kind of Lorentz violation we consider can be detected in such a context, so that other aspects of photon physics have to be studied.

  15. New effects in the interaction between electromagnetic sources mediated by nonminimal Lorentz violating interactions

    Energy Technology Data Exchange (ETDEWEB)

    Borges, L.H.C.; Ferrari, A.F. [Universidade Federal do ABC, Centro de Ciencias Naturais e Humanas, Santo Andre, SP (Brazil); Barone, F.A. [Universidade Federal de Itajuba, IFQ, Itajuba, MG (Brazil)

    2016-11-15

    This paper is dedicated to the study of interactions between external sources for the electromagnetic field in the presence of Lorentz symmetry breaking. We focus on a higher derivative, Lorentz violating interaction that arises from a specific model that was argued to lead to interesting effects in the low energy phenomenology of light pseudoscalars interacting with photons. The kind of higher derivative Lorentz violating interaction we discuss are called nonminimal. They are usually expected to be relevant only at very high energies, but we argue they might also induce relevant effects in low energy phenomena. Indeed, we show that the Lorentz violating background considered by us leads to several phenomena that have no counterpart in Maxwell theory, such as nontrivial torques on isolated electric dipoles, as well as nontrivial forces and torques between line currents and point like charges, as well as among Dirac strings and other electromagnetic sources. (orig.)

  16. Singularities of lightcone pedals of spacelike curves in Lorentz-Minkowski 3-space

    Directory of Open Access Journals (Sweden)

    Chen Liang

    2016-01-01

    Full Text Available In this paper, geometric properties of spacelike curves on a timelike surface in Lorentz-Minkowski 3-space are investigated by applying the singularity theory of smooth functions from the contact viewpoint.

  17. Constraints on violation of Lorentz invariance from atmospheric showers initiated by multi-TeV photons

    Energy Technology Data Exchange (ETDEWEB)

    Rubtsov, Grigory; Satunin, Petr; Sibiryakov, Sergey, E-mail: grisha@ms2.inr.ac.ru, E-mail: satunin@ms2.inr.ac.ru, E-mail: Sergey.Sibiryakov@cern.ch [Institute for Nuclear Research of the Russian Academy of Sciences, 60th October Anniversary Prospect, 7a, 117312 Moscow (Russian Federation)

    2017-05-01

    Parameterizing hypothetical violation of Lorentz invariance at high energies using the framework of effective quantum field theory, we discuss its effect on the formation of atmospheric showers by very-high-energy gamma rays. In the scenario where Lorentz invariance violation leads to a decrease of the photon velocity with energy the formation of the showers is suppressed compared to the Lorentz invariant case. Absence of such suppression in the high-energy part of spectrum of the Crab nebula measured independently by HEGRA and H.E.S.S. collaborations is used to set lower bounds on the energy scale of Lorentz invariance violation. These bounds are competitive with the strongest existing constraints obtained from timing of variable astrophysical sources and the absorption of TeV photons on the extragalactic background light. They will be further improved by the next generation of multi-TeV gamma-ray observatories.

  18. Lorentz invariance on trial in the weak decay of polarized atoms

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Stefan E., E-mail: s.mueller@kvi.nl [Kernfysisch Versneller Instituut (Netherlands)

    2013-03-15

    One of the most fundamental principles underlying our current understanding of nature is the invariance of the laws of physics under Lorentz transformations. Theories trying to unify the Standard Model with quantum gravity suggest that this invariance may be broken by the presence of Lorentz-violating background fields. Dedicated high-precision experiments at low energies could observe such suppressed signals from the Planck scale. At KVI, a test on Lorentz invariance of the weak interaction is performed searching for a dependence of the decay rate of spin-polarized nuclei on the orientation of their spin with respect to a fixed absolute galactical reference frame. An observation of such a dependence would imply a violation of Lorentz invariance.

  19. Imprints of supersymmetry in the Lorentz-symmetry breaking of Gauge Theories

    Energy Technology Data Exchange (ETDEWEB)

    Belich, H [Universidade Federal do Espirito Santo (UFES), Vitoria, ES (Brazil); Dias, G S; Leal, F J.L. [Instituto Federal de Educacao, Ciencia e Tecnologia do Espirito Santo (IFES), Vitoria, ES (Brazil); Durand, L G; Helayel-Neto, Jose Abdalla; Spalenza, W [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Grupo de Fisica Teorica Jose Leite Lopes (GFT-JLL), Petropolis, RJ (Brazil)

    2011-07-01

    Full text: The breaking of Lorentz symmetry that may take place at very high energies opens up a venue for the discussion of the interplay between the violations of supersymmetry and relativistic symmetry. Recently, there have appeared in the literature models which propose a residual (non-relativistic) supersymmetry after Lorentz symmetry has been broken in a Horava gravity scenario. We here propose an N=1-supersymmetric Abelian gauge model which realises the breaking of Lorentz invariance by means of a CPT-even term. Our attempt assumes the point of view that supersymmetry and Lorentz symmetry are broken down at the same scale. If this is the case, the fermionic sector of the supermultiplets that accomplish the breaking of the symmetries into consideration may give rise to condensates that play an important role in the photon and photino dispersion relations. Contemporarily, they may also point to a more fundamental origin for the (bosonic) tensors usually associated to the backgrounds that parametrize Lorentz-symmetry breaking. We also highlight that, by studying the the violation of Lorentz symmetry in connection with supersymmetry, we find out that the Myers-Pospelov Electrodynamics, proposed on the basis of an analysis of the set of dimension-five operators, naturally appears in the bosonic sector of our model. Also, as a result of the interconnection between the supersymmetry and Lorentz-symmetry breakings, the photino-photino and photon-photino mixings that correspond to the supersymmetric completion of the Myers-Pospelov purely photonic terms come out. Finally, we present some comments on the possible modifications the supersymmetric fermions may introduce in the dispersion relations for particles at (high) energies close to the scale where supersymmetry and Lorentz symmetry are broken. (author)

  20. Imprints of supersymmetry in the Lorentz-symmetry breaking of Gauge Theories

    International Nuclear Information System (INIS)

    Belich, H.; Dias, G.S.; Leal, F.J.L.; Durand, L.G.; Helayel-Neto, Jose Abdalla; Spalenza, W.

    2011-01-01

    Full text: The breaking of Lorentz symmetry that may take place at very high energies opens up a venue for the discussion of the interplay between the violations of supersymmetry and relativistic symmetry. Recently, there have appeared in the literature models which propose a residual (non-relativistic) supersymmetry after Lorentz symmetry has been broken in a Horava gravity scenario. We here propose an N=1-supersymmetric Abelian gauge model which realises the breaking of Lorentz invariance by means of a CPT-even term. Our attempt assumes the point of view that supersymmetry and Lorentz symmetry are broken down at the same scale. If this is the case, the fermionic sector of the supermultiplets that accomplish the breaking of the symmetries into consideration may give rise to condensates that play an important role in the photon and photino dispersion relations. Contemporarily, they may also point to a more fundamental origin for the (bosonic) tensors usually associated to the backgrounds that parametrize Lorentz-symmetry breaking. We also highlight that, by studying the the violation of Lorentz symmetry in connection with supersymmetry, we find out that the Myers-Pospelov Electrodynamics, proposed on the basis of an analysis of the set of dimension-five operators, naturally appears in the bosonic sector of our model. Also, as a result of the interconnection between the supersymmetry and Lorentz-symmetry breakings, the photino-photino and photon-photino mixings that correspond to the supersymmetric completion of the Myers-Pospelov purely photonic terms come out. Finally, we present some comments on the possible modifications the supersymmetric fermions may introduce in the dispersion relations for particles at (high) energies close to the scale where supersymmetry and Lorentz symmetry are broken. (author)

  1. Equilibria of a charged artificial satellite subject to gravitational and Lorentz torques

    International Nuclear Information System (INIS)

    Abdel-Aziz, Yehia A.; Shoaib, Muhammad

    2014-01-01

    The attitude dynamics of a rigid artificial satellite subject to a gravity gradient and Lorentz torques in a circular orbit are considered. Lorentz torque is developed on the basis of the electrodynamic effects of the Lorentz force acting on the charged satellite's surface. We assume that the satellite is moving in a Low Earth Orbit in the geomagnetic field, which is considered to be a dipole. Our model of torque due to the Lorentz force is developed for an artificial satellite with a general shape, and the nonlinear differential equations of Euler are used to describe its attitude orientation. All equilibrium positions are determined and conditions for their existence are obtained. The numerical results show that the charge q and radius ρ 0 of the center of charge for the satellite provide a certain type of semi-passive control for the attitude of the satellite. The technique for this kind of control would be to increase or decrease the electrostatic screening on the satellite. The results obtained confirm that the change in charge can affect the magnitude of the Lorentz torque, which can also affect control of the satellite. Moreover, the relationship between magnitude of the Lorentz torque and inclination of the orbit is investigated. (research papers)

  2. Equilibria of a charged artificial satellite subject to gravitational and Lorentz torques

    Science.gov (United States)

    Abdel-Aziz, Yehia A.; Shoaib, Muhammad

    2014-07-01

    The attitude dynamics of a rigid artificial satellite subject to a gravity gradient and Lorentz torques in a circular orbit are considered. Lorentz torque is developed on the basis of the electrodynamic effects of the Lorentz force acting on the charged satellite's surface. We assume that the satellite is moving in a Low Earth Orbit in the geomagnetic field, which is considered to be a dipole. Our model of torque due to the Lorentz force is developed for an artificial satellite with a general shape, and the nonlinear differential equations of Euler are used to describe its attitude orientation. All equilibrium positions are determined and conditions for their existence are obtained. The numerical results show that the charge q and radius ρ0 of the center of charge for the satellite provide a certain type of semi-passive control for the attitude of the satellite. The technique for this kind of control would be to increase or decrease the electrostatic screening on the satellite. The results obtained confirm that the change in charge can affect the magnitude of the Lorentz torque, which can also affect control of the satellite. Moreover, the relationship between magnitude of the Lorentz torque and inclination of the orbit is investigated.

  3. Conditions for Lorentz-invariant superluminal information transfer without signaling

    Science.gov (United States)

    Grössing, G.; Fussy, S.; Mesa Pascasio, J.; Schwabl, H.

    2016-03-01

    We understand emergent quantum mechanics in the sense that quantum mechanics describes processes of physical emergence relating an assumed sub-quantum physics to macroscopic boundary conditions. The latter can be shown to entail top-down causation, in addition to usual bottom-up scenarios. With this example it is demonstrated that definitions of “realism” in the literature are simply too restrictive. A prevailing manner to define realism in quantum mechanics is in terms of pre-determination independent of the measurement. With our counter-example, which actually is ubiquitous in emergent, or self-organizing, systems, we argue for realism without pre-determination. We refer to earlier results of our group showing how the guiding equation of the de Broglie-Bohm interpretation can be derived from a theory with classical ingredients only. Essentially, this corresponds to a “quantum mechanics without wave functions” in ordinary 3-space, albeit with nonlocal correlations. This, then, leads to the central question of how to deal with the nonlocality problem in a relativistic setting. We here show that a basic argument discussing the allegedly paradox time ordering of events in EPR-type two-particle experiments falls short of taking into account the contextuality of the experimental setup. Consequently, we then discuss under which circumstances (i.e. physical premises) superluminal information transfer (but not signaling) may be compatible with a Lorentz-invariant theory. Finally, we argue that the impossibility of superluminal signaling - despite the presence of superluminal information transfer - is not the result of some sort of conspiracy (á la “Nature likes to hide”), but the consequence of the impossibility to exactly reproduce in repeated experimental runs a state's preparation, or of the no-cloning theorem, respectively.

  4. Conditions for Lorentz-invariant superluminal information transfer without signaling

    International Nuclear Information System (INIS)

    Grössing, G; Fussy, S; Pascasio, J Mesa; Schwabl, H

    2016-01-01

    We understand emergent quantum mechanics in the sense that quantum mechanics describes processes of physical emergence relating an assumed sub-quantum physics to macroscopic boundary conditions. The latter can be shown to entail top-down causation, in addition to usual bottom-up scenarios. With this example it is demonstrated that definitions of “realism” in the literature are simply too restrictive. A prevailing manner to define realism in quantum mechanics is in terms of pre-determination independent of the measurement. With our counter-example, which actually is ubiquitous in emergent, or self-organizing, systems, we argue for realism without pre-determination. We refer to earlier results of our group showing how the guiding equation of the de Broglie-Bohm interpretation can be derived from a theory with classical ingredients only. Essentially, this corresponds to a “quantum mechanics without wave functions” in ordinary 3-space, albeit with nonlocal correlations. This, then, leads to the central question of how to deal with the nonlocality problem in a relativistic setting. We here show that a basic argument discussing the allegedly paradox time ordering of events in EPR-type two-particle experiments falls short of taking into account the contextuality of the experimental setup. Consequently, we then discuss under which circumstances (i.e. physical premises) superluminal information transfer (but not signaling) may be compatible with a Lorentz-invariant theory. Finally, we argue that the impossibility of superluminal signaling - despite the presence of superluminal information transfer - is not the result of some sort of conspiracy (á la “Nature likes to hide”), but the consequence of the impossibility to exactly reproduce in repeated experimental runs a state's preparation, or of the no-cloning theorem, respectively. (paper)

  5. Direct measurement of Lorentz transformation with Doppler effects

    Science.gov (United States)

    Chen, Shao-Guang

    , r is the unit vector from lamphouse point to counters. Or: L (0) L (pi) =L0 (1+(v/c)) L0 (1 - (v/c)) =L0 2 y2 =L2 Or: L ≡ [L(0)L(pi)]1/2 =L0 y , which y ≡ (1 - (v/c)2 )1/2 is just Fitzgerald-Lorentzian contraction-factor. Also, when a light-wave period p is defined as time unit, from Doppler's frequency-shift the count N with p of one period T of moving-clock is: T(q) = N(q) p = T0 /(1+(v/c) cos q) Or: T ≡ (T(0) T(pi))1/2 = T 0 /y , where T0 is the proper period when v = 0, which is just the moving-clock-slower effect. Let r from clock point to lamp-house ((v/c) symbol reverse), Doppler formula in the usual form is: f (q) = 1/T(q) = f0 (1 - (v/c) cos q). Therefore, Lorentz transformation is the square root average of positive and negative directions twice metrical results of Doppler's frequency-shift, which Doppler's once items ( positive and negative v/c ) are counteract only residual twice item (v/c)2 (relativity-factor). Then Lorentz transformation can be directly measured by Doppler's frequency-shift method. The half-life of moving mu-meson is statistical average of many particles, the usual explanation using relativity-factor y is correct. An airship moving simultaneously along contrary directions is impossible, which makes that the relativity-factor y and the twin-paradox are inexistent in the macroscopical movement. Thereby, in the navigations of airship or satellite only use the measurement of Doppler's frequency-shift but have no use for Lorentz transformation.

  6. Construcción de un índice de satisfacción del cliente mediante ecuaciones estructurales. Caso de estudio: clientes (personas naturales de un banco nacional

    Directory of Open Access Journals (Sweden)

    María Fernanda Castrillón

    2010-06-01

    Full Text Available La satisfacción del cliente es una variable importante para la gestión del servicio de los bancos; sin embargo, comúnmente es medida con metodologías que no tienen en cuenta: primero, que desde el punto de vista estadístico, es una variable sujeta a errores de medida y segundo, la posible interrelación de las variables que la determinan.Así mismo, debido al alto grado de abstracción del concepto, para la medición del nivel de satisfacción de los clientes con su banco, se requiere de una metodología que permita descomponer el concepto en dimensiones del servicio y estas a su vez en indicadores. La metodología empleada es la modelización mediante sistemas de ecuaciones estructurales, tomando como base para su especificación, consideraciones teóricas y variables latentes detectadas por medio de un análisis factorial. De esta forma, se construye una medida basada en la relación de algunos indicadores de servicio con las dimensiones de imagen,producto y procesos, que subyacen la estructura del nivel de satisfacción. Los resultados del modelo presentado en este trabajo, permiten una mejor comprensión de una estructura sencilla de la satisfacción de los clientes con el servicio de un banco y plantea una línea base de análisis para este concepto.

  7. Demostraciones algebraicas de las ecuaciones cuadráticas en SHARḤ AL-URJŪZA AL-YĀSMĪNIYYA de IBN AL-HĀ'IM

    OpenAIRE

    Fadil, Abdelaziz; Puig, Luis

    2014-01-01

    El álgebra árabe es operar con cantidades desconocidas aplicando las mismas reglas aritméticas que operan con los números conocidos. Esta conceptualización, junto con la definición de las especies de números, ha facilitado el desarrollo del cálculo algebraico de las expresiones algebraicas. En particular, ha permitido la denominación, enunciación, clasificación y formulación de seis ecuaciones cuadráticas. Se han propuesto demostraciones ingenuas, geométricas y algebraicas de lo...

  8. Secuencias didácticas para la enseñanza de las ecuaciones cuadráticas basadas en los estilos de aprendizaje

    OpenAIRE

    Rodríguez Quiroz, María Virginia

    2017-01-01

    El objetivo general del presente trabajo es el mejorar el aprendizaje de las matemáticas realizando modelos de enseñanza que muestren secuencias didácticas mediadas por el uso de las tecnologías de la información y las comunicaciones, y permitan a los estudiantes el tratamiento didáctico de las ecuaciones cuadráticas considerando sus estilos de aprendizaje. Teniendo en cuenta que el aprendizaje de la matemática se hace dificultoso para la mayoría de los estudiantes, lo cual ...

  9. Average intensity and coherence properties of a partially coherent Lorentz-Gauss beam propagating through oceanic turbulence

    Science.gov (United States)

    Liu, Dajun; Wang, Guiqiu; Wang, Yaochuan

    2018-01-01

    Based on the Huygens-Fresnel integral and the relationship of Lorentz distribution and Hermite-Gauss function, the average intensity and coherence properties of a partially coherent Lorentz-Gauss beam propagating through oceanic turbulence have been investigated by using numerical examples. The influences of beam parameters and oceanic turbulence on the propagation properties are also discussed in details. It is shown that the partially coherent Lorentz-Gauss beam with smaller coherence length will spread faster in oceanic turbulence, and the stronger oceanic turbulence will accelerate the spreading of partially coherent Lorentz-Gauss beam in oceanic turbulence.

  10. Nonparaxial propagation of Lorentz-Gauss beams in uniaxial crystal orthogonal to the optical axis.

    Science.gov (United States)

    Wang, Xun; Liu, Zhirong; Zhao, Daomu

    2014-04-01

    Analytical expressions for the three components of nonparaxial propagation of a polarized Lorentz-Gauss beam in uniaxial crystal orthogonal to the optical axis are derived and used to investigate its propagation properties in uniaxial crystal. The influences of the initial beam parameters and the parameters of the uniaxial crystal on the evolution of the beam-intensity distribution in the uniaxial crystal are examined in detail. Results show that the statistical properties of a nonparaxial Lorentz-Gauss beam in a uniaxial crystal orthogonal to the optical axis are closely determined by the initial beam's parameters and the parameters of the crystal: the beam waist sizes-w(0), w(0x), and w(0y)-not only affect the size and shape of the beam profile in uniaxial crystal but also determine the nonparaxial effect of a Lorentz-Gauss beam; the beam profile of a Lorentz-Gauss beam in uniaxial crystal is elongated in the x or y direction, which is determined by the ratio of the extraordinary refractive index to the ordinary refractive index; with increasing deviation of the ratio from unity, the extension of the beam profile augments. The results indicate that uniaxial crystal provides an effective and convenient method for modulating the Lorentz-Gauss beams. Our results may be valuable in some fields, such as optical trapping and nonlinear optics, where a light beam with a special profile and polarization is required.

  11. Constraining Anisotropic Lorentz Violation via the Spectral-lag Transition of GRB 160625B

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Jun-Jie; Wu, Xue-Feng; Shao, Lang [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Zhang, Bin-Bin [Instituto de Astrofísica de Andalucá (IAA-CSIC), P.O. Box 03004, E-18080 Granada (Spain); Mészáros, Peter [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Kostelecký, V. Alan, E-mail: xfwu@pmo.ac.cn, E-mail: kostelec@indiana.edu [Physics Department, Indiana University, Bloomington, IN 47405 (United States)

    2017-06-20

    Violations of Lorentz invariance can lead to an energy-dependent vacuum dispersion of light, which results in arrival-time differences of photons with different energies arising from a given transient source. In this work, direction-dependent dispersion constraints are obtained on nonbirefringent Lorentz-violating effects using the observed spectral lags of the gamma-ray burst GRB 160625B. This burst has unusually large high-energy photon statistics, so we can obtain constraints from the true spectral time lags of bunches of high-energy photons rather than from the rough time lag of a single highest-energy photon. Also, GRB 160625B is the only burst to date having a well-defined transition from positive lags to negative lags, providing a unique opportunity to distinguish Lorentz-violating effects from any source-intrinsic time lag in the emission of photons of different energy bands. Our results place comparatively robust two-sided constraints on a variety of isotropic and anisotropic coefficients for Lorentz violation, including the first bounds on Lorentz-violating effects from operators of mass dimension 10 in the photon sector.

  12. Acousto-electrical speckle pattern in Lorentz force electrical impedance tomography

    International Nuclear Information System (INIS)

    Grasland-Mongrain, Pol; Destrempes, François; Cloutier, Guy; Mari, Jean-Martial; Souchon, Rémi; Catheline, Stefan; Chapelon, Jean-Yves; Lafon, Cyril

    2015-01-01

    Ultrasound speckle is a granular texture pattern appearing in ultrasound imaging. It can be used to distinguish tissues and identify pathologies. Lorentz force electrical impedance tomography is an ultrasound-based medical imaging technique of the tissue electrical conductivity. It is based on the application of an ultrasound wave in a medium placed in a magnetic field and on the measurement of the induced electric current due to Lorentz force. Similarly to ultrasound imaging, we hypothesized that a speckle could be observed with Lorentz force electrical impedance tomography imaging. In this study, we first assessed the theoretical similarity between the measured signals in Lorentz force electrical impedance tomography and in ultrasound imaging modalities. We then compared experimentally the signal measured in both methods using an acoustic and electrical impedance interface. Finally, a bovine muscle sample was imaged using the two methods. Similar speckle patterns were observed. This indicates the existence of an ‘acousto-electrical speckle’ in the Lorentz force electrical impedance tomography with spatial characteristics driven by the acoustic parameters but due to electrical impedance inhomogeneities instead of acoustic ones as is the case of ultrasound imaging. (paper)

  13. Trouble with the Lorentz law of force: incompatibility with special relativity and momentum conservation.

    Science.gov (United States)

    Mansuripur, Masud

    2012-05-11

    The Lorentz law of force is the fifth pillar of classical electrodynamics, the other four being Maxwell's macroscopic equations. The Lorentz law is the universal expression of the force exerted by electromagnetic fields on a volume containing a distribution of electrical charges and currents. If electric and magnetic dipoles also happen to be present in a material medium, they are traditionally treated by expressing the corresponding polarization and magnetization distributions in terms of bound-charge and bound-current densities, which are subsequently added to free-charge and free-current densities, respectively. In this way, Maxwell's macroscopic equations are reduced to his microscopic equations, and the Lorentz law is expected to provide a precise expression of the electromagnetic force density on material bodies at all points in space and time. This Letter presents incontrovertible theoretical evidence of the incompatibility of the Lorentz law with the fundamental tenets of special relativity. We argue that the Lorentz law must be abandoned in favor of a more general expression of the electromagnetic force density, such as the one discovered by Einstein and Laub in 1908. Not only is the Einstein-Laub formula consistent with special relativity, it also solves the long-standing problem of "hidden momentum" in classical electrodynamics.

  14. Acousto-electrical speckle pattern in Lorentz force electrical impedance tomography

    Science.gov (United States)

    Grasland-Mongrain, Pol; Destrempes, François; Mari, Jean-Martial; Souchon, Rémi; Catheline, Stefan; Chapelon, Jean-Yves; Lafon, Cyril; Cloutier, Guy

    2015-05-01

    Ultrasound speckle is a granular texture pattern appearing in ultrasound imaging. It can be used to distinguish tissues and identify pathologies. Lorentz force electrical impedance tomography is an ultrasound-based medical imaging technique of the tissue electrical conductivity. It is based on the application of an ultrasound wave in a medium placed in a magnetic field and on the measurement of the induced electric current due to Lorentz force. Similarly to ultrasound imaging, we hypothesized that a speckle could be observed with Lorentz force electrical impedance tomography imaging. In this study, we first assessed the theoretical similarity between the measured signals in Lorentz force electrical impedance tomography and in ultrasound imaging modalities. We then compared experimentally the signal measured in both methods using an acoustic and electrical impedance interface. Finally, a bovine muscle sample was imaged using the two methods. Similar speckle patterns were observed. This indicates the existence of an ‘acousto-electrical speckle’ in the Lorentz force electrical impedance tomography with spatial characteristics driven by the acoustic parameters but due to electrical impedance inhomogeneities instead of acoustic ones as is the case of ultrasound imaging.

  15. Emergence of nonwhite noise in Langevin dynamics with magnetic Lorentz force

    Science.gov (United States)

    Chun, Hyun-Myung; Durang, Xavier; Noh, Jae Dong

    2018-03-01

    We investigate the low mass limit of Langevin dynamics for a charged Brownian particle driven by a magnetic Lorentz force. In the low mass limit, velocity variables relaxing quickly are coarse-grained out to yield effective dynamics for position variables. Without the Lorentz force, the low mass limit is equivalent to the high friction limit. Both cases share the same Langevin equation that is obtained by setting the mass to zero. The equivalence breaks down in the presence of the Lorentz force. The low mass limit cannot be achieved by setting the mass to zero. The limit is also distinct from the large friction limit. We derive the effective equations of motion in the low mass limit. The resulting stochastic differential equation involves a nonwhite noise whose correlation matrix has antisymmetric components. We demonstrate the importance of the nonwhite noise by investigating the heat dissipation by a driven Brownian particle, where the emergent nonwhite noise has a physically measurable effect.

  16. Gamma-Ray, Cosmic Ray and Neutrino Tests of Lorentz Invariance and Quantum Gravity Models

    Science.gov (United States)

    Stecker, Floyd

    2011-01-01

    High-energy astrophysics observations provide the best possibilities to detect a very small violation of Lorentz invariance such as may be related to the structure of space-time near the Planck scale of approximately 10(exp -35) m. I will discuss here the possible signatures of Lorentz invariance violation (LIV) from observations of the spectra, polarization, and timing of gamma-rays from active galactic nuclei and gamma-ray bursts. Other sensitive tests are provided by observations of the spectra of ultrahigh energy cosmic rays and neutrinos. Using the latest data from the Pierre Auger Observatory one can already derive an upper limit of 4.5 x 10(exp -23) to the amount of LIV of at a proton Lorentz factor of approximately 2 x 10(exp 11). This result has fundamental implications for quantum gravity models. I will also discuss the possibilities of using more sensitive space based detection techniques to improve searches for LIV in the future.

  17. The CTA Sensitivity to Lorentz-Violating Effects on the Gamma-Ray Horizon

    CERN Document Server

    Fairbairn, Malcolm; Ellis, John; Hinton, Jim; White, Richard

    2014-01-01

    The arrival of TeV-energy photons from distant galaxies is expected to be affected by their QED interaction with intergalactic radiation fields through electron-positron pair production. In theories where high-energy photons violate Lorentz symmetry, the kinematics of the process $\\gamma + \\gamma\\rightarrow e^+ + e^-$ is altered and the cross-section suppressed. Consequently, one would expect more of the highest-energy photons to arrive if QED is modified by Lorentz violation than if it is not. We estimate the sensitivity of Cherenkov Telescope Array (CTA) to changes in the $\\gamma$-ray horizon of the Universe due to Lorentz violation, and find that it should be competitive with other leading constraints.

  18. Maxwell-Chern-Simons vortices in a CPT-odd Lorentz-violating Higgs electrodynamics

    International Nuclear Information System (INIS)

    Casana, R.; Ferreira, M.M.; Hora, E. da; Neves, A.B.F.

    2014-01-01

    We study BPS vortices in a CPT-odd and Lorentz-violating Maxwell-Chern-Simons-Higgs (MCSH) electrodynamics attained from the dimensional reduction of the Carroll-Field-Jackiw-Higgs model. The Lorentz-violating parameter induces a pronounced behavior at origin (for the magnetic/electric fields and energy density) which is absent in the MCSH vortices. For some combination of the Lorentz-violating coefficients there always exists a sufficiently large winding number n 0 such that for all vertical stroke n vertical stroke ≥ vertical stroke n 0 vertical stroke the magnetic field flips sign, yielding two well-defined regions with opposite magnetic flux. However, the total magnetic flux remains quantized and proportional to the winding number. (orig.)

  19. Tests of Lorentz violation in νμ→νe oscillations

    International Nuclear Information System (INIS)

    Auerbach, L.B.; Burman, R.L.; Donahue, J.B.; Garvey, G.T.; Louis, W.C.; Mills, G.B.; Sandberg, V.D.; White, D.H.; Caldwell, D.O.; Yellin, S.; Church, E.D.; McIlhany, K.L.; Strossman, W.H.; Cochran, A.K.; Fazely, A.R.; Gunasingha, R.; Imlay, R.L.; Metcalf, W.J.; Sung, M.; Katori, T.

    2005-01-01

    A recently developed standard-model extension (SME) formalism for neutrino oscillations that includes Lorentz and CPT violation is used to analyze the sidereal time variation of the neutrino event excess measured by the liquid scintillator neutrino detector (LSND) experiment. The LSND experiment, performed at Los Alamos National Laboratory, observed an excess, consistent with neutrino oscillations, of ν e in a beam of ν μ . It is determined that the LSND oscillation signal is consistent with no sidereal variation. However, there are several combinations of SME coefficients that describe the LSND data; both with and without sidereal variations. The scale of Lorentz and CPT violation extracted from the LSND data is of order 10 -19 GeV for the SME coefficients a L and Exc L . This solution for Lorentz and CPT violating neutrino oscillations may be tested by other short baseline neutrino oscillation experiments, such as the MiniBooNE experiment

  20. Importance of Lorentz structure in the parton model: Target mass corrections, transverse momentum dependence, positivity bounds

    International Nuclear Information System (INIS)

    D'Alesio, U.; Leader, E.; Murgia, F.

    2010-01-01

    We show that respecting the underlying Lorentz structure in the parton model has very strong consequences. Failure to insist on the correct Lorentz covariance is responsible for the existence of contradictory results in the literature for the polarized structure function g 2 (x), whereas with the correct imposition we are able to derive the Wandzura-Wilczek relation for g 2 (x) and the target-mass corrections for polarized deep inelastic scattering without recourse to the operator product expansion. We comment briefly on the problem of threshold behavior in the presence of target-mass corrections. Careful attention to the Lorentz structure has also profound implications for the structure of the transverse momentum dependent parton densities often used in parton model treatments of hadron production, allowing the k T dependence to be derived explicitly. It also leads to stronger positivity and Soffer-type bounds than usually utilized for the collinear densities.

  1. Estimación de parámetros en sistemas de ecuaciones diferenciales ordinarias en modelos farmacocinéticos de dos compartimentos

    Directory of Open Access Journals (Sweden)

    José Arturo Montoya Laos

    2013-12-01

    Full Text Available En este trabajo se presenta una metodología estadística para estimar parámetros de sistemas de ecuaciones diferenciales ordinarias que modelan la cinética de fármacos en el organismo humano, utilizando modelos de dos compartimentos, los cuales se usan ampliamente en farmacocinética. La necesidad de usar un enfoque estadístico para estimar estos parámetros se debe principalmente a que la cinética de un fármaco varía de un individuo a otro, afectando los valores de los parámetros en el modelo. Se ilustra la metodología y el enfoque estadístico con datos de un estudio realizado en doce individuos, sobre la cinética de la teofilina en sus organismos. El modelo estadístico utilizado supone que para un tiempo dado, las observaciones se modelan con una densidad de probabilidad normal centrada en la solución numérica del sistema y su dispersión cambia en el tiempo, de acuerdo con el valor esperado del proceso. Para estimar los valores de los parámetros se utiliza un enfoque Bayesiano y el sistema de ecuaciones diferenciales se resuelve con un método numérico adecuado.

  2. AJUSTE DE ECUACIONES DE BIOMASA PARA Pinus durangensis (Martínez M. EN LA REGIÓN DE EL SALTO, DURANGO

    Directory of Open Access Journals (Sweden)

    E. Montes de Oca-Cano

    2009-01-01

    Full Text Available El objetivo del presente estudio fue ajustar ecuaciones lineales y no lineales para estimar biomasa por componente de hojas, ramas, fuste y total, para árboles con edades entre tres y diez años, en la región de El Salto, Dgo. Los resultados indican que las ecuaciones se ajustan mejor a nivel individual, el componente total muestra los mejores estadísticos de ajuste, mientras que las mayores variaciones se detectan en las ramas y en el fuste. Adicionalmente se analizan porcentajes de biomasa por componente donde se observa que el fuste aporta 46.9 % de la biomasa, las hojas 35.6 % y las ramas solamente 17.3 % de la biomasa total. Así mismo, dentro del rango de edad analizado, la biomasa en el fuste aumenta anualmente 2.96 %; la biomasa en las hojas disminuye 3.13 % y la biomasa en las ramas aumenta 0.17 %.

  3. Algoritmo de optimización para el cálculo de múltiples raíces de sistemas de ecuaciones no lineales

    Directory of Open Access Journals (Sweden)

    Jorge Cruz Duarte

    2013-01-01

    Full Text Available En este artículo se presenta una estrategia novedosa para la búsqueda de múltiples soluciones en sistemas de ecuaciones no lineales, mediante la metaheurística de optimización por enjambre de partículas, y su versión unificada. Inicialmente, se expone una sección de fundamentos, donde se muestran las bases de las técnicas numéricas utilizadas y también la transformación del problema de solución en uno de optimización. Se comprueba esta nueva estrategia con diferentes tipos de sistemas, variando sistemáticamente el tamaño de los mismos para observar el comportamiento de las metaheurísticas usadas. Luego de analizar los datos obtenidos, se encuentra que la estrategia implementada tiene un gran potencial de aplicación en problemas de ingeniería. Para los sistemas analizados en este escrito, se recomienda utilizar la versión unificada o la original, dependiendo de si el sistema es pequeño o grande (menor o mayor a cinco ecuaciones e incógnitas, respectivamente.

  4. A CPT-even and Lorentz-Violating nonminimal coupling in the Dirac equation

    International Nuclear Information System (INIS)

    Ferreira Junior, Manoel; Casana, M.R.; Santos, Frederico E.P. dos; Silva, E.O.; Passos, E.

    2013-01-01

    Full text: The Standard Model Extension (SME) has been the usual framework for investigating signals of Lorentz violation in physical systems. It is the natural framework for studying properties of physical systems with Lorentz-violation since it includes Lorentz-violating terms in all sectors of the minimal standard model. The Lorentz-violating (LV) terms are generated as vacuum expectation values of tensors defined in a high energy scale. This framework has inspired a great deal of investigation in recent years. Such works encompass several distinct aspects involving fermion systems and radiative corrections, CPT- probing experiments, the electromagnetic CPT- and Lorentz-odd term, the 19 electromagnetic CPT-even coefficients. Recently, some studies involving higher dimensional operators have also been reported with great interest, including nonminimal interactions. These many contributions have elucidated the effects induced by Lorentz violation and served to set up stringent upper bounds on the LV coefficients. In the present work, we propose a new CPT-even, dimension-five, nonminimal coupling linking the fermionic and gauge fields in the context of the Dirac equation, involving the CPT-even tensor of the gauge term of the SME. By considering the nonrelativistic limit of the modified Dirac equation, we explicitly evaluate the new contributions to the nonrelativistic Hamiltonian. These new terms imply a direct correction on the anomalous magnetic moment, a kind of electrical Zeeman-like effect on the atomic spectrum, and a Rashba-like coupling term. These effects are then used to impose upper bounds on the magnitude of the non minimally coupled LV coefficients at the level of 1 part in 10 16 . (author)

  5. A CPT-even and Lorentz-Violating nonminimal coupling in the Dirac equation

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira Junior, Manoel; Casana, M.R.; Santos, Frederico E.P. dos; Silva, E.O. [UFMA, Sao Luis (Brazil); Passos, E. [UFCG, Campina Grande, PB (Brazil)

    2013-07-01

    Full text: The Standard Model Extension (SME) has been the usual framework for investigating signals of Lorentz violation in physical systems. It is the natural framework for studying properties of physical systems with Lorentz-violation since it includes Lorentz-violating terms in all sectors of the minimal standard model. The Lorentz-violating (LV) terms are generated as vacuum expectation values of tensors defined in a high energy scale. This framework has inspired a great deal of investigation in recent years. Such works encompass several distinct aspects involving fermion systems and radiative corrections, CPT- probing experiments, the electromagnetic CPT- and Lorentz-odd term, the 19 electromagnetic CPT-even coefficients. Recently, some studies involving higher dimensional operators have also been reported with great interest, including nonminimal interactions. These many contributions have elucidated the effects induced by Lorentz violation and served to set up stringent upper bounds on the LV coefficients. In the present work, we propose a new CPT-even, dimension-five, nonminimal coupling linking the fermionic and gauge fields in the context of the Dirac equation, involving the CPT-even tensor of the gauge term of the SME. By considering the nonrelativistic limit of the modified Dirac equation, we explicitly evaluate the new contributions to the nonrelativistic Hamiltonian. These new terms imply a direct correction on the anomalous magnetic moment, a kind of electrical Zeeman-like effect on the atomic spectrum, and a Rashba-like coupling term. These effects are then used to impose upper bounds on the magnitude of the non minimally coupled LV coefficients at the level of 1 part in 10{sub 16}. (author)

  6. Estimación del gasto energético en el paciente quemado mediante la utilización de ecuaciones predictivas: revisión bibliográfica

    OpenAIRE

    Teresa Núñez-Vinaveirán; Manuel Sánchez; Pablo Millán; José Ramón Martínez-Méndez; Carmen Iglesias; César Casado-Pérez; Abelardo García-de-Lorenzo

    2014-01-01

    Introducción: La valoración de las necesidades calóricas del paciente quemado se ha basado en la medición del gasto energético en reposo (GER) mediante calorimetría indirecta, no siempre disponible en las unidades de quemados, o en su estimación mediante el uso de ecuaciones predictivas. Objetivos: analizar la historia y estado del arte del uso de las ecuaciones predictivas de GER en el paciente quemado crítico, y determinar su validez. Métodos: revisión bibliográfica de estudios y revisiones...

  7. Space-like surfaces with free boundary in the Lorentz-Minkowski space

    International Nuclear Information System (INIS)

    López, R; Pyo, J

    2012-01-01

    We investigate a variational problem in the Lorentz-Minkowski space L 3 whose critical points are space-like surfaces with a constant mean curvature and making a constant contact angle with a given support surface along its common boundary. We show that if the support surface is a pseudosphere, then the surface is a planar disc or a hyperbolic cap. We also study the problem of space-like hypersurfaces with free boundary in the higher dimensional Lorentz-Minkowski space L n+1 . (paper)

  8. On the duality in CPT-even Lorentz-breaking theories

    Energy Technology Data Exchange (ETDEWEB)

    Scarpelli, A.P.B. [Departamento de Policia Federal, Sao Paulo (Brazil); Ribeiro, R.F.; Nascimento, J.R.; Petrov, A.Yu. [Universidade Federal da Paraiba, Departamento de Fisica (Brazil)

    2015-07-15

    We generalize the duality between self-dual and Maxwell-Chern-Simons theories for the case of a CPT-even Lorentz-breaking extension of these theories. The duality is shown using the gauge embedding procedure, both in free and coupled cases, and with the master action approach. The physical spectra of both Lorentz-breaking theories are studied. The massive poles are shown to coincide and to respect the requirements for unitarity and causality at tree level. The extra massless poles which are present in the dualized model are shown to be nondynamical. (orig.)

  9. Transport coefficients in Lorentz plasmas with the power-law kappa-distribution

    International Nuclear Information System (INIS)

    Jiulin, Du

    2013-01-01

    Transport coefficients in Lorentz plasma with the power-law κ-distribution are studied by means of using the transport equation and macroscopic laws of Lorentz plasma without magnetic field. Expressions of electric conductivity, thermoelectric coefficient, and thermal conductivity for the power-law κ-distribution are accurately derived. It is shown that these transport coefficients are significantly modified by the κ-parameter, and in the limit of the parameter κ→∞ they are reduced to the standard forms for a Maxwellian distribution

  10. Bounds on Cubic Lorentz-Violating Terms in the Fermionic Dispersion Relation

    OpenAIRE

    Bertolami, O.; Rosa, J. G.

    2004-01-01

    We study the recently proposed Lorentz-violating dispersion relation for fermions and show that it leads to two distinct cubic operators in the momentum. We compute the leading order terms that modify the non-relativistic equations of motion and use experimental results for the hyperfine transition in the ground state of the ${}^9\\textrm Be^+$ ion to bound the values of the Lorentz-violating parameters $\\eta_1$ and $\\eta_2$ for neutrons. The resulting bounds depend on the value of the Lorenz-...

  11. Lorentz angle measurements in irradiated silicon detectors between 77 K and 300 K

    International Nuclear Information System (INIS)

    Bartsch, V.; Boer, W. de; Bol, J.

    2001-01-01

    Future experiments are using silicon detectors in a high radiation environment and in high magnetic fields. The radiation tolerance of silicon improves by cooling it to temperatures below 180 K. However, at low temperatures the mobility increases, which leads to larger deflections of the charge carriers by the Lorentz force. We present measurements of the Lorentz angle between 77 K and 300 K before and after irradiation with a primary beam of 21 MeV protons to a flux of 10 13 /cm 2 . (author)

  12. Analytic Lorentz integral transform of an arbitrary response function and its application to the inversion problem

    International Nuclear Information System (INIS)

    Barnea, N.; Liverts, E.

    2010-01-01

    In this paper we present an analytic expression for the Lorentz integral transform of an arbitrary response function expressed as a polynomial times a decaying exponent. The resulting expression is applied to the inversion problem of the Lorentz integral transform, simplifying the inversion procedure and improving the accuracy of the procedure. We have presented analytic formulae for a family of basis function often used in the inversion of the LIT function. These formulae allow for an efficient and accurate inversion. The quality and the stability of the resulting inversions were demonstrated through two different examples yielding outstanding results. (author)

  13. Ultra-large distance modification of gravity from Lorentz symmetry breaking at the Planck scale

    International Nuclear Information System (INIS)

    Gorbunov, Dmitry S.; Sibiryakov, Sergei M.

    2005-01-01

    We present an extension of the Randall-Sundrum model in which, due to spontaneous Lorentz symmetry breaking, graviton mixes with bulk vector fields and becomes quasilocalized. The masses of KK modes comprising the four-dimensional graviton are naturally exponentially small. This allows to push the Lorentz breaking scale to as high as a few tenth of the Planck mass. The model does not contain ghosts or tachyons and does not exhibit the van Dam-Veltman-Zakharov discontinuity. The gravitational attraction between static point masses becomes gradually weaker with increasing of separation and gets replaced by repulsion (antigravity) at exponentially large distances

  14. Ultra-large distance modification of gravity from Lorentz symmetry breaking at the Planck scale

    Energy Technology Data Exchange (ETDEWEB)

    Gorbunov, Dmitry S. [Institute for Nuclear Research of the Russian Academy of Sciences, 60th October Anniversary prospect, 7a, 117312 Moscow (Russian Federation); Sibiryakov, Sergei M. [Institute for Nuclear Research of the Russian Academy of Sciences, 60th October Anniversary prospect, 7a, 117312 Moscow (Russian Federation)

    2005-09-15

    We present an extension of the Randall-Sundrum model in which, due to spontaneous Lorentz symmetry breaking, graviton mixes with bulk vector fields and becomes quasilocalized. The masses of KK modes comprising the four-dimensional graviton are naturally exponentially small. This allows to push the Lorentz breaking scale to as high as a few tenth of the Planck mass. The model does not contain ghosts or tachyons and does not exhibit the van Dam-Veltman-Zakharov discontinuity. The gravitational attraction between static point masses becomes gradually weaker with increasing of separation and gets replaced by repulsion (antigravity) at exponentially large distances.

  15. Generalized Lorentz-Dirac Equation for a Strongly Coupled Gauge Theory

    Science.gov (United States)

    Chernicoff, Mariano; García, J. Antonio; Güijosa, Alberto

    2009-06-01

    We derive a semiclassical equation of motion for a “composite” quark in strongly coupled large-Nc N=4 super Yang-Mills theory, making use of the anti-de Sitter space/conformal field theory correspondence. The resulting nonlinear equation incorporates radiation damping, and reduces to the standard Lorentz-Dirac equation for external forces that are small on the scale of the quark Compton wavelength, but has no self-accelerating or preaccelerating solutions. From this equation one can read off a nonstandard dispersion relation for the quark, as well as a Lorentz-covariant formula for its radiation rate.

  16. Generalized Lorentz-Dirac Equation for a Strongly Coupled Gauge Theory

    International Nuclear Information System (INIS)

    Chernicoff, Mariano; Garcia, J. Antonio; Gueijosa, Alberto

    2009-01-01

    We derive a semiclassical equation of motion for a 'composite' quark in strongly coupled large-N c N=4 super Yang-Mills theory, making use of the anti-de Sitter space/conformal field theory correspondence. The resulting nonlinear equation incorporates radiation damping, and reduces to the standard Lorentz-Dirac equation for external forces that are small on the scale of the quark Compton wavelength, but has no self-accelerating or preaccelerating solutions. From this equation one can read off a nonstandard dispersion relation for the quark, as well as a Lorentz-covariant formula for its radiation rate.

  17. On the duality in CPT-even Lorentz-breaking theories

    International Nuclear Information System (INIS)

    Scarpelli, A.P.B.; Ribeiro, R.F.; Nascimento, J.R.; Petrov, A.Yu.

    2015-01-01

    We generalize the duality between self-dual and Maxwell-Chern-Simons theories for the case of a CPT-even Lorentz-breaking extension of these theories. The duality is shown using the gauge embedding procedure, both in free and coupled cases, and with the master action approach. The physical spectra of both Lorentz-breaking theories are studied. The massive poles are shown to coincide and to respect the requirements for unitarity and causality at tree level. The extra massless poles which are present in the dualized model are shown to be nondynamical. (orig.)

  18. TUBERCULOSIS COMO ENFERMEDAD OCUPACIONAL

    Science.gov (United States)

    Mendoza-Ticona, Alberto

    2014-01-01

    Existe evidencia suficiente para declarar a la tuberculosis como enfermedad ocupacional en diversos profesionales especialmente entre los trabajadores de salud. En el Perú están normados y reglamentados los derechos laborales inherentes a la tuberculosis como enfermedad ocupacional, como la cobertura por discapacidad temporal o permanente. Sin embargo, estos derechos aún no han sido suficientemente socializados. En este trabajo se presenta información sobre el riesgo de adquirir tuberculosis en el lugar de trabajo, se revisan las evidencias para declarar a la tuberculosis como enfermedad ocupacional en trabajadores de salud y se presenta la legislación peruana vigente al respecto. PMID:22858771

  19. Late-time acceleration and phantom divide line crossing with non-minimal coupling and Lorentz-invariance violation

    International Nuclear Information System (INIS)

    Nozari, Kourosh; Sadatian, S.D.

    2008-01-01

    We consider two alternative dark-energy models: a Lorentz-invariance preserving model with a non-minimally coupled scalar field and a Lorentz-invariance violating model with a minimally coupled scalar field. We study accelerated expansion and the dynamics of the equation of state parameter in these scenarios. While a minimally coupled scalar field does not have the capability to be a successful dark-energy candidate with line crossing of the cosmological constant, a non-minimally coupled scalar field in the presence of Lorentz invariance or a minimally coupled scalar field with Lorentz-invariance violation have this capability. In the latter case, accelerated expansion and phantom divide line crossing are the results of the interactive nature of this Lorentz-violating scenario. (orig.)

  20. Erratum (astro-ph/0510172) Robust Limits on Lorentz Violation from Gamma-Ray Bursts

    CERN Document Server

    AUTHOR|(CDS)2108556; Nanopoulos, D V; Sakharov, Alexander S; Sarkisyan-Grinbaum, E

    2008-01-01

    We correct the fitting formula used in refs. [1,2] to obtain a robust limit on a violation of Lorentz invariance that depends linearly on the photon energy. The correction leads to a slight increase of the limit on the scale of the violation, to M > 1.4 x 10^{16} GeV.

  1. Three-dimensional computation of magnetic fields and Lorentz forces of an LHC dipole magnet

    International Nuclear Information System (INIS)

    Daum, C.; Avest, D. ter

    1989-07-01

    Magnetic fields and Lorentz forces of an LHC dipole magnet are calculated using the method of image currents to represent the effect of the iron shield. The calculation is performed for coils of finite length using a parametrization for coil heads of constant perimeter. A comparison with calculations based on POISSON and TOSCA is made. (author). 5 refs.; 31 figs.; 6 tabs

  2. Entropic information for travelling solitons in Lorentz and CPT breaking systems

    International Nuclear Information System (INIS)

    Correa, R.A.C.; Rocha, Roldão da; Souza Dutra, A. de

    2015-01-01

    In this work we group four research topics apparently disconnected, namely solitons, Lorentz symmetry breaking, supersymmetry, and entropy. Following a recent work (Gleiser and Stamatopoulos, 2012), we show that it is possible to construct in the context of travelling wave solutions a configurational entropy measure in functional space, from the field configurations. Thus, we investigate the existence and properties of travelling solitons in Lorentz and CPT breaking scenarios for a class of models with two interacting scalar fields. Here, we obtain a complete set of exact solutions for the model studied which display both double and single-kink configurations. In fact, such models are very important in applications that include Bloch branes, Skyrmions, Yang–Mills, Q-balls, oscillons and various superstring-motivated theories. We find that the so-called Configurational Entropy (CE) for travelling solitons shows that the best value of parameter responsible to break the Lorentz symmetry is one where the energy density is distributed equally around the origin. In this way, the information-theoretical measure of travelling solitons in Lorentz symmetry violation scenarios opens a new window to probe situations where the parameters responsible for breaking the symmetries are arbitrary. In this case, the CE selects the best value of the parameter in the model

  3. On physical complementarity of Galileo and Lorentz groups in the electrodynamics of isotropic inertial moving media

    International Nuclear Information System (INIS)

    Barykin, V.N.

    1989-01-01

    A physical interpretation of the early detected ambiguity of the electrodynamic material equations of isotropic, inertially moving media which mathematically manifests itself through complementarity of the equations invariant under the Galileo group in some cases and in other ones - under the Lorentz group that can be experimentally discovered in the aberration phenomenon and Doppler effect

  4. Water-Methanol Mixtures with non-Lorentz-Berthelot Combining Rules: A Feasibility Study

    Czech Academy of Sciences Publication Activity Database

    Moučka, F.; Nezbeda, Ivo

    2011-01-01

    Roč. 159, 1 Sp.I:Sl (2011), s. 47-51 ISSN 0167-7322 Institutional research plan: CEZ:AV0Z40720504 Keywords : water-alcohol mixtures * non-Lorentz-Berthelot rules * excess mixing properties Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.580, year: 2011

  5. Lienard-Wiechert potentials as a consequence of Lorentz transformation of Coulomb potential

    International Nuclear Information System (INIS)

    Strel'tsov, V.N.

    1993-01-01

    A derivation of the electric potential of a moving charge as a result of the 'relativization' of the Coulomb potential is considered. The account of the Lorentz covariance demand and the action retardation of the electromagnetic field with necessity leads to the Lienard-Wiechert potentials. 11 refs. (author)

  6. Inverse operator method for solutions of nonlinear dynamical system and application to Lorentz equation

    International Nuclear Information System (INIS)

    Fang Jinqing; Yao Weiguang

    1993-01-01

    The inverse operator method (IOM) for solutions of nonlinear dynamical systems (NDS) is briefly described and realized by the Mathematics-Mechanization (MM) in computers. For the first time IOM and MM are successfully applied to study the chaotic behaviors of Lorentz equation

  7. Optimality of embeddings of Bessel-potential-type spaces into Lorentz-Karamata spaces

    Czech Academy of Sciences Publication Activity Database

    Gogatishvili, Amiran; Opic, Bohumír; Neves, J. S.

    2004-01-01

    Roč. 134, č. 6 (2004), s. 1127-1147 ISSN 0308-2105 R&D Projects: GA ČR GA201/01/0333 Institutional research plan: CEZ:AV0Z1019905 Keywords : slowly varying functions * Lorentz-Karamata spaces * Bessel potentials Subject RIV: BA - General Mathematics Impact factor: 0.487, year: 2004

  8. Stochastic charging of dust grains in planetary rings: Diffusion rates and their effects on Lorentz resonances

    Science.gov (United States)

    Schaffer, L.; Burns, J. A.

    1995-01-01

    Dust grains in planetary rings acquire stochastically fluctuating electric charges as they orbit through any corotating magnetospheric plasma. Here we investigate the nature of this stochastic charging and calculate its effect on the Lorentz resonance (LR). First we model grain charging as a Markov process, where the transition probabilities are identified as the ensemble-averaged charging fluxes due to plasma pickup and photoemission. We determine the distribution function P(t;N), giving the probability that a grain has N excess charges at time t. The autocorrelation function tau(sub q) for the strochastic charge process can be approximated by a Fokker-Planck treatment of the evolution equations for P(t; N). We calculate the mean square response to the stochastic fluctuations in the Lorentz force. We find that transport in phase space is very small compared to the resonant increase in amplitudes due to the mean charge, over the timescale that the oscillator is resonantly pumped up. Therefore the stochastic charge variations cannot break the resonant interaction; locally, the Lorentz resonance is a robust mechanism for the shaping of etheral dust ring systems. Slightly stronger bounds on plasma parameters are required when we consider the longer transit times between Lorentz resonances.

  9. Compatibility of the Ampere and Lorentz force laws with the virtual-work concept

    International Nuclear Information System (INIS)

    Graneau, P.

    1983-01-01

    Whenever the reaction forces between parts of an electric circuit have to be calculated, as in the design of railguns, a choice has to be made between three available formulae which have evolved during the past 160 years. The first was Ampere's force law for the mechanical interaction between two current elements. Neumann then derived the virtual-work formula from what may be called the Ampere-Neumann electrodynamics. The last to be introduced was the Lorentz force law. This paper investigates whether both the Amperian and the Lorentzian forces are compatible with the virtual-work concept. The conclusion is that only Ampere's formula agrees in all cases with the virtual-work idea, but in special circumstances the Lorentz law will give the same result. After demonstrating how Ampere's law can be derived from the virtual-work formula, it is shown that for two closed circuits the relativistic component of the Lorentz force vanishes under the double integral around the two circuits. The remaining nonvanishing term is also present in the Ampere electrodynamics. This is not the case when considering the reaction forces between two parts of an isolated circuit. The Lorentz force is then, in general, not compatible with the virtual-work concept unless the circuit possesses a high degree of symmetry

  10. Scattering of the (p - 3H) system with the Lorentz integral transform method

    International Nuclear Information System (INIS)

    Marchisio, M.A.; Leidemann, W.; Orlandini, G.; Barnea, N.

    2003-01-01

    It was shown how the Lorentz integral transform method (LIT), which in recent years has revealed to be a powerful tool in few-body calculations, can be applied to calculate the T matrix in (p- 3 H) scattering also for energies above the three-body breakup threshold. Refs. 7 (nevyjel)

  11. On a conjecture of Alley and Alder for fluids and Lorentz models

    NARCIS (Netherlands)

    Ernst, M.H.; Beijeren, H. van

    1981-01-01

    We discuss a conjecture of Alley and Alder predicting a relation between the four-point and the two-point velocity autocorrelation functions for fluids and Lorentz models at sufficiently long times. If the conjecture is correct a modified Burnett coefficient can be defined, which has a finite value,

  12. Reply to 'Comment on 'Lorentz contraction and current-carrying wires''

    International Nuclear Information System (INIS)

    Van Kampen, Paul

    2010-01-01

    This reply answers the issues raised in the Comment on my paper (van Kampen 2008 Eur. J. Phys. 29 879-83). The error of applying a single Lorentz transformation to a wire segment is discussed in some detail. (letters and comments)

  13. Unusual high-energy phenomenology of Lorentz-invariant noncommutative field theories

    International Nuclear Information System (INIS)

    Carone, Christopher D.; Kwee, Herry J.

    2006-01-01

    It has been suggested that one may construct a Lorentz-invariant noncommutative field theory by extending the coordinate algebra to additional, fictitious coordinates that transform nontrivially under the Lorentz group. Integration over these coordinates in the action produces a four-dimensional effective theory with Lorentz invariance intact. Previous applications of this approach, in particular, to a specific construction of noncommutative QED, have been studied only in a low-momentum approximation. Here we discuss Lorentz-invariant field theories in which the relevant physics can be studied without requiring an expansion in the inverse scale of noncommutativity. Qualitatively, we find that tree-level scattering cross sections are dramatically suppressed as the center-of-mass energy exceeds the scale of noncommutativity, that cross sections that are isotropic in the commutative limit can develop a pronounced angular dependence, and that nonrelativistic potentials (for example, the Coloumb potential) become nonsingular at the origin. We consider a number of processes in noncommutative QED that may be studied at a future linear collider. We also give an example of scattering via a four-fermion operator in which the noncommutative modifications of the interaction can unitarize the tree-level amplitude, without requiring any other new physics in the ultraviolet

  14. Hadronic Lorentz violation in chiral perturbation theory including the coupling to external fields

    Science.gov (United States)

    Kamand, Rasha; Altschul, Brett; Schindler, Matthias R.

    2018-05-01

    If any violation of Lorentz symmetry exists in the hadron sector, its ultimate origins must lie at the quark level. We continue the analysis of how the theories at these two levels are connected, using chiral perturbation theory. Considering a 2-flavor quark theory, with dimension-4 operators that break Lorentz symmetry, we derive a low-energy theory of pions and nucleons that is invariant under local chiral transformations and includes the coupling to external fields. The pure meson and baryon sectors, as well as the couplings between them and the couplings to external electromagnetic and weak gauge fields, contain forms of Lorentz violation which depend on linear combinations of quark-level coefficients. In particular, at leading order the electromagnetic couplings depend on the very same combinations as appear in the free particle propagators. This means that observations of electromagnetic processes involving hadrons—such as vacuum Cerenkov radiation, which may be allowed in Lorentz-violating theories—can only reliably constrain certain particular combinations of quark coefficients.

  15. Chaotic properties of dilute two- and three dimensional random Lorentz gases: Equilibrium systems

    NARCIS (Netherlands)

    van Beijeren, H.; Latz, A.; Dorfman, J.R.

    We compute the Lyapunov spectrum and the Kolmogorov-Sinai entropy for a moving particle placed in a dilute, random array of hard-disk or hard-sphere scatterers, i.e., the dilute Lorentz gas model. This is carried out in two ways. First we use simple kinetic theory arguments to compute the Lyapunov

  16. Lorentz-violating vortex solutions in the CPT-even electrodynamics of the Standard Model Extension

    International Nuclear Information System (INIS)

    Casana, Rodolfo; Ferreira Junior, Manoel M.; Hora, E. da

    2011-01-01

    Full text: In this work, we investigate the formation of static rotationally symmetric solutions on the (1+3) dimensional CPT-even and Lorentz-violating photonic sector of the Standard Model Extension (SME). The main goal of this work is to show the possibility of obtaining these solutions, even in the presence of Lorentz-breaking fields. A secondary goal is to examine the effects of these fields on topologically non-trivial configurations. In order to obtain these results, we focus on specific components of Lorentz-violating background, dealing with static Euler-Lagrange equations, from which we fix temporal gauge (absence of electric field) as a proper gauge choice. We assume the usual rotationally symmetric Ansatz, inserting it in the Euler-Lagrange equations previously obtained. This Ansatz describes the Higgs and gauge fields via profile functions g(r) and a(r), respectively. From this Ansatz, we construct suitable boundary conditions near the origin. Also, we write the energy density in terms of these two profile functions, obtaining from it asymptotic boundary conditions. This set of conditions is used to numerically solve the Euler-Lagrange equations (by means of the shooting method). Finally, we plot solutions for some physical quantities (Higgs field, magnetic field and energy density) for several values of the Lorentz-violating parameters. From these plots, we discuss the influence of these coefficients on the topologically non-trivial rotationally symmetric configurations, focusing on the profiles of both magnetic field and energy density. (author)

  17. Lorentz Contraction, Bell's Spaceships and Rigid Body Motion in Special Relativity

    Science.gov (United States)

    Franklin, Jerrold

    2010-01-01

    The meaning of Lorentz contraction in special relativity and its connection with Bell's spaceships parable is discussed. The motion of Bell's spaceships is then compared with the accelerated motion of a rigid body. We have tried to write this in a simple form that could be used to correct students' misconceptions due to conflicting earlier…

  18. Lorentz contraction, Bell's spaceships and rigid body motion in special relativity

    International Nuclear Information System (INIS)

    Franklin, Jerrold

    2010-01-01

    The meaning of Lorentz contraction in special relativity and its connection with Bell's spaceships parable is discussed. The motion of Bell's spaceships is then compared with the accelerated motion of a rigid body. We have tried to write this in a simple form that could be used to correct students' misconceptions due to conflicting earlier treatments.

  19. Solitary waves, steepening and initial collapse in the Maxwell-Lorentz system

    DEFF Research Database (Denmark)

    Sørensen, Mads Peter; Brio, Moysey; Webb, Garry

    2002-01-01

    We present a numerical study of Maxwell's equations in nonlinear dispersive optical media describing propagation of pulses in one Cartesian space dimension. Dispersion and nonlinearity are accounted for by a linear Lorentz model and an instantaneous Kerr nonlinearity, respectively. The dispersion......–Rosales weakly dispersive system. The weak dispersion in general cannot prevent the wave breaking with instantaneous or delayed nonlinearities....

  20. Experiencia basada en la triada TICs, enseñanza por proyectos y modelado para la enseñanza de sistemas de ecuaciones diferenciales

    Directory of Open Access Journals (Sweden)

    Jose-Arturo Molina-Mora

    2015-07-01

    Full Text Available Uno de los retos en la educación es la mejora continua a fin de buscar nuevas estrategias en la gestión del proceso enseñanza-aprendizaje y la calidad del mismo. La incorporación de las TICs (Tecnologías de la Información y la Comunicación, la enseñanza por proyectos y el modelado matemático se proponen en una estrategia para la enseñanza de los sistemas de ecuaciones diferenciales a nivel universitario. La implementación realizada mostró resultados favorables de los estudiantes, los cuales tuvieron que describir esquemáticamente el problema, plantear el modelo matemático, realizar y analizar simulaciones y predicciones, en todos los casos con problemas relacionados con el área académica del estudiante.

  1. Ecuaciones de predicción de la talla a partir de la altura de la rodilla de los adultos mayores de Costa Rica

    Directory of Open Access Journals (Sweden)

    Pamela Jiménez-Fontana

    2014-07-01

    Full Text Available La talla es un parámetro antropométrico que permite evaluar el estado de salud de los adultos mayores, ya que nos permite determinar el índice de masa corporal y, con este, los niveles de obesidad, el grado de desnutrición proteico calórica, y otros factores de riesgo. Sin embargo, en adultos mayores con dificultad de movimiento, enfermedades avanzadas, o cambios en la curvatura normal de la columna vertebral, es complicado realizar una correcta medición de la talla. Cuando no se puede realizar una correcta medición de la talla, se pueden utilizar modelos de regresión lineal utilizando otras variables antropométricas para estimar la talla. Por ende, el objetivo de este estudio es definir ecuaciones de predicción de la talla a partir de la altura de la rodilla y la edad para los adultos mayores de Costa Rica por sexo. El estudio utilizó los datos de la encuesta longitudinal CRELES, muestra representativa de los adultos mayores de Costa Rica. Los coeficientes de predicción estimados a partir de CRELES se compararon con los coeficientes de predicción estimados por los modelos (externos de Chumlea, Roche, y Steinbaugh (1985 y Palloni y Guend (2005. Los coeficientes de predicción estimados con base a CRELES son, en su mayoría, significativamente diferentes a los coeficientes de los modelos externos; además, los coeficientes de predicción estimados con la muestra CRELES producen residuos y errores puros menores que los modelos externos. Se recomienda utilizar las nuevas ecuaciones de predicción planteadas en este estudio para estimar la talla de adultos mayores costarricenses con problemas fisiológicos y de movilidad.

  2. Relativistic Anandan quantum phase and the Aharonov–Casher effect under Lorentz symmetry breaking effects in the cosmic string spacetime

    Energy Technology Data Exchange (ETDEWEB)

    Bakke, K., E-mail: kbakke@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, 58051-900, João Pessoa-PB (Brazil); Furtado, C., E-mail: furtado@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, 58051-900, João Pessoa-PB (Brazil); Belich, H., E-mail: belichjr@gmail.com [Departamento de Física e Química, Universidade Federal do Espírito Santo, Av. Fernando Ferrari, 514, Goiabeiras, 29060-900, Vitória, ES (Brazil)

    2016-09-15

    From the modified Maxwell theory coupled to gravity, we establish a possible scenario of the violation of the Lorentz symmetry and write an effective metric for the cosmic string spacetime. Then, we investigate the arising of an analogue of the Anandan quantum phase for a relativistic Dirac neutral particle with a permanent magnetic dipole moment in the cosmic string spacetime under Lorentz symmetry breaking effects. Besides, we analyse the influence of the effects of the Lorentz symmetry violation and the topology of the defect on the Aharonov–Casher geometric quantum phase in the nonrelativistic limit.

  3. Equações de referência para o teste de caminhada de seis minutos em indivíduos saudáveis Ecuaciones de referencia para el test de caminata de seis minutos en individuos sanos Reference equations for the 6-minute walk test in healthy individuals

    Directory of Open Access Journals (Sweden)

    Victor Zuniga Dourado

    2011-06-01

    Full Text Available O teste de caminhada de 6 minutos (TC6 tem sido amplamente utilizado no ambiente clínico. Algumas equações de referência para a previsão da distância percorrida no teste (DTC6 estão disponíveis na literatura. Esta revisão teve como objetivo discutir criticamente os achados da literatura, publicados em português e em inglês (LILACS, SCIELO, MEDLINE e PUBMED, que avaliaram os valores normais e elaboraram equações de referência para a previsão da DTC6 em indivíduos saudáveis, comparando-os aos resultados recentemente obtidos em indivíduos brasileiros. Idade, gênero, peso, estatura e índice de massa corporal foram os atributos demográficos e antropométricos mais frequentemente correlacionados com a DTC6. As equações resultantes desses atributos foram capazes de explicar entre 25 e 66% da variabilidade total da DTC6. Lamentavelmente, as equações estrangeiras não são adequadas para a população brasileira. Mesmo quando o teste é realizado sob padronização rigorosa, a diferença de performance no TC6 entre estrangeiros e brasileiros permanece, indicando a necessidade dos valores de referências específicos para cada população e/ou etnia. Nesse sentido, as equações desenvolvidas recentemente no Brasil são, provavelmente, as mais apropriadas para interpretar a performance de caminhada dos nossos compatriotas com doenças crônicas que afetam a capacidade para realizar exercícios. Estudos futuros com amostras substancialmente maiores (e.g. multicêntricos e com técnica de amostragem randomizada são necessários para que os valores de referência da DTC6 sejam mais representativos.El test de caminata de 6 minutos (TC6 ha sido ampliamente utilizado en el ambiente clínico. Algunas ecuaciones de referencia para la previsión de la distancia recorrida en el test (DTC6 están disponibles en la literatura. Esta revisión tuvo como objetivo discutir críticamente los hallazgos de la literatura, publicados en portugués y

  4. Strong equivalence, Lorentz and CPT violation, anti-hydrogen spectroscopy and gamma-ray burst polarimetry

    International Nuclear Information System (INIS)

    Shore, Graham M.

    2005-01-01

    The strong equivalence principle, local Lorentz invariance and CPT symmetry are fundamental ingredients of the quantum field theories used to describe elementary particle physics. Nevertheless, each may be violated by simple modifications to the dynamics while apparently preserving the essential fundamental structure of quantum field theory itself. In this paper, we analyse the construction of strong equivalence, Lorentz and CPT violating Lagrangians for QED and review and propose some experimental tests in the fields of astrophysical polarimetry and precision atomic spectroscopy. In particular, modifications of the Maxwell action predict a birefringent rotation of the direction of linearly polarised radiation from synchrotron emission which may be studied using radio galaxies or, potentially, gamma-ray bursts. In the Dirac sector, changes in atomic energy levels are predicted which may be probed in precision spectroscopy of hydrogen and anti-hydrogen atoms, notably in the Doppler-free, two-photon 1s-2s and 2s-nd (n∼10) transitions

  5. New test of Lorentz symmetry using ultrahigh-energy cosmic rays

    Science.gov (United States)

    Anchordoqui, Luis A.; Soriano, Jorge F.

    2018-02-01

    We propose an innovative test of Lorentz symmetry by observing pairs of simultaneous parallel extensive air showers produced by the fragments of ultrahigh-energy cosmic ray nuclei which disintegrated in collisions with solar photons. We show that the search for a cross-correlation of showers in arrival time and direction becomes background free for an angular scale ≲3 ° and a time window O (10 s ) . We also show that if the solar photo-disintegration probability of helium is O (10-5.5) then the hunt for spatiotemporal coincident showers could be within range of existing cosmic ray facilities, such as the Pierre Auger Observatory. We demonstrate that the actual observation of a few events can be used to constrain Lorentz violating dispersion relations of the nucleon.

  6. Dimensional reduction of a Lorentz and CPT-violating Maxwell-Chern-Simons model

    Energy Technology Data Exchange (ETDEWEB)

    Belich, H. Jr.; Helayel Neto, J.A. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Coordenacao de Teoria de Campos e Particulas; Grupo de Fisica Teorica Jose Leite Lopes, Petropolis, RJ (Brazil); E-mails: belich@cbpf.br; helayel@cbpf.br; Ferreira, M.M. Jr. [Grupo de Fisica Teorica Jose Leite Lopes, Petropolis, RJ (Brazil); Maranhao Univ., Sao Luiz, MA (Brazil). Dept. de Fisica]. E-mail: manojr@cbpf.br; Orlando, M.T.D. [Grupo de Fisica Teorica Jose Leite Lopes, Petropolis, RJ (Brazil); Espirito Santo Univ., Vitoria, ES (Brazil). Dept. de Fisica e Quimica; E-mail: orlando@cce.ufes.br

    2003-01-01

    Taking as starting point a Lorentz and CPT non-invariant Chern-Simons-like model defined in 1+3 dimensions, we proceed realizing its dimensional to D = 1+2. One then obtains a new planar model, composed by the Maxwell-Chern-Simons (MCS) sector, a Klein-Gordon massless scalar field, and a coupling term that mixes the gauge field to the external vector, {nu}{sup {mu}}. In spite of breaking Lorentz invariance in the particle frame, this model may preserve the CPT symmetry for a single particular choice of {nu}{sup {mu}} . Analyzing the dispersion relations, one verifies that the reduced model exhibits stability, but the causality can be jeopardized by some modes. The unitary of the gauge sector is assured without any restriction , while the scalar sector is unitary only in the space-like case. (author)

  7. Macroscopic QED in linearly responding media and a Lorentz-Force approach to dispersion forces

    Energy Technology Data Exchange (ETDEWEB)

    Raabe, Christian

    2008-07-08

    In this thesis, a very general quantization scheme for the macroscopic electromagnetic field in arbitrary linearly responding media is presented. It offers a unified approach to QED in such media. Applying the quantization scheme, a theory of the dispersion forces on the basis of the Lorentz force is developed. By regarding the dispersion force as the (ground-state or thermal-state) expectation value of the Lorentz force that acts on appropriately defined charge and current densities, Casimir, Casimir-Polder, and van der Waals forces are united in a very natural way that makes transparent their common physical basis. Application of the theory to planar structures yields generalizations of well-known Lifschitz and Casimir-type formulas. (orig.)

  8. Simultaneous alignment and Lorentz angle calibration in the CMS silicon tracker using Millepede II

    CERN Document Server

    Bartosik, Nazar

    2013-01-01

    The CMS silicon tracker consists of 25 684 sensors that provide measurements of trajectories of charged particles that are used by almost every physics analysis at CMS. In order to achieve high measurement precision, the positions and orientations of all sensors have to be determined very accurately. This is achieved by track-based alignment using the global fit approach of the Millepede II program. This approach is capable of determining about 200 000 parameters simultaneously.The alignment precision reached such a high level that even small calibration inaccuracies are noticeable. Therefore the alignment framework has been extended to treat position sensitive calibration parameters. Of special interest is the Lorentz angle which affects the hit positions due to the drift of the signal electrons in the magnetic field. We present the results from measurements of the Lorentz angle and its time dependence during full 2012 data taking period as well as general description of the alignment and calibration procedu...

  9. Lorentz angle measurements as part of the sensor R\\&D for the CMS Tracker upgrade

    CERN Document Server

    Nurnberg, Andreas Matthias

    2012-01-01

    $200 m^2$ silicon strip tracker was designed to withstand the radiation of 10 years of LHC operation. The foreseen high luminosity upgrade of the LHC imposes even higher demands on the radiation tolerance and thus requires the construction of a new tracking detector. To determine the properties of different silicon materials and production processes, a campaign has been started by the CMS Tracker Collaboration to identify the most promising candidate material for the new CMS tracker. The silicon sensors of the CMS tracker are operated in a 3.8 T magnetic field. Charges created by traversing ionizing particles inside the active sensor volume are deflected by the Lorentz force. The Lorentz angle, under which the charge drifts through the sensor, is strongly dependent on the mobility, which in turn depends on the electric field and may depend on the radiation damage created by the particles produced by the LHC. Studying this is ...

  10. Why Cerenkov Radiation May Not Occur, Even When It Is Allowed by Lorentz-Violating Kinematics

    Directory of Open Access Journals (Sweden)

    Brett Altschul

    2017-10-01

    Full Text Available In a Lorentz-violating quantum field theory, the energy-momentum relations for the field quanta are typically modified. This affects the kinematics, and processes that are normally forbidden may become allowed. One reaction that clearly becomes kinematically possible when photons’ phase speeds are less than 1 is vacuum Cerenkov radiation. However, in spite of expectations, and in defiance of phase space estimates, a electromagnetic Chern–Simons theory with a timelike Lorentz violation coefficient does not feature any energy losses through Cerenkov emission. There is an unexpected cancelation, made possible by the existence of unstable long-wavelength modes of the field. The fact that the theory possesses a more limited form of gauge symmetry than conventional electrodynamics also plays a role.

  11. Tests of local Lorentz invariance violation of gravity in the standard model extension with pulsars.

    Science.gov (United States)

    Shao, Lijing

    2014-03-21

    The standard model extension is an effective field theory introducing all possible Lorentz-violating (LV) operators to the standard model and general relativity (GR). In the pure-gravity sector of minimal standard model extension, nine coefficients describe dominant observable deviations from GR. We systematically implemented 27 tests from 13 pulsar systems to tightly constrain eight linear combinations of these coefficients with extensive Monte Carlo simulations. It constitutes the first detailed and systematic test of the pure-gravity sector of minimal standard model extension with the state-of-the-art pulsar observations. No deviation from GR was detected. The limits of LV coefficients are expressed in the canonical Sun-centered celestial-equatorial frame for the convenience of further studies. They are all improved by significant factors of tens to hundreds with existing ones. As a consequence, Einstein's equivalence principle is verified substantially further by pulsar experiments in terms of local Lorentz invariance in gravity.

  12. Maxwell–Lorentz Electrodynamics Revisited via the Lagrangian Formalism and Feynman Proper Time Paradigm

    Directory of Open Access Journals (Sweden)

    Nikolai N. Bogolubov

    2015-04-01

    Full Text Available We review new electrodynamics models of interacting charged point particles and related fundamental physical aspects, motivated by the classical A.M. Ampère magnetic and H. Lorentz force laws electromagnetic field expressions. Based on the Feynman proper time paradigm and a recently devised vacuum field theory approach to the Lagrangian and Hamiltonian, the formulations of alternative classical electrodynamics models are analyzed in detail and their Dirac type quantization is suggested. Problems closely related to the radiation reaction force and electron mass inertia are analyzed. The validity of the Abraham-Lorentz electromagnetic electron mass origin hypothesis is argued. The related electromagnetic Dirac–Fock–Podolsky problem and symplectic properties of the Maxwell and Yang–Mills type dynamical systems are analyzed. The crucial importance of the remaining reference systems, with respect to which the dynamics of charged point particles is framed, is explained and emphasized.

  13. Covariant Renormalizable Modified and Massive Gravity Theories on (Non) Commutative Tangent Lorentz Bundles

    CERN Document Server

    Vacaru, Sergiu I

    2014-01-01

    The fundamental field equations in modified gravity (including general relativity; massive and bimetric theories; Ho\\vrava-Lifshits, HL; Einstein--Finsler gravity extensions etc) posses an important decoupling property with respect to nonholonomic frames with 2 (or 3) +2+2+... spacetime decompositions. This allows us to construct exact solutions with generic off--diagonal metrics depending on all spacetime coordinates via generating and integration functions containing (un-) broken symmetry parameters. Such nonholonomic configurations/ models have a nice ultraviolet behavior and seem to be ghost free and (super) renormalizable in a sense of covariant and/or massive modifications of HL gravity. The apparent noncommutativity and breaking of Lorentz invariance by quantum effects can be encoded into fibers of noncommutative tangent Lorentz bundles for corresponding "partner" anisotropically induced theories. We show how the constructions can be extended to include conjectured covariant reonormalizable models with...

  14. The Apparent Lack of Lorentz Invariance in Zero-Point Fields with Truncated Spectra

    Directory of Open Access Journals (Sweden)

    Daywitt W. C.

    2009-01-01

    Full Text Available The integrals that describe the expectation values of the zero-point quantum-field-theoretic vacuum state are semi-infinite, as are the integrals for the stochastic electrodynamic vacuum. The unbounded upper limit to these integrals leads in turn to infinite energy densities and renormalization masses. A number of models have been put forward to truncate the integrals so that these densities and masses are finite. Unfortunately the truncation apparently destroys the Lorentz invariance of the integrals. This note argues that the integrals are naturally truncated by the graininess of the negative-energy Planck vacuum state from which the zero-point vacuum arises, and are thus automatically Lorentz invariant.

  15. A Study of Gaugeon Formalism for QED in Lorentz Violating Background

    Science.gov (United States)

    Shah, Mushtaq B.; Ganai, Prince A.

    2018-02-01

    At the energy regimes close to Planck scales, the usual structure of Lorentz symmetry fails to address certain fundamental issues and eventually breaks down, thus paving the way for an alternative road map. It is thus argued that some subgroup of proper Lorentz group could stand consistent and might possibly help us to circumvent this problem. It is this subgroup that goes by the name of Very Special Relativity (VSR). Apart from violating rotational symmetry, VSR is believed to preserve the very tenets of special relativity. The gaugeon formalism due to type-I Yokoyama and type-II Izawa are found to be invariant under BRST symmetry. In this paper, we analyze the scope of this invariance in the scheme of VSR. Furthermore, we will obtain VSR modified Lagrangian density using path integral derivation. We will explore the consistency of VSR with regard to these theories.

  16. Limit Laws and Recurrence for the Planar Lorentz Process with Infinite Horizon

    CERN Document Server

    Szász, D

    2006-01-01

    As Bleher observed the free flight vector of the planar, infinite horizon, periodic Lorentz process $\\{S_n | n=0, 1, 2, \\dots \\}$ belongs to the non-standard domain of attraction of the Gaussian law --- actually with the $\\sqrt{n \\log n}$ scaling. Our first aim is to establish his conjecture that, indeed, $\\frac{S_n}{\\sqrt{n \\log n}}$ converges in distribution to the Gaussian law (a Global Limit Theorem). Here the recent method of B\\'alint and Gou\\"ezel, \\cite{BG} helped us to essentially simplify the ideas of our earlier sketchy proof. Moreover, we can also derive a.) the local version of the Global Limit Theorem, b.) the recurrence of the planar, infinite horizon, periodic Lorentz process, and finally c.) the ergodicity of its infinite invariant measure.

  17. Foundations of symmetric spaces of measurable functions Lorentz, Marcinkiewicz and Orlicz spaces

    CERN Document Server

    Rubshtein, Ben-Zion A; Muratov, Mustafa A; Pashkova, Yulia S

    2016-01-01

    Key definitions and results in symmetric spaces, particularly Lp, Lorentz, Marcinkiewicz and Orlicz spaces are emphasized in this textbook. A comprehensive overview of the Lorentz, Marcinkiewicz and Orlicz spaces is presented based on concepts and results of symmetric spaces. Scientists and researchers will find the application of linear operators, ergodic theory, harmonic analysis and mathematical physics noteworthy and useful. This book is intended for graduate students and researchers in mathematics and may be used as a general reference for the theory of functions, measure theory, and functional analysis. This self-contained text is presented in four parts totaling seventeen chapters to correspond with a one-semester lecture course. Each of the four parts begins with an overview and is subsequently divided into chapters, each of which concludes with exercises and notes. A chapter called “Complements” is included at the end of the text as supplementary material to assist students with independent work.

  18. Dimensional reduction of a Lorentz and CPT-violating Maxwell-Chern-Simons model

    International Nuclear Information System (INIS)

    Belich, H. Jr.; Helayel Neto, J.A.; Ferreira, M.M. Jr.; Maranhao Univ., Sao Luiz, MA; Orlando, M.T.D.; Espirito Santo Univ., Vitoria, ES

    2003-01-01

    Taking as starting point a Lorentz and CPT non-invariant Chern-Simons-like model defined in 1+3 dimensions, we proceed realizing its dimensional to D = 1+2. One then obtains a new planar model, composed by the Maxwell-Chern-Simons (MCS) sector, a Klein-Gordon massless scalar field, and a coupling term that mixes the gauge field to the external vector, ν μ . In spite of breaking Lorentz invariance in the particle frame, this model may preserve the CPT symmetry for a single particular choice of ν μ . Analyzing the dispersion relations, one verifies that the reduced model exhibits stability, but the causality can be jeopardized by some modes. The unitary of the gauge sector is assured without any restriction , while the scalar sector is unitary only in the space-like case. (author)

  19. Rotating optical cavity experiment testing Lorentz invariance at the 10-17 level

    International Nuclear Information System (INIS)

    Herrmann, S.; Senger, A.; Moehle, K.; Nagel, M.; Kovalchuk, E. V.; Peters, A.

    2009-01-01

    We present an improved laboratory test of Lorentz invariance in electrodynamics by testing the isotropy of the speed of light. Our measurement compares the resonance frequencies of two orthogonal optical resonators that are implemented in a single block of fused silica and are rotated continuously on a precision air bearing turntable. An analysis of data recorded over the course of one year sets a limit on an anisotropy of the speed of light of Δc/c∼1x10 -17 . This constitutes the most accurate laboratory test of the isotropy of c to date and allows to constrain parameters of a Lorentz violating extension of the standard model of particle physics down to a level of 10 -17 .

  20. A Novel Approach for Automatic Control of Piezoelectric Elements Used for Lorentz Force Detuning Compensation

    CERN Document Server

    Przygoda, K; Napieralski, A; Grecki, M

    2010-01-01

    Abstract: Linear accelerators such as Free Electron Lasers (FELs) use superconducting (SC) resonant cavities to accelerate electron beam to high energies. TESLA type resonators are extremely sensitive to detuning induced by mechanical deformations – Lorentz force detuning (LFD), mainly due to the extremely high quality factor (Q) of the 1.3 GHz resonance mode, in the range of 1e6. The resulting modulation of a resonance frequency of the cavity makes power consumption and stability performances of the Low-Latency Radio Frequency (LLRF) control more critical. In order to minimize the RF control efforts and desired stabilities, the fast piezoelectric actuators with digital control systems are commonly used. The paper presents a novel approach for automatic control of piezoelectric actuators used for compensation of Lorentz force detuning, the practical application and carried out tests in accelerating module ACC6 in Free-Electron Laser in Hamburg (FLASH).

  1. Lorentz-force equations as Heisenberg equations for a quantum system in the euclidean space

    International Nuclear Information System (INIS)

    Rodriguez D, R.

    2007-01-01

    In an earlier work, the dynamic equations for a relativistic charged particle under the action of electromagnetic fields were formulated by R. Yamaleev in terms of external, as well as internal momenta. Evolution equations for external momenta, the Lorentz-force equations, were derived from the evolution equations for internal momenta. The mapping between the observables of external and internal momenta are related by Viete formulae for a quadratic polynomial, the characteristic polynomial of the relativistic dynamics. In this paper we show that the system of dynamic equations, can be cast into the Heisenberg scheme for a four-dimensional quantum system. Within this scheme the equations in terms of internal momenta play the role of evolution equations for a state vector, whereas the external momenta obey the Heisenberg equation for an operator evolution. The solutions of the Lorentz-force equation for the motion inside constant electromagnetic fields are presented via pentagonometric functions. (Author)

  2. The original Ampere force and Biot-Savart and Lorentz forces

    International Nuclear Information System (INIS)

    Pappas, P.T.

    1983-01-01

    The purpose of this paper is to present the results of a very simple experiment, which favours the original Ampere force and unambiguously disproves the Biot-Savart force of relativity, or its approximation in a covariant relativistic form, namely the Lorentz force. This experiment with its extra degree of freedom has the advantage over the many other similar ones, including Ampere's original experiment, which have been performed in the past and recently by Graneau, of giving results which are both qualitative and quantitative, as well as unambiguous. Due to the strong association of the Biot-Savart and Lorentz force to relativistic theories, the experiment can be also considered as limiting the generality of these theories

  3. Essay on gravitation: The cosmological constant problem in brane-worlds and gravitational Lorentz violations

    International Nuclear Information System (INIS)

    Csaki, Csaba; Erlich, Joshua; Grojean, Christophe

    2001-01-01

    Brane worlds are theories with extra spatial dimensions in which ordinary matter is localized on a (3+1) dimensional submanifold. Such theories could have interesting consequences for particle physics and gravitational physics. In this essay we concentrate on the cosmological constant (CC) problem in the context of brane worlds. We show how extra-dimensional scenarios may violate Lorentz invariance in the gravity sector of the effective 4D theory, while particle physics remains unaffected. In such theories the usual no-go theorems for adjustment of the CC do not apply, and we indicate a possible explanation of the smallness of the CC. Lorentz violating effects would manifest themselves in gravitational waves travelling with a speed different from light, which can be searched for in gravitational wave experiments

  4. Macroscopic QED in linearly responding media and a Lorentz-Force approach to dispersion forces

    International Nuclear Information System (INIS)

    Raabe, Christian

    2008-01-01

    In this thesis, a very general quantization scheme for the macroscopic electromagnetic field in arbitrary linearly responding media is presented. It offers a unified approach to QED in such media. Applying the quantization scheme, a theory of the dispersion forces on the basis of the Lorentz force is developed. By regarding the dispersion force as the (ground-state or thermal-state) expectation value of the Lorentz force that acts on appropriately defined charge and current densities, Casimir, Casimir-Polder, and van der Waals forces are united in a very natural way that makes transparent their common physical basis. Application of the theory to planar structures yields generalizations of well-known Lifschitz and Casimir-type formulas. (orig.)

  5. Numerical and experimental study of the effect of the induced electric potential in Lorentz force velocimetry

    Science.gov (United States)

    Hernández, Daniel; Boeck, Thomas; Karcher, Christian; Wondrak, Thomas

    2018-01-01

    Lorentz force velocimetry (LFV) is a contactless velocity measurement technique for electrically conducting fluids. When a liquid metal or a molten glass flows through an externally applied magnetic field, eddy currents and a flow-braking force are generated inside the liquid. This force is proportional to the velocity or flow rate of the fluid and, due to Newton’s third law, a force of the same magnitude but in opposite direction acts on the source of the applied magnetic field which in our case are permanent magnets. According to Ohm’s law for moving conductors at low magnetic Reynolds numbers, an electric potential is induced which ensures charge conservation. In this paper, we analyze the contribution of the induced electric potential to the total Lorentz force by considering two different scenarios: conducting walls of finite thickness and aspect ratio variation of the cross-section of the flow. In both the cases, the force component generated by the electric potential is always in the opposite direction to the total Lorentz force. This force component is sensitive to the electric boundary conditions of the flow of which insulating and perfectly conducting walls are the two limiting cases. In the latter case, the overall electric resistance of the system is minimized, resulting in a considerable increase in the measured Lorentz force. Additionally, this force originating from the electric potential also decays when the aspect ratio of the cross-section of the flow is changed. Hence, the sensitivity of the measurement technique is enhanced by either increasing wall conductivity or optimizing the aspect ratio of the cross-section of the flow.

  6. A measurement of Lorentz Angle of radiation-hard Pixel Sensors

    CERN Document Server

    Aleppo, M

    2001-01-01

    Silicon pixel detectors developed to meet LHC requirements were tested in a beam at CERN in the framework of the ATLAS collaboration. The experimental behaviour of irradiated and not-irradiated sensors in a magnetic field is discussed. The measurement of the Lorentz angle for these sensors at different operating conditions is presented. A simple model of the charge drift in silicon before and after irradiation is presented. The good agreement between the model predictions and the experimental results is shown.

  7. Search for violation of Lorentz invariance in top quark pair production and decay

    Czech Academy of Sciences Publication Activity Database

    Abazov, V. M.; Abbott, B.; Acharya, B.S.; Kupčo, Alexander; Lokajíček, Miloš

    2012-01-01

    Roč. 108, č. 26 (2012), "261603-1"-"261603-7" ISSN 0031-9007 R&D Projects: GA MŠk LA08047; GA MŠk(CZ) LG12006 Institutional research plan: CEZ:AV0Z10100502 Keywords : D0 * violation Lorentz * pair productionl * decay * Batavia TEVATRON, Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 7.943, year: 2012 http://prl.aps.org/abstract/PRL/v108/i26/e261603

  8. Spontaneous breaking of Lorentz symmetry by ghost condensation in perturbative quantum gravity

    Science.gov (United States)

    Faizal, Mir

    2011-10-01

    In this paper, we will study the spontaneous breakdown of the Lorentz symmetry by ghost condensation in perturbative quantum gravity. Our analysis will be done in the Curci-Ferrari gauge. We will also analyse the modification of the BRST and anti-BRST transformations by the formation of this ghost condensate. It will be shown that even though the modified BRST and anti-BRST transformations are not nilpotent, their nilpotency is restored on-shell.

  9. Searches for Lorentz Violation in Top-Quark Production and Decay at Hadron Colliders

    Energy Technology Data Exchange (ETDEWEB)

    Whittington, Denver Wade [Indiana Univ., Bloomington, IN (United States)

    2012-07-01

    We present a first-of-its-kind confirmation that the most massive known elementary particle obeys the special theory of relativity. Lorentz symmetry is a fundamental aspect of special relativity which posits that the laws of physics are invariant regardless of the orientation and velocity of the reference frame in which they are measured. Because this symmetry is a fundamental tenet of physics, it is important to test its validity in all processes. We quantify violation of this symmetry using the Standard-Model Extension framework, which predicts the effects that Lorentz violation would have on elementary particles and their interactions. The top quark is the most massive known elementary particle and has remained inaccessible to tests of Lorentz invariance until now. This model predicts a dependence of the production cross section for top and antitop quark pairs on sidereal time as the orientation of the experiment in which these events are produced changes with the rotation of the Earth. Using data collected with the DØ detector at the Fermilab Tevatron Collider, we search for violation of Lorentz invariance in events involving the production of a $t\\bar{t}$ pair. Within the experimental precision, we find no evidence for such a violation and set upper limits on parameters describing its possible strength within the Standard-Model Extension. We also investigate the prospects for extending this analysis using the ATLAS detector at the Large Hadron Collider which, because of the higher rate of $t\\bar{t}$ events at that experiment, has the potential to improve the limits presented here.

  10. Solution of the Lorentz-Dirac equation based on a new momentum expression

    CERN Document Server

    Yan, C C

    1998-01-01

    The Lorentz-Dirac equation is solved based on a new momentum expression given by p sup a =1/c sup 2 (u submu p supmu)u sup a +k du sup a /d tau. This new momentum expression is the form proposed by Barut modified to satisfy the condition imposed by Dirac. The solution turns out to be well behaved without violating causality or causing runaway. (author)

  11. Characterization of associate spaces of generalized weighted weak-Lorentz spaces and embeddings

    Czech Academy of Sciences Publication Activity Database

    Gogatishvili, Amiran; Aykol, C.; Guliyev, V.S.

    2015-01-01

    Roč. 228, č. 3 (2015), s. 223-233 ISSN 0039-3223 R&D Projects: GA ČR GA13-14743S Institutional support: RVO:67985840 Keywords : generalized weighted weak-Lorentz spaces * reverse Hardy inequalities * associate spaces * embeddings Subject RIV: BA - General Mathematics Impact factor: 0.623, year: 2015 http://journals.impan.gov.pl/sm/Inf/228-3-2.html

  12. Can Lorentz-breaking fermionic condensates form in large N strongly-coupled Lattice Gauge Theories?

    OpenAIRE

    Tomboulis, E. T.

    2010-01-01

    The possibility of Lorentz symmetry breaking (LSB) has attracted considerable attention in recent years for a variety of reasons, including the attractive prospect of the graviton as a Goldstone boson. Though a number of effective field theory analyses of such phenomena have recently been given it remains an open question whether they can take place in an underlying UV complete theory. Here we consider the question of LSB in large N lattice gauge theories in the strong coupling limit. We appl...

  13. Search for Violations of Lorentz Invariance and CPT Symmetry in B-(s)(0) Mixing

    NARCIS (Netherlands)

    Aaij, R.; Beteta, C. Abellan; Adeva, B.; Adinolfi, M.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Cartelle, P. Alvarez; Alves, A. A.; Amato, S.; Amerio, S.; Amhis, Y.; An, L.; Anderlini, L.; Andreassi, G.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Gutierrez, O. Aquines; Archilli, F.; d'Argent, P.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Bachmann, S.; Back, J. J.; Badalov, A.; Baesso, C.; Baker, S.; Baldini, W.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Batozskaya, V.; Battista, V.; Beaucourt, L.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Bel, L. J.; Onderwater, C. J. G.; Pellegrino, A.; Tolk, S.

    2016-01-01

    Violations of CPT symmetry and Lorentz invariance are searched for by studying interference effects in B-0 mixing and in B-s(0) mixing. Samples of B-0 -> J/psi K-S(0) and B-0(s) -> J/psi K+K- decays are recorded by the LHCb detector in proton-proton collisions at center-of-mass energies of 7 and 8

  14. An algorithm for calculating the Lorentz angle in silicon detectors [online

    OpenAIRE

    Bartsch, Valeria; De Boer, Willem; Bol, Johannes; Dierlamm, Alexander; Grigoriev, Eugene; Hauler, Florian; Heising, Stephan; Jungermann, Levin

    2001-01-01

    The CMS (Compact Muon Solenoid) detector will use silicon sensors in the harsh radiation environment of the LHC (Large Hadron Collider) and high magnetic fields. The drift direction of the charge carriers is aected by the Lorentz force due to the high magnetic field. Also the resulting radiation damage changes the properties of the drift. The CMS silicon strip detector is read out on the p-side of the sensors, where holes are coll...

  15. Experimental Studies on the Lorentz Symmetry in Post-Newtonian Gravity with Pulsars

    Directory of Open Access Journals (Sweden)

    Lijing Shao

    2016-12-01

    Full Text Available Local Lorentz invariance (LLI is one of the most important fundamental symmetries in modern physics. While the possibility of LLI violation (LLIv was studied extensively in flat spacetime, its counterpart in gravitational interaction also deserves significant examination from experiments. In this contribution, I review several recent studies of LLI in post-Newtonian gravity, using powerful tools of pulsar timing. It shows that precision pulsar timing experiments hold a unique position to probe LLIv in post-Newtonian gravity.

  16. A New Limit on Planck Scale Lorentz Violation from Gamma-ray Burst Polarization

    Science.gov (United States)

    Stecker, Floyd W.

    2011-01-01

    Constraints on possible Lorentz invariance violation (UV) to first order in E/M(sub Plank) for photons in the framework of effective field theory (EFT) are discussed, taking cosmological factors into account. Then. using the reported detection of polarized soft gamma-ray emission from the gamma-ray burst GRB041219a that is indicative' of an absence of vacuum birefringence, together with a very recent improved method for estimating the redshift of the burst, we derive constraints on the dimension 5 Lorentz violating modification to the Lagrangian of an effective local QFT for QED. Our new constraints are more than five orders of magnitude better than recent constraints from observations of the Crab Nebula.. We obtain the upper limit on the Lorentz violating dimension 5 EFT parameter absolute value of zeta of 2.4 x 10(exp -15), corresponding to a constraint on the dimension 5 standard model extension parameter. Kappa (sup 5) (sub (v)oo) much less than 4.2 X 10(exp -3)4 / GeV.

  17. High Energy Astrophysics Tests of Lorentz Invariance and Quantum Gravity Models

    Science.gov (United States)

    Stecker, Floyd W.

    2012-01-01

    High energy astrophysics observations provide the best possibilities to detect a very small violation of Lorentz invariance such as may be related to the structure of space-time near the Planck scale of approx.10(exp -35) m. I will discuss the possible signatures of Lorentz invariance violation (LIV) that can be manifested by observing of the spectra, polarization, and timing of gamma-rays from active galactic nuclei and gamma-ray bursts. Other sensitive tests are provided by observations of the spectra of ultrahigh energy cosmic rays and neutrinos. Using the latest data from the Pierre Auger Observatory one can already derive an upper limit of 4.5 x 10(exp -23) on the fraction of LIV at a Lorentz factor of approx. 2 x 10(exp 11). This result has fundamental implications for quantum gravity models. I will also discuss the possibilities of using more sensitive space-based detection techniques to improve searches for LIV in the future. I will also discuss how the LIV formalism casts doubt on the OPERA superluminal neutrino claim.

  18. Novel characteristics of energy spectrum for 3D Dirac oscillator analyzed via Lorentz covariant deformed algebra.

    Science.gov (United States)

    Betrouche, Malika; Maamache, Mustapha; Choi, Jeong Ryeol

    2013-11-14

    We investigate the Lorentz-covariant deformed algebra for Dirac oscillator problem, which is a generalization of Kempf deformed algebra in 3 + 1 dimension of space-time, where Lorentz symmetry are preserved. The energy spectrum of the system is analyzed by taking advantage of the corresponding wave functions with explicit spin state. We obtained entirely new results from our development based on Kempf algebra in comparison to the studies carried out with the non-Lorentz-covariant deformed one. A novel result of this research is that the quantized relativistic energy of the system in the presence of minimal length cannot grow indefinitely as quantum number n increases, but converges to a finite value, where c is the speed of light and β is a parameter that determines the scale of noncommutativity in space. If we consider the fact that the energy levels of ordinary oscillator is equally spaced, which leads to monotonic growth of quantized energy with the increment of n, this result is very interesting. The physical meaning of this consequence is discussed in detail.

  19. Exact Lorentz-violating all-loop ultraviolet divergences in scalar field theories

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, P.R.S. [Universidade Federal do Piaui, Departamento de Fisica, Teresina, PI (Brazil); Sena-Junior, M.I. [Universidade de Pernambuco, Escola Politecnica de Pernambuco, Recife, PE (Brazil); Universidade Federal de Alagoas, Instituto de Fisica, Maceio, AL (Brazil)

    2017-11-15

    In this work we evaluate analytically the ultraviolet divergences of Lorentz-violating massive O(N) λφ{sup 4} scalar field theories, which are exact in the Lorentz-violating mechanism, firstly explicitly at next-to-leading order and latter at any loop level through an induction procedure based on a theorem following from the exact approach, for computing the corresponding critical exponents. For attaining that goal, we employ three different and independent field-theoretic renormalization group methods. The results found for the critical exponents show that they are identical in the three distinct methods and equal to their Lorentz-invariant counterparts. Furthermore, we show that the results obtained here, based on the single concept of loop order of the referred terms of the corresponding β-function and anomalous dimensions, reduce to the ones obtained through the earlier non-exact approach based on a joint redefinition of the field and coupling constant of the theory, in the appropriate limit. (orig.)

  20. Lorentz invariance violation and electromagnetic field in an intrinsically anisotropic spacetime

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Zhe [Chinese Academy of Sciences, Institute of High Energy Physics, Beijing (China); Chinese Academy of Sciences, Theoretical Physics Center for Science Facilities, Beijing (China); Wang, Sai [Chinese Academy of Sciences, Institute of High Energy Physics, Beijing (China)

    2012-09-15

    Recently, Kostelecky [V.A. Kostelecky, Phys. Lett. B 701, 137 (2011)] proposed that the spontaneous Lorentz invariance violation (sLIV) is related to Finsler geometry. Finsler spacetime is intrinsically anisotropic and naturally induces Lorentz invariance violation (LIV). In this paper, the electromagnetic field is investigated in locally Minkowski spacetime. The Lagrangian is presented explicitly for the electromagnetic field. It is compatible with the one in the standard model extension (SME). We show the Lorentz-violating Maxwell equations as well as the electromagnetic wave equation. The formal plane wave solution is obtained for the electromagnetic wave. The speed of light may depend on the direction of light and the lightcone may be enlarged or narrowed. The LIV effects could be viewed as influence from an anisotropic media on the electromagnetic wave. In addition, birefringence of light will not emerge at the leading order in this model. A constraint on the spacetime anisotropy is obtained from observations on gamma-ray bursts (GRBs). (orig.)

  1. Search for violations of Lorentz invariance and $CPT$ symmetry in $B^0_{(s)}$ mixing

    CERN Document Server

    Aaij, Roel; Adeva, Bernardo; Adinolfi, Marco; Ajaltouni, Ziad; Akar, Simon; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio Augusto; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; An, Liupan; Anderlini, Lucio; Andreassi, Guido; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Aquines Gutierrez, Osvaldo; Archilli, Flavio; d'Argent, Philippe; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baesso, Clarissa; Baker, Sophie; Baldini, Wander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Batozskaya, Varvara; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Bel, Lennaert; Bellee, Violaine; Belloli, Nicoletta; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Benton, Jack; Berezhnoy, Alexander; Bernet, Roland; Bertolin, Alessandro; Betti, Federico; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bifani, Simone; Billoir, Pierre; Bird, Thomas; Birnkraut, Alex; Bizzeti, Andrea; Blake, Thomas; Blanc, Frédéric; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Borgheresi, Alessio; Borghi, Silvia; Borisyak, Maxim; Borsato, Martino; Boubdir, Meriem; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Braun, Svende; Britsch, Markward; Britton, Thomas; Brodzicka, Jolanta; Buchanan, Emma; Burr, Christopher; Bursche, Albert; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Calvi, Marta; Calvo Gomez, Miriam; Campana, Pierluigi; Campora Perez, Daniel; Capriotti, Lorenzo; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carniti, Paolo; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cauet, Christophe; Cavallero, Giovanni; Cenci, Riccardo; Charles, Matthew; Charpentier, Philippe; Chatzikonstantinidis, Georgios; Chefdeville, Maximilien; Chen, Shanzhen; Cheung, Shu-Faye; Chrzaszcz, Marcin; Cid Vidal, Xabier; Ciezarek, Gregory; Clarke, Peter; Clemencic, Marco; Cliff, Harry; Closier, Joel; Coco, Victor; Cogan, Julien; Cogneras, Eric; Cogoni, Violetta; Cojocariu, Lucian; Collazuol, Gianmaria; Collins, Paula; Comerma-Montells, Albert; Contu, Andrea; Cook, Andrew; Coombes, Matthew; Coquereau, Samuel; Corti, Gloria; Corvo, Marco; Couturier, Benjamin; Cowan, Greig; Craik, Daniel Charles; Crocombe, Andrew; Cruz Torres, Melissa Maria; Cunliffe, Samuel; Currie, Robert; D'Ambrosio, Carmelo; Dall'Occo, Elena; Dalseno, Jeremy; David, Pieter; Davis, Adam; De Aguiar Francisco, Oscar; De Bruyn, Kristof; De Capua, Stefano; De Cian, Michel; De Miranda, Jussara; De Paula, Leandro; De Simone, Patrizia; Dean, Cameron Thomas; Decamp, Daniel; Deckenhoff, Mirko; Del Buono, Luigi; Déléage, Nicolas; Demmer, Moritz; Derkach, Denis; Deschamps, Olivier; Dettori, Francesco; Dey, Biplab; Di Canto, Angelo; Di Ruscio, Francesco; Dijkstra, Hans; Dordei, Francesca; Dorigo, Mirco; Dosil Suárez, Alvaro; Dovbnya, Anatoliy; Dreimanis, Karlis; Dufour, Laurent; Dujany, Giulio; Dungs, Kevin; Durante, Paolo; Dzhelyadin, Rustem; Dziurda, Agnieszka; Dzyuba, Alexey; Easo, Sajan; Egede, Ulrik; Egorychev, Victor; Eidelman, Semen; Eisenhardt, Stephan; Eitschberger, Ulrich; Ekelhof, Robert; Eklund, Lars; El Rifai, Ibrahim; Elsasser, Christian; Ely, Scott; Esen, Sevda; Evans, Hannah Mary; Evans, Timothy; Falabella, Antonio; Färber, Christian; Farley, Nathanael; Farry, Stephen; Fay, Robert; Fazzini, Davide; Ferguson, Dianne; Fernandez Albor, Victor; Ferrari, Fabio; Ferreira Rodrigues, Fernando; Ferro-Luzzi, Massimiliano; Filippov, Sergey; Fiore, Marco; Fiorini, Massimiliano; Firlej, Miroslaw; Fitzpatrick, Conor; Fiutowski, Tomasz; Fleuret, Frederic; Fohl, Klaus; Fontana, Marianna; Fontanelli, Flavio; Forshaw, Dean Charles; Forty, Roger; Frank, Markus; Frei, Christoph; Frosini, Maddalena; Fu, Jinlin; Furfaro, Emiliano; 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Zavertyaev, Mikhail; Zhang, Liming; Zhang, Yanxi; Zhelezov, Alexey; Zheng, Yangheng; Zhokhov, Anatoly; Zhong, Liang; Zhukov, Valery; Zucchelli, Stefano

    2016-06-15

    Violations of $ CPT$ symmetry and Lorentz invariance are searched for by studying interference effects in $ B^0$ mixing and in $ B^0_s$ mixing. Samples of $ B^0\\to J/\\psi K^0_{\\mathrm{S}}$ and $ B^0_s\\to J/\\psi K^+ K^-$ decays are recorded by the LHCb detector in proton--proton collisions at centre-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb$^{-1}$. No periodic variations of the particle-antiparticle mass differences are found, consistent with Lorentz invariance and $ CPT$ symmetry. Results are expressed in terms of the Standard Model Extension parameter $\\Delta a_{\\mu}$ with precisions of $ \\mathcal{O}(10^{-15})$ and $ \\mathcal{O}(10^{-14})$ GeV for the $ B^0$ and $ B^0_s$ systems, respectively. With no assumption on Lorentz (non-)invariance, the $ CPT$-violating parameter $z$ in the $ B^0_s$ system is measured for the first time and found to be $ \\mathcal{R}e(z) = -0.022 \\pm 0.033 \\pm 0.005$ and $ \\mathcal{I}m(z) = 0.004 \\pm 0.011\\pm 0.002$, where the first uncertainti...

  2. Search for Violations of Lorentz Invariance and CPT Symmetry in B_{(s)}^{0} Mixing.

    Science.gov (United States)

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Sagidova, N; Saitta, B; Salustino Guimaraes, V; Sanchez Mayordomo, C; Sanmartin Sedes, B; Santacesaria, R; Santamarina Rios, C; Santimaria, M; Santovetti, E; Sarti, A; Satriano, C; Satta, A; Saunders, D M; Savrina, D; Schael, S; Schiller, M; Schindler, H; Schlupp, M; Schmelling, M; Schmelzer, T; Schmidt, B; Schneider, O; Schopper, A; Schubiger, M; Schune, M-H; Schwemmer, R; Sciascia, B; Sciubba, A; Semennikov, A; Sergi, A; Serra, N; Serrano, J; Sestini, L; Seyfert, P; Shapkin, M; Shapoval, I; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, V; Shires, A; Siddi, B G; Silva Coutinho, R; Silva de Oliveira, L; Simi, G; Sirendi, M; Skidmore, N; Skwarnicki, T; Smith, E; Smith, I T; Smith, J; Smith, M; Snoek, H; Sokoloff, M D; Soler, F J P; Soomro, F; Souza, D; Souza De Paula, B; Spaan, B; Spradlin, P; Sridharan, S; Stagni, F; Stahl, M; Stahl, S; Stefkova, S; Steinkamp, O; Stenyakin, O; Stevenson, S; Stoica, S; Stone, S; Storaci, B; Stracka, S; Straticiuc, M; Straumann, U; Sun, L; Sutcliffe, W; Swientek, K; Swientek, S; Syropoulos, V; Szczekowski, M; Szumlak, T; T'Jampens, S; Tayduganov, A; Tekampe, T; Tellarini, G; Teubert, F; Thomas, C; Thomas, E; van Tilburg, J; Tisserand, V; Tobin, M; Tolk, S; Tomassetti, L; Tonelli, D; Topp-Joergensen, S; Tournefier, E; Tourneur, S; Trabelsi, K; Traill, M; Tran, M T; Tresch, M; Trisovic, A; Tsaregorodtsev, A; Tsopelas, P; Tuning, N; Ukleja, A; Ustyuzhanin, A; Uwer, U; Vacca, C; Vagnoni, V; Valat, S; Valenti, G; Vallier, A; Vazquez Gomez, R; Vazquez Regueiro, P; Vázquez Sierra, C; Vecchi, S; van Veghel, M; Velthuis, J J; Veltri, M; Veneziano, G; Vesterinen, M; Viaud, B; Vieira, D; Vieites Diaz, M; Vilasis-Cardona, X; Volkov, V; Vollhardt, A; Voong, D; Vorobyev, A; Vorobyev, V; Voß, C; de Vries, J A; Waldi, R; Wallace, C; Wallace, R; Walsh, J; Wang, J; Ward, D R; Watson, N K; Websdale, D; Weiden, A; Whitehead, M; Wicht, J; Wilkinson, G; Wilkinson, M; Williams, M; Williams, M P; Williams, M; Williams, T; Wilson, F F; Wimberley, J; Wishahi, J; Wislicki, W; Witek, M; Wormser, G; Wotton, S A; Wraight, K; Wright, S; Wyllie, K; Xie, Y; Xu, Z; Yang, Z; Yin, H; Yu, J; Yuan, X; Yushchenko, O; Zangoli, M; Zavertyaev, M; Zhang, L; Zhang, Y; Zhelezov, A; Zheng, Y; Zhokhov, A; Zhong, L; Zhukov, V; Zucchelli, S

    2016-06-17

    Violations of CPT symmetry and Lorentz invariance are searched for by studying interference effects in B^{0} mixing and in B_{s}^{0} mixing. Samples of B^{0}→J/ψK_{S}^{0} and B_{s}^{0}→J/ψK^{+}K^{-} decays are recorded by the LHCb detector in proton-proton collisions at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3  fb^{-1}. No periodic variations of the particle-antiparticle mass differences are found, consistent with Lorentz invariance and CPT symmetry. Results are expressed in terms of the standard model extension parameter Δa_{μ} with precisions of O(10^{-15}) and O(10^{-14})  GeV for the B^{0} and B_{s}^{0} systems, respectively. With no assumption on Lorentz (non)invariance, the CPT-violating parameter z in the B_{s}^{0} system is measured for the first time and found to be Re(z)=-0.022±0.033±0.005 and Im(z)=0.004±0.011±0.002, where the first uncertainties are statistical and the second systematic.

  3. Tests of Lorentz and CPT violation with MiniBooNE neutrino oscillation excesses

    International Nuclear Information System (INIS)

    Katori, Teppei

    2014-01-01

    Lorentz and CPT symmetry violaton is a predicted phenomenon of Planck–scale physics. Various types of data are analyzed to search for Lorentz violation under the Standard–Model Extension (SME) framework, including neutrino oscillation data. MiniBooNE is a short–baseline neutrino oscillation experiment at Fermilab. The measured excesses from MiniBooNE cannot be reconciled within the neutrino Standard Model (vSM); thus it might be a signal of new physics, such as Lorentz violation. We have analyzed the sidereal time dependence of MiniBooNE data for signals of the possible sidereal time dependence of the ocillation signals. we find that the v e appearance data prefer a sidereal time–independent solution, and the v-bar e appearance data slightly prefer a sidereal time–dependent solution, however, the statistical significance is not high to claim the discovery. Limits of order 10 −20 GeV are placed on combinations of SME coefficients

  4. Lorentz laser-assisted stripping (Lolas) for H-/H0 injection into proton drivers

    International Nuclear Information System (INIS)

    Gastaldi, Ugo

    2002-01-01

    We discuss the main components of schemes for Lorentz laser-assisted stripping (abbreviated Lolas henceforth) proposed for injection into proton driver accumulators: H- → H0 + e- Lorentz stripping, H0→H0(n) laser excitation, H0(n)→p+ + e- Lorentz stripping. We mention results obtained in practice of H- beam transport and storage and of experiments addressing physics of the H- ion, of the H0 atom and of vacuum, which prove the feasibility of each Lolas component. For high enough injection energies, it is feasible to split without losses the H0 beam sent towards the accumulator into a fraction stripped to p+s and stored inside the accumulator and a complementary fraction of H0s delivered to high duty-cycle users. The fraction of stored beam can exceed 50% with one single Fabry-Perot cavity used to enhance the laser power density. Aspects of Lolas integration and optimization are pointed out

  5. Hoy como ayer

    OpenAIRE

    Rodríguez M.

    2010-01-01

    Leyendo el artículo titulado “Los medicamentos baratos” de la revista La Farmacia Española, publicada en Madrid el jueves 21 de diciembre de 1893, uno se pregunta cómo puede ser que se reconozca la situación como si fuera de ahora mismo, cómo puede ser que estemos igual que hace más de cien años. Entonces eran los descuentos que se empezaban a extender en las farmacias, francesas sobre todo, y que amenazaban el prestigio profesional de todo el colectivo. Con frases como éstas se define la sit...

  6. La razonabilidad como virtud

    OpenAIRE

    Muñoz Oliveira, Luis Humberto

    2008-01-01

    Consultable des del TDX Títol obtingut de la portada digitalitzada Esta tesis doctoral explora la idea de que la razonabilidad es una virtud fundamental para que las sociedades plurales puedan convertirse en, o mantenerse como, un sistema de cooperación donde la justicia sea posible. La hipótesis central es que la razonabilidad como virtud es una manera de ser tolerante de forma solidaria, es entender al conciudadano, escucharlo, saber que juntos acordaron las reglas de cooperación y ac...

  7. Constraints on the bulk Lorentz factor of gamma-ray bursts with the detection rate by Fermi LAT

    Science.gov (United States)

    Chen, Ye; Liu, Ruo-Yu; Wang, Xiang-Yu

    2018-05-01

    The bulk Lorentz factor(Γ) of the outflow is an essential parameter to understanding the physics of gamma-ray burst (GRB). Informations about the Lorentz factors of some individual GRBs have been obtained from the spectral features of the high-energy gamma-ray emissions (>100 MeV), assuming that the spectral breaks or cutoffs are due to the pair-production attenuation (i.e., γγ → e+e-). In this paper, we attempt to interpret the dependence of the LAT detection rate of GRBs on the number of high-energy gamma-rays, taking into account the attenuation effect. We first simulate a long-GRB sample with Monte Carlo method using the luminosity function, rate distribution with redshift and properties of the GRB spectrum. To characterize the distribution of the Lorentz factors, we assume that the Lorentz factors follow the relation Γ =Γ _0E_iso,52k, where Eiso, 52 is the isotropic photon energy in unit of 1052erg. After taking into account the attenuation effect related with the above Lorentz factor distribution, we are able to reproduce the LAT-detected rate of GRBs as the function of the number of gamma-rays for suitable choice of the values of Γ0 and k. The result suggests that the distribution of the bulk Lorentz factor for the majority of GRBs is in the range of 50 - 250.

  8. Introducción a la integración numérica de ecuaciones diferenciales algebraicas de índice 2 con métodos de tipo Runge-Kutta.

    OpenAIRE

    Rojo García, Diego

    2015-01-01

    Tras introducir los conceptos y resultados básicos relacionados con las ecuaciones diferenciales algebraicas, en particular los distintos tipos de índice, se ha abordado la integración numérica de las ecuaciones semi-explícitas de índice 2 mediante métodos Runge-Kutta semi-explícitos. Se han estudiado con detalle las condiciones de orden para dichos métodos, obteniendo para ello los desarrollos de Taylor de la solución exacta y de la solución numérica con la ayuda de la teoría de árboles adec...

  9. Revisiting University Students’ Knowledge that Involves Basic Differential Equation Questions (Conocimiento de los Estudiantes Universitarios con Respecto a Preguntas que Implican Ecuaciones Diferenciales: una Revisión

    Directory of Open Access Journals (Sweden)

    Matías Camacho

    2009-03-01

    Full Text Available This study documents the extent to which university students utilize diverse representations and mathematical processes to interpret and respond to a set of questions that involves fundamental concepts in the study of differential equations. Results indicate that students’ idea to solve a differential equation is reduced to the application of proper solution methods to a certain type of equation differential expressions. Thus, instructional activities should promote the students’ use of several representation systems in which they can reflect on the various aspects associated with the concept itself, the solution methods, procedures, and the corresponding meaning and connections among those representations. Este estudio muestra hasta qué punto los estudiantes de universidad utilizan diferentes procesos y representaciones matemáticas para interpretar y responder a un grupo de cuestiones que incluyen conceptos fundamentales relacionados con el estudio de las ecuaciones diferenciales. Los resultados obtenidos indican que la idea que tienen los estudiantes de resolver una ecuación diferencial, se reduce a la aplicación de una serie de métodos. Así, la instrucción debería promover el uso de diferentes sistemas de representación que les permita reflexionar sobre varios aspectos asociados al concepto, los métodos de solución, los procedimientos y los significados y conexiones entre las representaciones utilizadas.

  10. The Lorentz transformation as an expression of opposite spacetime relations - abandonment of the principle of relativity

    International Nuclear Information System (INIS)

    Renniger, M.

    1987-01-01

    Any increase of the characteristic energy of any body endowed with a clock, ΔE = E - E 0 (E 0 being the rest energy), is connected with an increase of its time lapse, t/t 0 = E/E 0 . Effective observation of this accelerating influence on the speed of any clock is restricted on the increase of the potential energy only. Increase of the kinetic energy (E/E 0 = 1/√(1-v 2 /c 2 )) is, on the contrary, connected with an increase of the energy: t/t 0 = E/E 0 = √(1-v 2 /c 2 ). Moreover, this amount is that one postulated by the Lorentz transformation. This effect is the well-known 'time dilatation' of the Special Theory of Relativity, the 'transversal Doppler effect'. The Lorentz transformation is of exclusively kinematical meaning and therefore takes no account of the energy increase connected with any motion. There is no reason, why the time accelerating effect of any energy should be absent in the case of kinetic energy, paying regard to it seems indispensable. Therefore the actual effect √(1-v 2 /c 2 ) has to be given as a superposition of the time accelerating effect 1/√(1-v 2 /c 2 ) and a decelerating kinematic effect of 'double' (inverse square amount: 1-v 2 /c 2 ). Modified transformation equations are derived which pay regard to this subdivision of the actual relations concerning time and local scales, and whose integrated form is nevertheless identical with the classical Lorentz transformation, if kinetic energy is the sole one being present. Of course this new subdivision of the content of meaning in the transformations is in contradiction with the 'principle of relativity', it presumes the existence of an inertial frame absolutely at rest related to the universe. A series of arguments is asserted which let appear the existence of such an absolute frame more fascinating than the equivalence of the variety of all inertial frames. (author)

  11. The Lorentz Transformation as a Planck Vacuum Phenomenon in a Galilean Coordinate System

    Directory of Open Access Journals (Sweden)

    Daywitt W. C.

    2011-04-01

    Full Text Available In a seminal Masters’ dissertation [1] Pemper derived the relativistic electric and mag- netic fields of a uniformly moving charge from the response of some continuum to the perturbation from the charge’s Coulomb field. The results seem to imply that the Maxwell equations and the Lorentz transformation are associated with some type of vacuum state. Unbeknownst at the time, Pemper had discovered the Planck vacuum (PV quasi-continuum [2] and its interaction with the free charge. The importance of this derivation, its obscurity in the literature, and its connection to the PV justifies the following rework of that derivation.

  12. The Lorentz Transformation as a Planck Vacuum Phenomenon in a Galilean Coordinate System

    Directory of Open Access Journals (Sweden)

    Daywitt W. C.

    2011-04-01

    Full Text Available In a seminal Masters' dissertation Pemper derived the relativistic electric and magnetic fields of a uniformly moving charge from the response of some continuum to the perturbation from the charge's Coulomb field. The results seem to imply that the Maxwell equations and the Lorentz transformation are associated with some type of vacuum state. Unbeknownst at the time, Pemper had discovered the Planck vacuum (PV quasi-continuum and its interaction with the free charge. The importance of this derivation, its obscurity in the literature, and its connection to the PV justifies the following rework of that derivation.

  13. Quantization of Space-like States in Lorentz-Violating Theories

    Science.gov (United States)

    Colladay, Don

    2018-01-01

    Lorentz violation frequently induces modified dispersion relations that can yield space-like states that impede the standard quantization procedures. In certain cases, an extended Hamiltonian formalism can be used to define observer-covariant normalization factors for field expansions and phase space integrals. These factors extend the theory to include non-concordant frames in which there are negative-energy states. This formalism provides a rigorous way to quantize certain theories containing space-like states and allows for the consistent computation of Cherenkov radiation rates in arbitrary frames and avoids singular expressions.

  14. The Lorentz Attractor and Other Attractors in the Economic System of a Firm

    International Nuclear Information System (INIS)

    Shapovalov, V I; Kazakov, N V

    2015-01-01

    A nonlinear model of the economic system of ''a firm'' is offered. It is shown that this model has several chaotic attractors, including the Lorentz attractor and a new attractor that, in our opinion, has not yet been described in the scientific literature. The chaotic nature of the attractors that were found was confirmed by computing the Lyapunov indicators. The functioning of our economic model is demonstrated with examples of firm behaviour that change the control parameters; these are well known in practice. In particular, it is shown that changes in the specific control parameters may change the system and avoid bankruptcy for the firm

  15. Testing Lorentz Invariance Emergence in the Ising Model using Monte Carlo simulations

    CERN Document Server

    Dias Astros, Maria Isabel

    2017-01-01

    In the context of the Lorentz invariance as an emergent phenomenon at low energy scales to study quantum gravity a system composed by two 3D interacting Ising models (one with an anisotropy in one direction) was proposed. Two Monte Carlo simulations were run: one for the 2D Ising model and one for the target model. In both cases the observables (energy, magnetization, heat capacity and magnetic susceptibility) were computed for different lattice sizes and a Binder cumulant introduced in order to estimate the critical temperature of the systems. Moreover, the correlation function was calculated for the 2D Ising model.

  16. Mechanisms explaining Coulomb's electric force & Lorentz's magnetic force from a classical perspective

    Science.gov (United States)

    Correnti, Dan S.

    2018-06-01

    The underlying mechanisms of the fundamental electric and magnetic forces are not clear in current models; they are mainly mathematical constructs. This study examines the underlying physics from a classical viewpoint to explain Coulomb's electric force and Lorentz's magnetic force. This is accomplished by building upon already established physics. Although no new physics is introduced, extension of existing models is made by close examination. We all know that an electron carries a bound cylindrical B-field (CBF) as it translates. Here, we show how the electron CBF plays an intrinsic role in the generation of the electric and magnetic forces.

  17. Lorentz-violating Yang-Mills theory. Discussing the Chern-Simons-like term generation

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Tiago R.S.; Sobreiro, Rodrigo F. [UFF-Universidade Federal Fluminense, Instituto de Fisica, Niteroi, RJ (Brazil)

    2017-12-15

    We analyze the Chern-Simons-like term generation in the CPT-odd Lorentz-violating Yang-Mills theory interacting with fermions. Moreover, we study the anomalies of this model as well as its quantum stability. The whole analysis is performed within the algebraic renormalization theory, which is independent of the renormalization scheme. In addition, all results are valid to all orders in perturbation theory. We find that the Chern-Simons-like term is not generated by radiative corrections, just like its Abelian version. Additionally, the model is also free of gauge anomalies and quantum stable. (orig.)

  18. Gauge-invariant Yang-Mills fields and the role of Lorentz gauge condition

    International Nuclear Information System (INIS)

    Skachkov, N.B.; Shevchenko, O.Yu.

    1985-01-01

    A new class of gauge-invariant (G.I.) fields is constructed. The inversion formulae that express these fields through the G.I. strength tensor are obtained. It is shown that for the G.I. fields the Lorentz gauge condition appears as the secondary constraint. These fields coincide with the usual ones in some definite gauges. The Dyson-Schwinger equations for the G.I. spinor propagator are derived. It is found that in QED this propagator has a simple pole singularity (p-m) -1 in the infrared limit

  19. Numerical studies on soliton propagation in the dielectric media by the nonlinear Lorentz computational model

    International Nuclear Information System (INIS)

    Abe, H.; Okuda, H.

    1994-06-01

    Soliton propagation in the dielectric media has been simulated by using the nonlinear Lorentz computational model, which was recently developed to study the propagation of electromagnetic waves in a linear and a nonlinear dielectric. The model is constructed by combining a microscopic model used in the semi-classical approximation for dielectric media and the particle model developed for the plasma simulations. The carrier wave frequency is retained in the simulation so that not only the envelope of the soliton but also its phase can be followed in time. It is shown that the model may be useful for studying pulse propagation in the dielectric media

  20. Application of a Lorentz transformation in six dimensions to an extension of dirac equation

    International Nuclear Information System (INIS)

    Sabry, A.A.

    2000-01-01

    On applying a six dimensional Lorentz transformation (by adding three time components to the usual 3 space components) a covariant extended Dirac equation in this six dimensional space is suggested. From the free field solution of the extended equation we obtained four solutions for E , the first component of energy which depends on very big masses M and M 0 . The observed masses of the leptons and their corresponding neutrinos satisfying the same free field equation, can then be obtained on using second quantisation procedures on the field operators

  1. Random-walk approach to the d -dimensional disordered Lorentz gas

    Science.gov (United States)

    Adib, Artur B.

    2008-02-01

    A correlated random walk approach to diffusion is applied to the disordered nonoverlapping Lorentz gas. By invoking the Lu-Torquato theory for chord-length distributions in random media [J. Chem. Phys. 98, 6472 (1993)], an analytic expression for the diffusion constant in arbitrary number of dimensions d is obtained. The result corresponds to an Enskog-like correction to the Boltzmann prediction, being exact in the dilute limit, and better or nearly exact in comparison to renormalized kinetic theory predictions for all allowed densities in d=2,3 . Extensive numerical simulations were also performed to elucidate the role of the approximations involved.

  2. Electromagnetic reactions of few-body systems with the Lorentz integral transform method

    International Nuclear Information System (INIS)

    Leidemann, W.

    2007-01-01

    Various electromagnetic few-body break-up reactions into the many-body continuum are calculated microscopically with the Lorentz integral transform (LIT) method. For three- and four-body nuclei the nuclear Hamiltonian includes two- and three-nucleon forces, while semirealistic interactions are used in case of six- and seven-body systems. Comparisons with experimental data are discussed. In addition various interesting aspects of the 4 He photodisintegration are studied: investigation of a tetrahedrical symmetry of 4 He and a test of non-local nuclear force models via the induced two-body currents

  3. Lorentz invariance and the zero-point stress-energy tensor

    OpenAIRE

    Visser, Matt

    2016-01-01

    Some 65 years ago (1951) Wolfgang Pauli noted that the net zero-point energy density could be set to zero by a carefully fine-tuned cancellation between bosons and fermions. In the current article I will argue in a slightly different direction: The zero-point energy density is only one component of the zero-point stress energy tensor, and it is this tensor quantity that is in many ways the more fundamental object of interest. I shall demonstrate that Lorentz invariance of the zero-point stres...

  4. Classical kinematics and Finsler structures for nonminimal Lorentz-violating fermions

    Energy Technology Data Exchange (ETDEWEB)

    Schreck, M. [Indiana University, Indiana University Center for Spacetime Symmetries, Bloomington, IN (United States)

    2015-05-15

    In the current paper the Lagrangian of a classical, relativistic point particle is obtained whose conjugate momentum satisfies the dispersion relation of a quantum wave packet that is subject to Lorentz violation based on a particular coefficient of the nonminimal standard-model extension (SME). The properties of this Lagrangian are analyzed and two corresponding Finsler structures are obtained. One structure describes a scaled Euclidean geometry, whereas the other is neither a Riemann nor a Randers or Kropina structure. The results of the article provide some initial understanding of classical Lagrangians of the nonminimal SME fermion sector. (orig.)

  5. A modified Lorentz theory as a test theory of special relativity

    Science.gov (United States)

    Chang, T.; Torr, D. G.; Gagnon, D. R.

    1988-01-01

    Attention has been given recently to a modified Lorentz theory (MLT) that is based on the generalized Galilean transformation. Some explicit formulas within the framework of MLT, dealing with the one-way velocity of light, slow-clock transport, and the Doppler effect are derived. A number of typical experiments are analyzed on this basis. Results indicate that the empirical equivalence between MLT and special relativity is still maintained to second order terms. The results of previous works that predict that the MLT might be distinguished from special relativity at the third order by Doppler centrifuge tests capable of a fractional frequency detection threshold of 10 to the -15th are confirmed.

  6. Classical kinematics and Finsler structures for nonminimal Lorentz-violating fermions

    International Nuclear Information System (INIS)

    Schreck, M.

    2015-01-01

    In the current paper the Lagrangian of a classical, relativistic point particle is obtained whose conjugate momentum satisfies the dispersion relation of a quantum wave packet that is subject to Lorentz violation based on a particular coefficient of the nonminimal standard-model extension (SME). The properties of this Lagrangian are analyzed and two corresponding Finsler structures are obtained. One structure describes a scaled Euclidean geometry, whereas the other is neither a Riemann nor a Randers or Kropina structure. The results of the article provide some initial understanding of classical Lagrangians of the nonminimal SME fermion sector. (orig.)

  7. Uniqueness of the Isotropic Frame and Usefulness of the Lorentz Transformation

    Science.gov (United States)

    Choi, Yang-Ho

    2018-05-01

    According to the postulates of the special theory of relativity (STR), physical quantities such as proper times and Doppler shifts can be obtained from any inertial frame by regarding it as isotropic. Nonetheless many inconsistencies arise from the postulates, as shown in this paper. However, there are numerous experimental results that agree with the predictions of STR. It is explained why they are accurate despite the inconsistencies. The Lorentz transformation (LT), unless subject to the postulates of STR, may be a useful method to approach physics problems. As an example to show the usefulness of LT, the problem of the generalized Sagnac effect is solved by utilizing it.

  8. Lorentz Symmetry Violations from Matter-Gravity Couplings with Lunar Laser Ranging

    Science.gov (United States)

    Bourgoin, A.; Le Poncin-Lafitte, C.; Hees, A.; Bouquillon, S.; Francou, G.; Angonin, M.-C.

    2017-11-01

    The standard-model extension (SME) is an effective field theory framework aiming at parametrizing any violation to the Lorentz symmetry (LS) in all sectors of physics. In this Letter, we report the first direct experimental measurement of SME coefficients performed simultaneously within two sectors of the SME framework using lunar laser ranging observations. We consider the pure gravitational sector and the classical point-mass limit in the matter sector of the minimal SME. We report no deviation from general relativity and put new realistic stringent constraints on LS violations improving up to 3 orders of magnitude previous estimations.

  9. CPT and Lorentz violation as signatures for Planck-scale physics

    International Nuclear Information System (INIS)

    Lehnert, Ralf

    2009-01-01

    In recent years, the breakdown of spacetime symmetries has been identified as a promising research field in the context of Planck-scale phenomenology. For example, various theoretical approaches to the quantum-gravity problem are known to accommodate minute violations of CPT invariance. This talk covers various topics within this research area. In particular, some mechanisms for spacetime-symmetry breaking as well as the Standard-Model Extension (SME) test framework will be reviewed; the connection between CPT and Lorentz invariance in quantum field theory will be exposed; and the a few experimental CPT tests with emphasis on matter-antimatter comparisons will be discussed.

  10. Lorentz angle studies for the SLD endcap Cerenkov Ring Imaging Detector

    International Nuclear Information System (INIS)

    Coyle, P.; Cavalli-Sforza, M.; Coyne, D.

    1987-11-01

    The design of the endcap Cerenkov Ring Imaging Detectors for SLD requires a detailed understanding of how electrons drift in gases under the influence of crossed electric and magnetic fields. In this report, we present recent measurements of Lorentz angles and drift velocities in gases suitable for the endcap CRID photon detectors. We compare these measurements to predictions from a theoretical model; good agreement is observed. Based on our results we present a design for detectors operating in a 0.6 Tesla transverse magnetic field. 14 refs., 10 figs., 4 tabs

  11. The Fresnel mode of Lorentz microscopy using a scanning transmission electron microscope

    International Nuclear Information System (INIS)

    Chapman, J.N.; Waddell, E.M.; Batson, P.E.; Ferrier, R.P.

    1979-01-01

    The most widely used method of investigating ferromagnetic films in the transmission electron microscope is the Fresnel or defocus mode of Lorentz microscopy. This may be implemented either in a fixed beam or a scanning instrument. Despite a rather inefficient utilization of electrons, several advantages accrue if the latter is used, and provided it is equipped with a field emission gun, low noise images may be obtained in acceptable recording times. To extract quantitative estimates of domain wall widths from such images it is necessary to measure accurately both instrumental and specimen parameters. Methods for this are discussed and an example of an analysis using a polycrystalline permalloy film is given. (Auth.)

  12. Intrinsic Regularization in a Lorentz invariant non-orthogonal Euclidean Space

    OpenAIRE

    Tornow, Carmen

    2006-01-01

    It is shown that the Lorentz transformations can be derived for a non-orthogonal Euclidean space. In this geometry one finds the same relations of special relativity as the ones known from the orthogonal Minkowski space. In order to illustrate the advantage of a non-orthogonal Euclidean metric the two-point Green’s function at x = 0 for a self-interacting scalar field is calculated. In contrast to the Minkowski space the one loop mass correction derived from this function gives a convergent r...

  13. Optimized cobalt nanowires for domain wall manipulation imaged by in situ Lorentz microscopy

    International Nuclear Information System (INIS)

    Rodríguez, L. A.; Magén, C.; Snoeck, E.; Gatel, C.; Serrano-Ramón, L.

    2013-01-01

    Direct observation of domain wall (DW) nucleation and propagation in focused electron beam induced deposited Co nanowires as a function of their dimensions was carried out by Lorentz microscopy (LTEM) upon in situ application of magnetic field. Optimal dimensions favoring the unambiguous DW nucleation/propagation required for applications were found in 500-nm-wide and 13-nm-thick Co nanowires, with a maximum nucleation field and the largest gap between nucleation and propagation fields. The internal DW structures were resolved using the transport-of-intensity equation formalism in LTEM images and showed that the optimal nanowire dimensions correspond to the crossover between the nucleation of transverse and vortex walls.

  14. Evaluating the Bulk Lorentz Factors of Outflow Material: Lessons Learned from the Extremely Energetic Outburst GRB 160625B

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yuan-Zhu; Wang, Hao; Zhang, Shuai; Liang, Yun-Feng; Jin, Zhi-Ping; He, Hao-Ning; Liao, Neng-Hui; Fan, Yi-Zhong; Wei, Da-Ming, E-mail: liangyf@pmo.ac.cn, E-mail: jin@pmo.ac.cn, E-mail: dmwei@pmo.ac.cn [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Science, Nanjing, 210008 (China)

    2017-02-10

    GRB 160625B is an extremely bright outburst with well-monitored afterglow emission. The geometry-corrected energy is high, up to ∼5.2 × 10{sup 52} erg or even ∼8 × 10{sup 52} erg, rendering it the most energetic GRB prompt emission recorded so far. We analyzed the time-resolved spectra of the prompt emission and found that in some intervals there were likely thermal-radiation components and the high energy emission was characterized by significant cutoff. The bulk Lorentz factors of the outflow material are estimated accordingly. We found out that the Lorentz factors derived in the thermal-radiation model are consistent with the luminosity-Lorentz factor correlation found in other bursts, as well as in GRB 090902B for the time-resolved thermal-radiation components, while the spectral cutoff model yields much lower Lorentz factors that are in tension with the constraints set by the electron pair Compton scattering process. We then suggest that these spectral cutoffs are more likely related to the particle acceleration process and that one should be careful in estimating the Lorentz factors if the spectrum cuts at a rather low energy (e.g., ∼tens of MeV). The nature of the central engine has also been discussed, and a stellar-mass black hole is favored.

  15. Ouabaina como Hormona

    OpenAIRE

    J. Hernando Ordoñez

    1996-01-01

    Comentario sobre su origen endógeno y sus aplicaciones terapéuticas

    Pocas drogas han sido más estudiadas que el grupo de los digitálicos, estrofantinas y ouabaina, cuyo estudio es objeto del presente trabajo.

    La ouabaina empezó a ser estudiada desde el siglo pasado. La primera referencia conocida corresponde a Pelikan, 1865 (1), como veneno que empleaban para las flechas en Gabón (Africa). (.)

  16. Hoy como ayer

    Directory of Open Access Journals (Sweden)

    Rodríguez M.

    2010-06-01

    Full Text Available Leyendo el artículo titulado “Los medicamentos baratos” de la revista La Farmacia Española, publicada en Madrid el jueves 21 de diciembre de 1893, uno se pregunta cómo puede ser que se reconozca la situación como si fuera de ahora mismo, cómo puede ser que estemos igual que hace más de cien años. Entonces eran los descuentos que se empezaban a extender en las farmacias, francesas sobre todo, y que amenazaban el prestigio profesional de todo el colectivo. Con frases como éstas se define la situación que se presentaba en aquel momento: “…el desprestigio de que vaya por unos cuantos desnaturalizándose el ejercicio de la farmacia en tal forma que se convierta en un comercio impuro y de la peor estofa; pero conviene mucho combatir con mano firme la tendencia a la baratería, tanto más cuanto que no puede dudarse que significa un rebajamiento a todas luces nocivo y que supone una desorganización que nos llevaría en breve a la más completa ruina, y lo que creo aún más grave, a la desmoralización y el desorden, que no se compadecen en modo alguno con lo que en realidad es hoy y ha sido siempre el ejercicio de una profesión genuinamente científica como lo es la de la farmacia”. La propuesta que se hacía para controlar la situación era “la limitación de farmacias, con vigilancia estrecha del Estado y tarifa uniforme oficial”, así como “hace falta mucha inteligencia y mucha unión, hace falta que nadie permanezca indiferente, que todos y cada uno pongan de su parte lo que puedan”. Nuestra profesión mezcla una doble vertiente sanitaria y comercial que no siempre es fácil mantener equilibrada y, por lo que se ve, esto ha ocurrido así desde siempre. El problema que existe hoy en día es la mercantilización de la farmacia, un desplazamiento de establecimiento sanitario hacia una simple empresa.

  17. Numerical simulation of 2 D laminar flow subjected to the Lorentz force effect in a channel with backward facing step

    Energy Technology Data Exchange (ETDEWEB)

    Farahbakhsh, Iman; Paknejad, Amin; Ghassemi, Hassan [Amirkabir Univ. of Technology, Tehran (Iran, Islamic Republic of)

    2012-10-15

    This paper presents the numerical solutions of a two dimensional laminar flow over a backward facing step in the presence of the Lorentz body force. The Navier Stokes equations in a vorticity stream function formulation are numerically solved using a uniform grid mesh of 2001 {Chi} 51 points. A second order central difference approximation is used for spatial derivatives. The solutions progress in time with a fourth order Runge Kutta method. The unsteady backward facing step flow solution is computed for Reynolds numbers 100 to 800. The size and genesis of the recirculating regions are dramatically affected by applying the Lorentz force. The results demonstrate that using an appropriate configuration for applying the Lorentz force can make it an essential tool for controlling the flow in channels with a backward facing step.

  18. Generation of geometrical phases and persistent spin currents in 1-dimensional rings by Lorentz-violating terms

    Energy Technology Data Exchange (ETDEWEB)

    Casana, R.; Ferreira, M.M., E-mail: manojr.ufma@gmail.com; Mouchrek-Santos, V.E.; Silva, Edilberto O.

    2015-06-30

    We have demonstrated that Lorentz-violating terms stemming from the fermion sector of the SME are able to generate geometrical phases on the wave function of electrons confined in 1-dimensional rings, as well as persistent spin currents, in the total absence of electromagnetic fields. We have explicitly evaluated the eigenenergies and eigenspinors of the electrons modified by the Lorentz-violating terms, using them to calculate the dynamic and the Aharonov–Anandan phases in the sequel. The total phase presents a pattern very similar to the Aharonov–Casher phase accumulated by electrons in rings under the action of the Rashba interaction. Finally, the persistent spin current were carried out and used to impose upper bounds on the Lorentz-violating parameters.

  19. CME Dynamics Using STEREO and LASCO Observations: The Relative Importance of Lorentz Forces and Solar Wind Drag

    Science.gov (United States)

    Sachdeva, Nishtha; Subramanian, Prasad; Vourlidas, Angelos; Bothmer, Volker

    2017-09-01

    We seek to quantify the relative contributions of Lorentz forces and aerodynamic drag on the propagation of solar coronal mass ejections (CMEs). We use Graduated Cylindrical Shell (GCS) model fits to a representative set of 38 CMEs observed with the Solar and Heliospheric Observatory (SOHO) and the Solar and Terrestrial Relations Observatory (STEREO) spacecraft. We find that the Lorentz forces generally peak between 1.65 and 2.45 R⊙ for all CMEs. For fast CMEs, Lorentz forces become negligible in comparison to aerodynamic drag as early as 3.5 - 4 R⊙. For slow CMEs, however, they become negligible only by 12 - 50 R⊙. For these slow events, our results suggest that some of the magnetic flux might be expended in CME expansion or heating. In other words, not all of it contributes to the propagation. Our results are expected to be important in building a physical model for understanding the Sun-Earth dynamics of CMEs.

  20. Testing the Equivalence Principle and Lorentz Invariance with PeV Neutrinos from Blazar Flares.

    Science.gov (United States)

    Wang, Zi-Yi; Liu, Ruo-Yu; Wang, Xiang-Yu

    2016-04-15

    It was recently proposed that a giant flare of the blazar PKS B1424-418 at redshift z=1.522 is in association with a PeV-energy neutrino event detected by IceCube. Based on this association we here suggest that the flight time difference between the PeV neutrino and gamma-ray photons from blazar flares can be used to constrain the violations of equivalence principle and the Lorentz invariance for neutrinos. From the calculated Shapiro delay due to clusters or superclusters in the nearby universe, we find that violation of the equivalence principle for neutrinos and photons is constrained to an accuracy of at least 10^{-5}, which is 2 orders of magnitude tighter than the constraint placed by MeV neutrinos from supernova 1987A. Lorentz invariance violation (LIV) arises in various quantum-gravity theories, which predicts an energy-dependent velocity of propagation in vacuum for particles. We find that the association of the PeV neutrino with the gamma-ray outburst set limits on the energy scale of possible LIV to >0.01E_{pl} for linear LIV models and >6×10^{-8}E_{pl} for quadratic order LIV models, where E_{pl} is the Planck energy scale. These are the most stringent constraints on neutrino LIV for subluminal neutrinos.

  1. A MAD Explanation for the Correlation between Bulk Lorentz Factor and Minimum Variability Timescale

    Science.gov (United States)

    Lloyd-Ronning, Nicole; Lei, Wei-hua; Xie, Wei

    2018-04-01

    We offer an explanation for the anti-correlation between the minimum variability timescale (MTS) in the prompt emission light curve of gamma-ray bursts (GRBs) and the estimated bulk Lorentz factor of these GRBs, in the context of a magnetically arrested disk (MAD) model. In particular, we show that previously derived limits on the maximum available energy per baryon in a Blandford-Znajek jet leads to a relationship between the characteristic MAD timescale in GRBs and the maximum bulk Lorentz factor: tMAD∝Γ-6, somewhat steeper than (although within the error bars of) the fitted relationship found in the GRB data. Similarly, the MAD model also naturally accounts for the observed anti-correlation between MTS and gamma-ray luminosity L in the GRB data, and we estimate the accretion rates of the GRB disk (given these luminosities) in the context of this model. Both of these correlations (MTS - Γ and MTS - L) are also observed in the AGN data, and we discuss the implications of our results in the context of both GRB and blazar systems.

  2. Aspects of quantum corrections in a Lorentz-violating extension of the abelian Higgs Model

    Energy Technology Data Exchange (ETDEWEB)

    Brito, L.C.T.; Fargnoli, H.G. [Universidade Federal de Lavras, MG (Brazil); Scarpelli, A.P. Baeta [Departamento de Policia Federal, Rio de Janeiro, RJ (Brazil)

    2013-07-01

    Full text: We have investigated new aspects related to the four-dimensional abelian gauge-Higgs model with the addition of the Carroll-Field-Jackiw term (CFJ). We have focused on one-loop quantum corrections to the photon and Higgs sectors and we have analyzed what kind of effects are induced at the quantum level by spontaneous gauge symmetry breaking due the presence of the CFJ term. We have shown that new finite and non-ambiguous Lorentz-breaking terms are induced in both sectors at second order in the background vector. Specifically in the pure gauge sector, a CPT-even aether term (free from ambiguities) is induced. A CPT-even term is also induced in the pure Higgs sector. Both terms have been mapped in the Standard Model Extension. Besides, aspects of the one-loop renormalization of the background vector dependent terms have been studied. The new divergences due the presence of the CFJ term were shown to be worked out by the renormalization condition which requires the vanishing of the vacuum expectation value of the Higgs field. So at one loop the CFJ term does not spoil the well known renormalizability of the model without Lorentz symmetry breaking terms. The calculations have been done within dimensional methods and in an arbitrary gauge choice. (author)

  3. Use of the Lorentz-Boosted Frame Transformation to Simulate Free-Electron Laser Amplifier Physics

    International Nuclear Information System (INIS)

    Fawley, W.M.; Vay, J.-L.

    2008-01-01

    Recently it has been pointed out that numerical simulation of some systems containing charged particles with highly relativistic directed motion can by speeded up by orders of magnitude by choice of the proper Lorentz boosted frame. A particularly good example is that of short wavelength free-electron lasers (FELs) in which a high energy (E0 (ge) 250 MeV) electron beam interacts with a static magnetic undulator. In the optimal boost frame with Lorentz factor gamma F, the red-shifted FEL radiation and blue shifted undulator have identical wavelengths and the number of required time-steps (presuming the Courant condition applies) decreases by a factor of g2 F for fully electromagnetic simulation. We have adapted the WARP code to apply this method to several FEL problems including coherent spontaneous emission (CSE) from pre-bunched e-beams, and strong exponential gain in a single pass amplifier configuration. We discuss our results and compare with those from the 'standard' FEL simulation approach which adopts the eikonal approximation for propagation of the radiation field

  4. Lorentz and CPT invariances and the Einstein-Podolsky-Rosen correlations

    International Nuclear Information System (INIS)

    Beauregard, O.C. de

    1984-01-01

    This paper shows that there is no conflict between Einstein-Podolsky-Rosen (EPR) correlation and the new 1925 - 55 ''microrelativity principle'' stating the Lorentz and CPT invariance of physical law at the microlevel. The CPT invariance concept is a perfectly legal heir of the 1876 Loschmidt T-invariance concept. Therefore, the EPR-paradox can be understood as synthetizing two earlier ''paradoxes'': the wavelike probability calculus, and the T- or CPT-symmetry of elementary physical processes. The CPT-invariance can be summarized as the basic requirement of second quantization, that particle emission and antiparticle absorption are mathematically equivalent. The phenomenology displays causality as arrowless at the microlevel. The relativistic S-matrix scheme displays the CPT invariance of causality concept at the microlevel. In order to strengthen the point that the Lorentz and CPT invariant schemes of relativistic quantum mechanics do contain the full formalization of the EPR correlation, the covariant calculations pertaining to the subject are presented. The formalization of the EPR correlation and its interpretation are contained in the existing relativistic quantum mechanics. (Kato, T.)

  5. Seismic sensitivity of normal-mode coupling to Lorentz stresses in the Sun

    Science.gov (United States)

    Hanasoge, Shravan M.

    2017-09-01

    Understanding the governing mechanism of solar magnetism remains an outstanding challenge in astrophysics. Seismology is the most compelling technique to infer the internal properties of the Sun and stars. Waves in the Sun, nominally acoustic, are sensitive to the emergence and cyclical strengthening of magnetic field, evidenced by measured changes in resonant oscillation frequencies that are correlated with the solar cycle. The inference of internal Lorentz stresses from these measurements has the potential to significantly advance our appreciation of the dynamo. Indeed, seismological inverse theory for the Sun is well understood for perturbations in composition, thermal structure and flows but, is not fully developed for magnetism, owing to the complexity of the ideal magnetohydrodynamic (MHD) equation. Invoking first-Born perturbation theory to characterize departures from spherically symmetric hydrostatic models of the Sun and applying the notation of generalized spherical harmonics, we calculate sensitivity functions of seismic measurements to the general time-varying Lorentz stress tensor. We find that eigenstates of isotropic (I.e. acoustic only) background models are dominantly sensitive to isotropic deviations in the stress tensor and much more weakly than anisotropic stresses (and therefore challenging to infer). The apple cannot fall far from the tree.

  6. Universal fit to p-p elastic diffraction scattering from the Lorentz contracted geometrical model

    International Nuclear Information System (INIS)

    Hansen, P.H.; Krisch, A.D.

    1976-01-01

    The prediction of the Lorentz contracted geometical model for proton-proton elastic scattering at small angles is examined. The model assumes that when two high energy particles collide, each behaves as a geometrical object which has a Gaussian density and is spherically symmetric except for the Lorentz contraction in the incident direction. It is predicted that dsigma/dt should be independent of energy when plotted against the variable β 2 P 2 sub(perpendicular) sigmasub(TOT)(s)/38.3. Thus the energy dependence of the diffraction peak slope (b in an esup(-b mod(t))plot) is given by b(s)=A 2 β 2 sigmasub(TOT)(s)/38.3 where β is the proton's c.m. velocity and A is its radius. Recently measured values of sigmasub(TOT)(s) were used and an excellent fit obtained to the elastic slope in both t regions [-t 2 and 0.1 2 ] at all energies from s=6 to 4000(GeV/c) 2 . (Auth.)

  7. Design and simulation of superconducting Lorentz Force Electrical Impedance Tomography (LFEIT)

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Boyang, E-mail: bs506@cam.ac.uk; Fu, Lin, E-mail: lf359@cam.ac.uk; Geng, Jianzhao, E-mail: jg717@cam.ac.uk; Zhang, Xiuchang, E-mail: xz326@cam.ac.uk; Zhang, Heng, E-mail: hz301@cam.ac.uk; Dong, Qihuan, E-mail: qd210@cam.ac.uk; Li, Chao, E-mail: cl644@cam.ac.uk; Li, Jing, E-mail: jl908@cam.ac.uk; Coombs, T.A., E-mail: tac1000@cam.ac.uk

    2016-05-15

    Highlights: • Design of superconducting magnets using Halbach Array configuration. • Combination of superconducting magnets together with Lorentz Force Electrical Impedance Tomography (LFEIT) system. • Simulation of superconducting LFEIT system based on the theory of magneto-acoustic effect. - Abstract: Lorentz Force Electrical Impedance Tomography (LFEIT) is a hybrid diagnostic scanner with strong capability for biological imaging, particularly in cancer and haemorrhages detection. This paper presents the design and simulation of a novel combination: a superconducting magnet together with LFEIT system. Superconducting magnets can generate magnetic field with high intensity and homogeneity, which could significantly enhance the imaging performance. The modelling of superconducting magnets was carried out using Finite Element Method (FEM) package, COMSOL Multiphysics, which was based on Partial Differential Equation (PDE) model with H-formulation coupling B-dependent critical current density and bulk approximation. The mathematical model for LFEIT system was built based on the theory of magneto-acoustic effect. The magnetic field properties from magnet design were imported into the LFEIT model. The basic imaging of electrical signal was developed using MATLAB codes. The LFEIT model simulated two samples located in three different magnetic fields with varying magnetic strength and homogeneity.

  8. Planck-scale Lorentz violation constrained by ultra-high-energy cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Maccione, L. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Univ. Hamburg, II. Inst. fuer Theoretische Physik (Germany); Taylor, A.M. [Max-Planck-Inst. fuer Kernphysik, Heidelberg (Germany); Mattingly, D.M.; Liberati, S. [Scuola Internazionale Superiore di Studi Avanzati SISSA, Trieste (Italy); Istituto Nazionale di Fisica Nucleare INFN, Sezione di Trieste (Italy)

    2009-09-15

    We investigate the consequences of higher dimension Lorentz violating, CPT even kinetic operators that couple standard model fields to a non-zero vector field in an Effective Field Theory framework. Comparing the ultra-high energy cosmic ray spectrum reconstructed in the presence of such terms with data from the Pierre Auger observatory allows us to establish two sided bounds on the coefficients of the mass dimension five and six operators for the proton and pion. Our bounds imply that for both protons and pions, the energy scale of Lorentz symmetry breaking must be well above the Planck scale. In particular, the dimension five operators are constrained at the level of 10{sup -3}M{sup -1}{sub Planck}. The magnitude of the dimension six proton coefficient is bounded at the level of 10{sup -6}M{sup -2}{sub Planck} except in a narrow range where the pion and proton coefficients are both negative and nearly equal. In this small area, the magnitude of the dimension six proton coefficient must only be below 10{sup -3}M{sup -2}{sub Planck}. Constraints on the dimension six pion coefficient are found to be much weaker, but still below M{sup -2}{sub Planck}. (orig.)

  9. Local effects of the quantum vacuum in Lorentz-violating electrodynamics

    Science.gov (United States)

    Martín-Ruiz, A.; Escobar, C. A.

    2017-02-01

    The Casimir effect is one of the most remarkable consequences of the nonzero vacuum energy predicted by quantum field theory. In this paper we use a local approach to study the Lorentz violation effects of the minimal standard model extension on the Casimir force between two parallel conducting plates in the vacuum. Using a perturbative method similar to that used for obtaining the Born series for the scattering amplitudes in quantum mechanics, we compute, at leading order in the Lorentz-violating coefficients, the relevant Green's function which satisfies given boundary conditions. The standard point-splitting technique allow us to express the vacuum expectation value of the stress-energy tensor in terms of the Green's function. We discuss its structure in the region between the plates. We compute the renormalized vacuum stress, which is obtained as the difference between the vacuum stress in the presence of the plates and that of the vacuum. The Casimir force is evaluated in an analytical fashion by two methods: by differentiating the renormalized global energy density and by computing the normal-normal component of the renormalized vacuum stress. We compute the local Casimir energy, which is found to diverge as approaching the plates, and we demonstrate that it does not contribute to the observable force.

  10. Test of Lorentz and CPT violation with short baseline neutrino oscillation excesses

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar-Arevalo, A.A. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, D.F. 04510 (Mexico); Anderson, C.E. [Yale University, New Haven, CT 06520 (United States); Bazarko, A.O. [Princeton University, Princeton, NJ 08544 (United States); Brice, S.J.; Brown, B.C. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Bugel, L. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Cao, J. [University of Michigan, Ann Arbor, MI 48109 (United States); Coney, L. [Columbia University, New York, NY 10027 (United States); Conrad, J.M. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Cox, D.C. [Indiana University, Bloomington, IN 47405 (United States); Curioni, A. [Yale University, New Haven, CT 06520 (United States); Dharmapalan, R. [University of Alabama, Tuscaloosa, AL 35487 (United States); Djurcic, Z. [Argonne National Laboratory, Argonne, IL 60439 (United States); Finley, D.A. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Fleming, B.T. [Yale University, New Haven, CT 06520 (United States); Ford, R.; Garcia, F.G. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Garvey, G.T. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Grange, J. [University of Florida, Gainesville, FL 32611 (United States); Green, C. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); and others

    2013-01-29

    The sidereal time dependence of MiniBooNE {nu}{sub e} and {nu}{sup Macron }{sub e} appearance data is analyzed to search for evidence of Lorentz and CPT violation. An unbinned Kolmogorov-Smirnov (K-S) test shows both the {nu}{sub e} and {nu}{sup Macron }{sub e} appearance data are compatible with the null sidereal variation hypothesis to more than 5%. Using an unbinned likelihood fit with a Lorentz-violating oscillation model derived from the Standard Model Extension (SME) to describe any excess events over background, we find that the {nu}{sub e} appearance data prefer a sidereal time-independent solution, and the {nu}{sup Macron }{sub e} appearance data slightly prefer a sidereal time-dependent solution. Limits of order 10{sup -20} GeV are placed on combinations of SME coefficients. These limits give the best limits on certain SME coefficients for {nu}{sub {mu}}{yields}{nu}{sub e} and {nu}{sup Macron }{sub {mu}}{yields}{nu}{sup Macron }{sub e} oscillations. The fit values and limits of combinations of SME coefficients are provided.

  11. Reconcile Planck-scale discreteness and the Lorentz-Fitzgerald contraction

    International Nuclear Information System (INIS)

    Rovelli, Carlo; Speziale, Simone

    2003-01-01

    A Planck-scale minimal observable length appears in many approaches to quantum gravity. It is sometimes argued that this minimal length might conflict with Lorentz invariance, because a boosted observer can see the minimal length further Lorentz contracted. We show that this is not the case within loop quantum gravity. In loop quantum gravity the minimal length (more precisely, minimal area) does not appear as a fixed property of geometry, but rather as the minimal (nonzero) eigenvalue of a quantum observable. The boosted observer can see the same observable spectrum, with the same minimal area. What changes continuously in the boost transformation is not the value of the minimal length: it is the probability distribution of seeing one or the other of the discrete eigenvalues of the area. We discuss several difficulties associated with boosts and area measurement in quantum gravity. We compute the transformation of the area operator under a local boost, propose an explicit expression for the generator of local boosts, and give the conditions under which its action is unitary

  12. Test of Lorentz and CPT violation with short baseline neutrino oscillation excesses

    International Nuclear Information System (INIS)

    Aguilar-Arevalo, A.A.; Anderson, C.E.; Bazarko, A.O.; Brice, S.J.; Brown, B.C.; Bugel, L.; Cao, J.; Coney, L.; Conrad, J.M.; Cox, D.C.; Curioni, A.; Dharmapalan, R.; Djurcic, Z.; Finley, D.A.; Fleming, B.T.; Ford, R.; Garcia, F.G.; Garvey, G.T.; Grange, J.; Green, C.

    2013-01-01

    The sidereal time dependence of MiniBooNE ν e and ν ¯ e appearance data is analyzed to search for evidence of Lorentz and CPT violation. An unbinned Kolmogorov–Smirnov (K–S) test shows both the ν e and ν ¯ e appearance data are compatible with the null sidereal variation hypothesis to more than 5%. Using an unbinned likelihood fit with a Lorentz-violating oscillation model derived from the Standard Model Extension (SME) to describe any excess events over background, we find that the ν e appearance data prefer a sidereal time-independent solution, and the ν ¯ e appearance data slightly prefer a sidereal time-dependent solution. Limits of order 10 −20 GeV are placed on combinations of SME coefficients. These limits give the best limits on certain SME coefficients for ν μ →ν e and ν ¯ μ →ν ¯ e oscillations. The fit values and limits of combinations of SME coefficients are provided.

  13. Implications of Lorentz covariance for the guidance equation in two-slit quantum interference

    International Nuclear Information System (INIS)

    Holland, Peter; Philippidis, Chris

    2003-01-01

    It is known that Lorentz covariance fixes uniquely the current and the associated guidance law in the trajectory interpretation of quantum mechanics for spin-(1/2) particles. In the nonrelativistic domain this implies a guidance law for the electron which differs by an additional spin-dependent term from that originally proposed by de Broglie and Bohm. In this paper, we explore some of the implications of the modified guidance law. We bring out a property of mutual dependence in the particle coordinates that arises in product states, and show that the quantum potential has scalar and vector components, which implies the particle is subject to a Lorentz-like force. The conditions for the classical limit and the limit of negligible spin are given, and the empirical sufficiency of the model is demonstrated. We then present a series of calculations of the trajectories based on two-dimensional Gaussian wave packets which illustrate how the additional spin-dependent term plays a significant role in structuring both the individual trajectories and the ensemble. The single packet corresponds to quantum inertial motion. The distinct features encountered when the wave function is a product or a superposition are explored, and the trajectories that model the two-slit experiment are given. The latter paths exhibit several new characteristics compared with the original de Broglie-Bohm ones, such as crossing of the axis of symmetry

  14. Quantitative in situ magnetization reversal studies in Lorentz microscopy and electron holography

    International Nuclear Information System (INIS)

    Rodríguez, L.A.; Magén, C.; Snoeck, E.; Gatel, C.; Marín, L.; Serrano-Ramón, L.

    2013-01-01

    A generalized procedure for the in situ application of magnetic fields by means of the excitation of the objective lens for magnetic imaging experiments in Lorentz microscopy and electron holography is quantitatively described. A protocol for applying magnetic fields with arbitrary in-plane magnitude and orientation is presented, and a freeware script for Digital Micrograph ™ is provided to assist the operation of the microscope. Moreover, a method to accurately reconstruct hysteresis loops is detailed. We show that the out-of-plane component of the magnetic field cannot be always neglected when performing quantitative measurements of the local magnetization. Several examples are shown to demonstrate the accuracy and functionality of the methods. - Highlights: • Generalized procedure for application of magnetic fields with the TEM objective lens. • Arbitrary in-plane magnetic field magnitude and orientation can be applied. • Method to accurately reconstruct hysteresis loops by electron holography. • Out-of-plane field component should be considered in quantitative measurements. • Examples to illustrate the method in Lorentz microscopy and electron holography

  15. FULL ELECTROMAGNETIC SIMULATION OF COHERENT SYNCHROTRON RADIATION VIA THE LORENTZ-BOOSTED FRAME APPROACH

    International Nuclear Information System (INIS)

    Fawley, William M.; Vay, Jean-Luc

    2010-01-01

    Numerical simulation of some systems containing charged particles with highly relativistic directed motion can by speeded up by orders of magnitude by choice of the proper Lorentz-boosted frame. Orders of magnitude speedup has been demonstrated for simulations from first principles of laser-plasma accelerator, free electron laser, and particle beams interacting with electron clouds. Here we address the application of the Lorentz-boosted frame approach to coherent synchrotron radiation (CSR), which can be strongly present in bunch compressor chicanes. CSR is particularly relevant to the next generation of x-ray light sources and is simultaneously difficult to simulate in the lab frame because of the large ratio of scale lengths. It can increase both the incoherent and coherent longitudinal energy spread, effects that often lead to an increase in transverse emittance. We have adapted the WARP code to simulate CSR emission along a simple dipole bend. We present some scaling arguments for the possible computational speed up factor in the boosted frame and initial 3D simulation results.

  16. Searching the laws of thermodynamics in the Lorentz-invariant thermal energy propagation equation

    International Nuclear Information System (INIS)

    Szőllősi, Tibor; Márkus, Ferenc

    2015-01-01

    Highlights: • We study the laws of thermodynamics in a Lorentz-invariant Lagrangian model. • We calculate the canonical momenta and tensor. • We give the correspondents of the laws of thermodynamics in the model. • The developed theory is considered to be coherent with the laws of thermodynamics. - Abstract: In earlier works it has been shown that the Lorentz-invariant description of thermal energy transfer can be deduced from a Lagrangian description, by which the definition of a dynamic temperature is involved at the same time. It is also proved that this formulation includes the classical Fourier heat propagation as a natural limit. However, the relation of the elaborated theory to the basic laws of thermodynamics remained open. This connection is studied in details in the present paper. It is posted that though strictly speaking the model is meaningless in equilibrium and corresponds only to the non-equilibrium parts of the temperature, it respects the laws of thermodynamics and provides a way to transfer some form of them into the validity-area of the model

  17. Experimental evaluation of the ‘transport-of-intensity’ equation for magnetic phase reconstruction in Lorentz transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kohn, Amit, E-mail: akohn@post.tau.ac.il [Department of Materials Science and Engineering, Faculty of Engineering, Tel Aviv University, 69978 Tel Aviv (Israel); Habibi, Avihay; Mayo, Martin [Department of Materials Engineering, Ben-Gurion University of the Negev, 84105 Beer Sheva (Israel)

    2016-01-15

    The ‘transport-of-intensity’ equation (TIE) is a general phase reconstruction methodology that can be applied to Lorentz transmission electron microscopy (TEM) through the use of Fresnel-contrast (defocused) images. We present an experimental study to test the application of the TIE for quantitative magnetic mapping in Lorentz TEM without aberration correction by examining sub-micrometer sized Ni{sub 80}Fe{sub 20} (Permalloy) elements. For a JEOL JEM 2100F adapted for Lorentz microscopy, we find that quantitative magnetic phase reconstructions are possible for defoci distances ranging between approximately 200 μm and 800 μm. The lower limit originates from competing sources of image intensity variations in Fresnel-contrast images, namely structural defects and diffraction contrast. The upper defocus limit is due to a numerical error in the estimation of the intensity derivative based on three images. For magnetic domains, we show quantitative reconstructions of the product of the magnetic induction vector and thickness in element sizes down to approximately 100 nm in lateral size and 5 nm thick resulting in a minimal detection of 5 T nm. Three types of magnetic structures are tested in terms of phase reconstruction: vortex cores, domain walls, and element edges. We quantify vortex core structures at a diameter of 12 nm while the structures of domain walls and element edges are characterized qualitatively. Finally, we show by image simulations that the conclusions of this experimental study are relevant to other Lorentz TEM in which spherical aberration and defocus are dominant aberrations. - Highlights: • Testing TIE for quantitative magnetic phase reconstruction in Lorentz TEM. • Quantitative magnetic phase reconstructions for defoci distances in 200–800 μm range. • Minimal detection of the product of the magnetic induction and thickness is 5 T nm. • Quantitative phase reconstruction for vortex core structures at 12 nm diameter. • Observations

  18. O ensaio como narrativa

    Directory of Open Access Journals (Sweden)

    Pedro Duarte

    2016-02-01

    Full Text Available O artigo tenta demonstrar que todos os textos, mesmo aqueles cuja natureza é teórica, têm alguma forma de narrativa. Nem sempre são personagens que os ocupam, podem ser ideias, mas mesmo assim há um enredo conceitual que se passa. Modernamente, a forma dessa narrativa foi sobretudo o sistema, com a pretensão totalizadora presente, por exemplo, na filosofia de Hegel. Contemporaneamente, porém, a forma do ensaio – surgida ainda na era moderna – ganha destaque por sua forma descontínua de narrar. O objetivo do artigo é apontar que, se o ensaio é uma forma, como explicitaram Lukács, Benjamin e Adorno, ele é também uma forma de narrar – ainda que de narrar conceitualmente objetos da cultura.

  19. La Justicia como virtud

    Directory of Open Access Journals (Sweden)

    Martínez-Sicluna y Sepúlveda, Consuelo

    2003-07-01

    Full Text Available El sentimiento de la justicia representa el hábito de conducta por el que nos vemos obligados, en cualquier relación, a dar a cada uno lo suyo. Ahora bien, esta disposición del espíritu se inscribe en las coordenadas que definen al hombre: verdad, libertad y bien. El hombre como ser racional y por tanto libre: el único ser que se determina a sí mismo y que alcanza en el bien el sentido de su proyección personal, esto es, la perfección. Dar a cada uno lo suyo es dar al sujeto el reconocimiento de este fundamento ontológico.

  20. Como comunicar la Alegria

    Directory of Open Access Journals (Sweden)

    Pablo Portales

    2015-01-01

    Full Text Available Se ofrece un amplio análisis sobre la industria electoral, recordando que un candidato a presidente es "un producto para la venta". Se Desmenuzan las estrategias utilizadas en el plebiscito chileno,las elecciones norteamericanas con el NO a BUSH. El Mercadeo Social es una nueva metodología utilizada en proyectos de desarrollo a nivel de campo por ello se hace un esclarecimiento y clarifica el vínculo con la comunicación. Se agrega temas como: Los modelos de recepción de mensajes cuyos marcos conceptuales y metodologías aún no se han adaptado al potencial de esta línea de trabajo.Se analiza la agonía de las radios mineras en Bolivia en la que 42 años de historia y heroísmo se desmoronan.

  1. El inquisidor como profesor

    Directory of Open Access Journals (Sweden)

    Adriano PROSPERI

    2009-12-01

    Full Text Available Giovanni Botero, en una célebre página de su Ragion di stato, se detuvo sobre el tema de la fuerza de la religión en los gobiernos. Esta función de la religión cristiana —para Botero, católica— es garante del orden público y se presenta también como opuesta a la generadora de desorden de Lutero y Calvino, quienes siembran por todo cizañas y revoluciones de estados y ruinas de los reinos. Estamos en los orígenes del esquema historiografía de la periodización de la Edad Moderna que confió precisamente a la Reforma el papel de nodriza de las revoluciones que nacieron en Europa.

  2. Ecuaciones de predicción de la talla a partir de la altura de la rodilla de los adultos mayores de Costa Rica

    Directory of Open Access Journals (Sweden)

    Pamela Jiménez - Fontana

    2014-01-01

    Full Text Available La talla es un parámetro antropométrico que permite evaluar el estado de salud de los adultos mayores, ya que nos permite determinar el índice de masa corporal y, con este, los niveles de o besidad, el grado de desnutrición proteico calórica, y otros factores de riesgo. Sin embargo, en adultos mayores con dificultad de movimiento, enfermedades avanzadas, o cambios en la curvatura normal de la columna vertebral, es complicado realizar una corr ecta medición de la talla. Cuando no se puede realizar una correcta medición de la talla, se pueden utilizar modelos de regresión lineal utilizando otras variables antropométricas para estimar la talla. Por ende, el objetivo de este estudio es definir ecua ciones de predicción de la talla a partir de la altura de la rodilla y la edad para los adultos mayores de Costa Rica por sexo. El estudio utilizó los datos de la encuesta longitudinal CRELES, muestra representativa de los adultos mayores de Costa Rica. Lo s coeficientes de predicción estimados a partir de CRELES se compararon con los coeficientes de predicción estimados por los modelos (externos de Chumlea, Roche, y Steinbaugh (1985 y Palloni y Guend (2005. Los coeficientes de predicción estimados con ba se a CRELES son, en su mayoría, significativamente diferentes a los coeficientes de los modelos externos; además, los coeficientes de predicción estimados con la muestra CRELES producen residuos y errores puros menores que los modelos externos. Se recomien da utilizar las nuevas ecuaciones de predicción planteadas en este estudio para estimar la talla de adultos mayores costarricenses con problemas fisiológicos y de movilidad.

  3. Effects of Lorentz violation through the γe → Wνe process in the Standard Model extension

    International Nuclear Information System (INIS)

    Aranda, J I; Ramírez-Zavaleta, F; Tututi, E S; Rosete, D A; Tlachino, F J; Toscano, J J

    2014-01-01

    Physics beyond the Fermi scale could show up through deviations of the gauge couplings predicted by the electroweak Yang–Mills sector. This possibility is explored in the context of the International Linear Collider through the helicity amplitudes for the γe → Wν e reaction to which the trilinear WWγ coupling contributes. The new physics effects on this vertex are parametrized in a model-independent fashion through an effective electroweak Yang–Mills sector, which is constructed by considering two essentially different sources of new physics. In one scenario, Lorentz violation will be considered exclusively as the source of new physics effects. This type of new physics is considered in an extension of the Standard Model (SM) that is known as the SM extension (SME), which is an effective field theory that contemplates CPT and Lorentz violation in a model-independent fashion. Any source of new physics that respects the Lorentz symmetry will be considered within the general context of the well-known conventional effective SM (CESM) extension. Both the SME and CESM descriptions include gauge invariant operators of dimension higher than 4, which, in general, transform as Lorentz tensors of rank higher than zero. In the former theory, observer Lorentz invariants are constructed by contracting these operators with constant Lorentz tensors, whereas in the latter the corresponding Lorentz invariant interactions are obtained contracting such operators with products of the metric tensor. In this work, we focus on a dimension 6 Lorentz 2-tensor, O αβ , which arises from an effective SU(2) L Yang–Mills sector. Contributions to the WWγ coupling arising from dimension 4 operators are ignored since they are strongly constrained. When these operators are contracted with a constant antisymmetric background tensor, b αβ , the corresponding observer invariant belongs to the SME, whereas if they are contracted with the metric tensor, g αβ , an effective interaction in

  4. Lorentz invariance violation in the neutrino sector: a joint analysis from big bang nucleosynthesis and the cosmic microwave background

    Science.gov (United States)

    Dai, Wei-Ming; Guo, Zong-Kuan; Cai, Rong-Gen; Zhang, Yuan-Zhong

    2017-06-01

    We investigate constraints on Lorentz invariance violation in the neutrino sector from a joint analysis of big bang nucleosynthesis and the cosmic microwave background. The effect of Lorentz invariance violation during the epoch of big bang nucleosynthesis changes the predicted helium-4 abundance, which influences the power spectrum of the cosmic microwave background at the recombination epoch. In combination with the latest measurement of the primordial helium-4 abundance, the Planck 2015 data of the cosmic microwave background anisotropies give a strong constraint on the deformation parameter since adding the primordial helium measurement breaks the degeneracy between the deformation parameter and the physical dark matter density.

  5. Lorentz invariance violation in the neutrino sector: a joint analysis from big bang nucleosynthesis and the cosmic microwave background

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Wei-Ming; Cai, Rong-Gen [Chinese Academy of Sciences, CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, P.O. Box 2735, Beijing (China); University of Chinese Academy of Sciences, School of Physical Sciences, Beijing (China); Guo, Zong-Kuan [Chinese Academy of Sciences, CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, P.O. Box 2735, Beijing (China); University of Chinese Academy of Sciences, School of Astronomy and Space Science, Beijing (China); Zhang, Yuan-Zhong [Chinese Academy of Sciences, CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, P.O. Box 2735, Beijing (China)

    2017-06-15

    We investigate constraints on Lorentz invariance violation in the neutrino sector from a joint analysis of big bang nucleosynthesis and the cosmic microwave background. The effect of Lorentz invariance violation during the epoch of big bang nucleosynthesis changes the predicted helium-4 abundance, which influences the power spectrum of the cosmic microwave background at the recombination epoch. In combination with the latest measurement of the primordial helium-4 abundance, the Planck 2015 data of the cosmic microwave background anisotropies give a strong constraint on the deformation parameter since adding the primordial helium measurement breaks the degeneracy between the deformation parameter and the physical dark matter density. (orig.)

  6. Symanzik–Becchi–Rouet–Stora lessons on renormalizable models with broken symmetry: The case of Lorentz violation

    Energy Technology Data Exchange (ETDEWEB)

    Del Cima, Oswaldo M.; Franco, Daniel H.T.; Piguet, Olivier, E-mail: opiguet@pq.cnpq.br

    2016-11-15

    In this paper, we revisit the issue intensively studied in recent years on the generation of terms by radiative corrections in models with broken Lorentz symmetry. The algebraic perturbative method of handling the problem of renormalization of the theories with Lorentz symmetry breaking, is used. We hope to make clear the Symanzik's aphorism: “Whether you like it or not, you have to include in the lagrangian all counter terms consistent with locality and power-counting, unless otherwise constrained by Ward identities.”{sup 1}.

  7. Lorentz invariance violation in the neutrino sector: a joint analysis from big bang nucleosynthesis and the cosmic microwave background

    International Nuclear Information System (INIS)

    Dai, Wei-Ming; Cai, Rong-Gen; Guo, Zong-Kuan; Zhang, Yuan-Zhong

    2017-01-01

    We investigate constraints on Lorentz invariance violation in the neutrino sector from a joint analysis of big bang nucleosynthesis and the cosmic microwave background. The effect of Lorentz invariance violation during the epoch of big bang nucleosynthesis changes the predicted helium-4 abundance, which influences the power spectrum of the cosmic microwave background at the recombination epoch. In combination with the latest measurement of the primordial helium-4 abundance, the Planck 2015 data of the cosmic microwave background anisotropies give a strong constraint on the deformation parameter since adding the primordial helium measurement breaks the degeneracy between the deformation parameter and the physical dark matter density. (orig.)

  8. On the classical Maxwell-Lorentz electrodynamics, the electron inertia problem, and the Feynman proper time paradigm

    International Nuclear Information System (INIS)

    Prykarpatsky, A.K.; Bogolubov, J.R.

    2016-01-01

    The classical Maxwell electromagnetic field and the Lorentz-type force equations are rederived in the framework of the Feynman proper time paradigm and the related vacuum field theory approach. The classical Ampere law origin is rederived, and its relationship with the Feynman proper time paradigm is discussed. The electron inertia problem is analyzed in detail within the Lagrangian and Hamiltonian formalisms and the related pressure-energy compensation principle of stochastic electrodynamics. The modified Abraham-Lorentz damping radiation force is derived and the electromagnetic electron mass origin is argued

  9. La persona como creatura

    Directory of Open Access Journals (Sweden)

    Emmanuel Housset

    2010-01-01

    Full Text Available El artículo de Emmanuel Housset implica un esfuerzo de rehabilitación del concepto «persona» para la filosofía contemporánea y la fenomenología. Para ello el autor busca mostrar cómo poco a poco «persona» tomó otra significación que la de «personaje» o sujeto de derecho. Es en autores como san Agustín y santo Tomás de Aquino que se halla un acceso diferente que pone el énfasis más bien en su carácter relacional y responsivo de la persona, antes que en su dimensión autónoma y autotélica. Tal dimensión aparece, según Housset, junto con la idea de persona como creatura y en oposición a la de individuo racional dueño de sí. La dimensión afectiva, la personalidad despertada por las diversas figuras de la alteridad son algunas de las dimensiones de la persona que examina el autor a partir del examen de la carne, las pasiones, la memoria, la historicidad y el amor alteridad.Emmanuel Housset's paper is an effort to revitalize the concept of 'person' for contemporary philosophy and phenomenology To this end the author looks to show how little by little the understanding of 'person' took on a different meaning to that of 'character' or "right bearing individual". It is in authors such as St. Augustine and St. Thomas Aquinas that a different approach is found, one that puts emphasis on the relational and responsive character of a person, rather than on the autonomous and auto telic dimension. According to Housset, such a dimension appears together with the idea of the person as a creation, and in opposition to the idea of the rational individual, that is his own master. The emotional dimension and the personality that is awoken by the many figures of alterity are some of the dimensions of the person that the author analyzes, based on examining the flesh, passions, memory historicity and love.

  10. Impacto de las telecomunicaciones en la gestión de las instituciones de educación superior públicas de México: Un modelo de ecuaciones estructurales (Impact of the telecommunications in the management of the public institutions of higher education of Mexico: A model of structural equations

    Directory of Open Access Journals (Sweden)

    Zambrano, Alberto

    2016-07-01

    Full Text Available Abstract: The present research had as objective to know information regarding the level of relation of the telecommunications and the user and financial management in the educational institutions of higher level (IES in Mexico, through a structural equations model. The methodology to know the impact of telecommunications in the management of users and financial management consisted of conducting surveys with 28 questions to a sample of 34 public universities in Mexico. The application of the same was of induced character, and of structured form with questions mostly by a Likert scale. Three hypotheses were formulated that we considered fundamental. To verify, a model of structural equations was designed with the telecommunications service, internal process management, user management and financial management as constructs. With data from the surveys, a cross-sectional database was created and introduced to specialized statistical analysis software called Smart PLS V. 2.0 (M3. The results of the statistical model show that the telecommunications service provided by IHEs in Mexico has a strong relationship with the management of internal processes and this in turn has a very strong relationship with user management and financial management. It is generally concluded that telecommunications that exist in public IES have a strong influence on user management and financial management supported by Internal Process Management. Resumen. La presente investigación tuvo como objetivo conocer información respecto al nivel de relación de las telecomunicaciones y las gestiones de usuarios y financieras en las instituciones educativas de nivel superior (IES en México, mediante un modelo de ecuaciones estructurales. La metodología para conocer el impacto de las telecomunicaciones en la gestión de usuarios y gestión financiera, consistió en realizar encuestas con 28 preguntas a una muestra de 34 universidades públicas de México. La aplicación de los

  11. El signo como emblema

    Directory of Open Access Journals (Sweden)

    Sáez, Carlos

    2003-06-01

    Full Text Available The aim of this article is to study the signs and symbols that appear in the hispanic medieval documents and manuscripts. These signs and symbols have usually been considered simply as mere elements to validate the charters. However, these alements were useful as a mean of visual communication between the high classes, able to generate charters, and the rest of medieval society—the majority illiterate— who received those charters. Because of their inability of understand an alphabetical code, they needed the graphic help to comprehend the message. Besides this, the article deals with non diplomatic signs and their function.

    Este artículo se centra en los signos o símbolos presentes en los documentos y manuscritos medievales hispanos, que habitualmente han sido tratados como meros elementos de validación de los diplomas. Pero estos elementos servían también de nexos de comunicación visual entre las clases poderosas, capaces de producir escritos, y los demás miembros de la sociedad medieval, receptores y destinatarios de tales escritos, en su mayoría analfabetos. Precisamente por esta razón, su incapacidad de descifrar un código alfabético, necesitan de auxilio gráfico para acercarse a la comprensión del mensaje. Asimismo, tratamos de los signos no diplomáticos y de su función.

  12. O analista como testemunha

    Directory of Open Access Journals (Sweden)

    Jô Gondar

    2016-04-01

    Full Text Available Resumo A proposta deste artigo é pensar o lugar da testemunha como um lugar terceiro que o analista, na clínica do traumático, é capaz de sustentar. Nos sonhos traumáticos, segundo Ferenczi, já existe a convocação de um terceiro. Não se trata da testemunha da esfera do Direito, tampouco do lugar do pai ou da Lei simbólica. Trata-se de um terceiro espaço que pode ser chamado de potencial, espaço intersticial, indeterminado e informe no qual circula - e aos poucos ganha forma -, algo que a princípio seria incomunicável. Esse espaço permite e suporta a literalidade da narrativa testemunhal, seus titubeios, paradoxos e silêncios. Mais do que uma teoria do trauma, a noção de espaço potencial seria a grande contribuição da psicanálise às pesquisas teóricas e clínicas com sobreviventes de campos de extermínio, de situações de tortura e de violência.

  13. Arte como espelho

    Directory of Open Access Journals (Sweden)

    Pedro Süssekind

    2016-12-01

    Full Text Available Este artigo tem como ponto de partida o exemplo da relação espelhada entre um livro e uma pintura de mesmo nome: o retrato que Lucian Freud fez do crítico de arte Martin Gayford e o diário que esse crítico escreveu sobre seu retratista, ambas as obras chamadas Homem com cachecol azul. A partir do exemplo, discuto a metáfora do espelho para caracterizar a arte, recorrendo para isso à teoria da representação artísticas elaborada pelo filósofo norte-americano Arthur Danto no artigo “O mundo da arte”, de 1964, e no primeiro capítulo do livro A transfiguração do lugar-comum, de 1981. Recorro, por fim, a dois exemplos artísticos de espelhamento na representação analisados por Danto em O abuso da beleza, de 2003, um quadro holandês do século dezessete e um poema de Rainer Maria Rilke.

  14. El riesgo como oportunidad

    Directory of Open Access Journals (Sweden)

    Daniela Gargantini

    2003-01-01

    Full Text Available Durante los últimos años el crecimiento mundial de catástrofes naturales ha ido en franco aumento. Sin embargo, desde un enfoque sistémico puede verificarse que la gran mayoría de los desastres se origina en los países en desarrollo (entre ellos los latinoamericanos, siendo las pérdidas en ellos significativamente más altas que en los países industrializados. Bajo esta postura los desastres no son sólo naturales sino socio- naturales, enfatizando la estrecha relación de causalidad entre modelos de desarrollo y urbanización y procesos de generación de riesgos, al incrementar la vulnerabilidad de los sectores más desprotegidos. El desastre pone en evidencia así una situación (la pobreza y segregación urbana ya existente, pero no considerada hasta el momento de la catástrofe. Frente a este panorama el desastre aparece como oportunidad que precipita tres catalizadores de políticas habitacionales: tierra, asistencia técnica y financiamiento, incrementando la celeridad y la creatividad de las respuestas. El interrogante que surge es por qué esperar el desastre para ponerlos en marcha, cuando ninguno de ellos es estrictamente dependiente de la situación de riesgo, sino sujeto de luchas de poder.

  15. Endomarketing: como diferencial competitivo

    Directory of Open Access Journals (Sweden)

    Karin Birck

    2013-05-01

    Full Text Available Atualmente, com a profissionalização das empresas e com a grande concorrência no mercado, observa-se uma demanda cada vez maior de gestores comprometidos com o bem-estar pessoal e profissional de seus colaboradores. E, com esse intuito, de apresentar algumas idéias básicas de gestão voltadas à aplicação nas mais diversas técnicas de Endomarketing. Demonstra assim, a importância da utilização de feedback, tanto por parte dos colaboradores quanto dos gestores, destacando a importância de trabalhos de motivação, do clima organizacional favorável e de uma comunicação interna eficaz e a necessidade ímpar de tratar o colaborador como o diferencial dentro de uma empresa. Desta forma, foi realizada uma pesquisa bibliográfica que auxiliará e dará subsídios que lhe permitam retribuir em ações e atitudes de sucesso e, também, fazer um confronto de idéias, onde os autores apresentam suas mais diversas opiniões. Contudo, valendo-se, muitas vezes, de narrativas de experiências de outros gestores e até mesmo de suas próprias, tirando cada um suas próprias conclusões.

  16. Confirmación de un modelo explicativo del estrés y de los síntomas psicosomáticos mediante ecuaciones estructurales Confirmation of a descriptive model of stress and psychosomatic symptoms using structural equations

    OpenAIRE

    Mónica Teresa González Ramírez; René Landero Hernández

    2008-01-01

    OBJETIVO: Evaluar mediante ecuaciones estructurales un modelo del estrés que integra la explicación de los síntomas psicosomáticos y la teoría transaccional del estrés. MÉTODOS: Se seleccionó una muestra representativa, aleatoria y estratificada de estudiantes de la Facultad de Psicología de la Universidad Autónoma de Nuevo León, México. Los sujetos se seleccionaron a partir del listado de alumnos proporcionado por la facultad. Se utilizaron cuestionarios de autoevaluación con adecuadas propi...

  17. Lorentz-violating contributions to the nuclear Schiff moment and nuclear EDM

    Science.gov (United States)

    Araujo, Jonas B.; Casana, Rodolfo; Ferreira, Manoel M.

    2018-03-01

    In the context of an atom endowed with nuclear electric dipole moments (EDM), we consider the effects on the Schiff moment of C P T -even Lorentz-violating (LV) terms that modify the Coulomb potential. First, we study the modifications on the Schiff moment when the nucleus interacts with the electronic cloud by means of a Coulomb potential altered only by the P -even LV components. Next, by supposing the existence of an additional intrinsic LV EDM generated by other LV sources, we assess the corrections to the Schiff moment when the interaction nucleus-electrons runs mediated by a Coulomb potential modified by both the P -odd and P -even LV components. We then use known estimates and EDM measurements to discuss upper bounds on the new Schiff moment components and the possibility of a nuclear EDM component ascribed to LV effects.

  18. Critical current enhancement by Lorentz force reduction in superconductor-ferromagnet nanocomposites

    International Nuclear Information System (INIS)

    Blamire, M G; Dinner, R B; Wimbush, S C; MacManus-Driscoll, J L

    2009-01-01

    Ferromagnetic pinning centres in superconductors form much deeper potential wells than equivalent insulating or metallic non-superconducting inclusions. However, the resultant pinning forces arising from magnetic inclusions are low because the magnetic interaction takes place over the length scale of the magnetic penetration depth which is large in technological superconductors. Nonetheless, we show that a magnetic inclusion can also reduce the Lorentz force on a vortex, yielding a substantially enhanced critical current density for a given pinning force. We calculate this enhancement for a single vortex pinned by a paramagnetic cylinder as well as a vortex lattice interacting with magnetic inclusions, and find that the inclusion of ferromagnetic particles or rods offers a practical means of enhancing the critical currents in oxide high temperature superconductors.

  19. Search for Violation of $CPT$ and Lorentz invariance in ${B_s^0}$ meson oscillations

    CERN Document Server

    Abazov, Victor Mukhamedovich; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd; Agnew, James P; Alexeev, Guennadi D; Alkhazov, Georgiy D; Alton, Andrew K; Askew, Andrew Warren; Atkins, Scott; Augsten, Kamil; Avila, Carlos A; Badaud, Frederique; Bagby, Linda F; Baldin, Boris; Bandurin, Dmitry V; Banerjee, Sunanda; Barberis, Emanuela; Baringer, Philip S; Bartlett, JFrederick; Bassler, Ursula Rita; Bazterra, Victor; Bean, Alice L; Begalli, Marcia; Bellantoni, Leo; Beri, Suman B; Bernardi, Gregorio; Bernhard, Ralf Patrick; Bertram, Iain A; Besancon, Marc; Beuselinck, Raymond; Bhat, Pushpalatha C; Bhatia, Sudeep; Bhatnagar, Vipin; Blazey, Gerald Charles; Blessing, Susan K; Bloom, Kenneth A; Boehnlein, Amber S; Boline, Daniel Dooley; Boos, Edward E; Borissov, Guennadi; Borysova, Maryna; Brandt, Andrew; Brandt, Oleg; Brock, Raymond L; Bross, Alan D; Brown, Duncan Paul; Bu, Xue-Bing; Buehler, Marc; Buescher, Volker; Bunichev, Viacheslav Yevgenyevich; Burdin, Sergey; Buszello, Claus Peter; Camacho-Perez, Enrique; Casey, Brendan Cameron Kieran; Castilla-Valdez, Heriberto; Caughron, Seth Aaron; Chakrabarti, Subhendu; Chan, Kwok Ming Leo; Chandra, Avdhesh; Chapon, Emilien; Chen, Guo; Cho, Sung-Woong; Choi, Suyong; Choudhary, Brajesh C; Cihangir, Selcuk; Claes, Daniel R; Clutter, Justace Randall; Cooke, Michael P; Cooper, William Edward; Corcoran, Marjorie D; Couderc, Fabrice; Cousinou, Marie-Claude; Cuth, Jakub; Cutts, David; Das, Amitabha; Davies, Gavin John; de Jong, Sijbrand Jan; De La Cruz-Burelo, Eduard; Deliot, Frederic; Demina, Regina; Denisov, Dmitri S; Denisov, Sergei P; Desai, Satish Vijay; Deterre, Cecile; DeVaughan, Kayle Otis; Diehl, HThomas; Diesburg, Michael; Ding, Pengfei; Dominguez, DAaron M; Dubey, Abhinav Kumar; Dudko, Lev V; Duperrin, Arnaud; Dutt, Suneel; Eads, Michael T; Edmunds, Daniel L; Ellison, John A; Elvira, VDaniel; Enari, Yuji; Evans, Harold G; Evdokimov, Anatoly V; Evdokimov, Valeri N; Faure, Alexandre; Feng, Lei; Ferbel, Thomas; Fiedler, Frank; Filthaut, Frank; Fisher, Wade Cameron; Fisk, HEugene; Fortner, Michael R; Fox, Harald; Fuess, Stuart C; Garbincius, Peter H; Garcia-Bellido, Aran; Garcia-Gonzalez, Jose Andres; Gavrilov, Vladimir B; Geng, Weigang; Gerber, Cecilia Elena; Gershtein, Yuri S; Ginther, George E; Gogota, Olga; Golovanov, Georgy Anatolievich; Grannis, Paul D; Greder, Sebastien; Greenlee, Herbert B; Grenier, Gerald Jean; Gris, Phillipe Luc; Grivaz, Jean-Francois; Grohsjean, Alexander; Gruenendahl, Stefan; Gruenewald, Martin Werner; Guillemin, Thibault; Gutierrez, Gaston R; Gutierrez, Phillip; Haley, Joseph Glenn Biddle; Han, Liang; Harder, Kristian; Harel, Amnon; Hauptman, John Michael; Hays, Jonathan M; Head, Tim; Hebbeker, Thomas; Hedin, David R; Hegab, Hatim; Heinson, Ann; Heintz, Ulrich; Hensel, Carsten; Heredia-De La Cruz, Ivan; Herner, Kenneth Richard; Hesketh, Gavin G; Hildreth, Michael D; Hirosky, Robert James; Hoang, Trang; Hobbs, John D; Hoeneisen, Bruce; Hogan, Julie; Hohlfeld, Mark; Holzbauer, Jenny Lyn; Howley, Ian James; Hubacek, Zdenek; Hynek, Vlastislav; Iashvili, Ia; Ilchenko, Yuriy; Illingworth, Robert A; Ito, Albert S; Jabeen, Shabnam; Jaffre, Michel J; Jayasinghe, Ayesh; Jeong, Min-Soo; Jesik, Richard L; Jiang, Peng; Johns, Kenneth Arthur; Johnson, Emily; Johnson, Marvin E; Jonckheere, Alan M; Jonsson, Per Martin; Joshi, Jyoti; Jung, Andreas Werner; Juste, Aurelio; Kajfasz, Eric; Karmanov, Dmitriy Y; Katsanos, Ioannis; Kaur, Manbir; Kehoe, Robert Leo Patrick; Kermiche, Smain; Khalatyan, Norayr; Khanov, Alexander; Kharchilava, Avto; Kharzheev, Yuri N; Kiselevich, Ivan Lvovich; Kohli, Jatinder M; Kozelov, Alexander V; Kraus, James Alexander; Kumar, Ashish; Kupco, Alexander; Kurca, Tibor; Kuzmin, Valentin Alexandrovich; Lammers, Sabine Wedam; Lebrun, Patrice; Lee, Hyeon-Seung; Lee, Seh-Wook; Lee, William M; Lei, Xiaowen; Lellouch, Jeremie; Li, Dikai; Li, Hengne; Li, Liang; Li, Qi-Zhong; Lim, Jeong Ku; Lincoln, Donald W; Linnemann, James Thomas; Lipaev, Vladimir V; Lipton, Ronald J; Liu, Huanzhao; Liu, Yanwen; Lobodenko, Alexandre; Lokajicek, Milos; Lopes de Sa, Rafael; Luna-Garcia, Rene; Lyon, Adam Leonard; Maciel, Arthur KA; Madar, Romain; Magana-Villalba, Ricardo; Malik, Sudhir; Malyshev, Vladimir L; Mansour, Jason; Martinez-Ortega, Jorge; McCarthy, Robert L; Mcgivern, Carrie Lynne; Meijer, Melvin M; Melnitchouk, Alexander S; Menezes, Diego D; Mercadante, Pedro Galli; Merkin, Mikhail M; Meyer, Arnd; Meyer, Jorg Manfred; Miconi, Florian; Mondal, Naba K; Mulhearn, Michael James; Nagy, Elemer; Narain, Meenakshi; Nayyar, Ruchika; Neal, Homer A; Negret, Juan Pablo; Neustroev, Petr V; Nguyen, Huong Thi; Nunnemann, Thomas P; Hernandez Orduna, Jose de Jesus; Osman, Nicolas Ahmed; Osta, Jyotsna; Pal, Arnab; Parashar, Neeti; Parihar, Vivek; Park, Sung Keun; Partridge, Richard A; Parua, Nirmalya; Patwa, Abid; Penning, Bjoern; Perfilov, Maxim Anatolyevich; Peters, Reinhild Yvonne Fatima; Petridis, Konstantinos; Petrillo, Gianluca; Petroff, Pierre; Pleier, Marc-Andre; Podstavkov, Vladimir M; Popov, Alexey V; Prewitt, Michelle; Price, Darren; Prokopenko, Nikolay N; Qian, Jianming; Quadt, Arnulf; Quinn, Gene Breese; Ratoff, Peter N; Razumov, Ivan A; Ripp-Baudot, Isabelle; Rizatdinova, Flera; Rominsky, Mandy Kathleen; Ross, Anthony; Royon, Christophe; Rubinov, Paul Michael; Ruchti, Randal C; Sajot, Gerard; Sanchez-Hernandez, Alberto; Sanders, Michiel P; Santos, Angelo Souza; Savage, David G; Savitskyi, Mykola; Sawyer, HLee; Scanlon, Timothy P; Schamberger, RDean; Scheglov, Yury A; Schellman, Heidi M; Schott, Matthias; Schwanenberger, Christian; Schwienhorst, Reinhard H; Sekaric, Jadranka; Severini, Horst; Shabalina, Elizaveta K; Shary, Viacheslav V; Shaw, Savanna; Shchukin, Andrey A; Simak, Vladislav J; Skubic, Patrick Louis; Slattery, Paul F; Smirnov, Dmitri V; Snow, Gregory R; Snow, Joel Mark; Snyder, Scott Stuart; Soldner-Rembold, Stefan; Sonnenschein, Lars; Soustruznik, Karel; Stark, Jan; Stoyanova, Dina A; Strauss, Michael G; Suter, Louise; Svoisky, Peter V; Titov, Maxim; Tokmenin, Valeriy V; Tsai, Yun-Tse; Tsybychev, Dmitri; Tuchming, Boris; Tully, Christopher George T; Uvarov, Lev; Uvarov, Sergey L; Uzunyan, Sergey A; Van Kooten, Richard J; van Leeuwen, Willem M; Varelas, Nikos; Varnes, Erich W; Vasilyev, Igor A; Verkheev, Alexander Yurievich; Vertogradov, Leonid S; Verzocchi, Marco; Vesterinen, Mika; Vilanova, Didier; Vokac, Petr; Wahl, Horst D; Wang, Michael HLS; Warchol, Jadwiga; Watts, Gordon Thomas; Wayne, Mitchell R; Weichert, Jonas; Welty-Rieger, Leah Christine; Williams, Mark Richard James; Wilson, Graham Wallace; Wobisch, Markus; Wood, Darien Robert; Wyatt, Terence R; Xie, Yunhe; Yamada, Ryuji; Yang, Siqi; Yasuda, Takahiro; Yatsunenko, Yuriy A; Ye, Wanyu; Ye, Zhenyu; Yin, Hang; Yip, Kin; Youn, Sungwoo; Yu, Jiaming; Zennamo, Joseph; Zhao, Tianqi Gilbert; Zhou, Bing; Zhu, Junjie; Zielinski, Marek; Zieminska, Daria; Zivkovic, Lidija

    2015-10-14

    We present the first search for CPT-violating effects in the mixing of ${B_s^0}$ mesons using the full Run II data set with an integrated luminosity of 10.4 fb$^{-1}$ of proton-antiproton collisions collected using the D0 detector at the Fermilab Tevatron Collider. We measure the CPT-violating asymmetry in the decay $B_s^0 \\to \\mu^\\pm D_s^\\pm$ as a function of celestial direction and sidereal phase. We find no evidence for CPT-violating effects and place limits on the direction and magnitude of flavor-dependent CPT- and Lorentz-invariance violating coupling coefficients. We find 95\\% confidence intervals of $\\Delta a_{\\perp} < 1.2 \\times 10^{-12}$ GeV and $(-0.8 < \\Delta a_T - 0.396 \\Delta a_Z < 3.9) \\times 10^{-13}$ GeV.

  20. Combined Lorentz force and ultrasound Doppler velocimetry in a vertical convection liquid metal flow

    Science.gov (United States)

    Zürner, Till; Vogt, Tobias; Resagk, Christian; Eckert, Sven; Schumacher, Jörg

    2017-11-01

    We report experimental studies on turbulent vertical convection flow in the liquid metal alloy gallium-indium-tin. Flow measurements were conducted by a combined use of local Lorentz force velocimetry (LLFV) and ultrasound Doppler velocimetry (UDV). It is known that the forced convection flow in a duct generates a force on the LLFV magnet system, that grows proportional to the flow velocity. We show that for the slower flow of natural convection LLFV retains this linear dependence in the range of micronewtons. Furthermore experimental results on the scaling of heat and momentum transport with the thermal driving are presented. The results cover a range of Rayleigh numbers 3 ×105 Deutsche Forschungsgemeinschaft under Grant No. GRK 1567.

  1. Large displacement bi-directional out-of-plane Lorentz actuator array for surface manipulation

    International Nuclear Information System (INIS)

    Park, Byoungyoul; Afsharipour, Elnaz; Chrusch, Dwayne; Shafai, Cyrus; Andersen, David; Burley, Greg

    2017-01-01

    This paper presents a large displacement out-of-plane Lorentz actuator array for surface manipulation. Actuators are formed from single crystal silicon flexible serpentine springs on either side of a rigid crossbar containing a narrow contact pillar. A rigid mounting rail system was employed to enable a 5  ×  5 array, which offers scalability of the array size. Analytical and finite element models were used to optimize actuator design. Individual actuators were tested to show linear deflection response of  ±150 µ m motion, using a  ±14.7 mA current in the presence of a 0.48 T magnetic field. This actuator array is suitable for various 2D surface modification applications due to its large deformation with low current and temperature of operation, and narrow contact area to a target surface. (paper)

  2. Multistable Microactuators Functioning on the Basis of Electromagnetic Lorentz Force: Nonlinear Structural and Electrothermal Analyses

    International Nuclear Information System (INIS)

    Han, Jeong Sam

    2010-01-01

    In this paper, the design and nonlinear simulation of a multistable electromagnetic microactuator, which provides four stable equilibrium positions within its operating range, have been discussed. Quadstable actuator motion has been made possible by using both X- and Y-directional bistable structures with snapping curved beams. Two pairs of the curved beams are attached to an inner frame in both X- and Y-directions to realize independent bistable behavior in each direction. For the actuation of the actuator at the micrometer scale, an electromagnetic actuation method in which Lorentz force is taken into consideration was used. By using this method, micrometer-stroke quadstability in a plane parallel to a substrate was possible. The feasibility of designing an actuator that can realize quadstable motion by using the electromagnetic actuation method has been thoroughly clarified by performing nonlinear static and dynamic analyses and electrothermal coupled-field analysis of the multistable microactuator

  3. Test of Lorentz symmetry with a 3He/129Xe clock-comparison experiment

    International Nuclear Information System (INIS)

    Gemmel, Claudia

    2011-01-01

    The minimal Standard Model Extension (SME) of Kostelecky and coworkers, which parametrizes the general treatment of CPT- and Lorentz invariance violation, predicts sidereal modulations of atomic transition frequencies as the Earth rotates relative to a Lorentz-violating background field. One method to search for these modulations is the so-called clock-comparison experiment, where the frequencies of co-located clocks are compared as they rotate with respect to the fixed stars. In this work an experiment is presented where polarized 3 He and 129 Xe gas samples in a glass cell serve as clocks, whose nuclear spin precession frequencies are detected with the help of highly sensitive SQUID sensors inside a magnetically shielded room. The unique feature of this experiment is the fact that the spins are precessing freely, with transverse relaxation times T * 2 of up to 4.4 h for 129 Xe and 14.1 h for 3 He. To be sensitive to Lorentz-violating effects, the influence of external magnetic fields is canceled via the weighted 3 He/ 129 Xe phase difference, ΔΦ=Φ he -(γ he )/(γ xe ) Φ xe . The Lorentz-violating SME parameters for the neutron, b n X and b n Y , are determined out of a χ 2 fit on the phase difference data of 7 spin precession measurements of 12 to 16 hours length. The piecewise defined fit model contains a sine and a cosine term to describe the sidereal modulation, as well as 7 offset terms, 7 linear terms and 7 . 2 exponential terms decreasing with T * 2,he and T * 2,xe , which are assigned to the respective measurement. The linear term in the weighted phase difference mainly arises from deviations of the gyromagnetic ratios from their literature values due to chemical shifts, while the exponential terms reflect the phase shifts resulting from demagnetization fields in the non-ideally spherical sample cell. The result of the χ 2 fit constrains the parameter b n perpendicular to =√((b n X ) 2 +(b n Y ) 2 ) to be -32 GeV at the 95% confidence level. This

  4. Coupled inflaton and electromagnetic fields from Gravitoelectromagnetic Inflation with Lorentz and Feynman gauges

    International Nuclear Information System (INIS)

    Membiela, Federico Agustín; Bellini, Mauricio

    2010-01-01

    Using a semiclassical approach to Gravitoelectromagnetic Inflation (GEMI), we study the origin and evolution of seminal inflaton and electromagnetic fields in the early inflationary universe from a 5D vacuum state. We use simultaneously the Lorentz and Feynman gauges. Our formalism is naturally not conformal invariant on the effective 4D de Sitter metric, which make possible the super adiabatic amplification of electric and magnetic field modes during the early inflationary epoch of the universe on cosmological scales. This is the first time that solutions for the electric field fluctuations are investigated in a systematic way as embeddings for inflationary models in 4D. An important and new result here obtained is that the spectrum of the electric field fluctuations depend with the scale, such that the spectral index increases quadratically as the scale decreases

  5. Coupled inflaton and electromagnetic fields from Gravitoelectromagnetic Inflation with Lorentz and Feynman gauges

    Energy Technology Data Exchange (ETDEWEB)

    Membiela, Federico Agustín; Bellini, Mauricio, E-mail: mbellini@mdp.edu.ar, E-mail: membiela@mdp.edu.ar [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350, (7600) Mar del Plata (Argentina)

    2010-10-01

    Using a semiclassical approach to Gravitoelectromagnetic Inflation (GEMI), we study the origin and evolution of seminal inflaton and electromagnetic fields in the early inflationary universe from a 5D vacuum state. We use simultaneously the Lorentz and Feynman gauges. Our formalism is naturally not conformal invariant on the effective 4D de Sitter metric, which make possible the super adiabatic amplification of electric and magnetic field modes during the early inflationary epoch of the universe on cosmological scales. This is the first time that solutions for the electric field fluctuations are investigated in a systematic way as embeddings for inflationary models in 4D. An important and new result here obtained is that the spectrum of the electric field fluctuations depend with the scale, such that the spectral index increases quadratically as the scale decreases.

  6. Charged tensor matter fields and Lorentz symmetry violation via spontaneous symmetry breaking

    International Nuclear Information System (INIS)

    Colatto, L.P.; Penna, A.L.A.; Santos, W.C.

    2003-10-01

    We consider a model with a charged vector field along with a Cremmer-Scherk-Kalb-Ramond (CSKR) matter field coupled to a U(1) gauge potential. We obtain a natural Lorentz symmetry violation due to the local U(1) spontaneous symmetry breaking mechanism triggered by the imaginary part of the vector matter. The choice of the unitary gauge leads to the decoupling of the gauge-Kr sector from the Higgs-Kr sector. The excitation spectrum is carefully analyzed and the physical modes are identified. We propose an identification of the neutral massive spin-1 Higgs-like field with the massive Z' boson of the so-called mirror matter models. (author)

  7. A simple levitation system using wireless power supply system and Lorentz force

    International Nuclear Information System (INIS)

    Oka, Koichi; Tanaka, Masako

    2016-01-01

    A new type of magnetic levitation mechanism has been proposed. The feature of this mechanism is using wireless power supply system and Lorentz forces for levitation. The stability of levitation is performed by passive control by magnetic flux configuration between permanent magnets and active control of electromagnets. In this paper, the concept of levitation mechanism is introduced, FEM analyses for levitation force and wireless power supply performance is examined. In concept two types of levitation systems which are different on the point of active control directions are introduced. In FEM analyses, the required current for levitation and the directions of generating forces are calculated. In the study of wireless power supply system, the required voltage for the levitation is expected. Finally the feasibility of the proposed levitation system will be verified. (paper)

  8. A unifying framework for ghost-free Lorentz-invariant Lagrangian field theories

    Science.gov (United States)

    Li, Wenliang

    2018-04-01

    We propose a framework for Lorentz-invariant Lagrangian field theories where Ostrogradsky's scalar ghosts could be absent. A key ingredient is the generalized Kronecker delta. The general Lagrangians are reformulated in the language of differential forms. The absence of higher order equations of motion for the scalar modes stems from the basic fact that every exact form is closed. The well-established Lagrangian theories for spin-0, spin-1, p-form, spin-2 fields have natural formulations in this framework. We also propose novel building blocks for Lagrangian field theories. Some of them are novel nonlinear derivative terms for spin-2 fields. It is nontrivial that Ostrogradsky's scalar ghosts are absent in these fully nonlinear theories.

  9. Beyond disciplinary borders. H. A. Lorentz and S. Ramón y Cajal.

    Science.gov (United States)

    Fernández Santarén, J; Kox, A J; Sánchez-Ron, J M

    2014-01-01

    Science is a multidisciplinary enterprise. Mathematics, physics, chemistry, biology, geology, and many other, perhaps not so " basic ", but not less interesting disciplines form what we call " science ". The task of history of science is to recover and put order in the past of such disciplines. Although, on most the occasions, those histories are limited by the territories of the different sciences, we know that their frontiers are not impermeable, that there are relationships between them. However, it is not frequent to find studies dealing with those relationships, especially dealing with relations among scientists belonging to different fields. In the present paper, we study a case in which two outstanding scientists, a physicist and a histologist (or neuroscientist, as we would say today), the Dutchman Hendrik A. Lorentz and the Spanish Santiago Ramón y Cajal, maintained a, albeit brief, relation. Both being such prominent scientific figures, of worldwide stature, the relation they maintained deserves to be known.

  10. Constraints on spacetime anisotropy and Lorentz violation from the GRAAL experiment

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Zhe [Chinese Academy of Sciences, Institute of High Energy Physics, Beijing (China); Chinese Academy of Sciences, Theoretical Physics Center for Science Facilities, Beijing (China); Wang, Sai [Chinese Academy of Sciences, Institute of High Energy Physics, Beijing (China)

    2013-02-15

    The GRAAL experiment could constrain the variations of the speed of light. The anisotropy of the speed of light may imply that the spacetime is anisotropic. Finsler geometry is a reasonable candidate to deal with the spacetime anisotropy. In this paper, the Lorentz invariance violation (LIV) of the photon sector is investigated in the locally Minkowski spacetime. The locally Minkowski spacetime is a class of flat Finsler spacetime and refers a metric with the anisotropic departure from the Minkowski one. The LIV matrices used to fit the experimental data are represented in terms of these metric deviations. The GRAAL experiment constrains the spacetime anisotropy to be less than 10{sup -14}. In addition, we find that the simplest Finslerian photon sector could be viewed as a geometric representation of the photon sector in the minimal standard model extension (SME). (orig.)

  11. Some aspects of the electromagnetic-impulse pendulum and Biot-Savart-Lorentz force

    International Nuclear Information System (INIS)

    Moyssides, P.G.; Hatzikonstantinou, P.

    1988-01-01

    The purpose of this paper is to cast light on various serious mistakes which have been involved during the analysis of two experiments, related to the correctness of the Biot-Savart-Lorentz force law. At first in the MIT experiment, carried out by Graneau et al., they claim that the calculated momentum, imparted to an electrodynamic-impulse pendulum, using the BSL force law, is 43% larger than the experimentally measured momentum of the pi-frame pendulum. It has been found that discrepancy, using their own data, is due to the use of a wrong value for the time constant parameter introduced in the current formula. In addition Pappas, like Graneau, although states that all the available energy is dissipated to Joule heating, considers that all the pendulum momentum is imparted to field momentum yielding an enormous amount of field-radiated energy, which is also completely wrong

  12. Lorentz-covariant reduced-density-operator theory for relativistic-quantum-information processing

    International Nuclear Information System (INIS)

    Ahn, Doyeol; Lee, Hyuk-jae; Hwang, Sung Woo

    2003-01-01

    In this paper, we derived a Lorentz-covariant quantum Liouville equation for the density operator which describes the relativistic-quantum-information processing from Tomonaga-Schwinger equation and an exact formal solution for the reduced density operator is obtained using the projector operator technique and the functional calculus. When all the members of the family of the hypersurfaces become flat hyperplanes, it is shown that our results agree with those of the nonrelativistic case, which is valid only in some specified reference frame. To show that our formulation can be applied to practical problems, we derived the polarization of the vacuum in quantum electrodynamics up to the second order. The formulation presented in this work is general and could be applied to related fields such as quantum electrodynamics and relativistic statistical mechanics

  13. Asymmetric transmission in planar chiral split-ring metamaterials: Microscopic Lorentz-theory approach

    DEFF Research Database (Denmark)

    Novitsky, Andrey; Galynsky, Vladimir M.; Zhukovsky, Sergei

    2012-01-01

    The electronic Lorentz theory is employed to explain the optical properties of planar split-ring metamaterials. Starting from the dynamics of individual free carriers, the electromagnetic response of an individual split-ring meta-atom is determined, and the effective permittivity tensor...... of the metamaterial is calculated for normal incidence of light. Whenever the split ring lacks in-plane mirror symmetry, the corresponding permittivity tensor has a crystallographic structure of an elliptically dichroic medium, and the metamaterial exhibits optical properties of planar chiral structures. Its...... transmission spectra are different for right-handed versus left-handed circular polarization of the incident wave, so the structure changes its transmittance when the direction of incidence is reversed. The magnitude of this change is shown to be related to the geometric parameters of the split ring...

  14. Calibrationless rotating Lorentz-force flowmeters for low flow rate applications

    Science.gov (United States)

    Hvasta, M. G.; Dudt, D.; Fisher, A. E.; Kolemen, E.

    2018-07-01

    A ‘weighted magnetic bearing’ has been developed to improve the performance of rotating Lorentz-force flowmeters (RLFFs). Experiments have shown that the new bearing reduces frictional losses within a double-sided, disc-style RLFF to negligible levels. Operating such an RLFF under ‘frictionless’ conditions provides two major benefits. First, the steady-state velocity of the RLFF magnets matches the average velocity of the flowing liquid at low flow rates. This enables an RLFF to make accurate volumetric flow measurements without any calibration or prior knowledge of the fluid properties. Second, due to minimized frictional losses, an RLFF is able to measure low flow rates that cannot be detected when conventional, high-friction bearings are used. This paper provides a brief background on RLFFs, gives a detailed description of weighted magnetic bearings, and compares experimental RLFF data to measurements taken with a commercially available flowmeter.

  15. RAPID PENUMBRA AND LORENTZ FORCE CHANGES IN AN X1.0 SOLAR FLARE

    International Nuclear Information System (INIS)

    Xu, Zhe; Jiang, Yunchun; Yang, Jiayang; Yang, Bo; Bi, Yi

    2016-01-01

    We present observations of the violent changes in photospheric magnetic structures associated with an X1.1 flare, which occurred in a compact δ-configuration region in the following part of AR 11890 on 2013 November 8. In both central and peripheral penumbra regions of the small δ sunspot, these changes took place abruptly and permanently in the reverse direction during the flare: the inner/outer penumbra darkened/disappeared, where the magnetic fields became more horizontal/vertical. Particularly, the Lorentz force (LF) changes in the central/peripheral region had a downward/upward and inward direction, meaning that the local pressure from the upper atmosphere was enhanced/released. It indicates that the LF changes might be responsible for the penumbra changes. These observations can be well explained as the photospheric response to the coronal field reconstruction within the framework of the magnetic implosion theory and the back reaction model of flares

  16. Singularities of spacelike constant mean curvature surfaces in Lorentz-Minkowski space

    DEFF Research Database (Denmark)

    Brander, David

    2011-01-01

    We study singularities of spacelike, constant (non-zero) mean curvature (CMC) surfaces in the Lorentz-Minkowski 3-space L-3. We show how to solve the singular Bjorling problem for such surfaces, which is stated as follows: given a real analytic null-curve f(0)(x), and a real analytic null vector...... field v(x) parallel to the tangent field of f(0), find a conformally parameterized (generalized) CMC H surface in L-3 which contains this curve as a singular set and such that the partial derivatives f(x) and f(y) are given by df(0)/dx and v along the curve. Within the class of generalized surfaces...

  17. Covariant quantization of the d=4 Brink-Schwarz superparticle using Lorentz harmonics

    International Nuclear Information System (INIS)

    Zima, V.G.; Fedoryuk, S.A.

    1995-01-01

    Covariant first and second quantizations of the free d=4 massless superparticle are implemented with the introduction of purely gauge auxiliary spinor Lorentz harmonics. It is shown that the general solution of the condition of masslessness is a sum of two independent chiral superfields with each of them corresponding to finite superspin. A translationally covariant, in general bijective correspondence between harmonic and massless superfields is constructed. By calculation of the commutation function it is shown that in the considered approach only harmonic fields with the correct connection between spin and statistics and with integer negative homogeneity index satisfy the microcausality condition. It is emphasized that the harmonic fields that arise are reducible at integer points. The index spinor technique is used to describe infinite-component fields of finite spin; the equations of motion of such fields are obtained, and for them Weinberg's theorem on the connection between massless helicity particles and the type of nongauge field that describes them is generalized

  18. Quantitative in situ magnetization reversal studies in Lorentz microscopy and electron holography.

    Science.gov (United States)

    Rodríguez, L A; Magén, C; Snoeck, E; Gatel, C; Marín, L; Serrano-Ramón, L; Prieto, J L; Muñoz, M; Algarabel, P A; Morellon, L; De Teresa, J M; Ibarra, M R

    2013-11-01

    A generalized procedure for the in situ application of magnetic fields by means of the excitation of the objective lens for magnetic imaging experiments in Lorentz microscopy and electron holography is quantitatively described. A protocol for applying magnetic fields with arbitrary in-plane magnitude and orientation is presented, and a freeware script for Digital Micrograph(™) is provided to assist the operation of the microscope. Moreover, a method to accurately reconstruct hysteresis loops is detailed. We show that the out-of-plane component of the magnetic field cannot be always neglected when performing quantitative measurements of the local magnetization. Several examples are shown to demonstrate the accuracy and functionality of the methods. © 2013 Elsevier B.V. All rights reserved.

  19. Effects of topography on the local variation in the magnetization of ultrasoft magnetic films : a Lorentz microscopy study

    NARCIS (Netherlands)

    Chechenin, N.G.; de Hosson, J.T.M.; Boerma, D.O

    2003-01-01

    This paper concentrates on a detailed analysis of Lorentz transmission electron microscopy (LTEM) observations in the study of the magnetic properties of soft magnetic films. Besides ripple fringes in the LTEM image that are commonly observed in nanocrystalline soft magnetic films, there also

  20. An Exciting Experiment for Pre-Engineering and Introductory Physics Students: Creating a DC Motor Using the Lorentz Force

    Science.gov (United States)

    Abdul-Razzaq, Wathiq N.; Boehm, Manfred H.; Bushey, Ryan K.

    2008-01-01

    Introductory physics laboratories have been demonstrated in some instances to be difficult or uninteresting to students at the collegiate level. We have developed a laboratory that introduces the concept of the Lorentz force and allows students to build a non-traditional DC motor out of easily acquired materials. Basic electricity and magnetism…

  1. Ion diode simulation with a finite-volume PIC approach for the numerical solution of the Maxwell-Lorentz system

    Energy Technology Data Exchange (ETDEWEB)

    Munz, C D; Schneider, R; Stein, E; Voss, U [Forschungszentrum Karlsruhe (Germany). Institut fuer Neutronenphysik und Reaktortechnik; Westermann, T [FH Karlsruhe (Germany). Fachbereich Naturwissenschaften; Krauss, M [Forschungszentrum Karlsruhe (Germany). Hauptabteilung Informations- und Kommunikationstechik

    1997-12-31

    The numerical concept realized in the the Karlsruhe Diode Code KADI2D is briefly reviewed. Several new aspects concerning the Maxwell field solver based on high resolution finite-volume methods are presented. A new approach maintaining charge conservation numerically for the Maxwell-Lorentz equations is shortly summarized. (author). 2 figs., 12 refs.

  2. Lorentz-covariant coordinate-space representation of the leading hadronic contribution to the anomalous magnetic moment of the muon

    Science.gov (United States)

    Meyer, Harvey B.

    2017-09-01

    We present a Lorentz-covariant, Euclidean coordinate-space expression for the hadronic vacuum polarisation, the Adler function and the leading hadronic contribution to the anomalous magnetic moment of the muon. The representation offers a high degree of flexibility for an implementation in lattice QCD. We expect it to be particularly helpful for the quark-line disconnected contributions.

  3. Ion diode simulation with a finite-volume PIC approach for the numerical solution of the Maxwell-Lorentz system

    International Nuclear Information System (INIS)

    Munz, C.D.; Schneider, R.; Stein, E.; Voss, U.; Westermann, T.; Krauss, M.

    1996-01-01

    The numerical concept realized in the the Karlsruhe Diode Code KADI2D is briefly reviewed. Several new aspects concerning the Maxwell field solver based on high resolution finite-volume methods are presented. A new approach maintaining charge conservation numerically for the Maxwell-Lorentz equations is shortly summarized. (author). 2 figs., 12 refs

  4. Lorentz-Symmetry Test at Planck-Scale Suppression With a Spin-Polarized 133Cs Cold Atom Clock.

    Science.gov (United States)

    Pihan-Le Bars, H; Guerlin, C; Lasseri, R-D; Ebran, J-P; Bailey, Q G; Bize, S; Khan, E; Wolf, P

    2018-06-01

    We present the results of a local Lorentz invariance (LLI) test performed with the 133 Cs cold atom clock FO2, hosted at SYRTE. Such a test, relating the frequency shift between 133 Cs hyperfine Zeeman substates with the Lorentz violating coefficients of the standard model extension (SME), has already been realized by Wolf et al. and led to state-of-the-art constraints on several SME proton coefficients. In this second analysis, we used an improved model, based on a second-order Lorentz transformation and a self-consistent relativistic mean field nuclear model, which enables us to extend the scope of the analysis from purely proton to both proton and neutron coefficients. We have also become sensitive to the isotropic coefficient , another SME coefficient that was not constrained by Wolf et al. The resulting limits on SME coefficients improve by up to 13 orders of magnitude the present maximal sensitivities for laboratory tests and reach the generally expected suppression scales at which signatures of Lorentz violation could appear.

  5. Lorentz-covariant coordinate-space representation of the leading hadronic contribution to the anomalous magnetic moment of the muon

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Harvey B. [Mainz Univ., PRISMA Cluster of Excellence, Inst. fuer Kernphysik und Helmholtz Institut Mainz (Germany)

    2017-09-15

    We present a Lorentz-covariant, Euclidean coordinate-space expression for the hadronic vacuum polarisation, the Adler function and the leading hadronic contribution to the anomalous magnetic moment of the muon. The representation offers a high degree of flexibility for an implementation in lattice QCD. We expect it to be particularly helpful for the quark-line disconnected contributions. (orig.)

  6. Ferrimagnetic/ferroelastic domain interactions in magnetite below the Verwey transition. Part I: electron holography and Lorentz microscopy

    DEFF Research Database (Denmark)

    Kasama, Takeshi; Harrison, R. J.; Church, N. S.

    2013-01-01

    -related crystal orientations to be distinguished. Off-axis electron holography and Lorentz electron microscopy are used to show that magnetic domains present at room temperature become subdivided into sub-micron-sized magnetic domains below the Verwey transition, with the magnetization direction in each magnetic...

  7. Effects of lorentz force on flow fields of free burning arc and wall stabilized non-transferred arc

    International Nuclear Information System (INIS)

    Peng Yi; Huang Heji; Pan Wenxia

    2013-01-01

    The flow fields of two typical DC plasma arcs, namely the transferred free burning arc and the non-transferred arc were simulated by solving hydrodynamic equations and electromagnetic equations. The effects of the Lorentz force on the characteristics of the flow fields of these two typical DC plasma arcs were estimated. Results show that in the case of the free burning arc, the Lorentz force due to the current self-induced magnetic field has significant impact on the flow fields, as the self-induced magnetic compression is the main arc constraint mechanism. However, in the case of the non-transferred arc generated in a torch with long and narrow inter-electrode inserts and an abruptly expanded anode, the Lorentz force has limited impact on the flow fields of the plasma especially at the downstream of the inter-electrode inserts, compared with the strong wall constraints and relatively high aerodynamic force. This is because the ratio of the electromagnetic force to the aerodynamic force is only about 0.01 in this region. When the main consideration is outlet parameters of the wall stabilized non-transferred DC arc plasma generator, in order to improve the efficiency of the numerical simulation program, the Lorentz force could be neglected in the non-transferred arc in some cases. (authors)

  8. Ouabaina como Hormona

    Directory of Open Access Journals (Sweden)

    J. Hernando Ordoñez

    1996-04-01

    Full Text Available

    Comentario sobre su origen endógeno y sus aplicaciones terapéuticas

    Pocas drogas han sido más estudiadas que el grupo de los digitálicos, estrofantinas y ouabaina, cuyo estudio es objeto del presente trabajo.

    La ouabaina empezó a ser estudiada desde el siglo pasado. La primera referencia conocida corresponde a Pelikan, 1865 (1, como veneno que empleaban para las flechas en Gabón (Africa. (.

    (. Vinieron luego los trabajos de Fraser, 1869, (2, 3, 6, Polaillon, 1871 (4, Amaud, 1888 (5, Vaquez y Lutembacher, 1917 (7, Stoll, 1939 (8, Lapicque, 1929 (9, Wiggers, 1927 (10, Ytantos otros (11, 12, 13. En la obra de Kisch (14 aparecen más de 700 referencias bibliográficas sobre el particular.

    Ouabaina de origen endógeno. Purificación
    Durante muchos años se conoció la ouabaina como de origen vegetal, elaborada por las plantas Strophanthus Glaber(k-estrofantina,AcocantheraOuabaio(Ouabaina yStrophanthus Kombe (k-estrofantina y kestrofantósido. Una propiedad común a todos los digitálicos, estrofantina y ouabaina es que todos son inhibidores de la bomba de Na-K, encargada de regular la salida de Na y la entrada de K celular.

    Estudiando los inhibido res de esta bomba han encontrado en años recientes resultados extraordinarios en relación con el origen endógeno de algunos de estos inhibidores, entre ellos la ouabaina. Por considerarlos de extrema importancia y actualidad científica me permito citar algunos de ellos. Hamlyn y Manunta (15, 16, 17, 18, Y 19 hicieron estudios sobre el particular y lograron identificar en el plasma humano un compuesto igual a la ouabaina. Estos hallazgos fueron confirmados después por otros autores (20, 21, 22, 23 Y24.

    Ham bl yn (19 da varios argumentos que ponen en evidencia que el compuesto químico encontrado es ouabaina pura, y, lo que es más interesante, que tiene un origen endógeno. a Por espectroscopia de alta resoluci

  9. O direito como imperativo

    Directory of Open Access Journals (Sweden)

    Cloter Miglioriani

    1988-08-01

    Full Text Available We have examined one of the facets which Law presents to society, looking at the theme through a brief history of Law, in which Roman Law stands out, up to modem times, comparing current juridical systems such as the Continental System, Common Law, and Soviet Law. We have looked at Law from the viewpoint of society 's need to have basic mies for living together, with the juridical ruZe being one of the most important. We have highlighted the views of Hart and Kelsen on the foundations of the validity of Law. We have also considered the obligatoriness of Law; giving the point of view of tadbruch who, explaining his ''Theory of the Obligatoriness of Law ", concluded that the obligatoriness of Law can only be withdraw when there is a Clash between morals, law, use and social conventions. We have looked at the notion of the imperativeness of Law the central theme of the work -drawing on the views of Miguel Reale, for whom the juridical nonn cannot be reduced to a "command of a volitional nature", but rather the obligatory character of the juridical nonn arises from the pressure of social values. Del Vecchio, who is also quoted, recognized that imperativeness exists in the juridical norm, whether it is preceptive (a positive command or permissive. Also mentioned is the opinion of Tercio Sampaio Ferraz, for whom the juridical norm has imperativeness to the extent that the imposition of behaviour is unconditionally guaranteed. Foi feita a abordagem de uma das facetas com que o Direito se apresenta à sociedade, enfocando o tema a partir de um brevíssimo histórico do Direito, onde revela a fase romana, até os períodos modernos, com comparações dos sistemas jurídicos hodiernos, como o sistema continental, o da Commum Law e o soviético. Foi enfocado o Direito em face da necessidade sociedade em ter básicas de convivência, despontando a regra jurídica como das mais importantes. Foi dado destaque às posições de Hart e Kelsen, sobre os

  10. Numerical and experimental study on vorticity measurement in liquid metal using local Lorentz force velocimetry

    Science.gov (United States)

    Hernández, Daniel; Marangoni, Rafael; Schleichert, Jan; Karcher, Christian; Fröhlich, Thomas; Wondrak, Thomas

    2018-03-01

    Local Lorentz force velocimetry (local LFV) is a contactless velocity measurement technique for liquid metals. Due to the relative movement between an electrically conductive fluid and a static applied magnetic field, eddy currents and a flow-braking Lorentz force are generated inside the metal melt. This force is proportional to the flow rate or to the local velocity, depending on the volume subset of the flow spanned by the magnetic field. By using small-size magnets, a localized magnetic field distribution is achieved allowing a local velocity assessment in the region adjacent to the wall. In the present study, we describe a numerical model of our experiments at a continuous caster model where the working fluid is GaInSn in eutectic composition. Our main goal is to demonstrate that this electromagnetic technique can be applied to measure vorticity distributions, i.e. to resolve velocity gradients as well. Our results show that by using a cross-shaped magnet system, the magnitude of the torque perpendicular to the surface of the mold significantly increases improving its measurement in a liquid metal flow. According to our numerical model, this torque correlates with the vorticity of the velocity in this direction. Before validating our numerical predictions, an electromagnetic dry calibration of the measurement system composed of a multicomponent force and torque sensor and a cross-shaped magnet was done using a rotating disk made of aluminum. The sensor is able to measure simultaneously all three components of force and torque, respectively. This calibration step cannot be avoided and it is used for an accurate definition of the center of the magnet with respect to the sensor’s coordinate system for torque measurements. Finally, we present the results of the experiments at the mini-LIMMCAST facility showing a good agreement with the numerical model.

  11. Optical Characterization of Lorentz Force Based CMOS-MEMS Magnetic Field Sensor.

    Science.gov (United States)

    Dennis, John Ojur; Ahmad, Farooq; Khir, M Haris Bin Md; Bin Hamid, Nor Hisham

    2015-07-27

    Magnetic field sensors are becoming an essential part of everyday life due to the improvements in their sensitivities and resolutions, while at the same time they have become compact, smaller in size and economical. In the work presented herein a Lorentz force based CMOS-MEMS magnetic field sensor is designed, fabricated and optically characterized. The sensor is fabricated by using CMOS thin layers and dry post micromachining is used to release the device structure and finally the sensor chip is packaged in DIP. The sensor consists of a shuttle which is designed to resonate in the lateral direction (first mode of resonance). In the presence of an external magnetic field, the Lorentz force actuates the shuttle in the lateral direction and the amplitude of resonance is measured using an optical method. The differential change in the amplitude of the resonating shuttle shows the strength of the external magnetic field. The resonance frequency of the shuttle is determined to be 8164 Hz experimentally and from the resonance curve, the quality factor and damping ratio are obtained. In an open environment, the quality factor and damping ratio are found to be 51.34 and 0.00973 respectively. The sensitivity of the sensor is determined in static mode to be 0.034 µm/mT when a current of 10 mA passes through the shuttle, while it is found to be higher at resonance with a value of 1.35 µm/mT at 8 mA current. Finally, the resolution of the sensor is found to be 370.37 µT.

  12. Simulación de la fluencia en caliente de un acero microaleado con un contenido medio de carbono. III parte. Ecuaciones constitutivas

    Directory of Open Access Journals (Sweden)

    Cabrera, J. M.

    1997-08-01

    Full Text Available According to the part 1 of this work the constitutive equations of the hot flow behaviour of a commercial microalloyed steel have been obtained. For this purpose, the uniaxial hot compression tests described in the part 2 were employed. Tests were carried out over a range of 5 orders of magnitude in strain rate and 300 °C of temperature. Experimental results are compared with the theoretical model introduced in the first part of this study. It is concluded that deviations between experimental and theoretical curves are lower than 10 %. It is shown that the classical hiperbolic sine constitutive equation described accurately the experimental behaviour provided that stresses are normalized by the Young's modulus and strain rates by the self-diffusion coefficient. An internal stress must also be introduced in the latter equation when the initial grain size is fine enough.

    Siguiendo el planteamiento teórico efectuado en la I parte de este trabajo, se determinaron las ecuaciones constitutivas del comportamiento a la deformación en caliente de un acero comercial microaleado con un contenido medio de carbono. Para este objetivo se emplearon los ensayos de compresión uniaxial en caliente ya descritos en la II parte, los cuales se efectuaron en un rango de cinco órdenes de magnitud en velocidad de deformación y 300 °C de temperatura. Se comparan los resultados experimentales con el modelo teórico introducido en la I parte y se verifica que el error es inferior al 10 %. Se comprobó que la clásica ecuación del seno hiperbólico podía describir con precisión el comportamiento observado siempre y cuando las tensiones se normalicen por el módulo de Young, las velocidades de deformación por el coeficiente de autodifusión de la austenita, y se considere un efecto adicional sobre la tensión cuando el tamaño de grano inicial sea suficientemente fino.

  13. Flowing equation gradually varied in rectangles channels on depth curve; Ecuacion del flujo gradualmente variado en canales rectangulares de fondo curvo

    Energy Technology Data Exchange (ETDEWEB)

    Sotelo-Avila, G.; Gallegos-Silva, J. [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    2002-03-01

    The study of channel flow usually have its basis in the hydrostatic distribution of pressure and the rectilinear flow hypotheses. It is from this hypothesis that the main flow equations are obtained. However, this is not applicable to a vertically curved flow that is present in a curved bed channel. This kind of channel is used to join two different slopes or in ski jumps. This kind of flow presents several changes from the rectilinear flow as in the velocity and pressure distributions and even in the energy loses. The authors of this article propose an equation of gradually varied flow for vertically-curved bed rectangular channels that adds a coefficient to modify the velocity in the calculus of the local friction gradient. With these results is possible now to analyze flow profiles in vertically-curved bed channels where before were used the methods for straight channels and therefore, increase accuracy. [Spanish] Las hipotesis del movimiento rectilineo y de distribucion hidrostatica de la presion son ciertamente las mas importantes en la hidraulica de canales, y de ellas se derivan los principales modelos de flujo que usualmente emplean. Sin embargo, no es valido aplicar la misma hipotesis y metodos de analisis al flujo curvilineo, que ocurre cuando el canal adopta curvaturas verticales en el fondo, las cuales inducen cambios importantes en la distribucion de la velocidad, presion y hasta en la perdida d energia. Tal es el caso de canales que contienen curvas verticales para unir tramos de distintas pendientes y producir el cambio en la direccion del flujo en cubetas deflectoras y vertedores en tunel. Los autores de este articulo proponen una ecuacion de flujo gradualmente variado en canales rectangulares de fondo curvo, esta es de gran utilidad en la determinacion del perfil del flujo con dichas caracteristicas, donde se plantea la adicion de un factor de amplificacion de la velocidad en el calculo del gradiente local de friccion, para tomar en cuenta el

  14. Europa como cultura

    Directory of Open Access Journals (Sweden)

    Javier San Martín

    2012-02-01

    Full Text Available El presente texto tiene un origen muy concreto. El día 15 de marzo de 2002, con motivo de la Cumbre Europea de Barcelona, Jorge Semprún reflexionaba, en las páginas de un conocido diario madrileño, sobre el significado que para él tenía ser europeo. Para ello emprendía tres "viajes intelectuales" a Viena, Praga y Buchenwald, los tres de gran significado histórico y cultural. Dado el interés del texto y del momento, me pareció entonces oportuno glosar algunos aspectos de aquel artículo, primero, para subrayar el valor de la aportación de Semprún, luego para corregir alguna inexactitud de carácter biográfico, debida posiblemente a la rapidez de la traducción, y, tercero, para ampliar con algún comentario la valiosa contribución de Sempnín, sobre todo en lo que concierne al sentido de Europa. En este texto se toma aquel comentario como punto de partida.The origins of this text are very specific. On 15 March 2002, on the occasion of the European Summit in Barcelona, and on the pages of a well-known Madrid newspaper, Jorge Semprún reflected on the meaning that being European had for him. To do this, he embarked on three "intellectual journeys" to Vienna, Prague and Buchenwald, all three of great historical and cultural significance. Given the interest of the text and of the moment, I considered it appropriate to comment on aspects of the article -firstly, to underline the value of Semprún's contribution; secondly, to correct certain biographical inaccuracies, possibly due to a hasty translation; and thirdly, to complement Semprún's valuable contribution, essentially concerning the meaning of Europe. This text takes that comment as its starting point.

  15. Gas de Síntesis como Combustible para la Generación de Energía-Edición Ênica

    OpenAIRE

    Valdés de León, Osvaldo A.

    2005-01-01

    El presente trabajo analiza el proceso de gasificación acoplado a un ciclo combinado, con la finalidad de producir energía eléctrica, para lo cual se utilizan como combustibles el carbón, el coque de petróleo y los residuos sólidos municipales. El análisis matemático se realiza a través de la modelación de las ecuaciones químicas y termodinámicas que lo describen. Se resuelve el modelo haciendo variar los parámetros que describen el mecanismo de gasificación (presión, temperatura y los flujos...

  16. El CO2 como disolvente y como reactivo

    OpenAIRE

    La Franca Pitarresi, Vincenzo Rosario

    2016-01-01

    Existen numerosas ventajas asociada con el uso de CO2 , tanto como disolvente que como reactivo, y todas se pueden resumir en cuatro categorías generales: beneficios ambiental, beneficios de salud y seguridad, beneficios en el procedimiento y beneficios químicos. Los procesos que implican el CO2 como disolvente no aumentaría las emisiones de CO2, más bien proporcionaría una oportunidad para el reciclaje de CO2 residual. Además, los esfuerzos para secuestrar el CO2 producido de los gases de co...

  17. Electromagnetic pion production in manifestly Lorentz invariant baryonic chiral perturbation theory; Elektromagnetische Pionproduktion in manifest Lorentz-invarianter baryonischer chiraler Stoerungstheorie

    Energy Technology Data Exchange (ETDEWEB)

    Lehnhart, B.C.

    2007-05-15

    This thesis is concerned with electromagnetic pion production within manifestly Lorentz-invariant chiral perturbation theory using the assumption of isospin symmetry. In a one-loop calculation up to the chiral order O(q{sup 4}), 105 Feynman diagrams contribute, consisting of 20 tree graphs and 85 loop diagrams. The tree graphs are classified as 16 pole diagrams and 4 contact graphs. Of the 85 loop diagrams, 50 diagrams are of order three and 35 diagrams are of fourth order. To calculate the pion production amplitude algorithms are developed on the basis of the Mathematica package FeynCalc. The one-photon-exchange approximation allows one to parametrise the pion production amplitude as the product of the polarisation vector of the (virtual) photon and the matrix element of the transition current. The polarisation vector is related to the leptonic vertex and the photon propagator and is well-known from QED. The dependence of the amplitude on the strong interaction is contained in the matrix element of the transition current, and we use chiral perturbation theory to describe this matrix element. The transition current can be expressed in terms of six gauge invariant amplitudes, each of which can again be decomposed into three isospin amplitudes. Linear combinations of these amplitudes allow us to describe the physical amplitudes. The one-loop integrals appearing within this calculation are determined numerically by the program LoopTools. In the case of tensorial integrals it is required to perform the method of Passarino and Veltman first. Furthermore, we apply the reformulated infrared regularisation which ensures that the results fulfill the chiral power counting. For this purpose algorithms are developed which determine the subtraction terms automatically. The obtained isospin amplitudes are integrated in the program MAID. As tests the s-wave multipoles E{sub 0+} and L{sub 0+} (using results up to chiral order O(q{sup 3})) are calculated in the threshold region

  18. Collected charge and Lorentz angle measurement on non-irradiated ATLAS silicon micro-strip sensors for the HL-LHC

    Energy Technology Data Exchange (ETDEWEB)

    Yildirim, Eda

    2017-02-15

    In this thesis, the collected charge and the Lorentz angle on non-irradiated and the irradiated miniature of the current test silicon micro-strip sensors (ATLAS12) of the future ATLAS inner tracker are measured. The samples are irradiated up to 5 x 10{sup 15} 1 MeV n{sub eq}/cm{sup 2} and some of them also measured after short-term annealing (80 min at 60 C). The measurements are performed at the DESY II test beam, which provides the advantage of tracking to suppress noise hits. The collected charge is measured at various bias voltages for each sample. The results are compared with the measurements performed using a Sr{sup 90} radioactive source. It is shown that the measurements with beam and radioactive source are consistent with each other, and the advantage of tracking at the beam measurements provides the measurement of collected charge on highly irradiated sensors at lower bias voltages. The Lorentz angle is measured for each sample at different magnetic field strengths between 0 T and 1 T, the results are extrapolated to 2 T, which is the magnetic field in the inner tracker of the ATLAS detector. Most of the measurements are performed at -500 V bias voltage, which is the planned operation bias voltage of the future strip tracker. Some samples are also measured at different bias voltages to observe the effect of bias voltage on the Lorentz angle. The signal reconstruction of the strip sensors are performed using the lowest possible signal-to-noise thresholds. For non-irradiated samples, the measured Lorentz angle agrees with the prediction of the BFK model. On the irradiated samples, the results suggest that the Lorentz angle decreases with increasing bias voltage due to the increasing electric field in the sensor. The Lorentz angle decreases with increasing irradiation level; however, if the sample is under-depleted, the effect of electric field dominates and the Lorentz angle increases. Once the irradiation level becomes too high, hence the collected charge

  19. Tree-level equivalence between a Lorentz-violating extension of QED and its dual model in electron-electron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Toniolo, Giuliano R.; Fargnoli, H.G.; Brito, L.C.T. [Universidade Federal de Lavras, Departamento de Fisica, Caixa Postal 3037, Lavras, Minas Gerais (Brazil); Scarpelli, A.P.B. [Setor Tecnico-Cientifico, Departamento de Policia Federal, Sao Paulo (Brazil)

    2017-02-15

    S-matrix amplitudes for the electron-electron scattering are calculated in order to verify the physical equivalence between two Lorentz-breaking dual models. We begin with an extended Quantum Electrodynamics which incorporates CPT-even Lorentz-violating kinetic and mass terms. Then, in a process of gauge embedding, its gauge-invariant dual model is obtained. The physical equivalence of the two models is established at tree level in the electron-electron scattering and the unpolarized cross section is calculated up to second order in the Lorentz-violating parameter. (orig.)

  20. Tree-level equivalence between a Lorentz-violating extension of QED and its dual model in electron-electron scattering

    International Nuclear Information System (INIS)

    Toniolo, Giuliano R.; Fargnoli, H.G.; Brito, L.C.T.; Scarpelli, A.P.B.

    2017-01-01

    S-matrix amplitudes for the electron-electron scattering are calculated in order to verify the physical equivalence between two Lorentz-breaking dual models. We begin with an extended Quantum Electrodynamics which incorporates CPT-even Lorentz-violating kinetic and mass terms. Then, in a process of gauge embedding, its gauge-invariant dual model is obtained. The physical equivalence of the two models is established at tree level in the electron-electron scattering and the unpolarized cross section is calculated up to second order in the Lorentz-violating parameter. (orig.)