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Sample records for lorentz como ecuaciones

  1. Ecuaciones Diferenciales II

    OpenAIRE

    Mañas Baena, Manuel; Martínez Alonso, Luis

    2015-01-01

    En este manual se revisan diferentes aspectos sobre las ecuaciones diferenciales en derivadas parciales de utilidad para los físicos. Se elaboraron como notas de clase de la asignatura Ecuaciones II, del plan 1993 de la Licenciatura de Física de la UCM. Actualmente cubre un 75% de la asignatura Métodos Matemáticos II del Grado de Física de la UCM.

  2. Ecuaciones de diferencias mejoradas para ecuaciones diferenciales

    OpenAIRE

    Lick, Wilbert

    2009-01-01

    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

  3. Ecuaciones de diferencias mejoradas para ecuaciones diferenciales

    OpenAIRE

    Lick, Wilbert

    2009-01-01

    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

  4. Ecuaciones diferenciales como modelos en clase de física y de matemáticas

    OpenAIRE

    2009-01-01

    Este artículo trata de la enseñanza y el aprendizaje de la modelación matemática en los cursos de física y de matemáticas. En el 2002, un nuevo currículo para el bachillerato en Francia acentuó el papel de las matemáticas como una herramienta para modelar en otras ciencias. Una descripción del proceso de modelación es presentada, así como el análisis de los manuales comúnmente usados en estos cursos. Este análisis revela el proceso de transposición del "proceso de modelación" practicado por l...

  5. 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.

  6. Motivación y satisfacción laboral como facilitadores del cambio organizacional: una explicación desde las ecuaciones estructurales

    Directory of Open Access Journals (Sweden)

    Monica Garcia Rubiano

    2014-01-01

    Full Text Available El propósito del presente artículo de investigación consistió en determinar las condiciones de la satisfacción y motivación laboral como facilitadores del cambio organizacional en diferentes empresas de Bogotá. Para ello, se emplearon tres instrumentos de evaluación: el Cuestionario de Motivación en el Trabajo (CMT, el Instrumento de Medición de Cambio Organizacional (IMC y el Cuestionario de Satisfacción Laboral S20/23. La investigación se realizó bajo un diseño ex post facto retrospectivo de grupo único. Los resultados evidencian que los factores de motivación más relevantes en cuanto al cambio organizacional son el poder y el reconocimiento; adicionalmente, la cultura de cambio se relaciona de manera positiva con la motivación de logro. Abstract This research paper aims to determine the conditions resulting in organizational change in different companies in Bogota, based on motivation and job satisfaction. Three assessment tools were applied in the research. These were: Work Motivation Questionnaire (WMQ, Instrument for Measurement of Organizational Change (MC and a Job Satisfaction Questionnaire (S20/23. This research was based on an ex post facto retrospective of unique group design which shows that the most important motivational factors in organizational change are power and recognition. In addition, the change pattern correlates positively with achievement and motivation.

  7. ESTUDIO DE ALGUNAS ECUACIONES DIFERENCIALES DE CARACTER CUASILINEAL ELIPTICO.

    OpenAIRE

    2009-01-01

    Esta tesis tiene como objetivo el estudio de tres problemas que se enmarcan dentro de la linea de las ecuaciones diferenciales parciales no lineales elípticas. En ci problema 1, estudiaremos existencia de una solución no trivial (u, y) de div (& ( Vi ) = 88p.

  8. De las ecuaciones en diferencias finitas a las ecuaciones sumatorias

    OpenAIRE

    Poveda Ramos, Gabriel

    2012-01-01

    0º Las ecuaciones en diferencias finitas coristltuyen un material relativamente poco conocido, a  pesar de que desde el siglo pasado George Boole escribir una obra ya clásica sobre ellas, especialmente sobre las del tipo ordinario, con una sola variable discreta independiente. Sin embargo, el caso de dichas ecuaciones ordinarias lineales, es bien conocido de los tratadistas [1,2,3,5,6] y sobre él se conocen los teoremas de existencia y unicidad de soluciones, de superposición de soluciones pa...

  9. Ecuaciones, teorías y ciencias que las usan

    OpenAIRE

    Rosa María Herrera

    2012-01-01

    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....

  10. 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.

  11. Uso preinstruccional de ecuaciones para describir y representar situaciones problema en un grupo de sexto grado

    OpenAIRE

    2000-01-01

    El estudio que aquí se reporta tuvo como propósito investigar el uso que niños de sexto grado hacen de las ecuaciones para escribir y representar situaciones problema antes de haber sido instruidos formalmente en álgebra. A diez estudiantes se les presentó una serie de tareas similares en seis contextos de problemas diferentes que representan situaciones lineales y no lineales. Los niños de este estudio mostraron una habilidad notable para generalizar situaciones problema y escribir ecuacione...

  12. 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

  13. 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...

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

    OpenAIRE

    Máximo Agüero Granados; Jorge Bernal; Guadalupe Frias; Mauricio Paulin

    2001-01-01

    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.

  15. 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.

  16. Ecuaciones diferenciales ordinarias para estudiantes de Física

    OpenAIRE

    Aguirregabiria Aguirre, Juan María

    2009-01-01

    Conceptos fundamentales. - Ecuaciones de primer orden. - Ecuaciones de orden superior. - Sistemas de ecuaciones. - Transformación de Laplace. - Solución para series de ecuaciones lineales. - Métodos aproximados. - Teoría de la estabilidad. - Problemas de contorno de Sturm-Liouville. - Apéndice: Teoremas fundamentales. Métodos simbólicos. Resumen de métodos analíticos exactos. Definición y propiedades de algunas funciones. Tablas de transformadas de Laplace. Tablas d...

  17. Existencia de soluciones de ecuaciones diferenciales implícitas

    OpenAIRE

    Zorba, Germán

    2013-01-01

    Las ecuaciones diferenciales implícitas -EDIs- aparecen frecuentemente en diferentes ciencias. Una EDI definida sobre una variedad M puede representarse de manera general así: φ(x, x' ) = 0 siendo una ecuacióon diferencial ordinaria -EDO- x' = f(x) el caso particular más simple. Las ecuaciones de Euler-Lagrange para un Lagrangiano dado, las ecuaciones de Lagrange-D'Alembert para un sistema no-holónomo y su versión reducida: las ecuaciones de Lagrange-D'Alember...

  18. Ecuaciones diferenciales ordinarias para estudiantes de Física

    OpenAIRE

    Aguirregabiria Aguirre, Juan María

    2009-01-01

    Conceptos fundamentales. - Ecuaciones de primer orden. - Ecuaciones de orden superior. - Sistemas de ecuaciones. - Transformación de Laplace. - Solución para series de ecuaciones lineales. - Métodos aproximados. - Teoría de la estabilidad. - Problemas de contorno de Sturm-Liouville. - Apéndice: Teoremas fundamentales. Métodos simbólicos. Resumen de métodos analíticos exactos. Definición y propiedades de algunas funciones. Tablas de transformadas de Laplace. Tablas d...

  19. Programa del método del elemento finito para ecuaciones diferenciales parciales parabólicas con frontera convexa

    OpenAIRE

    Miñano León, Wilder Roger

    2012-01-01

    Las soluciones analíticas o exactas para las ecuaciones diferenciales parciales requieren de un gran esfuerzo y complejidad matemática. En la actualidad muchos de estos problemas se resuelven utilizando un software de computadora. Las asignaturas de métodos numéricos, análisis numérico o cálculo numérico, tratan problemas sobre ecuaciones diferenciales parciales y utiliza algunos métodos, como los de diferencias finitas que son los más difundidos y en menor escala utilizan los elemento...

  20. 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.

  1. 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.

  2. Aplicaciones del método didáctico inductivo en la resolución de ecuaciones diferenciales ordinarias de primer orden en los estudiantes de la UFA-ESPE-L y su incidencia en los logros de aprendizaje en la asignatura de ecuaciones diferenciales ordinarias.

    OpenAIRE

    Reyes Bedoya, Wilson Patricio

    2015-01-01

    La presente investigacion tiene como proposito presentar un metodo educativo estandarizado para mejorar los logros de aprendizaje de los estudiantes en la asignatura de Ecuaciones Diferenciales Ordinarias en la Universidad de las Fuerzas Armadas - ESPE Extension Latacunga, utilizando una guia de aprendizaje para las ecuaciones diferenciales ordinarias de primer orden, elaborado siguiendo la estructura que propone el Metodo Inductivo. La necesidad de la investigacion se determin...

  3. Contribución al estudio de algunos modelos regidos por ecuaciones de evolución no autónomas y/o estocásticas

    OpenAIRE

    Márquez Durán, Antonio Miguel

    2005-01-01

    "Como es bien conocido, las ecuaciones de Navier-Stokes gobiernan el movimiento de fluidos comunes como el agua, el aire, el aceite, etc. No es objeto de nuestra Memoria el estudio de tales ecuaciones, sujeto de innumerables trabajos matemáticos desde la aparición del primer artículo de Leray. La segunda parte de la misma es una continuación del trabajo realizado durante el período de investigación previo a la Tesis (Tesina), y estará dedicada al estudio de una clase especial de ecuaciones en...

  4. 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...

  5. Cuatro decadas de teoria de la educacion: ?una ecuacion imposible?

    National Research Council Canada - National Science Library

    Jover, Gonzalo; Thoilliez, Bianca

    2010-01-01

    .... Para ello, los autores utilizan, a modo de metafora, el concepto de ecuacion, y presentan una serie de entrevistas realizadas a tres personas que han tenido un papel fundamental en el desarrollo...

  6. Soluciones explícitas de problemas mixtos para sistemas acoplados de ecuaciones en diferencias parciales

    OpenAIRE

    L. Jódar; Legua, Matilde

    1991-01-01

    En este artículo obtenemos una solución explícita computable de problemas mixtos para sistemas acoplados de ecuaciones en diferencias parciales que aparecen al considerar aproximaciones en diferencias para sistemas acoplados en derivadas parciales. El enfoque del problema puede considerarse como un método de separación de variables discreto matricial que utilizando series de Fourier discretas permite obtener una solución explícita del problema sin tener que resolver sistemas algrabraicos line...

  7. Integralab : un software para integración de funciones y solución de ecuaciones diferenciales por métodos numéricos

    OpenAIRE

    2006-01-01

    El trabajo presenta el diseño e implementación de un software que tiene por nombre IntegraLAB el cual sirve como una herramienta para resolver problemas de integración de funciones y solución de ecuaciones diferenciales ordinarias aplicando métodos numéricos.

  8. Generalizing the Lorentz transformations

    CERN Document Server

    Chappell, James M; Iannella, Nicolangelo; Hartnett, John G; Iqbal, Azhar; Abbott, Derek

    2016-01-01

    In this paper we develop a framework allowing a natural extension of the Lorentz transformations. To begin, we show that by expanding conventional four-dimensional spacetime to eight-dimensions that a natural generalization is indeed obtained. We then find with these generalized coordinate transformations acting on Maxwell's equations that the electromagnetic field transformations are nevertheless unchanged. We find further, that if we assume the absence of magnetic monopoles, in accordance with Maxwell's theory, our generalized transformations are then restricted to be the conventional ones. While the conventional Lorentz transformations are indeed recovered from our framework, we nevertheless provide a new perspective into why the Lorentz transformations are constrained to be the conventional ones. Also, this generalized framework may assist in explaining several unresolved questions in electromagnetism as well as to be able to describe quasi magnetic monopoles found in spin-ice systems.

  9. Lorentz violation naturalness revisited

    CERN Document Server

    Belenchia, Alessio; Liberati, Stefano

    2016-01-01

    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-en...

  10. Ecuaciones de predicción del gasto de energía en reposo en escolares de la Ciudad de México

    Directory of Open Access Journals (Sweden)

    Marlu Estephanie Becerril-Sánchez

    2015-05-01

    Full Text Available Introducción: existen diferentes ecuaciones de predicción para estimar el gasto de energía en reposo en niños; sin embargo, no hay consenso de cuál es la más adecuada para usarse en población pediátrica mexicana. Objetivo: conocer la concordancia del gasto de energía en reposo medido por calorimetría indirecta con el estimado con diferentes ecuaciones de predicción en un grupo de escolares de la Ciudad de México. Material y método: se realizó un estudio transversal en escolares de 6 a 12 años de edad (n = 63. El gasto de energía en reposo fue medido mediante calorimetría indirecta, se usó como referencia para conocer la exactitud de las ecuaciones de predicción de Schofield, de FAO/OMS, de Tverskaya y de Harris-Benedict. Para conocer la concordancia entre las ecuaciones y el gasto de energía en reposo se estimaron coeficientes de correlación intraclase (r. Resultados: en esta población las cuatro ecuaciones sobrestimaron el gasto de energía en reposo; en promedio, las diferencias fueron de 12.1 a 97.5 kcal/día. Las ecuaciones que tuvieron la mayor concordancia con el gasto de energía en reposo medido fueron las de Schofield y las de FAO/OMS (r = 0.74, mientras que las de Tverskaya y de Harris-Benedict tuvieron la menor (r = 0.64. La concordancia fue menor en los niños más pequeños, especialmente con las ecuaciones de Harris-Benedict (r = 0.33 y Tverskaya (r = 0.47. Conclusiones: aunque se requiere más investigación sobre la conveniencia de usar ecuaciones de predicción del gasto de energía en reposo en población pediátrica de México, nuestros resultados muestran que las ecuaciones de FAO/OMS o las de Schofield son las más adecuadas.

  11. 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

  12. 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.

  13. 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

  14. Teoría de bifurcación y aplicaciones en ecuaciones diferenciales

    OpenAIRE

    Alzate Berrío, Wilmar Arley

    2011-01-01

    En este trabajo se estudia la teoría básica de bifurcación así como algunas de sus aplicaciones en ecuaciones diferenciales. En el Capítulo 1 presentamos algunos resultados básicos y definimos el concepto de punto de bifurcación. En el Capítulo 2 se estudian el método de Reducción de Lyapunov-Schmidt y un teorema debido a Crandall y Rabinowitz. También estudiamos dos importantes teoremas: uno debido a Krasnoselsk'ii y otro debido a Rabinowitz. En el Capítulo 3 presentamos una aplicación para ...

  15. 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.…

  16. 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.

  17. Resolución de equivalencias financieras mediante ecuaciones con coeficientes borrosos

    Directory of Open Access Journals (Sweden)

    Maria Silvia Moriñigo

    2007-01-01

    Full Text Available A menudo sólo se conocen estimaciones de las variables financieras. Es usual que con objeto de utilizar modelos clásicos, apreciaciones como “una tasa de entre el 5% y el 7%”, se conviertan en cantidades exactas, como puede ser el promedio entre los valores extremos. En este trabajo se propone un enfoque más flexible que permite captar la incertidumbre mediante la utilización de algunos elementos de la teoría de los conjuntos borrosos. La imprecisión presente en el capital, interés y/o cantidad de períodos se modela mediante números borrosos triangulares. Al apelar a los enfoques clásicos para evaluar expresiones algebraicas con coeficientes borrosos que hacen uso del principio de extensión y aritmética de -cortes, se definen las extensiones fuzzy de las relaciones financieras elementales. Se obtienen las versiones fuzzy del valor actual y del valor final de un capital borroso y el VAN mediante la resolución de ecuaciones con coeficientes borrosos por el método de α - cortes. Estos desarrollos se aplican a distintos casos de estudio. Por último, se muestra que no siempre es posible hallar un análogo borroso de la TIR utilizando los métodos clásicos de resolución de ecuaciones con coeficientes borrosos. Se calcula valiéndose de un nuevo concepto de solución

  18. Simulación de sistemas Multi-Agente mediante un esquema Monte Carlo basado en ecuaciones diferenciales ordinarias

    OpenAIRE

    Zulueta Guerrero, Ekaitz; González González, Asier; Lopez Guede, José Manuel; Calvo Gordillo, Isidro

    2011-01-01

    [ES] En este trabajo se expone una metodología para modelar un sistema Multi-Agente (SMA), para que sea equivalente a un sistema de Ecuaciones Diferenciales Ordinarias (EDO), mediante un esquema basado en el método de Monte Carlo. Se muestra que el SMA puede describir con mayor riqueza modelos de sistemas dinámicos con variables cuantificadas discretas. Estos sistemas son muy acordes con los sistemas biológicos y fisiológicos, como el modelado de poblaciones o el modelado de enfermedades epid...

  19. DISEÑO, IMPLEMENTACIÓN Y CONVERGENCIA DE MÉTODOS ITERATIVOS PARA RESOLVER ECUACIONES Y SISTEMAS NO LINEALES UTILIZANDO FUNCIONES PESO

    OpenAIRE

    2014-01-01

    Resumen La resolución de ecuaciones y sistemas de ecuaciones no lineales figura entre los problemas más importantes, tanto desde un punto de vista teórico como práctico, de las matemáticas aplicadas, así como también de muchas ramas de las ciencias, la ingeniería, la física, la informática, la astronomía, las finanzas,.... Un vistazo a la bibliografía y la lista de grandes matemáticos que han trabajado en este tema pone de manifiesto un alto nivel de interés contemporá...

  20. Lorentz violation and neutrino oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Mewes, Matthew [Marquette University, P.O. Box 1881, Milwaukee, WI 53201 (United States)

    2011-12-15

    Lorentz violation naturally leads to neutrino oscillations and provides an alternative mechanism that may explain current data. This contribution to the proceedings of The XXII International Conference on Neutrino Physics and Astrophysics provides a brief review of possible signals of Lorentz violation in neutrino-oscillation experiments.

  1. QED Tests of Lorentz Symmetry

    CERN Document Server

    Bluhm, R

    2004-01-01

    A status report is given of some recent theoretical and experimental investigations looking for signals of Lorentz violation in QED. Experiments with light, charged particles, and atoms have exceptional sensitivity to small shifts in energy caused by Lorentz violation, including effects that could originate from new physics at the Planck scale.

  2. 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.

  3. Realisation of a Lorentz algebra in Lorentz violating theory

    Energy Technology Data Exchange (ETDEWEB)

    Ganguly, Oindrila [S. N. Bose National Centre for Basic Sciences, Kolkata (India)

    2012-11-15

    A Lorentz non-invariant higher derivative effective action in flat spacetime, characterised by a constant vector, can be made invariant under infinitesimal Lorentz transformations by restricting the allowed field configurations. These restricted fields are defined as functions of the background vector in such a way that background dependence of the dynamics of the physical system is no longer manifest. We show here that they also provide a field basis for the realisation of a Lorentz algebra and allow the construction of a Poincare invariant symplectic two-form on the covariant phase space of the theory. (orig.)

  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. La numerología y el álgebra chinas en la enseñanza actual de las ecuaciones lineales

    OpenAIRE

    Hernández, Abraham; Gallardo, Aurora

    2007-01-01

    Vía el análisis histórico–crítico, se reflexiona sobre la génesis de los números negativos y el cero, así como sobre las primeras aplicaciones de un método de resolución de ecuaciones surgido en el álgebra de la antigua China. En este estudio, el método Fang Cheng, al ser enseñado a alumnos del presente, posibilita la adición de números signados, el reconocimiento de la sustracción en todos los casos, aunque persiste el rechazo hacia las soluciones negativa y nula de ecuaciones.

  6. Problemas de contorno para ecuaciones en diferencias y ecuaciones diferenciales funcionales

    OpenAIRE

    Ferreiro Darriba, Juan Bosco

    2014-01-01

    Habitualmente se considera que los procesos reales que se producen a lo largo del tiempo, en un determinado espacio f sico, son continuos: se desarrollan como un ujo ininterrumpido desde que comienzan hasta que nalizan. Sin embargo, cuando queremos conocer la evoluci on de un determinado sistema a trav es del tiempo, no siempre estamos interesados en obtener la descripci on del mismo en todo momento. A menudo solo nos interesa conocer el estado del sistema en determinados in...

  7. Lorentz transformations: Einstein's derivation simplified

    CERN Document Server

    Rothenstein, B; Popescu, Stefan; Rothenstein, Bernhard

    2007-01-01

    We show that the Lorentz transformations for the space-time coordinates of the same event are a direct consequence of the principle of relativity and of Einstein's distant clocks synchronization procedure. In our approach, imposing the linear character of the Lorentz transformations we guess that the transformation equation for the space coordinate has the form x=ax'+cbt'. Imposing the condition that it accounts for the time dilation relativistic effect and taking into account the fact that due to the clock synchronization a la Einstein the space-time coordinates of the same event in the two frames are related by x=ct and x'=ct', we find out expressions for a and b. Dividing the transformation equation for the space coordinate by c we obtain the transformation equation for the time coordinate t=at'+b/cx'. Combining the two transformation equations we obtain directly the inverse Lorentz transformations.

  8. Lorentz-violating inflationary magnetogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Campanelli, Leonardo [Universita di Bari, Dipartimento di Fisica, Bari (Italy)

    2015-06-15

    A non-conformally invariant coupling between the inflaton and the photon in the minimal Lorentz-violating standard model extension is analyzed. For specific forms of the Lorentz-violating background tensor, the strong-coupling and back-reaction problems of magnetogenesis in de Sitter inflation with scale ∝ 10{sup 16} GeV are evaded, the electromagnetic-induced primordial spectra of (Gaussian and non-Gaussian) scalar and tensor curvature perturbations are compatible with cosmic microwave background observations, and the inflation-produced magnetic field directly accounts for cosmic magnetic fields. (orig.)

  9. Neutrino mixing and Lorentz invariance

    CERN Document Server

    Blasone, M; Pires-Pacheco, P; Blasone, Massimo; Magueijo, Joao; Pires-Pacheco, Paulo

    2003-01-01

    We use previous work on the Hilbert space for mixed fields to derive deformed dispersion relations for neutrino flavor states. We then discuss how these dispersion relations may be incorporated into frameworks encoding the breakdown of Lorentz invariance. We consider non-linear relativity schemes (of which doubly special relativity is an example), and also frameworks allowing for the existence of a preferred frame. In both cases we derive expressions for the spectrum and end-point of beta decay, which may be used as an experimental probe of the peculiar way in which neutrinos experience Lorentz invariance.

  10. Estudio numérico de sistemas de ecuaciones no lineales difusas

    Directory of Open Access Journals (Sweden)

    Patricio Cumsille

    2010-12-01

    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 técnicas analíticas estándares de soluciones no son adecuadas para resolverlos. Por esta razón, en este artículo nos centramos en el estudio de los resultados conocidos para los métodos numéricos clásicos y en su adaptación a la resolución de problemas difusos. Abstract. In this work we study the numerical resolution of systems of fuzzy nonlinear equations. More precisely, we describe, analyze and simulate numerical methods, such as Newton method, in order to approximate efficiently the solutions to such problems. One of the main issues of this type of problems is that the standard analytical techniques for finding solutions, are not appropriate to resolve them. For this reason, in this paper we focus in the study of known results for the classical methods and their adaptation to the resolution of fuzzy problems.

  11. 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.

  12. Lorentz violation, gravity, dissipation and holography

    National Research Council Canada - National Science Library

    Kiritsis, Elias

    2013-01-01

    We reconsider Lorentz Violation (LV) at the fundamental level. We argue that Lorentz Violation is intimately connected with gravity and that LV couplings in QFT must always be fields in a gravitational sector...

  13. Transport properties of stochastic Lorentz models

    NARCIS (Netherlands)

    Beijeren, H. van

    1982-01-01

    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 waiti

  14. Lorentz violation in supersymmetric field theories.

    Science.gov (United States)

    Nibbelink, Stefan Groot; Pospelov, Maxim

    2005-03-04

    We construct supersymmetric Lorentz violating operators for matter and gauge fields. We show that in the supersymmetric standard model the lowest possible dimension for such operators is five, and therefore they are suppressed by at least one power of an ultraviolet energy scale, providing a possible explanation for the smallness of Lorentz violation and its stability against radiative corrections. Supersymmetric Lorentz noninvariant operators do not lead to modifications of dispersion relations at high energies thereby escaping constraints from astrophysical searches for Lorentz violation.

  15. Fractional Fourier transform of Lorentz beams

    Institute of Scientific and Technical Information of China (English)

    Zhou Guo-Quan

    2009-01-01

    This paper introduces Lorentz beams to describe certain laser sources that produce highly divergent fields. The fractional Fourier transform (FRFT) is applied to treat the propagation of Lorentz beams. Based on the definition of convolution and the convolution theorem of the Fourier transform, an analytical expression for a Lorentz beam passing through a FRFT system has been derived. By using the derived formula, the properties of a Lorentz beam in the FRFT plane are illustrated numerically.

  16. 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.

  17. Ecuaciones de Boussinesq: estimaciones uniformes en el tiempo de las aproximaciones de Galerkin espectrales

    Directory of Open Access Journals (Sweden)

    R. C. Cabrales

    2009-01-01

    Full Text Available Obtenemos cotas para el error de las soluciones fuertes de las ecuaciones de Boussinesq que modelan los fluidos incompresibles y conductores de calor, suponiendo que dichas soluciones son condicionalmente asintóticamente estables.

  18. Nuclear beta decay with Lorentz violation

    NARCIS (Netherlands)

    Noordmans, J.P.; Wilschut, H. W.; Timmermans, R. G. E.

    2013-01-01

    We consider the possibility of Lorentz-invariance violation in weak-decay processes. We present a general approach that entails modifying the W-boson propagator by adding a Lorentz-violating tensor to it. We describe the effects of Lorentz violation on nuclear beta decay in this scenario. In

  19. Testing local Lorentz invariance with gravitational waves

    CERN Document Server

    Kostelecky, Alan

    2016-01-01

    The effects of local Lorentz violation on dispersion and birefringence of gravitational waves are investigated. The covariant dispersion relation for gravitational waves involving gauge-invariant Lorentz-violating operators of arbitrary mass dimension is constructed. The chirp signal from the gravitational-wave event GW150914 is used to place numerous first constraints on gravitational Lorentz violation.

  20. Testing local Lorentz invariance with gravitational waves

    Energy Technology Data Exchange (ETDEWEB)

    Kostelecký, V. Alan, E-mail: kostelec@indiana.edu [Physics Department, Indiana University, Bloomington, IN 47405 (United States); Mewes, Matthew [Physics Department, California Polytechnic State University, San Luis Obispo, CA 93407 (United States)

    2016-06-10

    The effects of local Lorentz violation on dispersion and birefringence of gravitational waves are investigated. The covariant dispersion relation for gravitational waves involving gauge-invariant Lorentz-violating operators of arbitrary mass dimension is constructed. The chirp signal from the gravitational-wave event GW150914 is used to place numerous first constraints on gravitational Lorentz violation.

  1. Análisis de los factores de riesgo en el seguro de automóvil mediante ecuaciones estructurales

    Directory of Open Access Journals (Sweden)

    María Jesús Segovia-Vargas

    2015-12-01

    Full Text Available La gestión de riesgos, asociada al seguro del automóvil, es una cuestión crucial a la que se enfrentan en la actualidad tanto actuarios como profesionales del sector. Es clave seleccionar adecuadamente los factores de riesgos para asignar las tarifas a los asegurados en función del riesgo asociado. Por tanto, el objetivo de este trabajo es comprobar empíricamente la validez de la utilización de los niveles de “bonus-malus” para clasificar adecuadamente a los asegurados a través de dos modelos de ecuaciones estructurales. Los análisis sobre una muestra de 4.365 pólizas automovilísticas españolas descritas a través de 11 factores de riesgo muestran que la variable BM contribuye a mejorar la capacidad explicativa del modelo pero no de manera significativa.

  2. Soluciones numericas continuas de ecuaciones diferenciales matriciales con cotas de error a priori.

    OpenAIRE

    2009-01-01

    EN ESTA MEMORIA SE CONSIDERAN DOS TIPOS DE ECUACIONES DIFERENCIALES MATRICIALES. EN PRIMER LUGAR SE CONSTRUYEN SOLUCIONES NUMERICAS PARA PROBLEMAS DE VALORES INICIALES MATRICIALES UTILIZANDO METODOS LINEALES MULTIPASO MATRICIALES. A CONTINUACION, VIA INTERPOLACION LINEAL MATRICIAL SE CONSTRUYEN SOLUCIONES NUMERICAS CONTINUAS CON COTAS DE ERROR EXPRESADOS EN TERMINOS DE LOS DATOS. PARTICULAR ATENCION SE PRESTAN A LAS ECUACIONES DE TIPO RICCATI Y LYAPUNOV GENERALIZADAS CON COEFICIENTES VARIABLE...

  3. Supergravity with broken Lorentz invariance

    Directory of Open Access Journals (Sweden)

    Marakulin Arthur

    2016-01-01

    Full Text Available The supersymmetric extension of the Lorentz violating Einstein-aether theory of gravity is considered. The most general Lagrangian of the linearized Einstein-aether supergravity is constructed using the superfield formalism. The constraints imposed by supersymmetry on the parameters of the theory are obtained.

  4. One way to Lorentz's Transformations

    CERN Document Server

    Bessonov, E G

    2012-01-01

    The derivation of Lorentz Transformations (LT) based on the Principle of Relativity and dependence of the rate of clocks tick (time dilation) on their velocity is presented. The analysis of different ways of the LT derivation allows to look at LT and their consequences from different standpoints, to make them more accessible to a wide circle of readers interested in the relativistic physics.

  5. Método de las características complejas para ecuaciones elípticas en ángulos no convexos

    OpenAIRE

    De La Paz Méndez, José Eligio

    2012-01-01

    Este trabajo está dedicado a algunos aspectos de la solución de problemas de frontera para las ecuaciones elípticas en los ángulos planos no convexos. Precisamente se trata de la justificación del método de las características complejas [2], [3], [5], [7] para ángulos no convexos. Este método encuentra aplicaciones para varios problemas de la Física Matemática tanto como para ángulos convexos y ángulos no convexos [6], [8], [9], [10], [11] [13]. En la parte principal de est...

  6. Solución de ecuaciones de grado superior mediante estrategias de aprendizaje basado en problemas y el uso de objetos de aprendizaje

    OpenAIRE

    Ulloa, Ricardo; Estrada, Ana Luisa

    2007-01-01

    Con la investigación objeto de este reporte, se estudiaron los efectos que tiene una propuesta didáctica centrada en el enfoque de Aprendizaje Basado en Problemas (ABP) y con empleo de Objetos para el Aprendizaje (LO), sobre el aprendizaje del tema ecuaciones de grado superior, por parte de alumnos de segundo de la Licenciatura en Matemática Educativa (LME) de la Universidad Autónoma de Nayarit (UAN). La etapa de experimentación se llevó a cabo durante tres meses. Se empleó como marco teórico...

  7. Lorentz Force Electrical Impedance Tomography

    CERN Document Server

    Grasland-Mongrain, Pol; Chapelon, Jean-Yves; Lafon, Cyril

    2014-01-01

    This article describes a method called Lorentz Force Electrical Impedance Tomography. The electrical conductivity of biological tissues can be measured through their sonication in a magnetic field: the vibration of the tissues inside the field induces an electrical current by Lorentz force. This current, detected by electrodes placed around the sample, is proportional to the ultrasonic pressure, to the strength of the magnetic field and to the electrical conductivity gradient along the acoustic axis. By focusing at different places inside the sample, a map of the electrical conductivity gradient can be established. In this study experiments were conducted on a gelatin phantom and on a beef sample, successively placed in a 300 mT magnetic field and sonicated with an ultrasonic transducer focused at 21 cm emitting 500 kHz bursts. Although all interfaces are not visible, in this exploratory study a good correlation is observed between the electrical conductivity image and the ultrasonic image. This method offers...

  8. 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.

  9. Imagen, Lealtad y Promoción Turística. Análisis con Ecuaciones Estructurales

    Directory of Open Access Journals (Sweden)

    Antonio Alvarez Sousa

    2015-01-01

    Full Text Available El objetivo de esta investigación es analizar como la imagen turística influye en la lealtad y en la promoción turística de un destino o producto. Para ello partimos de las teorías de las motivaciones turísticas, la imagen cognitiva y afectiva y como conforman la imagen general que influye en la lealtad posterior y en la promoción que pueden hacer los turistas por los distintos cauces de comunicación orgánica. También analizamos la importancia de este tipo de comunicación para promocionar un destino o un producto turístico. Empleamos la metodología de las ecuaciones estructurales y la aplicamos a los datos de una encuesta realizada a peregrinos del Camino de Santiago. Los resultados son que la imagen general, las motivaciones y la procedencia influyen en las actitudes de lealtad al destino así como en la intención de convencer a familiares y amigos, participar en blogs y webs e incluso en escribir un libro.

  10. Asymptotic behavior of Lorentz violation on orbifolds

    CERN Document Server

    Uekusa, Nobuhiro

    2010-01-01

    Momentum dependence of quantum corrections with higher-dimensional Lorentz violation is examined in electrodynamics on orbifolds. It is shown that effects of the Lorentz violation are not decoupled at high energy scales. Despite the loss of the higher-dimensional Lorentz invariance, a higher-dimensional Ward identity is found to be fulfilled for one-loop vacuum polarization. This implies that gauge invariance may be prior to Lorentz invariance as a guiding principle in higher-dimensional field theory. As a universal application of electrodynamics, an extra-dimensional aspect for Furry's theorem is emphasized.

  11. Validation of predictive equations for weight and height using a metric tape Validación de ecuaciones predictivas para el peso y talla utilizando cinta métrica

    Directory of Open Access Journals (Sweden)

    E. I. Rabito

    2008-12-01

    la realización de estas medidas de forma convencional. En estos casos son necesarios equipamientos especiales o la estimativa por medio de ecuaciones predictivas. Recientemente fueran desarrolladas ecuaciones predictivas de peso y talla que requieren como instrumento la cinta métrica. Objetivo: Validar tres ecuaciones predictivas para el peso y dos ecuaciones para talla, evaluando la concordancia de estas con las ecuaciones propuestas por Chumlea. Métodos: Los datos recogidos fueran de sexo, edad, y medidas antropométricas como peso (kg; talla (m; pliegue cutáneo sub-escapular (mm; circunferencia de la pantorrilla (cm, del brazo (cm y del abdomen (cm; longitud del brazo (cm y media envergadura (cm. La evaluación estadística fue realizada utilizando el coeficiente de Lin, para evaluar la concordancia entre las ecuaciones, y el coeficiente St. Laurent, para comparar los valores estimados del peso y talla con los valores reales. Resultados: Fueron evaluados 100 individuos de los cuales 52% son del sexo femenino, internados en el Hospital de Clínicas (HCFMRP-USP. Las ecuaciones que presentaron mayores coeficientes de concordancia fueran I y II, para el peso y el IV y V para talla. Lo coeficiente de St. Laurent ha indicado que las ecuaciones III y V presentan validad para peso y talla, respectivamente. Conclusión: Las ecuaciones III y V, validadas en este estudio, son recomendables por la facilidad de utilización.

  12. 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

  13. Constraining Lorentz violation with cosmology.

    Science.gov (United States)

    Zuntz, J A; Ferreira, P G; Zlosnik, T G

    2008-12-31

    The Einstein-aether theory provides a simple, dynamical mechanism for breaking Lorentz invariance. It does so within a generally covariant context and may emerge from quantum effects in more fundamental theories. The theory leads to a preferred frame and can have distinct experimental signatures. In this Letter, we perform a comprehensive study of the cosmological effects of the Einstein-aether theory and use observational data to constrain it. Allied to previously determined consistency and experimental constraints, we find that an Einstein-aether universe can fit experimental data over a wide range of its parameter space, but requires a specific rescaling of the other cosmological densities.

  14. Métodos multipaso variable aplicados a ecuaciones diferenciales de orden dos con retardo

    OpenAIRE

    2010-01-01

    El origen de las Ecuaciones Diferenciales lo encontramos en la formulación Newtoniana de algunos problemas físicos, en particular en la solución del problema gravitacional, aún cuando no podemos olvidar que la paternidad del Cálculo y las ecuaciones diferenciales siempre ha estado ligada a los nombres de Newton y Leibnitz. Con respecto a sus orígenes ya en el año 1671 Newton escribe en su libro de cálculo diferencial un método para resolver un problema de valor inicial mediante series constru...

  15. Lorentz-Force Hydrophone Characterization

    CERN Document Server

    Grasland-Mongrain, Pol; Gilles, Bruno; Poizat, Adrien; Chapelon, Jean-Yves; Lafon, Cyril

    2014-01-01

    A Lorentz-force hydrophone consists of a thin wire placed inside a magnetic field. When under the influence of an ultrasound pulse, the wire vibrates and an electrical signal is induced by the Lorentz force that is proportional to the pulse amplitude. In this study a compact prototype of such a hydrophone is introduced and characterized, and the hydrodynamic model previously developed is refined. It is shown that the wire tension has a negligible effect on the measurement of pressure. The frequency response of the hydrophone reaches 1 MHz for wires with a diameter ranging between 70 and 400 \\micro m. The hydrophone exhibits a directional response such that the signal amplitude differs by less than 3dB as the angle of the incident ultrasound pulse varies from -20$^o$ and +20$^o$. The linearity of the measured signal is confirmed across the 50 kPa to 10 MPa pressure range, and an excellent resistance to cavitation is observed. This hydrophone is of interest for high pressure ultrasound measurements including Hi...

  16. Estrategia didáctica para la enseñanza-aprendizaje de ecuaciones lineales con una incógnita y su aplicación en situaciones problema

    OpenAIRE

    2011-01-01

    Este proyecto de investigación tiene como propósito el desarrollo y planteamiento de una estrategia didáctica de enseñanza-aprendizaje de ecuaciones lineales con una incógnita y su aplicación en situaciones problema. Se realizará un diseño de investigación cuasiexperimental por cuanto se tiene como propósito diseñar e implementar esta estrategia didáctica, con ello se pretende que los estudiantes, al abordar el tema con la estrategia propuesta, mejoren su nivel de competencia interpretativa, ...

  17. Estrategia didáctica para la enseñanza-aprendizaje de ecuaciones lineales con una incógnita y su aplicación en situaciones problema

    OpenAIRE

    Erazo, Jhon Darwin

    2011-01-01

    Este proyecto de investigación tiene como propósito el desarrollo y planteamiento de una estrategia didáctica de enseñanza-aprendizaje de ecuaciones lineales con una incógnita y su aplicación en situaciones problema. Se realizará un diseño de investigación cuasiexperimental por cuanto se tiene como propósito diseñar e implementar esta estrategia didáctica, con ello se pretende que los estudiantes, al abordar el tema con la estrategia propuesta, mejoren su nivel de competencia interpretativa, ...

  18. Possibilities for Lorentz violation in nonleptonic decays

    NARCIS (Netherlands)

    Keri Vos, K.; Wilschut, H.W.; Timmermans, R.G.E.

    2015-01-01

    The weak interaction offers an interesting portal to search for Lorentz symmetry breaking. We explore the possibilities to study Lorentz violation in nonleptonic decays, focusing on the recent measurement of the KLOE collaboration of the directional dependence of the lifetime of the neutral kaon

  19. Cosmological constraints on Lorentz violation in electrodynamics.

    Science.gov (United States)

    Kostelecký, V A; Mewes, M

    2001-12-17

    Infrared, optical, and ultraviolet spectropolarimetry of cosmological sources is used to constrain the pure electromagnetic sector of a general Lorentz-violating standard-model extension. The coefficients for Lorentz violation are bounded to less than 3 x 10(-32).

  20. CPT violation implies violation of Lorentz invariance.

    Science.gov (United States)

    Greenberg, O W

    2002-12-02

    A interacting theory that violates CPT invariance necessarily violates Lorentz invariance. On the other hand, CPT invariance is not sufficient for out-of-cone Lorentz invariance. Theories that violate CPT by having different particle and antiparticle masses must be nonlocal.

  1. Lorentz violation and deep inelastic scattering

    Directory of Open Access Journals (Sweden)

    V. Alan Kostelecký

    2017-06-01

    Full Text Available The effects of quark-sector Lorentz violation on deep inelastic electron–proton scattering are studied. We show that existing data can be used to establish first constraints on numerous coefficients for Lorentz violation in the quark sector at an estimated sensitivity of parts in a million.

  2. Lorentz violation and deep inelastic scattering

    Science.gov (United States)

    Kostelecký, V. Alan; Lunghi, E.; Vieira, A. R.

    2017-06-01

    The effects of quark-sector Lorentz violation on deep inelastic electron-proton scattering are studied. We show that existing data can be used to establish first constraints on numerous coefficients for Lorentz violation in the quark sector at an estimated sensitivity of parts in a million.

  3. Noncommutative field theory and Lorentz violation.

    Science.gov (United States)

    Carroll, S M; Harvey, J A; Kostelecký, V A; Lane, C D; Okamoto, T

    2001-10-01

    The role of Lorentz symmetry in noncommutative field theory is considered. Any realistic noncommutative theory is found to be physically equivalent to a subset of a general Lorentz-violating standard-model extension involving ordinary fields. Some theoretical consequences are discussed. Existing experiments bound the scale of the noncommutativity parameter to (10 TeV)(-2).

  4. Hiding Lorentz invariance violation with MOND

    NARCIS (Netherlands)

    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

  5. Lorentz violation and deep inelastic scattering

    CERN Document Server

    Kostelecky, Alan; Vieira, A R

    2016-01-01

    The effects of quark-sector Lorentz violation on deep inelastic electron-proton scattering are studied. We show that existing data can be used to establish first constraints on numerous coefficients for Lorentz violation in the quark sector at an estimated sensitivity of parts in a million.

  6. Parton model in Lorentz invariant noncommutative space

    Science.gov (United States)

    Haghighat, M.; Ettefaghi, M. M.

    2004-08-01

    We consider the Lorentz invariant noncommutative QED and complete the Feynman rules for the theory up to the order θ2. In the Lorentz invariant version of the noncommutative QED the particles with fractional charges can be also considered. We show that in the parton model, even at the lowest order, the Bjorken scaling violates as ˜θ2Q4.

  7. Testing Lorentz invariance in β decay

    NARCIS (Netherlands)

    Sytema, Auke

    2016-01-01

    In this thesis we investigate violation of Lorentz invariance in the weak interaction, specifically in β decay. For this purpose an experiment is performed with nuclear-spin-polarized 20Na that decays by emitting a β particle. Lorentz invariance is the property that the laws of nature do not depend

  8. Question of Lorentz violation in muon decay

    NARCIS (Netherlands)

    Noordmans, J. P.; Onderwater, C. J. G.; Wilschut, H. W.; Timmermans, R. G. E.

    2016-01-01

    Possibilities to test the Lorentz invariance of the weak interaction in muon decay are considered. We derive the direction-dependent muon-decay rate with a general Lorentz-violating addition to the W-boson propagator. We discuss measurements of the directional and boost dependence of the Michel para

  9. Gluonic Lorentz violation and chiral perturbation theory

    Science.gov (United States)

    Noordmans, J. P.

    2017-04-01

    By applying chiral-perturbation-theory methods to the QCD sector of the Lorentz-violating Standard-Model Extension, we investigate Lorentz violation in the strong interactions. In particular, we consider the C P T -even pure-gluon operator of the minimal Standard-Model Extension. We construct the lowest-order chiral effective Lagrangian for three as well as two light quark flavors. We develop the power-counting rules and construct the heavy-baryon chiral-perturbation-theory Lagrangian, which we use to calculate Lorentz-violating contributions to the nucleon self-energy. Using the constructed effective operators, we derive the first stringent limits on many of the components of the relevant Lorentz-violating parameter. We also obtain the Lorentz-violating nucleon-nucleon potential. We suggest that this potential may be used to obtain new limits from atomic-clock or deuteron storage-ring experiments.

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

    Directory of Open Access Journals (Sweden)

    Mauricio Macías C.

    2014-01-01

    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.

  11. Sobre ecuaciones diferenciales con retraso, dinámica de poblaciones y números primos

    OpenAIRE

    Liz, Eduardo

    2006-01-01

    Aprovecharemos para dar a conocer algunos aspectos de las ecuaciones con retraso y pasearemos por el mundo de los sistemas dinámicos discretos. Por el medio aparecen números mágicos y personajes inquietantes que ayudarán a hacer más amena la lectura.

  12. 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.

  13. Lorentz violation and perpetual motion

    Science.gov (United States)

    Eling, Christopher; Foster, Brendan Z.; Jacobson, Ted; Wall, Aron C.

    2007-05-01

    We show that any Lorentz-violating theory with two or more propagation speeds is in conflict with the generalized second law of black hole thermodynamics. We do this by identifying a classical energy-extraction method, analogous to the Penrose process, which would decrease the black hole entropy. Although the usual definitions of black hole entropy are ambiguous in this context, we require only very mild assumptions about its dependence on the mass. This extends the result found by Dubovsky and Sibiryakov, which uses the Hawking effect and applies only if the fields with different propagation speeds interact just through gravity. We also point out instabilities that could interfere with their black hole perpetuum mobile, but argue that these can be neglected if the black hole mass is sufficiently large.

  14. Lorentz violation and perpetual motion

    CERN Document Server

    Eling, C; Jacobson, T; Wall, A C; Eling, Christopher; Foster, Brendan Z.; Jacobson, Ted; Wall, Aron C.

    2007-01-01

    We show that any Lorentz violating theory with two or more propagation speeds is in conflict with the generalized second law of black hole thermodynamics. We do this by identifying a classical energy-extraction method, analogous to the Penrose process, which would decrease the black hole entropy. Although the usual definitions of black hole entropy are ambiguous in this context, we require only very mild assumptions about its dependence on the mass. This extends the result found by Dubovsky and Sibiryakov, which uses the Hawking effect and applies only if the fields with different propagation speeds interact just through gravity. We also point out instabilities that could interfere with their black hole {\\it perpetuum mobile}, but argue that these can be neglected if the black hole mass is sufficiently large.

  15. Alternative theories of gravity and Lorentz violation

    Science.gov (United States)

    Xu, Rui; Foster, Joshua; Kostelecky, V. Alan

    2017-01-01

    General relativity has achieved many successes, including the prediction of experimental results. However, its incompatibility with quantum theory remains an obstacle. By extending the foundational properties of general relativity, alternative theories of gravity can be constructed. In this talk, we focus on fermion couplings in the weak-gravity limit of certain alternative theories of gravity. Under suitable experimental circumstances, some of these couplings match terms appearing in the gravitational SME, which is a general framework describing violations of local Lorentz invariance. Existing limits on Lorentz violation can therefore be used to constrain certain Lorentz-invariant alternative theories of gravity.

  16. Photon gravitational defection in Lorentz violating scenarios

    CERN Document Server

    Accioly, Antonio; Helayël-Neto, José

    2016-01-01

    The effect of Lorentz symmetry violation in the phenomenon of photon gravitational bending, is investigated. Using a semiclassical approach, where the photon is described by the Carrol-Field-Jackiw (CFJ) electrodynamics which is responsible for implementing the Lorentz symmetry violation, the gravitational deflection angle related to the CFJ photon is computed. As expected, this bending angle experiences a deviation from the usual Einstein result and the latter is recovered in the appropriate limit. A comparison between the theoretical prediction and the experimental results allows to conclude that no trace of Lorentz symmetry breaking is found provided the components of the background vector field are $\\lesssim 10^{-8}$ eV.

  17. What do we know about Lorentz invariance?

    Science.gov (United States)

    Tasson, Jay D

    2014-06-01

    The realization that Planck-scale physics can be tested with existing technology through the search for spacetime-symmetry violation brought about the development of a comprehensive framework, known as the gravitational standard-model extension (SME), for studying deviations from exact Lorentz and CPT symmetry in nature. The development of this framework and its motivation led to an explosion of new tests of Lorentz symmetry over the past decade and to considerable theoretical interest in the subject. This work reviews the key concepts associated with Lorentz and CPT symmetry, the structure of the SME framework, and some recent experimental and theoretical results.

  18. On the Lorentz Factor of Superluminal Sources

    CERN Document Server

    Onuchukwu, Chika Christian

    2013-01-01

    We investigate the properties of features seen within superluminal sources often referred to as components. Our result indicates a fairly strong correlation of r=0.6 for quasars, r=0.4 for galaxies, and r=0.8 for BL Lac objects in our sample between component sizes and distances from the stationary core. Assumption of free adiabatic expanding plasma enabled us to constrain in general the Lorentz factor for superluminal sources. Ourestimated Lorentz factor of 7 - 17 for quasars, 6 - 13 for galaxies and 4- 9 for BL Lac objects indicate that BL Lac have the lowest range of Lorentz factor.

  19. Classical Gravitational Interactions and Gravitational Lorentz Force

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    In quantum gauge theory of gravity, the gravitational field is represented by gravitational gauge field.The field strength of gravitational gauge field has both gravitoelectric component and gravitomagnetic component. In classical level, gauge theory of gravity gives classical Newtonian gravitational interactions in a relativistic form. Besides,it gives gravitational Lorentz force, which is the gravitational force on a moving object in gravitomagnetic field The direction of gravitational Lorentz force is not the same as that of classical gravitational Newtonian force. Effects of gravitational Lorentz force should be detectable, and these effects can be used to discriminate gravitomagnetic field from ordinary electromagnetic magnetic field.

  20. Lorentz gauge quantization in synchronous coordinates

    CERN Document Server

    Garner, Christopher

    2016-01-01

    It has been shown that the Gupta-Bleuler method of quantization can be used to impose the Lorentz gauge condition in static space-times but not in cosmological space-times. This implies that the Gupta-Bleuler approach fails in general in non-static space-times. More recently, however, the Dirac method of quantizing constrained dynamical systems has been successfully employed to impose the Lorentz gauge in conformally flat space-times. In this paper we generalize this result by using Dirac's method to impose the Lorentz gauge in a general space-time region where the metric is expressed in synchronous coordinates.

  1. What Do We Know About Lorentz Invariance?

    CERN Document Server

    Tasson, Jay D

    2014-01-01

    The realization that Planck-scale physics can be tested with existing technology through the search for spacetime-symmetry violation brought about the development of a comprehensive framework, known as the gravitational Standard-Model Extension (SME), for studying deviations from exact Lorentz and CPT symmetry in nature. The development of this framework and its motivation led to an explosion of new tests of Lorentz symmetry over the past decade and to considerable theoretical interest in the subject. This work reviews the key concepts associated with Lorentz and CPT symmetry, the structure of the SME framework, and some recent experimental and theoretical results.

  2. Testing Lorentz invariance in orbital electron capture

    CERN Document Server

    Vos, K K; Timmermans, R G E

    2015-01-01

    Searches for Lorentz violation were recently extended to the weak sector, in particular neutron and nuclear $\\beta$ decay [1]. From experiments on forbidden $\\beta$-decay transitions strong limits in the range of $10^{-6}$-$10^{-8}$ were obtained on Lorentz-violating components of the $W$-boson propagator [2]. In order to improve on these limits strong sources have to be considered. In this Brief Report we study isotopes that undergo orbital electron capture and allow experiments at high decay rates and low dose. We derive the expressions for the Lorentz-violating differential decay rate and discuss the options for competitive experiments and their required precision.

  3. Cosmological Background torsion limits from Lorentz violation

    CERN Document Server

    Garcia de Andrade, L C

    2001-01-01

    Cosmological limits on Lorentz invariance breaking in Chern-Simons $(3+1)-dimensional$ electrodynamics are used to place limits on torsion. Birefrigence phenomena is discussed by using extending the propagation equation to Riemann-Cartan spacetimes instead of treating it in purely Riemannian spaces. The parameter of Lorentz violation is shown to be proportional to the axial torsion vector which allows us to place a limit on cosmological background torsion from the Lorentz violation constraint which is given by $ 10^{-33} eV <|S^{\\mu}| < 10^{-32} eV$ where $|S^{\\mu}|$ is the axial torsion vector.

  4. Argumentos de una ecuacion diferencial de un circuito electrico a través de su campo de pendientes

    OpenAIRE

    2010-01-01

    En este trabajo se realiza una revisión a los textos y programas de estudio de ecuaciones diferenciales usados en los cursos de ingeniería electrónica en donde se observa que privilegian resolver las ecuaciones diferenciales de un circuito eléctrico por medio de métodos cuantitativos y la gráfica de la solución analítica, dejando a un lado el uso de los campos de pendientes que permita al alumno identificar el comportamiento gráfico de dichas ecuaciones diferenciales. En este trabajo se explo...

  5. 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.

  6. 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.)

  7. 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...... 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...

  8. Applications of Lorentz force in medical acoustics: Lorentz force hydrophone, Lorentz Force Electrical Impedance Tomography, Imaging of shear waves induced by Lorentz force

    CERN Document Server

    Grasland-Mongrain, Pol

    2014-01-01

    The ability of the Lorentz force to link a mechanical displacement to an electrical current presents a strong interest for medical acoustics, and three applications were studied in this thesis. In the first part of this work, a hydrophone was developed for mapping the particle velocity of an acoustic field. This hydrophone was constructed using a thin copper wire and an external magnetic field. A model was elaborated to determine the relationship between the acoustic pressure and the measured electrical current, which is induced by Lorentz force when the wire vibrates in the acoustic field of an ultrasound transducer. The built prototype was characterized and its spatial resolution, frequency response, sensitivity, robustness and directivity response were investigated. An imaging method called Lorentz Force Electrical Impedance Tomography was also studied. In this method, a biological tissue is vibrated by ultrasound in a magnetic field, which induces an electrical current by Lorentz force. The electrical imp...

  9. 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.

  10. Recent Progress in Lorentz and CPT Violation

    CERN Document Server

    Kostelecky, Alan

    2016-01-01

    This contribution to the CPT'16 meeting briefly highlights some of the recent progress in the phenomenology of Lorentz and CPT violation, with emphasis on research performed at the Indiana University Center for Spacetime Symmetries.

  11. Antimatter-Gravity Couplings, and Lorentz Symmetry

    CERN Document Server

    Tasson, Jay D

    2015-01-01

    Implications of possible CPT and Lorentz violation for antimatter-gravity experiments as well as other antimatter tests are considered in the context of the general field-theory-based framework of the Standard-Model Extension (SME).

  12. On Lorentz invariants in relativistic magnetic reconnection

    Science.gov (United States)

    Yang, Shu-Di; Wang, Xiao-Gang

    2016-08-01

    Lorentz invariants whose nonrelativistic correspondences play important roles in magnetic reconnection are discussed in this paper. Particularly, the relativistic invariant of the magnetic reconnection rate is defined and investigated in a covariant two-fluid model. Certain Lorentz covariant representations for energy conversion and magnetic structures in reconnection processes are also investigated. Furthermore, relativistic measures for topological features of reconnection sites, particularly magnetic nulls and separatrices, are analyzed.

  13. Probes of Lorentz Violation in Neutrino Propagation

    CERN Document Server

    Ellis, Jonathan Richard; Meregaglia, Anselmo; Rubbia, André; Sakharov, Alexander S

    2008-01-01

    It has been suggested that the interactions of energetic particles with the foamy structure of space-time thought to be generated by quantum-gravitational (QG) effects might violate Lorentz invariance, so that they do not propagate at a universal speed of light. We consider the limits that may be set on a linear or quadratic violation of Lorentz invariance in the propagation of energetic neutrinos, v/c=[1 +- (E/M_\

  14. Gauge anomalies in Lorentz-violating QED

    Science.gov (United States)

    Santos, Tiago R. S.; Sobreiro, Rodrigo F.

    2016-12-01

    In this work we study the issue of gauge anomalies in Lorentz-violating QED. To do so, we opt to use the Becchi-Rouet-Stora-Tyutin formalism within the algebraic renormalization approach, reducing our study to a cohomology problem. Since this approach is independent of the renormalization scheme, the results obtained here are expected to be general. We find that the Lorentz-violating QED is free of gauge anomalies to all orders in perturbation theory.

  15. Gauge anomalies in Lorentz-violating QED

    CERN Document Server

    Santos, Tiago R S

    2016-01-01

    In this work we study the issue of gauge anomalies in Lorentz-violating QED. To do so, we opt to use the BRST formalism within of the algebraic renormalization approach, reducing our study to a cohomology problem. Since that this approach is independent of the renormalization scheme, the results here obtained are expected to be general. We find that the Lorentz-violating QED is free of gauge anomalies to all orders in perturbation theory.

  16. Black Hole Thermodynamics and Lorentz Symmetry

    CERN Document Server

    Jacobson, Ted

    2008-01-01

    Recent developments point to a breakdown in the generalized second law of thermodynamics for theories with Lorentz symmetry violation. It appears possible to construct a perpetual motion machine of the second kind in such theories, using a black hole to catalyze the conversion of heat to work. Here we describe the arguments leading to that conclusion. We suggest the implication that Lorentz symmetry should be viewed as an emergent property of the macroscopic world, required by the second law of black hole thermodynamics.

  17. Macroscopic Objects, Intrinsic Spin, and Lorentz Violation

    CERN Document Server

    Atkinson, David W; Tasson, Jay D

    2013-01-01

    The framework of the Standard-Model Extension (SME) provides a relativistic quantum field theory for the study of Lorentz violation. The classical, nonrelativistic equations of motion can be extracted as a limit that is useful in various scenarios. In this work, we consider the effects of certain SME coefficients for Lorentz violation on the motion of macroscopic objects having net intrinsic spin in the classical, nonrelativistic limit.

  18. Lorentz violation and Condensed Matter Physics

    CERN Document Server

    Ajaib, Muhammad Adeel

    2014-01-01

    We present heuristic arguments that hint to a possible connection of Lorentz violation with observed phenomenon in condensed matter physics. Various references from condensed matter literature are cited where operators in the Standard Model Extension (SME) appear to be enhanced. Based on this we propose that, in the non-relativistic limit, Lorentz violation in the context of the SME exhibits itself in various condensed matter systems.

  19. Hadronic Lorentz violation in chiral perturbation theory

    Science.gov (United States)

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

    2017-03-01

    Any possible Lorentz violation in the hadron sector must be tied to Lorentz violation at the underlying quark level. The relationships between the theories at these two levels are studied using chiral perturbation theory. Starting from a two-flavor quark theory that includes dimension-4 Lorentz-violation operators, the effective Lagrangians are derived for both pions and nucleons, with novel terms appearing in both sectors. Since the Lorentz-violation coefficients for nucleons and pions are all related to a single set of underlying quark coefficients, one can compare the sensitivity of different types of experiments. Our analysis shows that atomic physics experiments currently provide constraints on the quark parameters that are stronger by about 10 orders of magnitude than astrophysical experiments with relativistic pions. Alternatively, it is possible to place approximate bounds on pion Lorentz violation using only proton and neutron observations. Under the assumption that the Lorentz-violating operators considered here are the only ones contributing to the relevant observables and taking the currently unknown hadronic low-energy constants to be of natural size, the resulting estimated bounds on four pion parameters are at the 10-23 level, representing improvements of 10 orders of magnitude.

  20. Test of Lorentz symmetry with trapped ions

    Science.gov (United States)

    Pruttivarasin, Thaned

    2016-05-01

    The outcome of an experiment should not depend on the orientation of the apparatus in space. This important cornerstone of physics is deeply engrained into the Standard Model of Physics by requiring that all fields must be Lorentz invariant. However, it is well-known that the Standard Model is incomplete. Some theories conjecture that at the Planck scale Lorentz symmetry might be broken and measurable at experimentally accessible energy scales. Therefore, a search for violation of Lorentz symmetry directly probes physics beyond the Standard model. We present a novel experiment utilizing trapped calcium ions as a direct probe of Lorentz-violation in the electron-photon sector. We monitor the energy between atomic states with different orientations of the electronic wave-functions as they rotate together with the motion of the Earth. This is analogous to the famous Michelson-Morley experiment. To remove magnetic field noise, we perform the experiment with the ions prepared in the decoherence-free states. Our result improves on the most stringent bounds on Lorentz symmetry for electrons by 100 times. The experimental scheme is readily applicable to many ion species, hence opening up paths toward much improved test of Lorentz symmetry in the future. (Ph. D. Advisor: Hartmut Haeffner, University of California, Berkeley).

  1. Lorentz violations in multifractal spacetimes

    CERN Document Server

    Calcagni, Gianluca

    2016-01-01

    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 manifest 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 $E_*>10^{14}\\,\\text{GeV}$ (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...

  2. 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.)

  3. Lorentz violations in multifractal spacetimes

    Science.gov (United States)

    Calcagni, Gianluca

    2017-05-01

    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_{*}>10^{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_{*}> 10^{17} {GeV} or greater.

  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. 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.

  6. 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.

  7. Lorentz covariance of loop quantum gravity

    CERN Document Server

    Rovelli, Carlo

    2010-01-01

    The kinematics of loop gravity can be given a manifestly Lorentz-covariant formulation: the conventional SU(2)-spin-network Hilbert space can be mapped to a space K of SL(2,C) functions, where Lorentz covariance is manifest. K can be described in terms of a certain subset of the "projected" spin networks studied by Livine, Alexandrov and Dupuis. It is formed by SL(2,C) functions completely determined by their restriction on SU(2). These are square-integrable in the SU(2) scalar product, but not in the SL(2,C) one. Thus, SU(2)-spin-network states can be represented by Lorentz-covariant SL(2,C) functions, as two-component photons can be described in the Lorentz-covariant Gupta-Bleuler formalism. As shown by Wolfgang Wieland in a related paper, this manifestly Lorentz-covariant formulation can also be directly obtained from canonical quantization. We show that the spinfoam dynamics of loop quantum gravity is locally SL(2,C)-invariant in the bulk, and yields states that are preciseley in K on the boundary. This c...

  8. Why is High Energy Physics Lorentz Invariant?

    CERN Document Server

    Afshordi, Niayesh

    2015-01-01

    Despite the tremendous empirical success of equivalence principle, there are several theoretical motivations for existence of a preferred reference frame (or aether) in a consistent theory of quantum gravity. However, if quantum gravity had a preferred reference frame, why would high energy processes enjoy such a high degree of Lorentz symmetry? While this is often considered as an argument against aether, here I provide three independent arguments for why perturbative unitarity (or weak coupling) of the Lorentz-violating effective field theories put stringent constraints on possible observable violations of Lorentz symmetry at high energies. In particular, the interaction with the scalar graviton in a consistent low-energy theory of gravity and a (radiatively and dynamically) stable cosmological framework, leads to these constraints. The violation (quantified by the relative difference in maximum speed of propagation) is limited to $\\lesssim 10^{-10} E({\\rm eV})^{-4}$ (superseding all current empirical bound...

  9. Baryogenesis in Lorentz-violating gravity theories

    Science.gov (United States)

    Sakstein, Jeremy; Solomon, Adam R.

    2017-10-01

    Lorentz-violating theories of gravity typically contain constrained vector fields. We show that the lowest-order coupling of such vectors to U (1)-symmetric scalars can naturally give rise to baryogenesis in a manner akin to the Affleck-Dine mechanism. We calculate the cosmology of this new mechanism, demonstrating that a net B - L can be generated in the early Universe, and that the resulting baryon-to-photon ratio matches that which is presently observed. We discuss constraints on the model using solar system and astrophysical tests of Lorentz violation in the gravity sector. Generic Lorentz-violating theories can give rise to the observed matter-antimatter asymmetry without violating any current bounds.

  10. Looking for Lorentz violation with gravitational waves

    CERN Document Server

    Schreck, M

    2016-01-01

    The current letter has been inspired by the recent direct detection of gravitational waves reported by Advanced LIGO. In this context, a particular Lorentz-violating framework for classical, massive particles is on the focus. The latter is characterized by a preferred direction in spacetime comprised of CPT-odd components with mass dimension 1. Curvature effects in spacetime, which are caused by a propagating gravitational wave, are assumed to deform the otherwise constant background field. In accordance with spontaneous Lorentz violation, a particular choice for the vector field is taken, which was proposed elsewhere. The geodesic equations for a particle that is subject to this type of Lorentz violation are obtained. Subsequently, their numerical solutions are computed and discussed. The particular model considered leads to changes in the particle trajectory, which interferometric gravitational-wave experiments could be sensitive for. Since such effects have not been observed in the gravitational-wave event...

  11. Infrared Lorentz violation and slowly instantaneous electricity.

    Science.gov (United States)

    Dvali, Gia; Papucci, Michele; Schwartz, Matthew D

    2005-05-20

    We study a modification of electromagnetism which violates Lorentz invariance at large distances. In this theory, electromagnetic waves are massive, but the static force between charged particles is Coulomb, not Yukawa. At very short distances the theory looks just like QED. But for distances larger than 1/m the massive dispersion relation of the waves can be appreciated, and the Coulomb force can be used to communicate faster than the speed of light. In fact, electrical signals are transmitted instantly, but take a time approximately 1/m to build up to full strength. After that, undamped oscillations of the electric field are set in and continue until they are dispersed by the arrival of the Lorentz-obeying part of the transmission. Experimental constraints imply that the Compton wavelength of the photon may be as small as 6000 km. This bound is weaker than for a Lorentz-invariant mass, essentially because the Coulomb constraint is removed.

  12. On the Lorentz factor of superluminal sources

    Institute of Scientific and Technical Information of China (English)

    Chika Christian Onuchukwu; Augustine A.Ubachukwu

    2013-01-01

    We investigate the properties of features seen within superluminal sources often referred to as components.Our result indicates a fairly strong correlation of r ~ 0.5 for quasars,r ~ 0.4 for galaxies and r ~ 0.7 for BL Lac objects in our sample between component sizes and distances from the stationary core.The assumption of free adiabatic expanding plasma enables us to constrain the Lorentz factor for superluminal sources.Our estimated Lorentz factor of γ ~ 9-13 for quasars,γ ~ 7-11for galaxies and γ ~ 4-9 for BL Lac objects indicates that BL Lacs have the lowest range of Lorentz factors.

  13. Velocity in Lorentz-Violating Fermion Theories

    CERN Document Server

    Altschul, B D; Colladay, Don

    2004-01-01

    We consider the role of the velocity in Lorentz-violating fermionic quantum theory, especially emphasizing the nonrelativistic regime. Information about the velocity will be important for the kinematical analysis of scattering and other problems. Working within the minimal standard model extension, we derive new expressions for the velocity. We find that generic momentum and spin eigenstates may not have well-defined velocities. We also demonstrate how several different techniques may be used to shed light on different aspects of the problem. A relativistic operator analysis allows us to study the behavior of the Lorentz-violating Zitterbewegung. Alternatively, by studying the time evolution of Gaussian wave packets, we find that there are Lorentz-violating modifications to the wave packet spreading and the spin structure of the wave function.

  14. Passive Lorentz transformations with spacetime algebra

    CERN Document Server

    Paiva, C R

    2005-01-01

    In special relativity spacetime algebra developed by David Hestenes, STA, provides a powerful and insightful approach to an invariant formulation of physics, the spacetime physics, through an elegant and concise manipulation of active Lorentz transformations. Therefore, it should come as an oddity, to say the least, to relate STA with passive Lorentz transformations. Nevertheless, length contraction, time dilation and all that are the bread and butter of most introductory courses on relativistic physics. To overcome the coordinate virus, it is necessary to be able to translate and dissolve passive Lorentz transformations in the fluidity and flexibility of STA, thereby bridging the gap between relativistic physics and proper spacetime physics. That is the aim of this paper.

  15. Testing Lorentz invariance in weak decays

    Energy Technology Data Exchange (ETDEWEB)

    Sytema, Auke; Dijck, Elwin; Hoekstra, Steven; Jungmann, Klaus; Mueller, Stefan; Noordmans, Jacob; Onderwater, Gerco; Pijpker, Coen; Timmermans, Rob; Vos, Keri; Willmann, Lorenz; Wilschut, Hans [Van Swinderen Institute, University of Groningen (Netherlands)

    2015-07-01

    Lorentz invariance is the invariance of physical laws under orientations and boosts. It is a key assumption in Special Relativity and the Standard Model of Particle Physics. Several theories unifying General Relativity and Quantum Mechanics allow breaking of Lorentz invariance. At the Van Swinderen Institute in Groningen a theoretical and experimental research program was started to study Lorentz invariance violation (LIV) in weak interactions. The theoretical work allowed a systematic approach to LIV in weak decays. Limits could be set on parameters that quantify LIV. A novel beta decay experiment was designed which tests rotational invariance with respect to the orientation of nuclear spin. In particular, using the isotope {sup 20}Na, the decay rate dependence on the nuclear polarization direction was measured. Searching for sidereal variations, systematic errors can be suppressed. The result of the experiment is presented.

  16. Test of Lorentz Invariance with Atmospheric Neutrinos

    CERN Document Server

    :,; Haga, Y; Hayato, Y; Ikeda, M; Iyogi, K; Kameda, J; Kishimoto, Y; Miura, M; Moriyama, S; Nakahata, M; Nakano, Y; Nakayama, S; Sekiya, H; Shiozawa, M; Suzuki, Y; Takeda, A; Tanaka, H; Tomura, T; Ueno, K; Wendell, R A; Yokozawa, T; Irvine, T; Kajita, T; Kametani, I; Kaneyuki, K; Lee, K P; McLachlan, T; Nishimura, Y; Richard, E; Okumura, K; Labarga, L; Fernandez, P; Gustafson, J; Kearns, E; Raaf, J L; Berkman, S; Tanaka, H A; Tobayama, S; Stone, J L; Sulak, L R; Goldhaber, M; Carminati, G; Kropp, W R; Mine, S; Weatherly, P; Renshaw, A; Smy, M B; Sobel, H W; Takhistov, V; Ganezer, K S; Hartfiel, B L; Hill, J; Keig, W E; Hong, N; Kim, J Y; Lim, I T; Akiri, T; Himmel, A; Scholberg, K; Walter, C W; Wongjirad, T; Ishizuka, T; Tasaka, S; Jang, J S; Learned, J G; Matsuno, S; Smith, S N; Hasegawa, T; Ishida, T; Ishii, T; Kobayashi, T; Nakadaira, T; Nakamura, K; Oyama, Y; Sakashita, K; Sekiguchi, T; Tsukamoto, T; Suzuki, A T; Takeuchi, Y; Bronner, C; Hirota, S; Huang, K; Ieki, K; Kikawa, T; Minamino, A; Murakami, A; Nakaya, T; Suzuki, K; Takahashi, S; Tateishi, K; Fukuda, Y; Choi, K; Itow, Y; Mitsuka, G; Mijakowski, P; Hignight, J; Imber, J; Jung, C K; Yanagisawa, C; Ishino, H; Kibayashi, A; Koshio, Y; Mori, T; Sakuda, M; Yamaguchi, R; Yano, T; Kuno, Y; Tacik, R; Kim, S B; Okazawa, H; Choi, Y; Nishijima, K; Koshiba, M; Suda, Y; Totsuka, Y; Yokoyama, M; Martens, K; Marti, Ll; Vagins, M R; Martin, J F; de Perio, P; Konaka, A; Wilking, M J; Chen, S; Zhang, Y; Connolly, K; Wilkes, R J

    2014-01-01

    A search for neutrino oscillations induced by Lorentz violation has been performed using 4,438 live-days of Super-Kamiokande atmospheric neutrino data. The Lorentz violation is included in addition to standard three-flavor oscillations using the non-perturbative Standard Model Extension (SME), allowing the use of the full range of neutrino path lengths, ranging from 15 to 12,800 km, and energies ranging from 100 MeV to more than 100 TeV in the search. No evidence of Lorentz violation was observed, so limits are set on the renormalizable isotropic SME coefficients in the $e\\mu$, $\\mu\\tau$, and $e\\tau$ sectors, improving the existing limits by up to seven orders of magnitude and setting limits for the first time in the neutrino $\\mu\\tau$ sector of the SME.

  17. Comments on Holography with Broken Lorentz Invariance

    CERN Document Server

    Gordeli, Ivan

    2009-01-01

    Recently a family of solutions of the Einstein equations in backgrounds with broken Lorentz invariance was found ArXiv:0712.1136. We show that the gravitational solution recently obtained by Kachru, Liu and Mulligan in ArXiv:0808.1725 is a part of the former solution which was derived earlier in the framework of extra dimensional theories. We show how the energy-momentum and Einstein tensors are related and establish a correspondence between parameters which govern Lorentz invariance violation. At the end we speculate on relations between the RG flow of a boundary theory and asymptotic behavior of gravitational solutions in the bulk.

  18. Lorentz violation in simple QED processes

    CERN Document Server

    de Brito, G P; Kroff, D; Malta, P C; Marques, C

    2016-01-01

    We determine the effect of a CPT-even and Lorentz violating non-minimal coupling on the differential cross sections for some of the most important tree-level processes in QED, namely, Compton and Bhabha scatterings, as well as electron-positron annihilation. Experimental limits constraining the allowed deviation of the differential cross sections relative to pure QED allow us to place upper bounds on the Lorentz violating parameters. A constraint based on the decay rate of para-positronium is also obtained.

  19. Deduction of Lorentz Transformations from Classical Thermodynamics

    Directory of Open Access Journals (Sweden)

    Angela M. Ares de Parga

    2015-01-01

    Full Text Available The Lorentz transformations are obtained by assuming that the laws of classical thermodynamics are invariant under changes of inertial reference frames. As Maxwell equations are used in order to deduce a wave equation that shows the constancy of the speed of light, by means of the laws of classical thermodynamics, the invariance of the Carnot cycle is deduced under reference frame changes. Starting with this result and the blackbody particle number density in a rest frame, the Lorentz transformations are obtained. A discussion about the universality of classical thermodynamics is given.

  20. Einstein-Yang-Mills-Lorentz Black Holes

    CERN Document Server

    Cembranos, Jose A R

    2015-01-01

    Different black hole solutions of the coupled Einstein-Yang-Mills equations are well known from long time. They have attracted much attention from mathematicians and physicists from 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 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.

  1. Black Hole Thermodynamics and Lorentz Symmetry

    Science.gov (United States)

    Jacobson, Ted; Wall, Aron C.

    2010-08-01

    Recent developments point to a breakdown in the generalized second law of thermodynamics for theories with Lorentz symmetry violation. It appears possible to construct a perpetual motion machine of the second kind in such theories, using a black hole to catalyze the conversion of heat to work. Here we describe and extend the arguments leading to that conclusion. We suggest the inference that local Lorentz symmetry may be an emergent property of the macroscopic world with origins in a microscopic second law of causal horizon thermodynamics.

  2. Testing Lorentz Symmetry using Chiral Perturbation Theory

    CERN Document Server

    Noordmans, J P

    2016-01-01

    We consider the low-energy effects of a selected set of Lorentz- and CPT-violating quark and gluon operators by deriving the corresponding chiral effective lagrangian. Using this effective lagrangian, low-energy hadronic observables can be calculated. We apply this to magnetometer experiments and derive the best bounds on some of the Lorentz-violating coefficients. We point out that progress can be made by studying the nucleon-nucleon potential, and by considering storage-ring experiments for deuterons and other light nuclei.

  3. Particle-Dependent Deformations of Lorentz Symmetry

    Directory of Open Access Journals (Sweden)

    Giovanni Amelino-Camelia

    2012-07-01

    Full Text Available I report results suggesting that it is possible to introduce laws of relativistic kinematics endowing different types of particles with suitably different deformed-Lorentz-symmetry properties. I also consider some possible applications of these results, among which I highlight those relevant for addressing a long-standing challenge in the description of composite particles, such as atoms, within quantum-gravity-inspired scenarios with Planck-scale deformations of Lorentz symmetry. Some of the new elements here introduced in the formulation of relativistic kinematics appear to also provide the starting point for the development of a correspondingly novel mathematical formulation of spacetime-symmetry algebras.

  4. 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.

  5. 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…

  6. On the Origin of Gravitational Lorentz Covariance

    CERN Document Server

    Khoury, Justin; Tolley, Andrew J

    2013-01-01

    We provide evidence that general relativity is the unique spatially covariant effective field theory of the transverse, traceless graviton degrees of freedom. The Lorentz covariance of general relativity, having not been assumed in our analysis, is thus plausibly interpreted as an accidental or emergent symmetry of the gravitational sector.

  7. Testing Lorentz and CPT invariance with neutrinos

    CERN Document Server

    Diaz, Jorge S

    2016-01-01

    Neutrino experiments can be considered sensitive tools to test Lorentz and CPT invariance. Taking advantage of the great variety of neutrino experiments, including neutrino oscillations, weak decays, and astrophysical neutrinos, the generic experimental signatures of the breakdown of these fundamental symmetries in the neutrino sector are presented.

  8. Deviations from Fick's law in Lorentz gases

    NARCIS (Netherlands)

    Lowe, C.P.; Frenkel, D.; Hoef, M.A. van der

    1997-01-01

    We have calculated the self-dynamic structure factorF(k,t) for tagged particle motion in hopping Lorentz gases. We find evidence that, even at long times, the probability distribution function for the displacement of the particles is highly non-Gaussian. At very small values of the wave vector this

  9. Emergent Lorentz invariance in fermion sector

    Directory of Open Access Journals (Sweden)

    Kharuk Ivan

    2016-01-01

    Full Text Available By using holographic description of strongly interacting field theories we show that under common assumptions Lorentz invariance emerges as an effective low–energy symmetry of the theory, despite fundamental theory at hight energies being Lorentz–violating. We consider fermions sector and show that the notion of chirality also automatically arises in the infrared.

  10. Deviations from Fick's law in Lorentz gases

    NARCIS (Netherlands)

    Lowe, C.P.; Frenkel, D.; Hoef, M.A. van der

    1997-01-01

    We have calculated the self-dynamic structure factorF(k,t) for tagged particle motion in hopping Lorentz gases. We find evidence that, even at long times, the probability distribution function for the displacement of the particles is highly non-Gaussian. At very small values of the wave vector this

  11. Extra dimensions and violations of Lorentz symmetry

    CERN Document Server

    Overduin, James M

    2016-01-01

    We use experimental limits on Lorentz violation to obtain new constraints on Kaluza-Klein-type theories in which the extra dimensions may be large but do not necessarily have units of length. The associated variation in fundamental quantities such as rest mass must occur slowly, on cosmological scales.

  12. Testing Lorentz invariance in orbital electron capture

    NARCIS (Netherlands)

    Vos, K. K.; Wilschut, H. W.; Timmermans, R. G. E.

    2015-01-01

    Searches for Lorentz violation were recently extended to the weak sector, in particular neutron and nuclear beta decay [Noordmans, Wilschut, and Timmermans, Phys. Rev. C 87, 055502 (2013)]. From experiments on forbidden beta-decay transitions, strong limits in the range of 10(-6) to 10(-8) were obta

  13. 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, VI

  14. Lorentz Violating Julia-Toulouse Mechanism

    CERN Document Server

    Gaete, P; Gaete, Patricio; Wotzasek, Clovis

    2007-01-01

    We propose a new Lorentz invariant violating extension for the pure photonic sector of the Standard Model due to the condensation of topological defects in the context of the Julia-Toulouse mechanism. Possible physical consequences leading to direct measurable effects over the confining properties of the elementary particles are explored.

  15. Interpolation theorems on weighted Lorentz martingale spaces

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper several interpolation theorems on martingale Lorentz spaces are given.The proofs are based on the atomic decompositions of martingale Hardy spaces over weighted measure spaces.Applying the interpolation theorems,we obtain some inequalities on martingale transform operator.

  16. 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.

  17. Resolución Numérica de sistemas acoplados de ecuaciones en derivadas parciales

    OpenAIRE

    Jódar, L.; Legua, Matilde

    1991-01-01

    En este artículo se presenta un niétodo para la obtención de soluciones numéricas precisas de problemas mixtos para sistemas acoplados de ecuaciones en derivadas parciales. Dichas soluciones aproximadas están expresadas en forma analítica finita y computable, obtenidas mediante la truncación de una serie infinita y la substitución de ciertas exponenciales de matrices mediante aproximantes de Padé. Dado un intervalo de interés y un error admisible E, indicamos un procedimiento para la obtenció...

  18. Sistemas de ecuaciones polinomiales ralas: aspectos teóricos y algoritmos

    OpenAIRE

    Herrero, María Isabel

    2013-01-01

    Esta tesis se centra en la resolución efectiva de sistemas de ecuaciones polinomiales reales (es decir, dadas por polinomios con estructura monomial prefijada). A lo largo del trabajo, se analizan distintos aspectos teóricos de las variedades afines definidas por estos sistemas y, en base a los resultados de este análisis, se diseñan nuevos algoritmos simbólicos probabilísticos para describirlas cuyas complejidades dependen de invariantes algebraico-combinatorios asociados al sistema. En prim...

  19. Métodos numéricos integrales para ecuaciones Fokker-Planck

    OpenAIRE

    Donoso Vargas, José Manuel

    2011-01-01

    El trabajo presenta un método numérico de resolucion para ecuaciones de fokker-planck no lineales. El modelo mejora el tratamiento de problemas cinéticos con mas de una cantidad conservada, subsanando las deficiencias que, en este sentido, presentan los esquemas habituales en diferencias. El método se basa en la ecuación integral de evolución para la distribución a través de la probabilidad de transición o propagador. En el segundo capitulo se propone un sencillo algoritmo para la obtención d...

  20. Diferencias finitas para la solución de ecuaciones diferenciales ordinarias fraccionarias

    OpenAIRE

    Pérez Contreras, Pablo José

    2014-01-01

    En esta tesis se presenta un algoritmo para la solución numérica de ecuaciones diferenciales de orden fraccionario Dα∗ x(t) = f(t, x(t)), x(0) = x0. donde Dα∗ x(t) es la derivada de orden α en el sentido de Caputo de x(t) para α > 0. El algoritmo está basado en un cambio de variable que suprime el núcleo presente en los operadores diferencial e integral fraccionarios, de manera que podemos establecer una cuadratura sencilla de orden 1 para el operador de integración fraccional. Posteriormente...

  1. Ecuaciones diferenciales linealmente implícitas. Teoría cualitativa, aspectos computacionales y aplicaciones

    OpenAIRE

    Riaza, Ricardo

    2000-01-01

    La presente tesis doctoral analiza la dinámica de ciertos sistemas diferenciales, vinculados a diferentes problemas de determinación de raíces, optimización y aprendizaje. El modelado en tiempo continuo conduce a un estudio de diversos aspectos cualitativos, ralacionados con las singularidades de sistemas linealmente implícitos (o cuasilineales) y de ecuaciones algebraico-diferenciales (DAEs). La orientación cualitativa del trabajo motiva la utilización de técnicas celulares o de cell mapping...

  2. Lorentz Covariant Canonical Symplectic Algorithms for Dynamics of Charged Particles

    CERN Document Server

    Wang, Yulei; Qin, Hong

    2016-01-01

    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 (LCCSA) 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 discrete symplectic structure and Lorentz symmetry of the system. For situations with time-dependent electromagnetic fields, which is 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 th...

  3. Search for anisotropic Lorentz invariance violation with {\\gamma}-rays

    CERN Document Server

    Kislat, Fabian

    2015-01-01

    While Lorentz invariance, the fundamental symmetry of Einstein's theory of General Relativity, has been tested to a great level of detail, Grand Unified Theories that combine gravity with the other three fundamental forces may result in a violation of Lorentz symmetry at the Planck scale. These energies are unattainable experimentally. However, minute deviations from Lorentz invariance may still be present at much lower energies. These deviations can accumulate over large distances, making astrophysical measurements the most sensitive tests of Lorentz symmetry. One effect of Lorentz invariance violation is an energy dependent photon dispersion of the vacuum resulting in differences of the light travel time from distant objects. The Standard-Model Extension (SME) is an effective theory to describe the low-energy behaviour of a more fundamental Grand Unified Theory, including Lorentz and CPT violating terms. In the SME the Lorentz violating operators can in part be classified by their mass-dimension d, with the...

  4. 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.

  5. BPS Lorentz-violating vortex solutions

    Energy Technology Data Exchange (ETDEWEB)

    Casana, Rodolfo; Ferreira Junior, Manoel M. [Universidade Federal do Maranhao (UFMA), Sao Luis, MA (Brazil). Dept. de Fisica; Hora, E. da [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil). Departamento de Fisica

    2011-07-01

    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

  6. 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.

  7. Concordancia entre los modelos de SCORE y Framingham y las ecuaciones AHA/ACC como evaluadores de riesgo cardiovascular

    Directory of Open Access Journals (Sweden)

    Oscar Mauricio Muñoz V

    2017-03-01

    Conclusiones: En la actualidad existe pobre acuerdo entre las diferentes escalas de evaluación del riesgo cardiovascular usadas en Colombia, hecho que conlleva incertidumbre para la toma de decisiones terapéuticas. Los datos de este estudio demuestran la necesidad de validar los modelos de SCORE y AHA/ACC en Colombia y Latinoamérica.

  8. Estudio del comportamiento asintótico de las ecuaciones de Navier-Stokes no autónomas y algunas de sus variantes Study of the asynmptotic behavioru of the non-autonomous Navier-Stokes equations and some of their variations

    OpenAIRE

    García Luengo, Julia María

    2013-01-01

    Una de las ramas de la Física más interesantes y complicadas de investigar es la Mecánica de Fluidos, que estudia el comportamiento de los fluidos en reposo (Estática de Fluidos) o en movimiento (Dinámica de Fluidos), así como las aplicaciones y mecanismos de ingeniería que utilizan fluidos. La Mecánica de Fluidos es primordial en campos tan diversos como la aeronáutica, la ingeniería química, civil e industrial, la meteorología, las construcciones navales y la oceanografía. Las ecuaciones ...

  9. Gravitomagnetism and the Lorentz Invariance of Gravity

    CERN Document Server

    Kopeikin, S M

    2006-01-01

    Experimental discovery of the gravitomagnetic fields generated by translational and/or rotational currents of matter is one of primary goals of modern gravitational physics. The rotational (intrinsic) gravitomagnetic field of the Earth is currently measured by the Gravity Probe B. The present paper makes use of a parametrized post-Newtonian (PN) expansion of the Einstein equations to demonstrate how the extrinsic gravitomagnetic field generated by the translational current of matter can be measured by observing the relativistic time delay caused by a moving gravitational lens. We prove that measuring the extrinsic gravitomagnetic field is equivalent to testing of the relativistic effect of the aberration of gravity caused by the Lorentz transformation of the gravitational field. We unfold that the recent Jovian deflection experiment is a null-type experiment testing the Lorentz invariance of the gravitational field (aberration of gravity), thus, confirming existence of the extrinsic gravitomagnetic field asso...

  10. Lorentz Transformation and General Covariance Principle

    CERN Document Server

    Kleyn, Aleks

    2008-01-01

    I tell about different mathematical tool that is important in general relativity. The text of the book includes definition of geometrical object, concept of reference frame, geometry of metric-affinne manifold. Using this concept I learn few physical applications: dynamics and Lorentz transformation in gravitational fields, Doppler shift. A reference frame in event space is a smooth field of orthonormal bases. Every reference frame is equipped by anholonomic coordinates. Using anholonomic coordinates allows to find out relative speed of two observers and appropriate Lorentz transformation. Synchronization of a reference frame is an anholonomic time coordinate. Simple calculations show how synchronization influences time measurement in the vicinity of the Earth. Measurement of Doppler shift from the star orbiting the black hole helps to determine mass of the black hole. We call a manifold with torsion and nonmetricity the metric\\hyph affine manifold. The nonmetricity leads to a difference between the auto para...

  11. From scale invariance to Lorentz symmetry

    CERN Document Server

    Sibiryakov, Sergey

    2014-01-01

    It is shown that a unitary translationally invariant field theory in (1+1) dimensions satisfying isotropic scale invariance, standard assumptions about the spectrum of states and operators and the requirement that signals propagate with finite velocity possesses an infinite dimensional symmetry given by one or a product of several copies of conformal algebra. In particular, this implies presence of one or several Lorentz groups acting on the operator algebra of the theory.

  12. The Lorentz anomaly via operator product expansion

    Energy Technology Data Exchange (ETDEWEB)

    Fredenhagen, Stefan, E-mail: stefan.fredenhagen@aei.mpg.de [Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-Institut Am Mühlenberg 1, 14476 Golm (Germany); Hoppe, Jens, E-mail: hoppe@kth.se; Hynek, Mariusz, E-mail: mkhynek@kth.se [Department of Mathematics, Royal Institute of Technology, KTH 100 44 Stockholm (Sweden)

    2015-10-15

    The emergence of a critical dimension is one of the most striking features of string theory. One way to obtain it is by demanding closure of the Lorentz algebra in the light-cone gauge quantisation, as discovered for bosonic strings more than forty years ago. We give a detailed derivation of this classical result based on the operator product expansion on the Lorentzian world-sheet.

  13. Maxwell Duality, Lorentz Invariance, and Topological Phase

    CERN Document Server

    Dowling, J P; Franson, J D; Dowling, Jonathan P.; Williams, Colin P.

    1999-01-01

    We discuss the Maxwell electromagnetic duality relations between the Aharonov-Bohm, Aharonov-Casher, and He-McKellar-Wilkens topological phases, which allows a unified description of all three phenomena. We also elucidate Lorentz transformations that allow these effects to be understood in an intuitive fashion in the rest frame of the moving quantum particle. Finally, we propose a realistic set up for measuring and interpreting the He-McKellar-Wilkens phase directly in an experiment.

  14. Unravelling Lorentz Covariance and the Spacetime Formalism

    Directory of Open Access Journals (Sweden)

    Cahill R. T.

    2008-10-01

    Full Text Available We report the discovery of an exact mapping from Galilean time and space coordinates to Minkowski spacetime coordinates, showing that Lorentz covariance and the space-time construct are consistent with the existence of a dynamical 3-space, and absolute motion. We illustrate this mapping first with the standard theory of sound, as vibrations of a medium, which itself may be undergoing fluid motion, and which is covariant under Galilean coordinate transformations. By introducing a different non-physical class of space and time coordinates it may be cast into a form that is covariant under Lorentz transformations wherein the speed of sound is now the invariant speed. If this latter formalism were taken as fundamental and complete we would be lead to the introduction of a pseudo-Riemannian spacetime description of sound, with a metric characterised by an invariant speed of sound. This analysis is an allegory for the development of 20th century physics, but where the Lorentz covariant Maxwell equations were constructed first, and the Galilean form was later constructed by Hertz, but ignored. It is shown that the Lorentz covariance of the Maxwell equations only occurs because of the use of non-physical space and time coordinates. The use of this class of coordinates has confounded 20th century physics, and resulted in the existence of a allowing dynamical 3-space being overlooked. The discovery of the dynamics of this 3-space has lead to the derivation of an extended gravity theory as a quantum effect, and confirmed by numerous experiments and observations

  15. Unravelling Lorentz Covariance and the Spacetime Formalism

    Directory of Open Access Journals (Sweden)

    Cahill R. T.

    2008-10-01

    Full Text Available We report the discovery of an exact mapping from Galilean time and space coordinates to Minkowski spacetime coordinates, showing that Lorentz covariance and the space- time construct are consistent with the existence of a dynamical 3-space, and “absolute motion”. We illustrate this mapping first with the standard theory of sound, as vibra- tions of a medium, which itself may be undergoing fluid motion, and which is covari- ant under Galilean coordinate transformations. By introducing a different non-physical class of space and time coordinates it may be cast into a form that is covariant under “Lorentz transformations” wherein the speed of sound is now the “invariant speed”. If this latter formalism were taken as fundamental and complete we would be lead to the introduction of a pseudo-Riemannian “spacetime” description of sound, with a metric characterised by an “invariant speed of sound”. This analysis is an allegory for the development of 20th century physics, but where the Lorentz covariant Maxwell equa- tions were constructed first, and the Galilean form was later constructed by Hertz, but ignored. It is shown that the Lorentz covariance of the Maxwell equations only occurs because of the use of non-physical space and time coordinates. The use of this class of coordinates has confounded 20th century physics, and resulted in the existence of a “flowing” dynamical 3-space being overlooked. The discovery of the dynamics of this 3-space has lead to the derivation of an extended gravity theory as a quantum effect, and confirmed by numerous experiments and observations

  16. Astroparticle Physics Tests of Lorentz Invariance Violation

    Science.gov (United States)

    Lang, R. G.; de Souza, V.

    2017-06-01

    Testing Lorentz invariance is essential as it is one of the pillars of modern physics. Moreover, its violation is foreseen in several popular Quantum Gravity models. Several authors study the effects of Lorentz invariance violation (LIV) in the propagation of ultra-high energy cosmic rays. These particles are the most energetic events ever detected and therefore represent a promising framework to test LIV. In this work we present an analytic calculation of the inelasticity for any a + b → c + d interaction using first order perturbation in the dispersion relation that violates Lorentz invariance. The inelasticity can be calculated by solving a third-order polynomial equation containing: a) the kinematics of the interaction, b) the LIV term for each particle and c) the geometry of the interaction. We use the inelasticity we calculate to investigate the proton propagation in the intergalactic media. The photopion production of the proton interaction with the CMB is taken into account using the inelasticity and the attenuation length in different LIV scenarios. We show how the allowed phase space for the photopion production changes when LIV is considered for the interaction. The calculations presented here are going to be extended in order to calculated the modified ultra-high energy cosmic rays spectrum and compare it to the data.

  17. Extended Lorentz code of a superluminal particle

    CERN Document Server

    Ter-Kazarian, G

    2012-01-01

    While the OPERA experimental scrutiny is ongoing in the community, in the present article we construct a toy model of {\\it extended Lorentz code} (ELC) of the uniform motion, which will be a well established consistent and unique theoretical framework to explain the apparent violations of the standard Lorentz code (SLC), the possible manifestations of which arise in a similar way in all particle sectors. We argue that in the ELC-framework the propagation of the superluminal particle, which implies the modified dispersion relation, could be consistent with causality. Furthermore, in this framework, we give a justification of forbiddance of Vavilov-Cherenkov (VC)-radiation/or analog processes in vacuum. To be consistent with the SN1987A and OPERA data, we identify the neutrinos from SN1987A and the light as so-called {\\it 1-th type} particles carrying the {\\it individual Lorentz motion code} with the velocity of light $c_{1}\\equiv c$ in vacuum as maximum attainable velocity for all the 1-th type particles. Ther...

  18. Transformações de Galileu e de Lorentz: um estudo via teoria de grupos

    OpenAIRE

    Rocha,A.N.; Rizzuti, B. F.; Mota,D.S.

    2013-01-01

    Neste trabalho destacaremos a conexão entre teoria de grupos e transformações entre referenciais. A partir da definição da representação dos grupos abstratos de Galileu e de Lorentz sobre o espaço-tempo, somos levados naturalmente às transformações de Galileu e de Lorentz nos regimes newtoniano e relativístico. Além de fornecer um material introdutório para assuntos mais avançados, como teoria de grupos e suas representações, este artigo apresenta também uma formulação alternativa à teoria da...

  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

    2011-02-01

    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 nodosy 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 violation in Bhabha scattering at finite temperature

    Science.gov (United States)

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

    2017-06-01

    Corrections to the Bhabha scattering cross section, due to Lorentz violation, at finite temperature are calculated. The vertex interaction between fermions and photons is modified by introducing the Lorentz violation, for the Standard Model extension, from C P T odd nonminimal coupling. The finite temperature corrections are calculated using the thermo field dynamics formalism. The Lorentz violation corrections are presented for zero to high temperatures.

  1. Lorentz symmetry breaking effects on relativistic EPR correlations

    Energy Technology Data Exchange (ETDEWEB)

    Belich, H. [Universidade Federal do Espirito Santo, Departamento de Fisica e Quimica, Vitoria, ES (Brazil); Furtado, C.; Bakke, K. [Universidade Federal da Paraiba, Departamento de Fisica, Caixa Postal 5008, Joao Pessoa, PB (Brazil)

    2015-09-15

    Lorentz symmetry breaking effects on relativistic EPR (Einstein-Podolsky-Rosen) correlations are discussed. From the modified Maxwell theory coupled to gravity, we establish a possible scenario of the Lorentz symmetry violation and write an effective metric for the Minkowski spacetime. Then we obtain the Wigner rotation angle via the Fermi-Walker transport of spinors and consider the WKB (Wentzel-Kramers-Brillouin) approximation in order to study the influence of Lorentz symmetry breaking effects on the relativistic EPR correlations. (orig.)

  2. Neutrino Oscillations, Lorentz/CPT Violation, and Dark Energy

    CERN Document Server

    Ando, Shin'ichiro; Mocioiu, Irina

    2009-01-01

    If dark energy (DE) couples to neutrinos, then there may be apparent violations of Lorentz/CPT invariance in neutrino oscillations. The DE-induced Lorentz/CPT violation takes a specific form that introduces neutrino oscillations that are energy independent, differ for particles and antiparticles, and can lead to novel effects for neutrinos propagating through matter. We show that ultra-high-energy neutrinos may provide one avenue to seek this type of Lorentz/CPT violation in \

  3. Low Energy Lorentz Violation from Modified Dispersion at High Energies.

    Science.gov (United States)

    Husain, Viqar; Louko, Jorma

    2016-02-12

    Many quantum theories of gravity propose Lorentz-violating dispersion relations of the form ω=|k|f(|k|/M⋆), with recovery of approximate Lorentz invariance at energy scales much below M⋆. We show that a quantum field with this dispersion predicts drastic low energy Lorentz violation in atoms modeled as Unruh-DeWitt detectors, for any f that dips below unity somewhere. As an example, we show that polymer quantization motivated by loop quantum gravity predicts such Lorentz violation below current ion collider rapidities.

  4. Looking for Lorentz Violation in Short-Range Gravity

    CERN Document Server

    Xu, Rui

    2016-01-01

    General violations of Lorentz symmetry can be described by the Standard-Model Extension (SME) framework. The SME predicts modifications to existing physics and can be tested in high-precision experiments. By looking for small deviations from Newton gravity, short-range gravity experiments are expected to be sensitive to possible gravitational Lorentz-violation signals. With two group's short-range gravity data analyzed recently, no nonminimal Lorentz violation signal is found at the micron distance scale, which gives stringent constraints on nonminimal Lorentz-violation coefficients in the SME.

  5. Lorentz-violating spinor electrodynamics and Penning traps

    CERN Document Server

    Ding, Yunhua

    2016-01-01

    The prospects are explored for testing Lorentz- and CPT-violating quantum electrodynamics in experiments with Penning traps. We present the Lagrange density of Lorentz-violating spinor electrodynamics with operators of mass dimensions up to six, and we discuss some of its properties. The theory is used to derive Lorentz- and CPT-violating perturbative shifts of the energy levels of a particle confined to a Penning trap. Observable signals are discussed for trapped electrons, positrons, protons, and antiprotons. Existing experimental measurements on anomaly frequencies are used to extract new or improved bounds on numerous coefficients for Lorentz and CPT violation, using sidereal variations of observables and comparisons between particles and antiparticles.

  6. Physical interpretation of a modified Lorentz dielectric function for metals based on the Lorentz-Dirac force

    Science.gov (United States)

    Prokopidis, Konstantinos; Kalialakis, Christos

    2014-10-01

    It is proposed that a recently used ad hoc modified Lorentz dielectric function for metals can be physically interpreted via the Lorentz-Dirac force. The Lorentz-Dirac force considers the radiation reaction of electrons, an effect that is ignored in classical dispersion relationships. A suitable reduced order form of the Lorentz-Dirac force that does not suffer from pre-acceleration and runaway artifacts is employed in the derivation of the modified dispersion model. The frequency characteristics and the causality of the Lorentz-Dirac dielectric model are studied in detail. Furthermore, the superiority of the Lorentz-Dirac dielectric function as a means of improved fitting of experimental data is demonstrated for gold, silver, and silicon in the infrared and optical region.

  7. Lorentz Invariance Violation in Modified Gravity

    CERN Document Server

    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. We analyse briefly the OPERA results and show that they could be reproduced with chameleon models. We suggest that neutrinos emitted radially, at different energies, and observed on the other side of the earth would provide a test of these models.

  8. 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.

  9. Spontaneously broken Lorentz symmetry and gravity

    CERN Document Server

    Jacobson, T; Jacobson, Ted; Mattingly, David

    2000-01-01

    We study a generally covariant model in which local Lorentz invariance is broken "spontaneously" by a dynamical unit timelike vector field $u^a$---the "aether". Such a model makes it possible to study the gravitational and cosmological consequences of preferred frame effects, such as ``variable speed of light" or high frequency dispersion, while preserving a generally covariant metric theory of gravity. In this paper we restrict attention to an action for an effective theory of the aether which involves only the antisymmetrized derivative $\

  10. Testing Lorentz violation using propagating UHECRs

    Institute of Scientific and Technical Information of China (English)

    Cong-Xin Qiu; Zi-Gao Dai

    2009-01-01

    Lorentz invariant violation (LIV) test is important for studying modem physics.All the known astrophysical constraints either have a very small examinable parameter space or are only suitable for some special theoretical models. Here, we suggest that it is possible to directly detect the time-delay of ultra-high-energy cosmic-rays (UHECRs). We discuss some difficulties in our method, including the intergalactic magnetic fields. It seems that none of them are crucial, hence this method could give a larger examinable parameter space and a stronger constraint on LIV.

  11. 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.

  12. Lorentz-invariant and Lorentz-non-invariant aspects of a scalar tachyon field Lagrangian and the scalar tachyon Feynman propagator

    CERN Document Server

    Perepelitsa, Vassili F

    2016-01-01

    Some features of a Lorentz-violating (but Lorentz-covariant) Lagrangian of a scalar tachyon field are considered in this note. It is shown that the equation of motion and the Feynman propagator resulting from it are Lorentz-invariant, while the Lorentz symmetry of the suggested tachyon field model can be defined as spontaneously broken.

  13. Abandonar el Tabaco: Meta-análisis y Modelo de Ecuaciones Estructurales desde la Teoría de la Conducta Planificada

    Directory of Open Access Journals (Sweden)

    Gabriela Topa

    2012-01-01

    Full Text Available Los meta-análisis sobre la Teoría de la conducta planificada (TCP no se han aplicado al abandono del tabaco pese a que progresivamente se incrementa el número de estudios primarios. Nosotros llevamos a cabo un meta-análisis de 121 tamaños del efecto (ES sobre la TCP y el abandono del tabaco y examinamos las influencias de cuatro potenciales variables moderadoras. Se obtuvieron ES globales con valores medios (ES = .28 para intenciónconducta, ES = .33 para control percibido-intención, ES = .29 para norma subjetiva-intención o grandes (ES = .40 para actitud-intención. Los resultados de los análisis de moderadores mostraron que el intervalo de tiempo entre intención y conducta, la correspondencia de la escala, y la edad de los participantes moderaban el ES. Finalmente, la matriz de correlaciones conjunta fue usada como entrada para análisis de modelos de ecuaciones estructurales (SEM, poniendo a prueba un modelo más amplio. La TCP explica efectivamente la intención y la conducta de dejar de fumar.

  14. 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.

  15. Test of Lorentz Invarience from Compton Scattering

    CERN Document Server

    Mohanmurthy, Prajwal; Narayan, Amrendra

    2015-01-01

    In the recent times, test of Lorentz Invariance has been used as a means to probe theories of physics beyond the standard model, especially those such as extensions to String Theory and Quantum Gravity. Tests of Lorentz invariance could go a long way in setting the stage for possible quantum gravity theories which are beyond the standard model. We describe a simple way of utilizing the polarimeters, which are a critical beam instrument at precision and intensity frontier nuclear physics labs such as Stanford Linear Accelerator Center (SLAC) and Jefferson Lab (JLab), to limit the dependence of speed of light with the energy of the photons. Furthermore, we also describe a way of limiting directional dependence of speed of light at previously unprecedented levels of precision by studying the sidereal variations. We obtain a limit of MSME parameters: $\\sqrt{\\kappa_X^2 + \\kappa_Y^2} < 2.4 \\times 10^{-17}$ and $\\sqrt{\\left( 2c_{TX} - (\\tilde{\\kappa}_{0^+}^{YZ} \\right)^2 + \\left( 2c_{TY} - (\\tilde{\\kappa}_{0^+}^{...

  16. 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 ...

  17. Background Dependent Lorentz Violation from String Theory

    CERN Document Server

    Li, Tianjun

    2011-01-01

    We revisit Lorentz violations in the Type IIB string theory with D3-branes and D7-branes. We study the relativistic particle velosities in details, and show that there exist both subluminal and superluminal particle propagations. In particular, the additional contributions to the particle velosity \\delta v\\equiv (v-c)/c from string theory is proportional to both the particle energy and the D3-brane number density, and is inversely proportional to the string scale. Thus, we can realize the background dependent Lorentz violation naturally by varying the D3-brane number density in space time. To explain the superluminal neutrino propagations in the OPERA and MINOS experiments, we obtain the string scale should be around 10^5 GeV. With very tiny D3-brane number density at the interstellar scale, we can also explain the time delays for the high energy photons compared to the low energy photons in the MAGIC, HESS, and FERMI experiments simultaneously. Interestingly, we can automatically satisfy all the stringent co...

  18. Testing Lorentz symmetry with Lunar Laser Ranging

    CERN Document Server

    Bourgoin, A; Bouquillon, S; Poncin-Lafitte, C Le; Francou, G; Angonin, M -C

    2016-01-01

    Lorentz symmetry violations can be parametrized by an effective field theory framework that contains both General Relativity (GR) and the Standard Model of particle physics called the Standard-Model Extension (SME). We present new constraints on pure gravity SME coefficients obtained by analyzing Lunar Laser Ranging (LLR) observations. We use a new numerical lunar ephemeris computed in the SME framework and we perform a LLR data analysis using a set of 20721 normal points covering the period August 1969 to December 2013. We emphasize that linear combination of SME coefficients to which LLR data are sensitive are not the same as those fitted in previous post-fit residuals analysis using LLR observations and based on theoretical grounds. We found no evidence for Lorentz violation at the level of $10^{-8}$ for $\\bar{s}^{TX}$, $10^{-12}$ for $\\bar{s}^{XY}$ and $\\bar{s}^{XZ}$, $10^{-11}$ for $\\bar{s}^{XX}-\\bar{s}^{YY}$ and $\\bar{s}^{XX}+\\bar{s}^{YY}-2\\bar{s}^{ZZ}-0.045\\bar{s}^{YZ}$ and $10^{-9}$ for $\\bar{s}^{TY}+...

  19. Testing Lorentz Symmetry with Lunar Laser Ranging

    Science.gov (United States)

    Bourgoin, A.; Hees, A.; Bouquillon, S.; Le Poncin-Lafitte, C.; Francou, G.; Angonin, M.-C.

    2016-12-01

    Lorentz symmetry violations can be parametrized by an effective field theory framework that contains both general relativity and the standard model of particle physics called the standard-model extension (SME). We present new constraints on pure gravity SME coefficients obtained by analyzing lunar laser ranging (LLR) observations. We use a new numerical lunar ephemeris computed in the SME framework and we perform a LLR data analysis using a set of 20 721 normal points covering the period of August, 1969 to December, 2013. We emphasize that linear combination of SME coefficients to which LLR data are sensitive and not the same as those fitted in previous postfit residuals analysis using LLR observations and based on theoretical grounds. We found no evidence for Lorentz violation at the level of 10-8 for s¯T X, 10-12 for s¯X Y and s¯X Z, 10-11 for s¯X X-s¯Y Y and s¯X X+s¯Y Y-2 s¯Z Z-4.5 s¯Y Z, and 10-9 for s¯T Y+0.43 s¯T Z. We improve previous constraints on SME coefficient by a factor up to 5 and 800 compared to postfit residuals analysis of respectively binary pulsars and LLR observations.

  20. QCD breaks Lorentz invariance and colour

    Science.gov (United States)

    Balachandran, A. P.

    2016-03-01

    In the previous work [A. P. Balachandran and S. Vaidya, Eur. Phys. J. Plus 128, 118 (2013)], we have argued that the algebra of non-Abelian superselection rules is spontaneously broken to its maximal Abelian subalgebra, that is, the algebra generated by its completing commuting set (the two Casimirs, isospin and a basis of its Cartan subalgebra). In this paper, alternative arguments confirming these results are presented. In addition, Lorentz invariance is shown to be broken in quantum chromodynamics (QCD), just as it is in quantum electrodynamics (QED). The experimental consequences of these results include fuzzy mass and spin shells of coloured particles like quarks, and decay life times which depend on the frame of observation [D. Buchholz, Phys. Lett. B 174, 331 (1986); D. Buchholz and K. Fredenhagen, Commun. Math. Phys. 84, 1 (1982; J. Fröhlich, G. Morchio and F. Strocchi, Phys. Lett. B 89, 61 (1979); A. P. Balachandran, S. Kürkçüoğlu, A. R. de Queiroz and S. Vaidya, Eur. Phys. J. C 75, 89 (2015); A. P. Balachandran, S. Kürkçüoğlu and A. R. de Queiroz, Mod. Phys. Lett. A 28, 1350028 (2013)]. In a paper under preparation, these results are extended to the ADM Poincaré group and the local Lorentz group of frames. The renormalisation of the ADM energy by infrared gravitons is also studied and estimated.

  1. 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.)

  2. Análisis Dinámico - Ecuaciones diferenciales no lineales de primer orden: la ecuación de Bernouilli

    OpenAIRE

    Boj del Val, Eva; Getán Oliván, Jesús

    2014-01-01

    En este material referente a análisis dinámico se encuentra teoría y ejercicios resuletos sobre ecuaciones diferenciales no lineales de primer orden, concretamente sobre la ecuación de Bernouilli.

  3. Testing Lorentz Invariance with neutrino burst from supernova neutronization

    CERN Document Server

    Chakraborty, Sovan; Sigl, Günter

    2012-01-01

    Quantum-gravity (QG) effects might generate Lorentz invariance violation by the interaction of energetic particles with the foamy structure of the space-time. As a consequence, particles may not travel at the universal speed of light. We propose to constrain Lorentz invariance violation for energetic neutrinos exploiting the $\

  4. Testing local Lorentz invariance with short-range gravity

    Science.gov (United States)

    Kostelecký, V. Alan; Mewes, Matthew

    2017-03-01

    The Newton limit of gravity is studied in the presence of Lorentz-violating gravitational operators of arbitrary mass dimension. The linearized modified Einstein equations are obtained and the perturbative solutions are constructed and characterized. We develop a formalism for data analysis in laboratory experiments testing gravity at short range and demonstrate that these tests provide unique sensitivity to deviations from local Lorentz invariance.

  5. Lorentz violation in neutron decay and allowed nuclear beta decay

    NARCIS (Netherlands)

    Noordmans, J. P.; Wilschut, H. W.; Timmermans, R. G. E.

    2013-01-01

    Background: The search for violations of Lorentz invariance is nowadays motivated by attempts to unify the standard model of particle physics with general relativity. Such theories of "quantum gravity" predict Lorentz-violating signals that could be detected in low-energy precision experiments. In

  6. Limits on Lorentz violation from charged-pion decay

    NARCIS (Netherlands)

    P. Noordmans, J.; K. Vos, K.

    2014-01-01

    Charged-pion decay offers many opportunities to study Lorentz violation. Using an effective field theory approach, we study Lorentz violation in the lepton, W-boson, and quark sectors and derive the differential pion-decay rate, including muon polarization. Using coordinate redefinitions we are able

  7. Testing Lorentz and CPT Symmetries in Penning Traps

    CERN Document Server

    Ding, Yunhua

    2016-01-01

    A modified Dirac equation with general Lorentz- and CPT-violating operators in the electromagnetic field is studied. Constraints on and possible sensitivities to Lorentz-violating coefficients in the nonminimal sector up to mass-dimension six can be obtained by analyzing Penning-trap results involving anomaly frequencies.

  8. Lorentz-Dirac equation and circularly moving charges

    Science.gov (United States)

    Comay, E.

    1987-09-01

    The Lorentz-Dirac equation of radiation reaction is tested in a system of circularly moving changes. It is shown that this equation together with the Lienard-Wiechert retarded fields is consistent with energy conservation. Therefore, in this particular experiment, any alternative expression of radiation reaction must agree with the Lorentz-Dirac equation.

  9. Testing local Lorentz invariance with short-range gravity

    CERN Document Server

    Kostelecky, Alan

    2016-01-01

    The Newton limit of gravity is studied in the presence of Lorentz-violating gravitational operators of arbitrary mass dimension. The linearized modified Einstein equations are obtained and the perturbative solutions are constructed and characterized. We develop a formalism for data analysis in laboratory experiments testing gravity at short range and demonstrate that these tests provide unique sensitivity to deviations from local Lorentz invariance.

  10. Negative refraction and positive refraction are not Lorentz covariant

    Energy Technology Data Exchange (ETDEWEB)

    Mackay, Tom G., E-mail: T.Mackay@ed.ac.u [School of Mathematics and Maxwell Institute for Mathematical Sciences, University of Edinburgh, Edinburgh EH9 3JZ (United Kingdom)] [NanoMM - Nanoengineered Metamaterials Group, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802-6812 (United States); Lakhtakia, Akhlesh, E-mail: akhlesh@psu.ed [NanoMM - Nanoengineered Metamaterials Group, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802-6812 (United States)

    2009-12-28

    Refraction into a half-space occupied by a pseudochiral omega material moving at constant velocity was studied by directly implementing the Lorentz transformations of electric and magnetic fields. Numerical studies revealed that negative refraction, negative phase velocity and counterposition are not Lorentz-covariant phenomenons in general.

  11. Elastic Sturmian spirals in the Lorentz-Minkowski plane

    Directory of Open Access Journals (Sweden)

    Uçum Ali

    2016-01-01

    Full Text Available In this paper we consider some elastic spacelike and timelike curves in the Lorentz-Minkowski plane and obtain the respective vectorial equations of their position vectors in explicit analytical form. We study in more details the generalized Sturmian spirals in the Lorentz-Minkowski plane which simultaneously are elastics in this space.

  12. Solución de redes hidráulicas mediante la aplicación del modelo de balance de nodos y el método de linealización de ecuaciones

    Directory of Open Access Journals (Sweden)

    Paulo César Narváez Rincón

    2011-01-01

    Full Text Available El dimensionamiento de redes de distribución de fluidos es un problema común a diferentes áreas de la ingeniería, como la química y la civil, presente en el diseño de acueductos, sistemas de distribución de gas domiciliario, redes contra incendio y plantas de transformación química. Este trabajo presenta un modelo para su simulación, mediante la aplicación del balance de nodos y la teoría de linelización de ecuaciones. Permite dimensionar una red compleja, en la que pueden estar presentes accesorios, bombas, válvulas de control, boquillas de aspersión y equipos de proceso. Es aplicable a redes abiertas, cerradas o combinaciones de las dos.

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

    Institute of Scientific and Technical Information of China (English)

    张辉; 范宝春; 陈志华

    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.%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 Geld 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.

  14. Attitude dynamics and control of spacecraft using geomagnetic Lorentz force

    CERN Document Server

    Abdel-Aziz, Yehia A

    2014-01-01

    The attitude stabilization of a charged rigid spacecraft in Low Earth Orbit (LEO) using torques due to Lorentz force in pitch and roll directions is considered. A spacecraft that generates an electrostatic charge on its surface in the Earth magnetic field will be subject to perturbations from Lorentz force. The Lorentz force acting on an electrostatically charged spacecraft may provide a useful thrust for controlling a spacecraft's orientation. We assume that the spacecraft is moving in the Earth's magnetic field in an elliptical orbit under the effects of the gravitational, geomagnetic and Lorentz torques. The magnetic field of the Earth is modeled as a non-tilted dipole. A model incorporating all Lorentz torques as a function of orbital elements has been developed on the basis of electric and magnetic fields. The stability of the spacecraft orientation is investigated both analytically and numerically. The existence and stability of equilibrium positions is investigated for different values of the charge to...

  15. Lorentz- and CPT-violating extension of the standard model

    CERN Document Server

    Kostelecky, V A

    1999-01-01

    The formulation and some experimental implications of a general Lorentz-violating extension of the standard model are reviewed. The theory incorporates both CPT-preserving and CPT-breaking terms. It is otherwise a conventional quantum field theory, obtained under the assumption that Lorentz symmetry is spontaneously broken in an underlying model. The theory contains the usual standard-model gauge structure, and it is power-counting renormalizable. Energy and momentum are conserved. Despite the violation of Lorentz symmetry, the theory exhibits covariance under Lorentz transformations of the observer inertial frame. A general Lorentz-violating extension of quantum electrodynamics can be extracted. The standard-model extension implies potentially observable effects in a wide variety of experiments, including among others measurements on neutral-meson oscillations, comparative studies in Penning traps, spectroscopy of hydrogen and antihydrogen, bounds on cosmological birefringence, measurements of muon propertie...

  16. Effective Theory Approach to the Spontaneous Breakdown of Lorentz Invariance

    CERN Document Server

    Armendariz-Picon, Cristian; Penco, Riccardo

    2010-01-01

    We generalize the coset construction of Callan, Coleman, Wess and Zumino to theories in which the Lorentz group is spontaneously broken down to one of its subgroups. This allows us to write down the most general low-energy effective Lagrangian in which Lorentz invariance is non-linearly realized, and to explore the consequences of broken Lorentz symmetry without having to make any assumptions about the mechanism that triggers the breaking. We carry out the construction both in flat space, in which the Lorentz group is a global spacetime symmetry, and in a generally covariant theory, in which the Lorentz group can be treated as a local internal symmetry. As an illustration of this formalism, we construct the most general effective field theory in which the rotation group remains unbroken, and show that the latter is just the Einstein-aether theory.

  17. Discussion on Neutrino Oscillation and CPT/Lorentz Invariance Violation

    CERN Document Server

    Luo, Cui-Bai; Du, Yi-Lun; Wang, Yong-Long; Zong, Hong-Shi

    2016-01-01

    Depending on deformed canonical anticommutation relations, massless neutrino oscillation based on CPT /Lorentz invariance viol ation is discussed. It is found that the deformed canonical anti-commutation relations should satisfy the condition of new Moy al product and new non standard commutation relations. Furthermore, by comparing the neutrino experimental data and the above relations, we find that the orders of magnitude of noncommutative parameters or Lorentz invariant Violation parameters $\\mathi t{A}$ is not self-consistent. This means that the previous studies about Lorentz invariance violation in noncommutative field theory may not naturally explain massless neutrino oscillation. In other words, it should be impossible to explain neutrino os cillation by lorentz invariance violation. This conclusion is supported by the latest atmospheric neutrinos experimental resul ts from Super-Kamiokande Collaboration, which show that no evidence of Lorentz invariance violation on atmospheric neutrinos w as observe...

  18. Symmetry of the Lorentz boost: the relativity of colocality and Lorentz time contraction

    Science.gov (United States)

    Sharp, Jonathan C.

    2016-09-01

    Since the Lorentz boost is symmetric under exchange of x and ct, special relativistic phenomena will also manifest this symmetry. Firstly, simultaneity becomes paired with ‘colocality’ (‘at the same place’), and the ‘Relativity of Colocality’ becomes the dual to the well-known ‘Relativity of Simultaneity’. Further, Lorentz time contraction arises from reversal of the observation conditions pertaining to time dilation, expressible figuratively as ‘Moving clocks run slow, but moving time runs fast’. Symmetry also dictates that the most fundamental observational modes are: (1) the simultaneous observation of length, a process involving both the relativity of simultaneity and length contraction; and (2) the colocal measurement of duration, involving both the relativity of colocality and time contraction. Only the first of these modes is well known. The adoption of this symmetrical lexicon provides a necessary logical basis for interpretational studies of observation and measurement in special relativity.

  19. On asymptotic flatness and Lorentz charges

    Energy Technology Data Exchange (ETDEWEB)

    Compere, Geoffrey [KdV Institute for Mathematics, Universiteit van Amsterdam (Netherlands); Dehouck, Francois; Virmani, Amitabh, E-mail: gcompere@uva.nl, E-mail: fdehouck@ulb.ac.be, E-mail: avirmani@ulb.ac.be [Physique Theorique et Mathematique, Universite Libre de Bruxelles, Bruxelles (Belgium)

    2011-07-21

    In this paper we establish two results concerning four-dimensional asymptotically flat spacetimes at spatial infinity. First, we show that the six conserved Lorentz charges are encoded in two unique, distinct, but mutually dual symmetric divergence-free tensors that we construct from the equations of motion. Second, we show that the integrability of Einstein's equations in the asymptotic expansion is sufficient to establish the equivalence between counter-term charges defined from the variational principle and charges defined by Ashtekar and Hansen. These results clarify earlier constructions of conserved charges in the hyperboloid representation of spatial infinity. In showing this, the parity condition on the mass aspect is not needed. Along the way in establishing these results, we prove two lemmas on tensor fields on three-dimensional de Sitter spacetime stated by Ashtekar-Hansen and Beig-Schmidt and state and prove three additional lemmas.

  20. Radio Astronomical Polarimetry and the Lorentz Group

    CERN Document Server

    Britton, M C

    1999-01-01

    In radio astronomy the polarimetric properties of radiation are often modified during propagation and reception. Effects such as Faraday rotation, receiver cross-talk, and differential amplification act to change the state of polarized radiation. A general description of such transformations is useful for the investigation of these effects and for the interpretation and calibration of polarimetric observations. Such a description is provided by the Lorentz group, which is intimately related to the transformation properties of polarized radiation. In this paper the transformations that commonly arise in radio astronomy are analyzed in the context of this group. This analysis is then used to construct a model for the propagation and reception of radio waves. The implications of this model for radio astronomical polarimetry are discussed.

  1. Lorentz invariance with an invariant energy scale

    CERN Document Server

    Magueijo, J; Magueijo, Joao; Smolin, Lee

    2002-01-01

    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 non-linear 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, and we highlight the similarities between the group action found and a transformation previously proposed by Fock. 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.

  2. Testing Lorentz symmetry with planetary orbital dynamics

    CERN Document Server

    Hees, Aurélien; Poncin-Lafitte, Christophe Le; Bourgoin, Adrien; Rivoldini, Attilio; Lamine, Brahim; Meynadier, Frédéric; Guerlin, Christine; Wolf, Peter

    2015-01-01

    Planetary ephemerides are a very powerful tool to constrain deviations from the theory of General Relativity using orbital dynamics. The effective field theory framework called the Standard-Model Extension (SME) has been developed in order to systematically parametrize hypothetical violations of Lorentz symmetry (in the Standard Model and in the gravitational sector). In this communication, we use the latest determinations of the supplementary advances of the perihelia and of the nodes obtained by planetary ephemerides analysis to constrain SME coefficients from the pure gravity sector and also from gravity-matter couplings. Our results do not show any deviation from GR and they improve current constraints. Moreover, combinations with existing constraints from Lunar Laser Ranging and from atom interferometry gravimetry allow us to disentangle contributions from the pure gravity sector from the gravity-matter couplings.

  3. Lorentz Invariance Violation and Generalized Uncertainty Principle

    CERN Document Server

    Tawfik, A; Ali, A Farag

    2016-01-01

    Recent approaches for quantum gravity are conjectured to give predictions for a minimum measurable length, a maximum observable momentum and an essential generalization for the Heisenberg uncertainty principle (GUP). The latter is based on a momentum-dependent modification in the standard dispersion relation and leads to Lorentz invariance violation (LIV). The main features of the controversial OPERA measurements on the faster-than-light muon neutrino anomaly are used to calculate the time of flight delays $\\Delta t$ and the relative change $\\Delta v$ in the speed of neutrino in dependence on the redshift $z$. The results are compared with the OPERA measurements. We find that the measurements are too large to be interpreted as LIV. Depending on the rest mass, the propagation of high-energy muon neutrino can be superluminal. The comparison with the ultra high energy cosmic rays seems to reveals an essential ingredient of the approach combining string theory, loop quantum gravity, black hole physics and doubly ...

  4. Universal Gravitation as Lorentz-covariant Dynamics

    CERN Document Server

    Kauffmann, Steven Kenneth

    2014-01-01

    Einstein's equivalence principle implies that the acceleration of a particle in a "specified" gravitational field is independent of its mass. While this is certainly true to great accuracy for bodies we observe in the Earth's gravitational field, a hypothetical body of mass comparable to the Earth's would perceptibly cause the Earth to fall toward it, which would feed back into the strength as a function of time of the Earth's gravitational field affecting that body. In short, Einstein's equivalence principle isn't exact, but is an approximation that ignores recoil of the "specified" gravitational field, which sheds light on why general relativity has no clearly delineated native embodiment of conserved four-momentum. Einstein's 1905 relativity of course doesn't have the inexactitudes he unwittingly built into GR, so it is natural to explore a Lorentz-covariant gravitational theory patterned directly on electromagnetism, wherein a system's zero-divergence overall stress-energy, including all gravitational fee...

  5. Recent Results on the Periodic Lorentz Gas

    CERN Document Server

    Golse, François

    2009-01-01

    The Drude-Lorentz model for the motion of electrons in a solid is a classical model in statistical mechanics, where electrons are represented as point particles bouncing on a fixed system of obstacles (the atoms in the solid). Under some appropriate scaling assumption -- known as the Boltzmann-Grad scaling by analogy with the kinetic theory of rarefied gases -- this system can be described in some limit by a linear Boltzmann equation, assuming that the configuration of obstacles is random [G. Gallavotti, [Phys. Rev. (2) vol. 185 (1969), 308]). The case of a periodic configuration of obstacles (like atoms in a crystal) leads to a completely different limiting dynamics. These lecture notes review several results on this problem obtained in the past decade as joint work with J. Bourgain, E. Caglioti and B. Wennberg.

  6. Dynamical properties of the Lorentz gas

    Science.gov (United States)

    Sharma, K. C.; Ranganathan, S.; Egelstaff, P. A.; Soper, A. K.

    1987-07-01

    A Lorentz gas interacting with a Lennard-Jones (LJ) potential and obeying classical equations of motion has been simulated by the molecular-dynamics method. A system of 255 Ar particles and one H2 molecule at a reduced Ar density 0.413 and temperature 2.475 is simplified by allowing the ``argon'' to have infinite mass, and the hydrogen molecule interacts with Ar atoms via the LJ potential. The simulated incoherent dynamic structure factor Ss(Q,ω) for the hydrogen molecule, which is corrected for the rotational states, is found to be in reasonable agreement with the experimental data of Egelstaff et al. (unpublished). One-parameter phenomenological model calculations are also compared to these data.

  7. Lorentz invariance violation and generalized uncertainty principle

    Science.gov (United States)

    Tawfik, Abdel Nasser; Magdy, H.; Ali, A. Farag

    2016-01-01

    There are several theoretical indications that the quantum gravity approaches may have predictions for a minimal measurable length, and a maximal observable momentum and throughout a generalization for Heisenberg uncertainty principle. The generalized uncertainty principle (GUP) is based on a momentum-dependent modification in the standard dispersion relation which is conjectured to violate the principle of Lorentz invariance. From the resulting Hamiltonian, the velocity and time of flight of relativistic distant particles at Planck energy can be derived. A first comparison is made with recent observations for Hubble parameter in redshift-dependence in early-type galaxies. We find that LIV has two types of contributions to the time of flight delay Δ t comparable with that observations. Although the wrong OPERA measurement on faster-than-light muon neutrino anomaly, Δ t, and the relative change in the speed of muon neutrino Δ v in dependence on redshift z turn to be wrong, we utilize its main features to estimate Δ v. Accordingly, the results could not be interpreted as LIV. A third comparison is made with the ultra high-energy cosmic rays (UHECR). It is found that an essential ingredient of the approach combining string theory, loop quantum gravity, black hole physics and doubly spacial relativity and the one assuming a perturbative departure from exact Lorentz invariance. Fixing the sensitivity factor and its energy dependence are essential inputs for a reliable confronting of our calculations to UHECR. The sensitivity factor is related to the special time of flight delay and the time structure of the signal. Furthermore, the upper and lower bounds to the parameter, a that characterizes the generalized uncertainly principle, have to be fixed in related physical systems such as the gamma rays bursts.

  8. 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.

  9. The Impact of Lorentz Violation on the Klein Tunneling Effect

    CERN Document Server

    Xiao, Zhi

    2016-01-01

    We discuss the impact of a tiny Lorentz-violating $b^\\mu$ term on the one dimensional motion of a Dirac particle scattering on a rectangular barrier. We assume the experiment is performed in a particular inertial frame, where the components of $b^\\mu$ are assumed constants. The results show that Lorentz-violation modification to the transmission rate depends on the observer Lorentz nature of $b^\\mu$. For a spacelike or lightlike $b^\\mu$ the induced resonant frequency shift depends on the polarization, while for timelike $b^\\mu$ there is essentially no modification.

  10. On radiation reaction and the Abraham-Lorentz-Dirac equation

    CERN Document Server

    de Oca, Alejandro Cabo Montes

    2013-01-01

    It is underlined that the Lienard-Wiechert solutions indicate that after the external force is instantly removed from a small charged particle, the field in its close neighborhood becomes a Lorentz boosted Coulomb field. It suggests that the force of the self-field on the particle should instantaneously vanish after a sudden removal of the external force. A minimal modification of Abraham-Lorentz-Dirac equation is searched seeking to implement this property. A term assuring this behavior is added to the equation by maintaining Lorentz covariance and vanishing scalar product with the four-velocity. The simple Dirac constant force example does not show runaway acceleration.

  11. Limits on Lorentz violation from synchrotron and inverse Compton sources.

    Science.gov (United States)

    Altschul, B

    2006-05-26

    We derive new bounds on Lorentz violations in the electron sector from existing data on high-energy astrophysical sources. Synchrotron and inverse Compton data give precisely complementary constraints. The best bound on a specific combination of electron Lorentz-violating coefficients is at the 6 x 10(-20) level, and independent bounds are available for all the Lorentz-violating c coefficients at the 2 x 10(-14)level or better. This represents an improvement in some bounds by 14 orders of magnitude.

  12. Combined Search for Lorentz Violation in Short-Range Gravity.

    Science.gov (United States)

    Shao, Cheng-Gang; Tan, Yu-Jie; Tan, Wen-Hai; Yang, Shan-Qing; Luo, Jun; Tobar, Michael Edmund; Bailey, Quentin G; Long, J C; Weisman, E; Xu, Rui; Kostelecký, V Alan

    2016-08-12

    Short-range experiments testing the gravitational inverse-square law at the submillimeter scale offer uniquely sensitive probes of Lorentz invariance. A combined analysis of results from the short-range gravity experiments HUST-2015, HUST-2011, IU-2012, and IU-2002 permits the first independent measurements of the 14 nonrelativistic coefficients for Lorentz violation in the pure-gravity sector at the level of 10^{-9}  m^{2}, improving by an order of magnitude the sensitivity to numerous types of Lorentz violation involving quadratic curvature derivatives and curvature couplings.

  13. 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.

  14. Limits on Lorentz violation from forbidden β decays.

    Science.gov (United States)

    Noordmans, J P; Wilschut, H W; Timmermans, R G E

    2013-10-25

    Forbidden (slow) β decays offer new opportunities to test the invariance of the weak interaction under Lorentz transformations. Within a general effective field theory framework we analyze and reinterpret the only two relevant experiments, performed in the 1970s, dedicated to search for a preferred direction in space in first- and second-forbidden β decays. We show that the results of these experiments put strong and unique limits on Lorentz violation, and in particular on the presence of several interactions in the modern Lorentz-violating standard model extension. We discuss prospects to improve on these limits.

  15. Combined search for Lorentz violation in short-range gravity

    CERN Document Server

    Shao, Cheng-Gang; Tan, Wen-Hai; Yang, Shan-Qing; Luo, Jun; Tobar, Michael Edmund; Bailey, Quentin G; Long, J C; Weisman, E; Xu, Rui; Kostelecky, Alan

    2016-01-01

    Short-range experiments testing the gravitational inverse-square law at the submillimeter scale offer uniquely sensitive probes of Lorentz invariance. A combined analysis of results from the short-range gravity experiments HUST-2015, HUST-2011, IU-2012, and IU-2002 permits the first independent measurements of the 14 nonrelativistic coefficients for Lorentz violation in the pure-gravity sector at the level of $10^{-9}$ m$^2$, improving by an order of magnitude the sensitivity to numerous types of Lorentz violation involving quadratic curvature derivatives and curvature couplings.

  16. Møller scattering and Lorentz-violating Z bosons

    Science.gov (United States)

    Fu, Hao; Lehnert, Ralf

    2016-11-01

    Lorentz-symmetry breakdown in weak-interaction physics is studied. In particular, the CPT-even Lorentz-violating contributions to the Z boson in the minimal Standard-Model Extension are considered, and in this context polarized electron-electron scattering is investigated. Corrections to the usual parity-violating asymmetry are determined at tree level. Together with available data, this result can be used to improve existing estimates for the Lorentz-violating kW coefficient by two orders of magnitude. Some implications for past and future experiments are mentioned.

  17. Standard model with Lorentz and CPT violations in Finsler spacetime

    CERN Document Server

    Chang, Zhe

    2012-01-01

    Standard model with intrinsic Lorentz and CPT violations is proposed in a Finsler geometric framework. We present explicitly Lorentz and CPT--breaking Lagrangians of the matter fields and the gauge fields in locally Minkowski spacetime. The Lorentz invariance violation is found to be originated from the spacetime background deviating from the Minkowski one. Similarly, the CPT violation is determined by the behaviors of the locally Minkowski metric under the parity and time reversal operations. To help understanding phenomenologies, we compare the Finslerian model with the standard--model extension (SME) term by term at a first order approximation.

  18. Restrictive scenarios from Lorentz Invariance Violation to cosmic rays propagation

    CERN Document Server

    Martínez-Huerta, H

    2016-01-01

    Lorentz Invariance Violation introduced as a generic modification to particle dispersion relations is used to study high energy cosmic ray attenuation processes. It is shown to reproduce the same physical effects for vacuum Cherenkov radiation, as in models with spontaneous breaking of Lorentz symmetry. This approximation is also implemented for the study of photon decay in vacuum, where stringent limits to the violation scale are derived from the direct observation of very high energy cosmic ray photon events on gamma telescopes. Photo production processes by cosmic ray primaries on photon background are also addressed, to show that Lorentz violation may turn off this attenuation process at energies above a well defined secondary threshold.

  19. Composition of Lorentz Transformations in Terms of Their Generators

    CERN Document Server

    Martínez, F S J

    2001-01-01

    Two-forms in Minkowski space-time may be considered as generators of Lorentz transformations. Here, the covariant and general expression for the composition law (Baker-Campbell-Hausdorff formula) of two Lorentz transformations in terms of their generators is obtained. Every subalgebra of the Lorentz algebra of such generators, up to one, may be generated by a sole pair of generators. When the subalgebra is known, the above BCH formula for the two two-forms simplifies. Its simplified expressions for all such subalgebras are also given.

  20. 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.

  1. Probes of Lorentz violation in neutrino propagation

    Science.gov (United States)

    Ellis, John; Harries, Nicholas; Meregaglia, Anselmo; Rubbia, André; Sakharov, Alexander S.

    2008-08-01

    It has been suggested that the interactions of energetic particles with the foamy structure of space-time thought to be generated by quantum-gravitational (QG) effects might violate Lorentz invariance, so that they do not propagate at a universal speed of light. We consider the limits that may be set on a linear or quadratic violation of Lorentz invariance in the propagation of energetic neutrinos, v/c=[1±(E/MνQG1)] or [1±(E/MνQG2)2], using data from supernova explosions and the OPERA long-baseline neutrino experiment. Using the SN1987a neutrino data from the Kamioka II, IMB, and Baksan experiments, we set the limits MνQG1>2.7(2.5)×1010GeV for subluminal (superluminal) propagation and MνQG2>4.6(4.1)×104GeV at the 95% confidence level. A future galactic supernova at a distance of 10 kpc would have sensitivity to MνQG1>2(4)×1011GeV for subluminal (superluminal) propagation and MνQG2>2(4)×105GeV. With the current CERN neutrinos to Gran Sasso extraction spill length of 10.5μs and with standard clock synchronization techniques, the sensitivity of the OPERA experiment would reach MνQG1˜7×105GeV (MνQG2˜8×103GeV) after 5 years of nominal running. If the time structure of the super proton synchrotron radio frequency bunches within the extracted CERN neutrinos to Gran Sasso spills could be exploited, these figures would be significantly improved to MνQG1˜5×107GeV (MνQG2˜4×104GeV). These results can be improved further if a similar time resolution can be achieved with neutrino events occurring in the rock upstream of the OPERA detector: we find potential sensitivities to MνQG1˜4×108GeV and MνQG2˜7×105GeV.

  2. Test of Lorentz Violation with Astrophysical Neutrino Flavor

    CERN Document Server

    Katori, Teppei; Salvado, Jordi

    2016-01-01

    The high-energy astrophysical neutrinos recently discovered by IceCube opened a new way to test Lorentz and CPT violation through the astrophysical neutrino mixing properties. The flavor ratio of astrophysical neutrinos is a very powerful tool to investigate tiny effects caused by Lorentz and CPT violation. There are 3 main findings; (1) current limits on Lorentz and CPT violation in neutrino sector are not tight and they allow for any flavor ratios, (2) however, the observable flavor ratio on the Earth is tied with the flavor ratio at production, this means we can test both the presence of new physics and the astrophysical neutrino production mechanism simultaneously, and (3) the astrophysical neutrino flavor ratio is one of the most stringent tests of Lorentz and CPT violation.

  3. Lorentz breaking Effective Field Theory and observational tests

    CERN Document Server

    Liberati, Stefano

    2012-01-01

    Analogue models of gravity have provided an experimentally realizable test field for our ideas on quantum field theory in curved spacetimes but they have also inspired the investigation of possible departures from exact Lorentz invariance at microscopic scales. In this role they have joined, and sometime anticipated, several quantum gravity models characterized by Lorentz breaking phenomenology. A crucial difference between these speculations and other ones associated to quantum gravity scenarios, is the possibility to carry out observational and experimental tests which have nowadays led to a broad range of constraints on departures from Lorentz invariance. We shall review here the effective field theory approach to Lorentz breaking in the matter sector, present the constraints provided by the available observations and finally discuss the implications of the persisting uncertainty on the composition of the ultra high energy cosmic rays for the constraints on the higher order, analogue gravity inspired, Lore...

  4. Vacuum photon splitting in Lorentz-violating quantum electrodynamics.

    Science.gov (United States)

    Kostelecký, V Alan; Pickering, Austin G M

    2003-07-18

    Radiative corrections arising from Lorentz violation in the fermion sector induce a nonzero amplitude for vacuum photon splitting. At one loop, the on-shell amplitude acquires both CPT-even and CPT-odd contributions forbidden in conventional electrodynamics.

  5. CPT/Lorentz Invariance Violation and Quantum Field Theory

    CERN Document Server

    Arias, P; Gamboa-Rios, J; López-Sarrion, J; Méndez, F; Arias, Paola; Das, Ashok; Gamboa, Jorge; Lopez-Sarrion, Justo; Mendez, Fernando

    2006-01-01

    Analogies between the noncommutative harmonic oscillator and noncommutative fields are analyzed. Following this analogy we construct examples of quantum fields theories with explicit CPT and Lorentz symmetry breaking. Some applications to baryogenesis and neutrino oscillation are also discussed

  6. Lorentz-violating Euler-Heisenberg effective action

    CERN Document Server

    Furtado, J

    2014-01-01

    In this work, we study the radiative generation of the Lorentz-violating Euler-Heisenberg action, in the weak field approximation. For this, we first consider a nonperturbative calculation in the coefficient $c_{\\mu\

  7. Vacuum Photon Splitting in Lorentz-Violating Quantum Electrodynamics

    CERN Document Server

    Kostelecky, V A; Kostelecky, Alan; Pickering, Austin

    2003-01-01

    Radiative corrections arising from Lorentz violation in the fermion sector induce a nonzero amplitude for vacuum photon splitting. At one loop, the on-shell amplitude acquires both CPT-even and CPT-odd contributions forbidden in conventional electrodynamics.

  8. Tests of Lorentz Symmetry in the Gravitational Sector

    Directory of Open Access Journals (Sweden)

    Aurélien Hees

    2016-12-01

    Full Text Available Lorentz symmetry is one of the pillars of both General Relativity and the Standard Model of particle physics. Motivated by ideas about quantum gravity, unification theories and violations of CPT symmetry, a significant effort has been put the last decades into testing Lorentz symmetry. This review focuses on Lorentz symmetry tests performed in the gravitational sector. We briefly review the basics of the pure gravitational sector of the Standard-Model Extension (SME framework, a formalism developed in order to systematically parametrize hypothetical violations of the Lorentz invariance. Furthermore, we discuss the latest constraints obtained within this formalism including analyses of the following measurements: atomic gravimetry, Lunar Laser Ranging, Very Long Baseline Interferometry, planetary ephemerides, Gravity Probe B, binary pulsars, high energy cosmic rays, … In addition, we propose a combined analysis of all these results. We also discuss possible improvements on current analyses and present some sensitivity analyses for future observations.

  9. THE HOMOTHETIC MOTIONS IN THE LORENTZ 3-SPACE

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this article, the properties of the homothetic motions in three-dimensional Lorentz space are investigated. Also, some geometric results between velocity and acceleration vectors of a point in a spatial motion are obtained.

  10. Lorentz-violating spinor electrodynamics and Penning traps

    Science.gov (United States)

    Ding, Yunhua; Kostelecký, V. Alan

    2016-09-01

    The prospects are explored for testing Lorentz- and C P T -violating quantum electrodynamics in experiments with Penning traps. We present the Lagrange density of Lorentz-violating spinor electrodynamics with operators of mass dimensions up to 6, and we discuss some of its properties. The theory is used to derive Lorentz- and C P T -violating perturbative shifts of the energy levels of a particle confined to a Penning trap. Observable signals are discussed for trapped electrons, positrons, protons, and antiprotons. Existing experimental measurements on anomaly frequencies are used to extract new or improved bounds on numerous coefficients for Lorentz and C P T violation, using sidereal variations of observables and comparisons between particles and antiparticles.

  11. Tests of Lorentz symmetry in the gravitational sector

    CERN Document Server

    Hees, Aurélien; Bourgoin, Adrien; Bars, Hélène Pihan-Le; Guerlin, Christine; Poncin-Lafitte, Christophe Le

    2016-01-01

    Lorentz symmetry is one of the pillars of both General Relativity and the Standard Model of particle physics. Motivated by ideas about quantum gravity, unification theories and violations of CPT symmetry, a significant effort has been put the last decades into testing Lorentz symmetry. This review focuses on Lorentz symmetry tests performed in the gravitational sector. We briefly review the basics of the pure gravitational sector of the Standard-Model Extension (SME) framework, a formalism developed in order to systematically parametrize hypothetical violations of the Lorentz invariance. Furthermore, we discuss the latest constraints obtained within this formalism including analyses of the following measurements: atomic gravimetry, Lunar Laser Ranging, Very Long Baseline Interferometry, planetary ephemerides, Gravity Probe B, binary pulsars, high energy cosmic rays,... In addition, we propose a combined analysis of all these results. We also discuss possible improvements on current analyses and present some s...

  12. Larmor and the Prehistory of the Lorentz Transformations

    Science.gov (United States)

    Kittel, C.

    1974-01-01

    A historical analysis is given of the development in 1900 of the Lorentz transformation of coordinates and time, and of electric and magnetic field components. The earlier work of Voight is discussed. (RH)

  13. The Lorentz-Dirac equation and the structure of spacetime

    CERN Document Server

    De Souza, M M

    1995-01-01

    A new interpretation of the causality implementation in the Lienard-Wiechert solution raises new doubts against the validity of the Lorentz-Dirac equation and the limits of validity of the Minkowski structure of spacetime.

  14. Lorentz invariant CPT breaking in the Dirac equation

    CERN Document Server

    Fujikawa, Kazuo

    2016-01-01

    If one modifies the Dirac equation in momentum space to $[\\gamma^{\\mu}p_{\\mu}-m-\\Delta m(\\theta(p_{0})-\\theta(-p_{0})) \\theta(p_{\\mu}^{2})]\\psi(p)=0$, the symmetry of positive and negative energy eigenvalues is lifted by $m\\pm \\Delta m$ for a small $\\Delta m$. The mass degeneracy of the particle and antiparticle is thus lifted in a Lorentz invariant manner since the combinations $\\theta(\\pm p_{0})\\theta(p_{\\mu}^{2})$ with step functions are manifestly Lorentz invariant. We explain an explicit construction of this CPT breaking term in coordinate space, which is Lorentz invariant but non-local at a distance scale of the Planck length. The application of this Lorentz invariant CPT breaking mechanism to the possible mass splitting of the neutrino and antineutrino in the Standard Model is briefly discussed.

  15. Lorentz-violating effects in three-dimensional $QED$

    CERN Document Server

    Bufalo, R

    2014-01-01

    Inspired in discussions presented lately regarding Lorentz-violating interaction terms in \\cite{13,6}, we propose here a slightly different version for the coupling term. We will consider a modified quantum electrodynamics with violation of Lorentz symmetry defined in a $\\left( 2+1\\right) $-dimensional spacetime. We define the Lagrangian density with a Lorentz-violating interaction, where the the spacetime dimensionality is explicitly taken into account in its definition. The work encompasses an analysis of this model at both zero and finite-temperature, where very interesting features are known to occur due to the spacetime dimensionality. With that in mind we expect that the spacetime dimensionality may provide new insights about the radiative generation of higher-derivative terms into the action, implying in a new Lorentz-violating electrodynamics, as well the nonminimal coupling may provide interesting implications on the thermodynamical quantities.

  16. 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.

  17. Tests of Lorentz Symmetry in Single Beta Decay

    Directory of Open Access Journals (Sweden)

    Jorge S. Díaz

    2014-01-01

    Full Text Available Low-energy experiments studying single beta decay can serve as sensitive probes of Lorentz invariance that can complement interferometric searches for deviations from this spacetime symmetry. Experimental signatures of a dimension-three operator for Lorentz violation which are unobservable in neutrino oscillations are described for the decay of polarized and unpolarized neutrons as well as for measurements of the spectral endpoint in beta decay.

  18. Consistency analysis of a nonbirefringent Lorentz-violating planar model

    CERN Document Server

    Casana, Rodolfo; Moreira, Roemir P M

    2011-01-01

    In this work analyze the physical consistency of a nonbirefringent Lorentz-violating planar model via the analysis of the pole structure of its Feynman's propagators. The nonbirefringent planar model, obtained from the dimensional reduction of the CPT-even gauge sector of the standard model extension, is composed of a gauge and a scalar fields, being affected by Lorentz-violating (LIV) coefficients encoded in the symmetric tensor $\\kappa_{\\mu\

  19. UHECR bounds on Lorentz violation in the photon sector

    OpenAIRE

    Klinkhamer, F. R.

    2008-01-01

    The aim of this brief review is to present a case study of how astrophysics data can be used to get bounds on Lorentz-violating parameters. For this purpose, a particularly simple Lorentz-violating modification of the Maxwell theory of photons is considered, which maintains gauge invariance, CPT, and renormalization. With a standard spin-one-half Dirac particle minimally coupled to this nonstandard photon, the resulting modified-quantum-electrodynamics model involves nineteen dimensionless "d...

  20. Letter: On the Solutions of the Lorentz-Dirac Equation

    Science.gov (United States)

    Vogt, D.; Letelier, P. S.

    2003-12-01

    We discuss the unstable character of the solutions of the Lorentz-Dirac equation and stress the need of methods like order reduction to derive a physically acceptable equation of motion. The discussion is illustrated with the paradigmatic example of the non-relativistic harmonic oscillator with radiation reaction. We also illustrate the removal of the noncausal pre-acceleration with the introduction of a small correction in the Lorentz-Dirac equation.

  1. 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.

  2. Cavity tests of parity-odd Lorentz violations in electrodynamics

    Science.gov (United States)

    Mewes, Matthew; Petroff, Alexander

    2007-03-01

    Electromagnetic resonant cavities form the basis for a number modern tests of Lorentz invariance. The geometry of most of these experiments implies unsuppressed sensitivities to parity-even Lorentz violations only. Parity-odd violations typically enter through suppressed boost effects, causing a reduction in sensitivity by roughly 4 orders of magnitude. Here we discuss possible techniques for achieving unsuppressed sensitivities to parity-odd violations using asymmetric resonators.

  3. Finsler-like structures from Lorentz-breaking classical particles

    CERN Document Server

    Russell, Neil

    2015-01-01

    A method is presented for deducing classical point-particle Lagrange functions corresponding to a class of quartic dispersion relations. Applying this to particles violating Lorentz symmetry in the minimal Standard-Model Extension leads to a variety of novel lagrangians in flat spacetime. Morphisms in these classical systems are studied that echo invariance under field redefinitions in the quantized theory. The Lagrange functions found offer new possibilities for understanding Lorentz-breaking effects by exploring parallels with Finsler-like geometries.

  4. Lorentz Harmonics, Squeeze Harmonics and Their Physical Applications

    Directory of Open Access Journals (Sweden)

    Marilyn E. Noz

    2011-02-01

    Full Text Available Among the symmetries in physics, the rotation symmetry is most familiar to us. It is known that the spherical harmonics serve useful purposes when the world is rotated. Squeeze transformations are also becoming more prominent in physics, particularly in optical sciences and in high-energy physics. As can be seen from Dirac’s light-cone coordinate system, Lorentz boosts are squeeze transformations. Thus the squeeze transformation is one of the fundamental transformations in Einstein’s Lorentz-covariant world. It is possible to define a complete set of orthonormal functions defined for one Lorentz frame. It is shown that the same set can be used for other Lorentz frames. Transformation properties are discussed. Physical applications are discussed in both optics and high-energy physics. It is shown that the Lorentz harmonics provide the mathematical basis for squeezed states of light. It is shown also that the same set of harmonics can be used for understanding Lorentz-boosted hadrons in high-energy physics. It is thus possible to transmit physics from one branch of physics to the other branch using the mathematical basis common to them.

  5. Ecuaciones alométricas para árboles tropicales: aplicación al inventario forestal de Sinaloa, México

    Directory of Open Access Journals (Sweden)

    Jos\\u00E9 N\\u00E1var-Ch\\u00E1idez

    2013-01-01

    Full Text Available El obje- tivo del presente trabajo fue desarrollar una ecuación alomé- trica actualizada para la biomasa aérea total (M de árboles medidos en campo y de sitios inventariados en los bosques secos de Sinaloa, México. Los resultados mostraron que: (a la ecuación alométrica desarrollada incrementó la precisión en contraste con las ecuaciones convencionales de biomasa, (b la alometría desarrollada ex situ proyecta valores de M que pueden desviarse por cerca del doble de las mediciones de M y (c las evaluaciones al nivel del sitio también pue-den desviarse por más del doble cuando se usan ecuaciones desarrolladas ex situ. Se probaron dos procedimientos para aumentar la precisión en la evaluación de M para árboles y sitios, cuando se ajustan ecuaciones desarrolladas ex situ: (i con el teorema del límite central usar las ecuaciones alomé- tricas disponibles para estimar un promedio y (ii calibrar las ecuaciones por el ajuste de parámetros a nivel local, los cuales pueden ser calculados con el uso de programas estadís- ticos. Estas opciones pueden incrementar la precisión de las evaluaciones de M de árboles y sitios, y eventualmente de las selvas tropicales secas del norte de México.

  6. 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.

  7. The electrodeless Lorentz force thruster experiment

    Science.gov (United States)

    Weber, Thomas E.

    The Electrodeless Lorentz Force (ELF) thruster is a novel type of plasma thruster, which utilizes Rotating Magnetic Field current drive within a diverging magnetic field to form, accelerate, and eject a Field Reversed Configuration plasmoid. The ELF program is a result of a Small Business Technology Transfer grant awarded to MSNW LLC by the Air Force Office of Scientific Research for the research of the revolutionary space propulsion concept represented by ELF. These grants are awarded to small businesses working in collaboration with a university, in this case, the University of Washington. The program was split into two concurrent research efforts; a numerical modeling study undertaken at the UW branch of the Plasma Science and Innovation Center, and an experimental effort taking place at the UW Plasma Dynamics Laboratory with additional support from MSNW (the latter being the subject of this dissertation). It is the aim of this dissertation is to present to the reader the necessary background information needed to understand the operation of the ELF thruster, an overview of the experimental setup, a review of the significant experimental findings, and a discussion regarding the operation and performance of the thruster.

  8. Direct Lorentz force compensation flowmeter for electrolytes

    Science.gov (United States)

    Vasilyan, S.; Froehlich, Th.

    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 106 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.

  9. Entropy production due to Lorentz invariance violation

    Science.gov (United States)

    Mohammadzadeh, Hosein; Farahmand, Mehrnoosh; Maleki, Mahnaz

    2017-07-01

    It is generally believed that the concept of the spacetime continuum should be modified for distances as small as the Planck length. This is a length scale at which the spacetime might have a discrete structure and quantum gravity effects are dominant. Presumably, the microscopic fluctuations within the geometry of spacetime should result in an enormous entropy production. In the present work, we look for the effects of Lorentz invariance violation (LIV) in flat and curved backgrounds that can be measured by quantum entanglement and quantum thermodynamic entropies for scalar modes. Our results show that the general behavior of these entropies is the same. We also consider variations of the entropies with respect to LIV and cosmological and field parameters. Using the properties of these entropies, along with detecting the most entangled modes, we extract information about the past existence of LIV, which in turn might be useful in recovering the quantum structure of gravity. Indeed, the occurrence of a peak in the behavior of these entropies for a specific momentum could provide information about the expansion parameters. Moreover, information about the LIV parameter is codified in this peak.

  10. Lorentz symmetry and very long baseline interferometry

    Science.gov (United States)

    Le Poncin-Lafitte, C.; Hees, A.; Lambert, S.

    2016-12-01

    Lorentz symmetry violations can be described by an effective field theory framework that contains both general relativity and the Standard Model of particle physics called the Standard Model extension (SME). Recently, postfit analysis of Gravity Probe B and binary pulsars led to an upper limit at the 10-4 level on the time-time coefficient s¯T T of the pure-gravity sector of the minimal SME. In this work, we derive the observable of very long baseline interferometry (VLBI) in SME and then implement it into a real data analysis code of geodetic VLBI observations. Analyzing all available observations recorded since 1979, we compare estimates of s¯T T and errors obtained with various analysis schemes, including global estimations over several time spans, and with various Sun elongation cutoff angles, and by analysis of radio source coordinate time series. We obtain a constraint on s¯ T T=(-5 ±8 )×10-5 , directly fitted to the observations and improving by a factor of 5 previous postfit analysis estimates.

  11. Lorentz Force Based Satellite Attitude Control

    Science.gov (United States)

    Giri, Dipak Kumar; Sinha, Manoranjan

    2016-07-01

    Since the inception of attitude control of a satellite, various active and passive control strategies have been developed. These include using thrusters, momentum wheels, control moment gyros and magnetic torquers. In this present work, a new technique named Lorentz force based Coulombic actuators for the active control is proposed. This method uses electrostatic charged shells, which interact with the time varying earth's magnetic field to establish a full three axes control of the satellite. It is shown that the proposed actuation mechanism is similar to a satellite actuated by magnetic coils except that the resultant magnetic moment vanishes under two different conditions. The equation for the required charges on the the Coulomb shells attached to the satellite body axes is derived, which is in turn used to find the available control torque for actuating the satellite along the orbit. Stability of the proposed system for very high initial angular velocity and exponential stability about the origin are proved for a proportional-differential control input. Simulations are carried out to show the efficacy of the proposed system for the attitude control of the earth-pointing satellite.

  12. 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.

  13. Dynamical 3-Space: neo-Lorentz Relativity

    CERN Document Server

    Cahill, Reginald T

    2012-01-01

    The major extant relativity theories - Galileo's Relativity (GaR), Lorentz's Relativity (LR) and Einstein's Special Relativity (SR), with the latter much celebrated, while the LR is essentially ignored. Indeed it is often incorrectly claimed that SR and LR are experimentally indistinguishable. Here we show that (i) SR and LR are experimentally distinguishable, (ii) that comparison of gas-mode Michelson interferometer experiments with spacecraft earth-flyby Doppler shift data demonstrate that it is LR that is consistent with the data, while SR is in conflict with the data, (iii) SR is exactly derivable from GaR by means of a mere linear change of space and time coordinates that mixes the Galilean space and time coordinates. So it is GaR and SR that are equivalent. Hence the well-known SR relativistic effects are purely coordinate effects, and cannot correspond to the observed relativistic effects. The connections between these three relativity theories has become apparent following the discovery that space is ...

  14. Lorentz symmetry and Very Long Baseline Interferometry

    CERN Document Server

    Poncin-Lafitte, C Le; lambert, S

    2016-01-01

    Lorentz symmetry violations can be described by an effective field theory framework that contains both General Relativity and the Standard Model of particle physics called the Standard-Model extension (SME). Recently, post-fit analysis of Gravity Probe B and binary pulsars lead to an upper limit at the $10^{-4}$ level on the time-time coefficient $\\bar s^{TT}$ of the pure-gravity sector of the minimal SME. In this work, we derive the observable of Very Long Baseline Interferometry (VLBI) in SME and then we implement it into a real data analysis code of geodetic VLBI observations. Analyzing all available observations recorded since 1979, we compare estimates of $\\bar s^{TT}$ and errors obtained with various analysis schemes, including global estimations over several time spans and with various Sun elongation cut-off angles, and with analysis of radio source coordinate time series. We obtain a constraint on $\\bar s^{TT}=(-5\\pm 8)\\times 10^{-5}$, directly fitted to the observations and improving by a factor 5 pr...

  15. Geometrical Lorentz Violation and Quantum Mechanical Physics

    CERN Document Server

    Mignani, R; Cardone, F

    2013-01-01

    On the basis of the results of some experiments dealing with the violation of Local Lorentz Invariance (LLI) and on the formalism of the Deformed Special Relativity (DSR), we examine the connections between the local geometrical structure of space-time and the foundation of Quantum Mechanics. We show that Quantum Mechanics, beside being an axiomatic theory, can be considered also a deductive physical theory, deducted from the primary physical principle of Relativistic Correlation. This principle is synonym of LLI and of a rigid and at minkowskian space-time. The results of the experiments mentioned above show the breakdown of LLI and hence the violation of the principle of Relativistic Correlation. The formalism of DSR allows to highlight the deep meaning of LLI breakdown in terms of the geometrical structure of local space-time which, far from being rigid and at, is deformed by the energy of the physical phenomena that take place and in this sense it has an active part in the dynamics of the whole physical p...

  16. 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.

  17. Teoría de Floquet para ecuaciones en diferencias lineales de segundo orden y homogéas

    OpenAIRE

    Jiménez Jiménez, M. Jose

    2015-01-01

    En este trabajo aportamos una versión del teorema de Floquet aplicable a cualquier ecuación en diferencias lineal de segundo orden con coeficientes casi–periódicos. Obtenemos que este tipo de ecuaciones son equivalentes a una ecuación de Chebyshev, cuyo parámetro solo depende de los valores de los coeficientes casi–periódicos y puede ser determinado por una recurrencia no lineal. Además, resolvemos dicha recurrencia, obtenemos una expresión cerrada para este parámetro y proporcionamos c...

  18. Identificación organizacional y proactividad personal en grupos de trabajo : un modelo de ecuaciones estructurales

    OpenAIRE

    Topa Cantisano, Gabriela; Morales Domínguez, Francisco

    2006-01-01

    El presente estudio explora la relación entre la identificación con la organización, las conductas de ciudadanía y la iniciativa personal dentro de los grupos de trabajo. Incluyendo una muestra de 336 empleados se prueba el ajuste de diferentes modelos causales a los datos. Los análisis de ecuaciones estructurales muestran que la identificación con la organización pronostica los resultados relativos a las conductas de ciudadanía organizacional y la iniciativa personal de los empleados pero qu...

  19. Resolución de ecuaciones diferenciales en derivadas parciales dependientes del tiempo de segundo orden utilizando diferencias finitas generalizadas

    OpenAIRE

    Ureña, Francisco; Benito, Juan José; Gavete, Luis; Álvarez, Ramón

    2003-01-01

    En este artículo se muestra la eficiencia del método de diferencias finitas generalizadas (MDFG) en la resolución , por el método explícito, de ecuaciones diferenciales en derivadas parciales dependientes del tiempo de segundo orden para una o dos dimensiones espaciales. La obtención de fórmulas explícitas en diferencias finitas generalizadas permite establecer un sencillo criterio de estabilidad, que viene expresado en función de los coeficientes de la ecuación de la estrella. ...

  20. Análisis cognitivo de situaciones problema con sistemas de ecuaciones algebraicas en el contexto del balance de materia

    OpenAIRE

    Elia Trejo Trejo; Patricia Camarena Gallardo

    2011-01-01

    En este artículo se informa una investigación en la que se realiza un análisis cognitivo a un grupo de enfoque, donde los estudiantes de una carrera técnica universitaria abordan los sistemas de ecuaciones algebraicas lineales en el contexto del balance de materia en situaciones problema de mezclas químicas. El análisis cognitivo del grupo de enfoque se fundamenta en las teorías de los Campos Conceptuales y en la Matemática en el Contexto de las Ciencias. Para el análisis se atienden, en part...

  1. Aproximación de ecuaciones diferenciales mediante una nueva técnica variacional y aplicaciones

    OpenAIRE

    Legaz Almansa, María José

    2012-01-01

    [SPA] En esta Tesis presentamos el estudio teórico y numérico de sistemas de ecuaciones diferenciales basado en el análisis de un funcional asociado de forma natural al problema original. Probamos que cuando se utiliza métodos del descenso para minimizar dicho funcional, el algoritmo decrece el error hasta obtener la convergencia dada la no existencia de mínimos locales diferentes a la solución original. En cierto sentido el algoritmo puede considerarse un método tipo Newton gl...

  2. Lorentz, the Solvay Councils and the Physics Institute

    Science.gov (United States)

    Berends, Frits A.

    2015-09-01

    This paper describes the crucial role which Lorentz played in shaping and continuing the Solvay Councils and the Physics Institute. At the same time it will become clear that Lorentz* intensive involvement in these activities added significantly to his influence on, and recognition in, the international physics community. The first Solvay Council in 1911 was an initiative of the German physical chemist Walther Nernst. It was generously supported by the wealthy industrialist and philantropist Ernest Solvay. About five months before the Council*s start Nernst invited Lorentz to chair the meeting. That was no simple task in view of the fundamental problem of the quanta and the practical problem of communication in different languages. Lorentz*s way of presiding the conference impressed all participants. When, after the meeting, Solvay was willing to support research in the field, it was only natural to ask Lorentz for a plan. Within two months Lorentz provided Solvay with a draft which would serve as an outline for the statutes of an institute. The international Solvay Institute of Physics was founded on 1 May 1912. It would support research proposals in a specified field and would regularly organize Councils. An international scientific committee would decide on grants which could be requested from everywhere. Between the Institute*s beginnings and the outbreak of WWI, 97 requests were considered and 40 proposals - originating from 7 countries - were accepted. A second Council took place in 1913. Lorentz was given the possibility to spend considerable time on chairing the scientific committee when in 1912 his full time professorship in Leiden was changed into a part-time one. During WWI Lorentz maintained contacts with Solvay and with several of his foreign colleagues in the countries at war. He tried to remain objective, impartial and helpful, and did not lose hope that pre-war international scientific relations would eventually be re-established. After the war he

  3. 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.

  4. Simulación de ensayos triaxiales cíclicos con presión de confinamiento constante y variable empleando ecuaciones empíricas

    Directory of Open Access Journals (Sweden)

    Hugo Alexander Rondón Quintana

    2009-01-01

    para intentar predecir la acumulación de las deformaciones permanentes que experimentan materiales granulares no tratados (GNT en ensayos triaxiales cíclicos con presión de confinamiento constante (PCC y variable (PCV. Con base en el análisis de dichas ecuaciones, se escogieron las más utilizadas en el mundo con el fin de simular el comportamiento que experimentó un GNT en ensayos tipo PCC y PCV. Las simulaciones realizadas demuestran que la mayor parte de las ecuaciones empíricas que se utilizan para predecir la acumulación de la deformación permanente de un material granular bajo carga cíclica no pueden reproducir su comportamiento en ensayos PCC y PCV. Adicionalmente, los parámetros que emplean dichas ecuaciones no son constantes del material.

  5. A Real Lorentz-FitzGerald Contraction

    Science.gov (United States)

    Barceló, Carlos; Jannes, Gil

    2008-02-01

    Many condensed matter systems are such that their collective excitations at low energies can be described by fields satisfying equations of motion formally indistinguishable from those of relativistic field theory. The finite speed of propagation of the disturbances in the effective fields (in the simplest models, the speed of sound) plays here the role of the speed of light in fundamental physics. However, these apparently relativistic fields are immersed in an external Newtonian world (the condensed matter system itself and the laboratory can be considered Newtonian, since all the velocities involved are much smaller than the velocity of light) which provides a privileged coordinate system and therefore seems to destroy the possibility of having a perfectly defined relativistic emergent world. In this essay we ask ourselves the following question: In a homogeneous condensed matter medium, is there a way for internal observers, dealing exclusively with the low-energy collective phenomena, to detect their state of uniform motion with respect to the medium? By proposing a thought experiment based on the construction of a Michelson-Morley interferometer made of quasi-particles, we show that a real Lorentz-FitzGerald contraction takes place, so that internal observers are unable to find out anything about their ‘absolute’ state of motion. Therefore, we also show that an effective but perfectly defined relativistic world can emerge in a fishbowl world situated inside a Newtonian (laboratory) system. This leads us to reflect on the various levels of description in physics, in particular regarding the quest towards a theory of quantum gravity.

  6. 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...

  7. Resolución numérica de las ecuaciones de aguas poco profundas monodimensionales mediante un algoritmo lagrangiano de elementos finitos

    OpenAIRE

    González-Vida, José Manuel; Parés, Carlos

    2002-01-01

    En este trabajo se abordan, en una versión simplificada, las dificultades que surgen en la resolución de las ecuaciones de aguas poco profundas en el caso de la aparición (o desaparición) de zonas sin agua en el dominio de cálculo mediante un método de elementos finitos en el que los nodos se desplazan con el fluido. Se tratan las formulaciones conservativa y no conservativa de las ecuaciones y se presentan finalmente algunos resultados numéricos. Peer Reviewed

  8. De la Resolución de Ecuaciones Polinómicas al Algebra Abstracta: un Paseo a Través de la Historia

    OpenAIRE

    Ochoviet, Cristina

    2014-01-01

    Realizaremos un paseo histórico a lo que ha sido la resolución de ecuaciones polinómicas y en general el desarrollo del álgebra. La intención es presentar una síntesis de algunos de las dificultades que se enfrentaron a lo largo de la historia, en la construcción de los significados y conceptos matemáticos, referidos principalmente a la resolución de ecuaciones polinómicas y al desarrollo del álgebra abstracta. Creemos que el conocimiento de estas nos brinda información importante acerca de l...

  9. Convergencia y análisis numérico de un método de tercer orden para sistemas de ecuaciones no lineales

    OpenAIRE

    Amat Plata, Sergio; Bermúdez Edo, María Concepción; Busquier Sáez, Sonia; Manzano García, Fernando

    2007-01-01

    A lo largo de la Historia la resolución de ecuaciones no lineales ha preocupado a gran cantidad de científicos. Hoy en día, con los adelantos tecnológicos, estas ecuaciones son aproximadas de forma eficiente por medio de métodos iterativos. La idea es generar una sucesión de aproximaciones x0, x1, x2, ... que bajo ciertas condiciones converge a la raíz deseada. En este trabajo, presentamos una extensión a espacios de Banach de un método de tercer orden recientemente presentado en el cas...

  10. Editor de ecuaciones para la plataforma de simulación de sistemas biológicos

    Directory of Open Access Journals (Sweden)

    Gilberto Arias Naranjo

    2011-10-01

    Full Text Available El surgimiento de la Biología de Sistemas introdujo el uso de herramientas computacionales en el estudio y modelación de sistemas biológicos. Una de estas herramientas es la plataforma de simulación de sistemas biológicos BioSyS, la cual realiza exploraciones intensivas en modelos de sistemas biológicos y permite realizar meta análisis sobre los resultados que estas exploraciones arrojan. En este trabajo se presenta un software que se integra a la plataforma BioSyS y permite la edición de sistemas de ecuaciones a través de una interfaz amigable que representa las expresiones mediante una notación simbólica. La herramienta cuenta además con una biblioteca de expresiones dando la posibilidad al usuario de conservar los fragmentos de fórmulas que más utiliza, exporta a diferentes formatos, incluido el estándar de representación matemática MathML y brinda mecanismos para analizar la homogeneidad dimensional de las ecuaciones escritas ayudando así a los investigadores en la revisión de las mismas.

  11. 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.

  12. A theoretical model for the Lorentz force particle analyzer

    Science.gov (United States)

    Moreau, René; Tao, Zhen; Wang, Xiaodong

    2016-07-01

    In a previous paper [X. Wang et al., J. Appl. Phys. 120, 014903 (2016)], several experimental devices have been presented, which demonstrate the efficiency of electromagnetic techniques for detecting and sizing electrically insulating particles entrained in the flow of a molten metal. In each case, a non-uniform magnetic field is applied across the flow of the electrically conducting liquid, thereby generating a braking Lorentz force on this moving medium and a reaction force on the magnet, which tends to be entrained in the flow direction. The purpose of this letter is to derive scaling laws for this Lorentz force from an elementary theoretical model. For simplicity, as in the experiments, the flowing liquid is modeled as a solid body moving with a uniform velocity U. The eddy currents in the moving domain are derived from the classic induction equation and Ohm's law, and expressions for the Lorentz force density j ×B and for its integral over the entire moving domain follow. The insulating particles that are eventually present and entrained with this body are then treated as small disturbances in a classic perturbation analysis, thereby leading to scaling laws for the pulses they generate in the Lorentz force. The purpose of this letter is both to illustrate the eddy currents without and with insulating particles in the electrically conducting liquid and to derive a key relation between the pulses in the Lorentz force and the main parameters (particle volume and dimensions of the region subjected to the magnetic field).

  13. Attitude dynamics and control of spacecraft using geomagnetic Lorentz force

    Science.gov (United States)

    Abdel-Aziz, Yehia A.; Shoaib, Muhammad

    2015-01-01

    Attitude stabilization of a charged rigid spacecraft in Low Earth Orbit using torques due to Lorentz force in pitch and roll directions is considered. A spacecraft that generates an electrostatic charge on its surface in the Earth's magnetic field will be subject to perturbations from the Lorentz force. The Lorentz force acting on an electrostatically charged spacecraft may provide a useful thrust for controlling a spacecraft's orientation. We assume that the spacecraft is moving in the Earth's magnetic field in an elliptical orbit under the effects of gravitational, geomagnetic and Lorentz torques. The magnetic field of the Earth is modeled as a non-tilted dipole. A model incorporating all Lorentz torques as a function of orbital elements has been developed on the basis of electric and magnetic fields. The stability of the spacecraft orientation is investigated both analytically and numerically. The existence and stability of equilibrium positions is investigated for different values of the charge to mass ratio (α*). Stable orbits are identified for various values of α*. The main parameters for stabilization of the spacecraft are α* and the difference between the components of the moment of inertia for the spacecraft.

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

    Indian Academy of Sciences (India)

    Xinwu Cao; Bo Chai; Ming Zhou; Minfeng Gu

    2014-09-01

    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 between the bulk Lorentz factor and the Eddington ratio. Recent investigations suggested that the most super-massive black holes in elliptical galaxies have on average higher spins than the black holes in spiral galaxies. The correlation between black hole mass and bulk Lorentz factor of the jet components found in this work implies that the motion velocity of the jet components is probably governed by the black hole spin. The faster moving jets are magnetically accelerated by the magnetic fields threading the horizon of more rapidly rotating black holes.

  15. On the origin of neutrino oscillations through Lorentz violation

    Science.gov (United States)

    Leite, Julio

    2015-07-01

    The possibility of generating neutrino masses and oscillations through Lorentz- violating models is investigated. In the first model, an interaction between a fermion doublet and a Lorentz-violating gauge field, which play the role of a regulator field and, eventually, decouples from the fermions, is considered. In this case, by solving the (non-perturbative) Schwinger-Dyson equation, we show how masses and oscillations are generated dynamically. In the second model, fermions with LV kinematics interact via a four-fermion interaction and masses are shown to be generated dynamically when using another non-perturbative method. In both models, the recovery of Lorentz invariance is discussed and it is shown that the only physical observables are the dynamical masses that lead to neutrino oscillations.

  16. Spontaneous breaking of Lorentz symmetry for canonical gravity

    CERN Document Server

    Gielen, Steffen

    2012-01-01

    In the Ashtekar-Barbero formulation of canonical general relativity based on an SU(2) connection, Lorentz covariance is a subtle issue which has been the focus of some debate. Here we present a Lorentz covariant formulation generalising the notion of a foliation of spacetime to a field of local observers which specify a time direction only locally. This field spontaneously breaks the local SO(3,1) symmetry down to a subgroup SO(3); we show that the apparent symmetry breaking to SO(3) is not in conflict with Lorentz covariance. We give a geometric picture of our construction as Cartan geometrodynamics and outline further applications of the formalism of local observers, motivating the idea that observer space, instead of spacetime, should serve as the fundamental arena for gravitational physics.

  17. Restrictions from Lorentz invariance violation on cosmic ray propagation

    Science.gov (United States)

    Martínez-Huerta, H.; Pérez-Lorenzana, A.

    2017-03-01

    Lorentz invariance violation introduced as a generic modification to particle dispersion relations is used to study high energy cosmic ray attenuation processes. It is shown to reproduce the same physical effects for vacuum Cherenkov radiation, as in some particular models with spontaneous breaking of Lorentz symmetry. This approximation is also implemented for the study of photon decay in vacuum, where stringent limits to the violation scale are derived from the direct observation of very high energy cosmic ray photon events on gamma telescopes. Photo production processes by cosmic ray primaries on photon background are also addressed, to show that Lorentz violation may turn off this attenuation process at energies above a well-defined secondary threshold.

  18. Spontaneous Breaking of Lorentz Symmetry with an antisymmetric tensor

    CERN Document Server

    Hernaski, Carlos A

    2016-01-01

    Spontaneous violation of Lorentz symmetry by the vacuum condensation of an antisymmetric $2$-tensor is considered. The coset construction for nonlinear realization of spacetime symmetries is employed to build the most general low-energy effective action for the Goldstone modes interacting with photons. We analyze the model within the context of the Standard-Model Extension and noncommutative QED. Experimental bounds for some parameters of the model are discussed, and we readdress the subtle issues of stability and causality in Lorentz non-invariant scenarios. Besides the two photon polarizations, just one Goldstone mode must be dynamical to set a sensible low-energy effective model, and the enhancement of the stability by accounting interaction terms points to a protection against observational Lorentz violation.

  19. Constraints on Lorentz violation from gravitational Čerenkov radiation

    Directory of Open Access Journals (Sweden)

    V. Alan Kostelecký

    2015-10-01

    Full Text Available Limits on gravitational Čerenkov radiation by cosmic rays are obtained and used to constrain coefficients for Lorentz violation in the gravity sector associated with operators of even mass dimensions, including orientation-dependent effects. We use existing data from cosmic-ray telescopes to obtain conservative two-sided constraints on 80 distinct Lorentz-violating operators of dimensions four, six, and eight, along with conservative one-sided constraints on three others. Existing limits on the nine minimal operators at dimension four are improved by factors of up to a billion, while 74 of our explicit limits represent stringent first constraints on nonminimal operators. Prospects are discussed for future analyses incorporating effects of Lorentz violation in the matter sector, the role of gravitational Čerenkov radiation by high-energy photons, data from gravitational-wave observatories, the tired-light effect, and electromagnetic Čerenkov radiation by gravitons.

  20. Constraints on Lorentz violation from gravitational Cherenkov radiation

    CERN Document Server

    Kostelecky, Alan

    2015-01-01

    Limits on gravitational Cherenkov radiation by cosmic rays are obtained and used to constrain coefficients for Lorentz violation in the gravity sector associated with operators of even mass dimensions, including orientation-dependent effects. We use existing data from cosmic-ray telescopes to obtain conservative two-sided constraints on 80 distinct Lorentz-violating operators of dimensions four, six, and eight, along with conservative one-sided constraints on three others. Existing limits on the nine minimal operators at dimension four are improved by factors of up to a billion, while 74 of our explicit limits represent stringent first constraints on nonminimal operators. Prospects are discussed for future analyses incorporating effects of Lorentz violation in the matter sector, the role of gravitational Cherenkov radiation by high-energy photons, data from gravitational-wave observatories, the tired-light effect, and electromagnetic Cherenkov radiation by gravitons.

  1. Dynamical ambiguities in models with spontaneous Lorentz violation

    CERN Document Server

    Bonder, Yuri

    2016-01-01

    Spontaneous Lorentz violation is a viable mechanism to look for Planck scale physics. In this work, we study spontaneous Lorentz violation models, in flat spacetime, where a vector field produces such a violation and matter is modeled by a complex scalar field. We show that it is possible to construct a Hamilton density for which the evolution respects the dynamical constraints. However, we also find that the initial data, as required by standard field theory, does not determine the fields evolution in a unique way. In addition, we present some examples where the physical effects of such ambiguities can be recognized. As a consequence, the proposals in which the electromagnetic and gravitational interactions emerge from spontaneous Lorentz violation are challenged.

  2. Lorentz symmetry breaking as a quantum field theory regulator

    CERN Document Server

    Visser, Matt

    2009-01-01

    Perturbative expansions of relativistic quantum field theories typically contain ultraviolet divergences requiring regularization and renormalization. Many different regularization techniques have been developed over the years, but most regularizations require severe mutilation of the logical foundations of the theory. In contrast, breaking Lorentz invariance, while it is certainly a radical step, at least does not damage the logical foundations of the theory. We shall explore the features of a Lorentz symmetry breaking regulator in a simple polynomial scalar field theory, and discuss its implications. We shall quantify just "how much" Lorentz symmetry breaking is required to fully regulate the theory and render it finite. This scalar field theory provides a simple way of understanding many of the key features of Horava's recent article [arXiv:0901.3775 [hep-th

  3. Testing Lorentz Symmetry with the Double Chooz Eexperiment

    CERN Document Server

    Katori, Teppei

    2013-01-01

    The Double Chooz reactor-based oscillation experiment searches for an electron antineutrino disappearance signal to investigate the neutrino mass matrix mixing angle theta 13. Double Chooz's reported evidence for this disappearance is generally interpreted as mass-driven mixing through this parameter. However, the electron antineutrino candidates collected by the experiment can also be used to search for a signature of the violation of Lorentz invariance. We study the sidereal time dependence of the antineutrino signal rate and probe Lorentz violation within the Standard-Model Extension (SME) framework. We find that the data prefer the sidereal time independent solution, and a number of limits are applied to the relevant SME coefficients, including the first constraints on those associated with Lorentz violation in the e-tau mixing sector.

  4. Concurrent tests of Lorentz invariance in $\\beta$-decay experiments

    CERN Document Server

    Vos, K K; Timmermans, R G E

    2015-01-01

    Modern experiments on neutron and allowed nuclear $\\beta$ decay search for new semileptonic interactions, beyond the ``left-handed'' electroweak force. We show that ongoing and planned $\\beta$-decay experiments, with isotopes at rest and in flight, can be exploited as sensitive tests of Lorentz invariance. The variety of correlations that involve the nuclear spin, the direction of the emitted $\\beta$ particle, and the recoil direction of the daughter nucleus allow for relatively simple experiments that give direct bounds on Lorentz violation. The pertinent observables are decay-rate asymmetries and their dependence on sidereal time. We discuss the potential of several asymmetries that together cover a large part of the parameter space for Lorentz violation in the gauge sector. High counting statistics is required.

  5. Ecuaciones diferenciales ordinarias y sus aplicaciones a la Ingeniería Civil

    OpenAIRE

    Calixto Molina, Manuel

    2010-01-01

    Libro que consta de dos partes una teórica y otra practica, donde se discuten los problemas de valores iniciales, como vibraciones mecánicas y eléctricas. Problemas de valores en la frontera como flexión y pandeo en vigas. También se discute un modelo matemático y las causas subyacentes al derrumbe del puente colgante "Tacoma Narrows"

  6. Lorentz Violation in Deep Inelastic Electron-Proton Scattering

    CERN Document Server

    Lunghi, Enrico

    2016-01-01

    Lorentz violation in the quark sector induces a sidereal time dependence in electron-proton, proton-antiproton and proton-proton cross sections. At high energies nonperturbative effects are buried in universal nucleon parton distribution functions and Lorentz violating effects are calculable in perturbation theory. We focus on deep inelastic electron-proton scattering data collected from ZEUS and H1 at HERA and show that a sideral time analysis of these events is able to set strong constraints on most of the coefficients we consider.

  7. Spacetime Variation of Lorentz-Violation Coefficients at Nonrelativistic Scale

    CERN Document Server

    Lane, Charles D

    2016-01-01

    The notion of uniform and/or constant tensor fields of rank $>0$ is incompatible with general curved spacetimes. This work considers the consequences of certain tensor-valued coefficients for Lorentz violation in the Standard-Model Extension varying with spacetime position. We focus on two of the coefficients, $a_\\mu$ and $b_\\mu$, that characterize Lorentz violation in massive fermions, particularly in those fermions that constitute ordinary matter. We calculate the nonrelativistic hamiltonian describing these effects, and use it to extract the sensitivity of several precision experiments to coefficient variation.

  8. Search for Lorentz Violation in km$^3$-Scale Neutrino Telescopes

    CERN Document Server

    Argüelles, C A; Conrad, J M; Katori, T; Kheirandish, A

    2016-01-01

    Kilometer$^3$-scale neutrino detectors such as IceCube, ANTARES, and the proposed Km3Net neutrino observatory in the Mediterranean have measured, and will continue to characterize, the atmospheric neutrino spectrum above 1 TeV. Such precise measurements enable us to probe new neutrino physics, in particular, those that arise from Lorentz violation. In this paper, we first relate the effective new physics hamiltonian terms with the Lorentz violating literature. Second, we calculate the oscillation probability formulas for the two-level $\

  9. Lorentz violation in brane cosmology, accelerated expansion and fundamental constants

    CERN Document Server

    Ahmadi, F; Sepangi, H R

    2006-01-01

    The notion of Lorentz violation in four dimensions is extended to a 5-dimensional brane-world scenario by utilizing a dynamical vector field assumed to point in the bulk direction, with Lorentz invariance holding on the brane. The cosmological consequences of this theory consisting of the time variation in the gravitational coupling $G$ and cosmological term $\\Lambda_4$ are explored. The brane evolution is addressed by studying the generalized Friedmann and Raychaudhuri equations. The behavior of the expansion scale factor is then considered for different possible scenarios where the bulk cosmological constant is zero, positive or negative.

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

    CERN Document Server

    Lehnert, Ralf

    2016-01-01

    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.

  11. How is Lorentz invariance encoded in the Hamiltonian?

    Science.gov (United States)

    Kajuri, Nirmalya

    2016-07-01

    One of the disadvantages of the Hamiltonian formulation is that Lorentz invariance is not manifest in the former. Given a Hamiltonian, there is no simple way to check whether it is relativistic or not. One would either have to solve for the equations of motion or calculate the Poisson brackets of the Noether charges to perform such a check. In this paper we show that, for a class of Hamiltonians, it is possible to check Lorentz invariance directly from the Hamiltonian. Our work is particularly useful for theories where the other methods may not be readily available.

  12. How is Lorentz Invariance encoded in the Hamiltonian?

    CERN Document Server

    Kajuri, Nirmalya

    2016-01-01

    One of the disadvantages of the Hamiltonian formulation is that Lorentz invariance is not manifest in the former. Given a Hamiltonian, there is no simple way to check whether it is relativistic or not. One would either have to solve for the equations of motion or calculate the Poisson Brackets of the Noether charges to perform such a check. In this paper we show that, for a class of Hamiltonians, it is possible to check Lorentz invariance directly from the Hamiltonian. Our work is particularly useful for theories where the other methods may not be readily available.

  13. Limits on violations of Lorentz Symmetry from Gravity Probe B

    CERN Document Server

    Bailey, Quentin G; Overduin, James M

    2013-01-01

    Generic violations of Lorentz symmetry can be described by an effective field theory framework that contains both general relativity and the standard model of particle physics called the Standard-Model Extension (SME). We obtain new constraints on the gravitational sector of the SME using recently published final results from Gravity Probe B. These include for the first time an upper limit at the 10^(-3) level on the time-time component of the new tensor field responsible for inducing local Lorentz violation in the theory, and an independent limit at the 10^(-7) level on a combination of components of this tensor field.

  14. Lorentz-to-Gauss multiplication (LGM) in FT NMR

    Energy Technology Data Exchange (ETDEWEB)

    Makhiyanov, N. [Production Association ``Nizhnekamskneftekhym``, Nizhnekamsk, Tatarstan (Russian Federation); Kupka, T. [Uniwersytet Slaski, Katowice (Poland)]|[Zaklad Fizyki Ciala Stalego, Polska Akademia Nauk, Zabrze (Poland); Pasterna, G. [Institute of Nuclear Physics, Cracow (Poland); Dziegielewski, J.O. [Uniwersytet Slaski, Katowice (Poland)

    1994-12-31

    High resolution proton and carbon NMR spectra of macromolecules and biomolecules are often overcrowded and with many partly overlapped signals. Several data processing methods to resolve partly overlapped NMR peaks have been reported. Among the Lorentz-to-Gauss and CDRE (Convulsion Difference Resolution Enhancement) methods are wide used. In this work calculation of the best set of parameters were carried out from a raw spectral data (initial FID and the corresponding untreated spectrum) and a method of prediction of optimal Lorentz-to-Gauss method parameters are suggested. The feasibility of this approach to improve the quality of NMR spectra from various resonating nuclei was shown too. 8 refs, 1 fig.

  15. 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.)

  16. Signals for Lorentz and CPT Violation in Atomic Spectroscopy Experiments and Other Systems

    CERN Document Server

    Vargas, Arnaldo J

    2016-01-01

    The prospects of studying nonminimal operators for Lorentz violation using spectroscopy experiments with light atoms and muon spin-precession experiments are presented. Possible improvements on bounds on minimal and nonminimal operators for Lorentz violation are discussed.

  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. Solución de sistemas acoplados de ecuaciones en diferencias de segundo orden sin aumentar la dimensión del problema

    OpenAIRE

    Navarro, E.; L. Jódar; Morera, José L.

    1992-01-01

    En este artículo se estudian condiciones de existencia de soluciones de problemas de contorno para sistemas acoplados de ecuaciones en diferencias de segundo orden. Condiciones de existencia y expresión explícita de la solución general del problema son dadas sin aumentar la dimensión del problema. Peer Reviewed

  19. Simetrías de Lie y soluciones exactas para ecuaciones de Schrödinger no lineales con no linealidad inhomogénea

    OpenAIRE

    Belmonte Beitia, Juan; Pérez García, Víctor Manuel; Vekslerchik, Vadym; Torres VIllarroya, Pedro José

    2007-01-01

    Usando teoría de grupos de Lie y transformaciones canónicas, construimos soluciones explícitas de ecuaciones de Schrödinger no lineales con no linealidad modulada en el espacio. Presentamos la teor´ıa general y apoyandonos en esta, estudiamos diferentes ejemplos, presentando soluciones explícitas.

  20. 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.

  1. Four easy routes to the Lorentz transformations: addendum to ‘Lorentz transformations and the wave equation’

    Science.gov (United States)

    Heras, Ricardo

    2017-01-01

    In this paper I briefly discuss and compare four easy derivations of the Lorentz transformations. Two of these derivations assume the invariance of the Minkowski spacetime interval in inertial frames and the other two assume the invariance of the d’Alembert operator in these frames. These derivations are suitable for a first view of special relativity. Finally, I discuss the comment made by Di Rocco on my original paper, ‘Lorentz transformations and the wave equation’ (2016 Eur. J. Phys. 37 025603).

  2. BPS Maxwell-Chern-Simons-like vortices in a Lorentz-violating framework

    CERN Document Server

    Casana, R; Da Hora, E; Neves, A B F

    2013-01-01

    We have analyzed Maxwell-Chern-Simons-Higgs BPS vortices in a Lorentz-violating CPT-odd context. The Lorentz violation induces profiles with a conical behavior at the origin. For some combination of the coefficients for Lorentz violation there always exists a sufficiently large winding number for which the magnetic field flips its sign.

  3. BPS Maxwell-Chern Vortices in a Lorentz-Violating Framework

    Science.gov (United States)

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

    2014-01-01

    We have analyzed Maxwell-Chern-Simons-Higgs BPS vortices in a Lorentz-violating CPT-odd context. The Lorentz violation induces profiles with a conical behavior at the origin. For some combination of the coefficients for Lorentz violation there always exists a sufficiently large winding number for which the magnetic field flips its sign.

  4. Lorentz covariant field theory on noncommutative spacetime based on DFR algebra

    CERN Document Server

    Okumura, Y

    2003-01-01

    Lorentz covariance is the fundamental principle of every relativistic field theory which insures consistent physical descriptions. Even if the space-time is noncommutative, field theories on it should keep Lorentz covariance. In this letter, it is shown that the field theory on noncommutative spacetime is Lorentz covariant if the noncommutativity emerges from the algebra of spacetime operators described by Doplicher, Fredenhagen and Roberts.

  5. Lorentz space estimates for the Coulombian renormalized energy

    CERN Document Server

    Serfaty, Sylvia

    2011-01-01

    In this paper we obtain optimal estimates for the "currents" associated to point masses in the plane, in terms of the Coulombian renormalized energy of Sandier-Serfaty \\cite{ss1,ss3}. To derive the estimates, we use a technique that we introduced in \\cite{st}, which couples the "ball construction method" to estimates in the Lorentz space $L^{2,\\infty}$.

  6. 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.

  7. 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

  8. Lorentz invariance and the semiclassical approximation of loop quantum gravity

    Energy Technology Data Exchange (ETDEWEB)

    Kozameh, Carlos N; Parisi, Florencia [Facultad de Matematica, AstronomIa y FIsica, Universidad Nacional de Cordoba, Ciudad Universitaria (5000) Cordoba (Argentina)

    2004-06-07

    It is shown that the field equations derived from an effective interaction Hamiltonian for Maxwell and gravitational fields in the semiclassical approximation of loop quantum gravity using rotational invariant states (such as weave states) are Lorentz invariant. To derive this result, which is in agreement with the observational evidence, we use the geometrical properties of the electromagnetic field.

  9. Time correlation functions for the one-dimensional Lorentz gas

    NARCIS (Netherlands)

    Mazo, R.M.; Beijeren, H. van

    1983-01-01

    The velocity autocorrelation function and related quantities are investigated for the one-dimensional deterministic Lorentz gas, consisting of randomly distributed fixed scatterers and light particles moving back and forth between two of these at a constant given speed. An expansion for the velocity

  10. The generators of Lorentz transformation in momentum space

    Institute of Scientific and Technical Information of China (English)

    张鹏飞; 阮图南

    2002-01-01

    In the momentum space, the angular momentum operator and the boost vector operator,i.e. the generators for the Lorentz transformation of a particle with arbitrary spin and nonzero mass are discussed. Some new expressions are obtained in terms of the orbital and spin parts.``

  11. Spontaneous Lorentz violation: the case of infrared QED

    Energy Technology Data Exchange (ETDEWEB)

    Balachandran, A. P., E-mail: bal@phy.syr.edu [Physics Department, Syracuse University, 13244-1130, Syracuse, NY (United States); Kürkçüoǧlu, S., E-mail: kseckin@metu.edu.tr [Department of Physics, Middle East Technical University, 06800, Ankara (Turkey); Queiroz, A. R. de, E-mail: amilcarq@unb.br [Instituto de Física, Universidade de Brasília, Caixa Postal 04455, 70919-970, Brasília, DF (Brazil); Departamento de Física Teórica, Facultad de Ciencias, Universidad de Zaragoza, 50009, Zaragoza (Spain); Vaidya, S., E-mail: vaidya@cts.iisc.ernet.in [Centre for High Energy Physics, Indian Institute of Science, 560012, Bangalore (India)

    2015-02-24

    It is by now clear that the infrared sector of quantum electrodynamics (QED) has an intriguingly complex structure. Based on earlier pioneering work on this subject, two of us recently proposed a simple modification of QED by constructing a generalization of the U(1) charge group of QED to the “Sky” group incorporating the well-known spontaneous Lorentz violation due to infrared photons, but still compatible in particular with locality (Balachandran and Vaidya, Eur Phys J Plus 128:118, 2013). It was shown that the “Sky” group is generated by the algebra of angle-dependent charges and a study of its superselection sectors has revealed a manifest description of spontaneous breaking of the Lorentz symmetry. We further elaborate this approach here and investigate in some detail the properties of charged particles dressed by the infrared photons. We find that Lorentz violation due to soft photons may be manifestly codified in an angle-dependent fermion mass, modifying therefore the fermion dispersion relations. The fact that the masses of the charged particles are not Lorentz invariant affects their spin content, and time dilation formulas for decays should also get corrections.

  12. Spontaneous Lorentz violation: the case of infrared QED

    Energy Technology Data Exchange (ETDEWEB)

    Balachandran, A.P. [Syracuse University, Physics Department, Syracuse, NY (United States); Kuerkcueoglu, S. [Middle East Technical University, Department of Physics, Ankara (Turkey); Queiroz, A.R. de [Universidade de Brasilia, Instituto de Fisica, Brasilia (Brazil); Universidad de Zaragoza, Departamento de Fisica Teorica, Facultad de Ciencias, Zaragoza (Spain); Vaidya, S. [Indian Institute of Science, Centre for High Energy Physics, Bangalore (India)

    2015-02-01

    It is by now clear that the infrared sector of quantum electrodynamics (QED) has an intriguingly complex structure. Based on earlier pioneering work on this subject, two of us recently proposed a simple modification of QED by constructing a generalization of the U(1) charge group of QED to the ''Sky'' group incorporating the well-known spontaneous Lorentz violation due to infrared photons, but still compatible in particular with locality (Balachandran and Vaidya, Eur Phys J Plus 128:118, 2013). It was shown that the ''Sky'' group is generated by the algebra of angle-dependent charges and a study of its superselection sectors has revealed a manifest description of spontaneous breaking of the Lorentz symmetry. We further elaborate this approach here and investigate in some detail the properties of charged particles dressed by the infrared photons. We find that Lorentz violation due to soft photons may be manifestly codified in an angle-dependent fermion mass, modifying therefore the fermion dispersion relations. The fact that the masses of the charged particles are not Lorentz invariant affects their spin content, and time dilation formulas for decays should also get corrections. (orig.)

  13. Kink shape solutions of the Maxwell-Lorentz system

    DEFF Research Database (Denmark)

    Sørensen, Mads Peter; Webb, G.M.; Brio, M.

    2005-01-01

    In the limit of high amplitude oscillating electromagnetic fields, a sequence of kink antikink shaped optical waves has been found in the Maxwell's equations coupled to a single Lorentz oscillator and with Kerr nonlinearity. The individual kinks and antikinks result from a traveling wave assumpti...

  14. Constraints on torsion from bounds on lorentz violation.

    Science.gov (United States)

    Kostelecký, V Alan; Russell, Neil; Tasson, Jay D

    2008-03-21

    Exceptional sensitivity to space-time torsion can be achieved by searching for its couplings to fermions. Recent experimental searches for Lorentz violation are exploited to extract new constraints involving 19 of the 24 independent torsion components down to levels of order 10(-31) GeV.

  15. Constraints on nonmetricity from bounds on Lorentz violation

    Science.gov (United States)

    Foster, Joshua; Kostelecký, V. Alan; Xu, Rui

    2017-04-01

    Spacetime nonmetricity can be studied experimentally through its couplings to fermions and photons. We use recent high-precision searches for Lorentz violation to deduce first constraints involving the 40 independent nonmetricity components down to levels of order 10-43 GeV .

  16. Limits on Lorentz violation in neutral-Kaon decay

    NARCIS (Netherlands)

    Vos, K.K.; Wilschut, H. W.; Timmermans, R. G. E.

    2013-01-01

    The KLOE collaboration recently reported bounds on the directional dependence of the lifetime of the short-lived neutral kaon K_S with respect to the cosmic microwave background dipole anisotropy. We interpret their results in a general framework developed to probe Lorentz violation in the weak

  17. 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.

  18. Acoustic Tests of Lorentz Symmetry Using Quartz Oscillators

    Directory of Open Access Journals (Sweden)

    Anthony Lo

    2016-02-01

    Full Text Available We propose and demonstrate a test of Lorentz symmetry based on new, compact, and reliable quartz oscillator technology. Violations of Lorentz invariance in the matter and photon sector of the standard model extension generate anisotropies in particles’ inertial masses and the elastic constants of solids, giving rise to measurable anisotropies in the resonance frequencies of acoustic modes in solids. A first realization of such a “phonon-sector” test of Lorentz symmetry using room-temperature stress-compensated-cut crystals yields 120 h of data at a frequency resolution of 2.4×10^{−15} and a limit of c[over ˜]_{Q}^{n}=(−1.8±2.2×10^{−14}  GeV on the most weakly constrained neutron-sector c coefficient of the standard model extension. Future experiments with cryogenic oscillators promise significant improvements in accuracy, opening up the potential for improved limits on Lorentz violation in the neutron, proton, electron, and photon sector.

  19. Limits on Lorentz Violation from Forbidden beta Decays

    NARCIS (Netherlands)

    Noordmans, J.P.; Wilschut, H.W.; Timmermans, R.G.E.

    2013-01-01

    Forbidden (slow) beta decays offer new opportunities to test the invariance of the weak interaction under Lorentz transformations. Within a general effective field theory framework we analyze and reinterpret the only two relevant experiments, performed in the 1970s, dedicated to search for a

  20. Lorentz-violating effects in three-dimensional QED

    Science.gov (United States)

    Bufalo, R.

    2014-08-01

    Inspired in discussions presented lately regarding Lorentz-violating interaction terms in B. Charneski, M. Gomes, R. V. Maluf and A. J. da Silva, Phys. Rev. D86, 045003 (2012); R. Casana, M. M. Ferreira Jr., R. V. Maluf and F. E. P. dos Santos, Phys. Lett. B726, 815 (2013); R. Casana, M. M. Ferreira Jr., E. Passos, F. E. P. dos Santos and E. O. Silva, Phys. Rev. D87, 047701 (2013), we propose here a slightly different version for the coupling term. We will consider a modified quantum electrodynamics with violation of Lorentz symmetry defined in a (2+1)-dimensional space-time. We define the Lagrangian density with a Lorentz-violating interaction, where the space-time dimensionality is explicitly taken into account in its definition. The work encompasses an analysis of this model at both zero and finite-temperature, where very interesting features are known to occur due to the space-time dimensionality. With that in mind, we expect that the space-time dimensionality may provide new insights about the radiative generation of higher-derivative terms into the action, implying in a new Lorentz-violating electrodynamics, as well the nonminimal coupling may provide interesting implications on the thermodynamical quantities.

  1. 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.

  2. Path Integrals and Lorentz Violation in Polymer Quantized Scalar Fields

    CERN Document Server

    Kajuri, Nirmalya

    2014-01-01

    We obtain a path integral formulation of polymer quantized scalar field theory, starting from the Hilbert Space framework. This brings the polymer quantized scalar field theory under the ambit of Feynman diagrammatic techniques. The path integral formulation also shows that Lorentz invariance is lost for the Klein-Gordon field.

  3. 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…

  4. Generalization of the Lorentz-Dirac equation to include spin

    Science.gov (United States)

    Barut, A. O.; Unal, Nuri

    1989-11-01

    For the classical point electron with Zitterbewegung (hence spin) we derive, after regularization, the radiation reaction force and covariant equations for the dynamical variables (xμ, πμ, vμ, and Sμν), which reduce to the Lorentz-Dirac equation in the spinless limit.

  5. 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…

  6. On the conformal geometry of transverse Riemann Lorentz manifolds

    Science.gov (United States)

    Aguirre, E.; Fernández, V.; Lafuente, J.

    2007-06-01

    Physical reasons suggested in [J.B. Hartle, S.W. Hawking, Wave function of the universe, Phys. Rev. D41 (1990) 1815-1834] for the Quantum Gravity Problem lead us to study type-changing metrics on a manifold. The most interesting cases are Transverse Riemann-Lorentz Manifolds. Here we study the conformal geometry of such manifolds.

  7. Intrinsic Geometry of Curves and the Lorentz Equation

    Science.gov (United States)

    Caltenco, J. H.; Linares, R. M. Y.; López-Bonilla, J. L.

    2002-07-01

    We show that the trajectory of a point charge in a uniform electromagnetic field is a helix if the Lorentz equation governs its motion. Our approach is totally relativistic, and it is based on the use of the Frenet-Serret formulae which describe the intrinsic geometry of world lines in Minkowski spacetime.

  8. High-Energy Nuclear Physics with Lorentz Symmetry Violation

    CERN Document Server

    González-Mestres, L

    1997-01-01

    If textbook Lorentz invariance is actually a property of the equations describing a sector of the excitations of vacuum above some critical distance scale, several sectors of matter with different critical speeds in vacuum can coexist and an absolute rest frame (the vacuum rest frame) may exist without contradicting the apparent Lorentz invariance felt by "ordinary" particles (particles with critical speed in vacuum equal to $c$ , the speed of light). Sectorial Lorentz invariance, reflected by the fact that all particles of a given dynamical sector have the same critical speed in vacuum, will then be an expression of a fundamental sectorial symmetry (e.g. preonic grand unification or extended supersymmetry) protecting a parameter of the equations of motion. Furthermore, the sectorial Lorentz symmetry may be only a low-energy limit, in the same way as the relation $\\omega $ (frequency) = $c_s$ (speed of sound) $k$ (wave vector) holds for low-energy phonons in a crystal. In this context, phenomena such as the a...

  9. Spacetime Variation of Lorentz-Violation Coefficients at Nonrelativistic Scale

    CERN Document Server

    Lane, Charles D

    2016-01-01

    When the Standard-Model Extension (SME) is applied in curved spacetime, the Lorentz-violation coefficients must depend on spacetime position. This work describes some of the consequences of this spacetime variation. We focus on effects that appear at a nonrelativistic scale and extract sensitivity of completed experiments to derivatives of SME coefficient fields.

  10. 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

  11. Lorentz force sigmometry: A contactless method for electrical conductivity measurements

    Science.gov (United States)

    Uhlig, Robert P.; Zec, Mladen; Ziolkowski, Marek; Brauer, Hartmut; Thess, André

    2012-05-01

    The present communication reports a new technique for the contactless measurement of the specific electrical conductivity of a solid body or an electrically conducting fluid. We term the technique "Lorentz force sigmometry" where the neologism "sigmometry" is derived from the Greek letter sigma, often used to denote the electrical conductivity. Lorentz force sigmometry (LoFoS) is based on similar principles as the traditional eddy current testing but allows a larger penetration depth and is less sensitive to variations in the distance between the sensor and the sample. We formulate the theory of LoFoS and compute the calibration function which is necessary for determining the unknown electrical conductivity from measurements of the Lorentz force. We conduct a series of experiments which demonstrate that the measured Lorentz forces are in excellent agreement with the numerical predictions. Applying this technique to an aluminum sample with a known electrical conductivity of σAl=20.4MS/m and to a copper sample with σCu=57.92MS/m we obtain σAl=21.59MS/m and σCu=60.08MS/m, respectively. This demonstrates that LoFoS is a convenient and accurate technique that may find application in process control and thermo-physical property measurements for solid and liquid conductors.

  12. Ecuaciones cuadráticas y procedimientos algorítmicos. Diofanto y las matemáticas en Mesopotamia

    Directory of Open Access Journals (Sweden)

    Piedad Yuste

    2009-11-01

    Full Text Available En este ensayo presento un análisis comparativo entre los diversos procedimientos creados, respectivamente, por los matemáticos babilonios y Diofanto de Alejandría para resolver ecuaciones de segundo grado. Observaremos cómo los primeros recurrieron a la composición de diagramas mientras Diofanto aplicó un algoritmo abstracto que no consiguió generalizar.In this paper I present a comparative analysis among the diverse procedures invented respectively by the Babylonian mathematicians and Diophantus of Alexandria to solve quadratic equations. We will observe how the first ones appealed to the composition of diagrams while Diophantus applied an abstract algorithm that he was not able to generalize.

  13. 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.

  14. Average intensity and spreading of a Lorentz-Gauss beam in turbulent atmosphere.

    Science.gov (United States)

    Zhou, Guoquan; Chu, Xiuxiang

    2010-01-18

    The propagation of a Lorentz-Gauss beam in turbulent atmosphere is investigated. Based on the extended Huygens-Fresnel integral and the Hermite-Gaussian expansion of a Lorentz function, analytical formulae for the average intensity and the effective beam size of a Lorentz-Gauss beam are derived in turbulent atmosphere. The average intensity distribution and the spreading properties of a Lorentz-Gauss beam in turbulent atmosphere are numerically demonstrated. The influences of the beam parameters and the structure constant of the atmospheric turbulence on the propagation of a Lorentz-Gauss beam in turbulent atmosphere are also discussed in detail.

  15. 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.

  16. Predicción de ecuaciones para el porcentaje de grasa a partir de circunferencias corporales en niños pre-púberes

    Directory of Open Access Journals (Sweden)

    Rossana Gómez Campos

    2013-06-01

    Full Text Available Introducción: El análisis de la composición corporal a través de métodos directos e indirectos permite el estudio de los distintos componentes del cuerpo humano, constituyéndose en el eje central para valorar el estado nutricional. Objetivo: Desarrollar ecuaciones de predicción del % de grasa corporal a partir de circunferenciales corporales del brazo, cintura y pantorrilla y proponer percentiles para diagnosticar el estado nutricional de niños escolares de ambos sexos de 4-10 años. Métodos: Fueron seleccionados de forma intencional (no-probabilística 515 niños, siendo 261 niños y 254 niñas pertenecientes al Programa de interacción y desarrollo del niño y del adolescente de la Universidad Estatal de Campinas (Sao Paulo, Brasil. Se evaluó las variables antropométricas de peso, estatura, pliegues cutáneos tricipital y subescapular y las circunferencias corporales del brazo, cintura y pantorrilla. Se determino el % de grasa a través de la ecuación propuesta por Boileau, Lohman y Slaughter (1985. A través del método de regresión se generaron 2 ecuaciones para predecir el porcentaje de grasa a partir de las circunferencias corporales; las ecuaciones 1 y 2 fueron validadas a través del método de validación cruzada. Resultados: Las ecuaciones obtenidas mostraron altos valores predictivos, oscilando con un R²= 64-69%. En la validación cruzada entre el criterio y las ecuaciones de regresión propuestas no hubo diferencias significativas (p < 0,05 y se observó un alto grado de concordancia a un CI 95%. Conclusión: Las ecuaciones son validadas y son una alternativa para evaluar el porcentaje de grasa en niños escolares de ambos sexos de 4-10 años del Programa de interacción y desarrollo del niño y del adolescente de la Universidad Es tatal de Campinas (Sao Paulo, Brasil.

  17. 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

  18. Influences of Lorentz force on the hydrofoil lift

    Institute of Scientific and Technical Information of China (English)

    Yaohui Chen; Baochun Fan; Zhihua Chen; Hongzhi Li

    2009-01-01

    In this paper, Lorentz forces are proved to be able to suppress separation in flows over hydrofoils. Further-more, a differential equation of pressure distributions on the hydrofoil surface is derived, from which it is found that BVF (boundary vortex flux) cr is a suitable criterion for describing the lift coefficient variations during the electromagnetic control process. According to our numerical results, the peri-odic variations of lift for a hydrofoil at an attack angle of 17 o are analyzed and its inherent mechanism is discussed in detail with the concept of BVE On the other hand, the effects of Lorentz force on the hydrofoil's lift are investigated both experimentally and numerically for different magnitudes and locations.

  19. Earth's Inner Core dynamics induced by the Lorentz force

    CERN Document Server

    Lasbleis, M; Cardin, P; Labrosse, S

    2015-01-01

    Seismic studies indicate that the Earth's inner core has a complex structure and exhibits a strong elastic anisotropy with a cylindrical symmetry. Among the various models which have been proposed to explain this anisotropy, one class of models considers the effect of the Lorentz force associated with the magnetic field diffused within the inner core. In this paper we extend previous studies and use analytical calculations and numerical simulations to predict the geometry and strength of the flow induced by the poloidal component of the Lorentz force in a neutrally or stably stratified growing inner core, exploring also the effect of different types of boundary conditions at the inner core boundary (ICB). Unlike previous studies, we show that the boundary condition that is most likely to produce a significant deformation and seismic anisotropy is impermeable, with negligible radial flow through the boundary. Exact analytical solutions are found in the case of a negligible effect of buoyancy forces in the inne...

  20. Manipulating the Lorentz force via the chirality of nanoparticles

    Science.gov (United States)

    Wang, Maoyan; Li, Hailong; Dong, Yuliang; Zhang, Xiaochuan; Du, Ming; Wang, Rui; Xu, Tong; Wu, Jian

    2016-12-01

    We demonstrate that a single plane wave pulls a chiral nanoparticle toward the light source. The nanoparticle exhibits optical gain in a particular wavelength region. The equivalence of the generalized and alternative expressions of the Lorentz force density relating to bound charges for chiral media is numerically validated. By considering the two-dimensional electromagnetic problem of incident plane waves normally impinged on active chiral cylinders, it is shown that the gradient force is mainly contributed by the bound electric and magnetic current densities of the cross-polarized waves. We also investigate how the medium parameters and impedance mismatch can be used to manipulate the pulling or pushing Lorentz forces between two chiral cylinders. This finding may provide a recipe to understand the light interaction with multiple chiral nanoparticles of arbitrary shapes (in general) with the aid of the numerical approach. It could be a promising avenue in controlling the optical micromanipulation for chiral nanoparticles with mirroring asymmetry.

  1. High Energy Astrophysics Tests of Lorentz Invariance Violation

    Science.gov (United States)

    Stecker, Floyd W.

    2004-01-01

    Observations of the multi-TeV spectra of the nearby BL Lac objects Mkn 421 and Mkn 501 exhibit the high energy cutoffs predicted to be the result of intergalactic annihilation interactions, primarily with IR photons having a flux level as determined by various astronomical observations. After correcting for such intergalactic absorption, these spectra can be explained within the framework of synchrotron self-Compton emission models. Stecker & Glashow have shown that the existence of this annihilation via electron-positron pair production puts strong constraints on Lorentz violation. We will show that such constraints have important implications for some quantum gravity models and large extra dimension models. We will also discuss the potentially important effects of a smaller Lorentz violation which is consistent with these constraints on the propagation and spectra of ultrahigh energy cosmic rays.

  2. Testing Lorentz invariance of dark matter with satellite galaxies

    Science.gov (United States)

    Bettoni, Dario; Nusser, Adi; Blas, Diego; Sibiryakov, Sergey

    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.

  3. Quantum gravity and Lorentz invariance violation in the standard model.

    Science.gov (United States)

    Alfaro, Jorge

    2005-06-10

    The most important problem of fundamental physics is the quantization of the gravitational field. A main difficulty is the lack of available experimental tests that discriminate among the theories proposed to quantize gravity. Recently, Lorentz invariance violation by quantum gravity (QG) has been the source of growing interest. However, the predictions depend on an ad hoc hypothesis and too many arbitrary parameters. Here we show that the standard model itself contains tiny Lorentz invariance violation terms coming from QG. All terms depend on one arbitrary parameter alpha that sets the scale of QG effects. This parameter can be estimated using data from the ultrahigh energy cosmic ray spectrum to be |alpha|< approximately 10(-22)-10(-23).

  4. Lorentz noninvariant oscillations of massless neutrinos are excluded

    CERN Document Server

    Barger, Vernon; Marfatia, Danny; Whisnant, Kerry

    2011-01-01

    The bicycle model of Lorentz noninvariant neutrino oscillations without neutrino masses naturally predicts maximal mixing and a 1/E dependence of the oscillation argument for muon-neutrino to tau-neutrino oscillations of atmospheric and long-baseline neutrinos, but cannot also simultaneously fit the data for solar neutrinos and KamLAND. We search for other possible structures of the effective Hamiltonian for Lorentz noninvariant oscillations of massless neutrinos that naturally have a 1/E dependence at high neutrino energy. Due to the lack of any evidence for direction dependence, we consider only direction-independent oscillations. Although we find a number of models with a 1/E dependence for atmospheric and long-baseline neutrinos, none can also simultaneously fit solar and KamLAND data.

  5. Sfermions and gauginos in a Lorentz-violating theory

    CERN Document Server

    Allen, R E; Allen, Roland E.; Yokoo, Seiichirou

    2005-01-01

    In Lorentz-violating supergravity, sfermions have spin 1/2 and other unusual properties. If the dark matter consists of such particles, there is a natural explanation for the apparent absence of cusps and other small scale structure: The Lorentz-violating dark matter is cold because of the large particle mass, but still moves at nearly the speed of light. Although the R-parity of a sfermion, gaugino, or gravitino is +1 in the present theory, these particles have an "S-parity'' which implies that the LSP is stable and that they are produced in pairs. On the other hand, they can be clearly distinguished from the superpartners of standard supersymmetry by their highly unconventional properties.

  6. Teleparallel equivalent of general relativity and local Lorentz transformation: Revisited

    CERN Document Server

    Nashed, Gamal G L

    2016-01-01

    It is well known that the field equations of teleparallel theory which is equivalent to general relativity (TEGR) completely agree with the field equation of general relativity (GR). However, TEGR has six extra degrees of freedom which spoil the true physics. These extra degrees are related to the local Lorentz transformation. In this study, we give three different tetrads of flat horizon space-time that depend only on the radial coordinate. One of these tetrads contains an arbitrary function which comes from local Lorentz transformation. We show by explicate calculations that this arbitrary function spoils the calculations of the conserved charges. We formulate {\\it a skew-symmetric tensor} whose vanishing value put a constraint on the arbitrary function. This constraint makes the conserved charges are free from the arbitrary function.

  7. Noncommutativity in (2+1)-dimensions and the Lorentz group

    CERN Document Server

    Falomir, H; Gamboa, J; Méndez, F; Loewe, M

    2012-01-01

    In this article we considered models of particles living in a three-dimensional space-time with a nonstandard noncommutativity induced by shifting canonical coordinates and momenta with generators of a unitary irreducible representation of the Lorentz group. The Hilbert space gets the structure of a direct product with the representation space, where we are able to construct operators which realize the algebra of Lorentz transformations. We study the modified Landau problem for both Schr\\"odinger and Dirac particles, whose Hamiltonians are obtained through a kind of non-Abelian Bopp's shift of the dynamical variables from the ones of the usual problem in the normal space. The spectrum of these models are considered in perturbation theory, both for small and large noncommutativity parameters. We find no constraint between the parameters referring to no-commutativity in coordinates and momenta but they rather play similar roles. Since the representation space of the unitary irreducible representations SL(2,R) c...

  8. Convolution of Lorentz Invariant Ultradistributions and Field Theory

    CERN Document Server

    Bollini, C G

    2003-01-01

    In this work, a general definition of convolution between two arbitrary four dimensional Lorentz invariant (fdLi) Tempered Ultradistributions is given, in both: Minkowskian and Euclidean Space (Spherically symmetric tempered ultradistributions). The product of two arbitrary fdLi distributions of exponential type is defined via the convolution of its corresponding Fourier Transforms. Several examples of convolution of two fdLi Tempered Ultradistributions are given. In particular we calculate exactly the convolution of two Feynman's massless propagators. An expression for the Fourier Transform of a Lorentz invariant Tempered Ultradistribution in terms of modified Bessel distributions is obtained in this work (Generalization of Bochner's formula to Minkowskian space). At the same time, and in a previous step used for the deduction of the convolution formula, we obtain the generalization to the Minkowskian space, of the dimensional regularization of the perturbation theory of Green Functions in the Euclidean conf...

  9. Inertial frames without the relativity principle: breaking Lorentz symmetry

    CERN Document Server

    Baccetti, Valentina; Visser, Matt

    2013-01-01

    We investigate inertial frames in the absence of Lorentz invariance, reconsidering the usual group structure implied by the relativity principle. We abandon the relativity principle, discarding the group structure for the transformations between inertial frames, while requiring these transformations to be at least linear (to preserve homogeneity). In theories with a preferred frame (aether), the set of transformations between inertial frames forms a groupoid/pseudogroup instead of a group, a characteristic essential to evading the von Ignatowsky theorems. In order to understand the dynamics, we also demonstrate that the transformation rules for energy and momentum are in general affine. We finally focus on one specific and compelling model implementing a minimalist violation of Lorentz invariance.

  10. Lorentz Angle Measurement for CO2/Isobutane Gas Mixtures

    CERN Document Server

    Hoshina, K; Khalatyan, N S; Nitoh, O; Okuno, H; Kato, Y; Kobayashi, M; Kurihara, Y; Kuroiwa, H; Nakamura, Y; Sakieda, K; Suzuki, Y; Watanabe, T

    2002-01-01

    We have developed a Lorentz angle measurement system for cool gas mixtures in the course of our R&D for a proposed JLC central drift chamber (JLC-CDC). The measurement system is characterized by the use of two laser beams to produce primary electrons and flash ADCs to read their signals simultaneously. With this new system, we have measured Lorentz angles for CO2/isobutane gas mixtures with different proportions (95:5, 90:10, and 85:15), varying drift field from 0.6 to 2.0 kV/cm and magnetic field up to 1.5 T. The results of the measurement are in good agreement with GARFIELD/MAGBOLTZ simulations.

  11. Non Linear Lorentz Transformation and Doubly Special Relativity

    CERN Document Server

    Atehortua, A N; Mira, J M; Vanegas, N

    2012-01-01

    We generate non-linear representations of the Lorentz Group by unitary transformation over the Lorentz generators. To do that we use deformed scale transformations by introducing momentum-depending parameters. The momentum operator transformation is found to be equivalent to a particle momentum transformation. The configuration space transformation is found to depend on the old momentum operator and we show that this transformation generates models with two scales, one for the velocity ($c$) and another one for the energy. A Lagrangian formalism is proposed for these models and an effective metric for the deformed Minkowski space is found. We show that the Smolin model is one in a family of doubly special relativity. Finally we construct an ansatz for the quantization of such theories.

  12. On multipliers of Fourier series in the Lorentz space

    Science.gov (United States)

    Ydyrys, Aizhan Zh.; Tleukhanova, Nazerke T.

    2016-08-01

    We study the multipliers of Fourier series on the Lorentz spaces, in particular, the sufficient conditions for a sequence of complex numbers {λk}k∈Z in order to make it a multiplier of trigonometric Fourier series of space Lp,r [0; 1] in the Lq,r [0; 1]. In the paper there is a new multipliers theorem which is supplement of the well-known theorems, and given a counterexample.

  13. Modified gravity and binary pulsars: the Lorentz violating case

    CERN Document Server

    Blas, Diego

    2016-01-01

    The dynamics of binary pulsars can be used to test different aspects of gravitation. This is particularly important to constrain alternatives to general relativity in regimes which are not probed by other methods. In this short contribution, I will describe the case of theories of gravity without Lorentz invariance. The latter are important in the context of quantum gravity and modify the laws of gravity at basically all scales.

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

    Indian Academy of Sciences (India)

    Yoshihiko Togawa; Ken Harada; Tetsuya Akashi; Hiroto Kasai; Tsuyoshi Matsuda; Atsutaka maeda; Akira Tonomura

    2006-01-01

    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 potential under the oscillating magnetic field in a temporally symmetric manner. Based on the observation of the individual motion of vortices, we clarify the elementary process involved in this rectification.

  15. Black hole entropy and Lorentz-diffeomorphism Noether charge

    OpenAIRE

    Jacobson, Ted; Mohd, Arif

    2015-01-01

    We show that, in the first or second order orthonormal frame formalism, black hole entropy is the horizon Noether charge for a combination of diffeomorphism and local Lorentz symmetry involving the Lie derivative of the frame. The Noether charge for diffeomorphisms alone is unsuitable, since a regular frame cannot be invariant under the flow of the Killing field at the bifurcation surface. We apply this formalism to Lagrangians polynomial in wedge products of the frame field 1-form and curvat...

  16. A Michelson-Morley Test of Lorentz Symmetry for Electrons

    CERN Document Server

    Pruttivarasin, T; Porsev, S G; Tupitsyn, I I; Safronova, M; Hohensee, M A; Haeffner, H

    2014-01-01

    All evidence so far suggests that the absolute spatial orientation of an experiment never affects its outcome. This is reflected in the Standard Model of physics by requiring all particles and fields to be invariant under Lorentz transformations. The most well-known test of this important cornerstone of physics are Michelson-Morley-type experiments\\cite{MM, Herrmann2009,Eisele2009} verifying the isotropy of the speed of light. Lorentz symmetry also implies that the kinetic energy of an electron should be independent of the direction of its velocity, \\textit{i.e.,} its dispersion relation should be isotropic in space. In this work, we search for violation of Lorentz symmetry for electrons by performing an electronic analogue of a Michelson-Morley experiment. We split an electron-wavepacket bound inside a calcium ion into two parts with different orientations and recombine them after a time evolution of 95~ms. As the Earth rotates, the absolute spatial orientation of the wavepackets changes and anisotropies in ...

  17. 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.

  18. 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.

  19. Análisis discriminante como seleccionador de variables influyentes en el cálculo de la probabilidad de incumplimiento.

    OpenAIRE

    Pérez Ramírez, Fredy Ocaris; Támara Ayús, Armando Lenín

    2012-01-01

    En este artículo se presenta el marco teórico del análisis discriminante y cómo este se aplica como seleccionador de variables influyentes en el cálculo de la probabilidad de incumplimiento. Es así como a través del análisis de una cartera comercial perteneciente a una entidad financiera, se desarrolla un modelo que permita calcular la probabilidad de default a cada uno de los clientes, adicional, se encuentran las ecuaciones que nos lleven a pronosticar el incumplimiento

  20. 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.

  1. 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.

  2. Secuencia de tareas de la unidad didáctica Método gráfico para resolver sistemas de ecuaciones lineales 2x2

    OpenAIRE

    Castro, Diana Paola; Bernal, Mónica Liliana; Torres, Fernando; Pinzón, Álvaro Andrés

    2014-01-01

    Presentaremos la secuencia de tareas diseñada para la unidad didáctica Método gráfico para resolver sistemas de ecuaciones lineales 2x2, fundamentada a partir del modelo del análisis didáctico. Describiremos el diseño final de la secuencia de tareas y mostraremos su contribución a los objetivos de aprendizaje.

  3. Secuencia de tareas de la unidad didáctica Método gráfico para resolver sistemas de ecuaciones lineales 2x2

    OpenAIRE

    Castro, Diana Paola; Bernal, Mónica Liliana; Torres, Fernando; Pinzón, Álvaro Andrés

    2014-01-01

    Presentaremos la secuencia de tareas diseñada para la unidad didáctica Método gráfico para resolver sistemas de ecuaciones lineales 2x2, fundamentada a partir del modelo del análisis didáctico. Describiremos el diseño final de la secuencia de tareas y mostraremos su contribución a los objetivos de aprendizaje.

  4. 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.

  5. 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

  6. Constaints on Lorentz symmetry violations using lunar laser ranging observations

    Science.gov (United States)

    Bourgoin, Adrien

    2016-12-01

    General Relativity (GR) and the standard model of particle physics provide a comprehensive description of the four interactions of nature. A quantum gravity theory is expected to merge these two pillars of modern physics. From unification theories, such a combination would lead to a breaking of fundamental symmetry appearing in both GR and the standard model of particle physics as the Lorentz symmetry. Lorentz symmetry violations in all fields of physics can be parametrized by an effective field theory framework called the standard-model extension (SME). Local Lorentz Invariance violations in the gravitational sector should impact the orbital motion of bodies inside the solar system, such as the Moon. Thus, the accurate lunar laser ranging (LLR) data can be analyzed in order to study precisely the lunar motion to look for irregularities. For this purpose, ELPN (Ephéméride Lunaire Parisienne Numérique), a new lunar ephemeris has been integrated in the SME framework. This new numerical solution of the lunar motion provides time series dated in temps dynamique barycentrique (TDB). Among that series, we mention the barycentric position and velocity of the Earth-Moon vector, the lunar libration angles, the time scale difference between the terrestrial time and TDB and partial derivatives integrated from variational equations. ELPN predictions have been used to analyzed LLR observations. In the GR framework, the residuals standard deviations has turned out to be the same order of magnitude compare to those of INPOP13b and DE430 ephemerides. In the framework of the minimal SME, LLR data analysis provided constraints on local Lorentz invariance violations. Spetial attention was paid to analyze uncertainties to provide the most realistic constraints. Therefore, in a first place, linear combinations of SME coefficients have been derived and fitted to LLR observations. In a second time, realistic uncertainties have been determined with a resampling method. LLR data

  7. 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

  8. 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.

  9. Discussion on Lorentz invariance violation of noncommutative field theory and neutrino oscillation

    Science.gov (United States)

    Luo, Cui-Bai; Shi, Song; Du, Yi-Lun; Wang, Yong-Long; Zong, Hong-Shi

    2017-03-01

    Depending on deformed canonical anticommutation relations, massless neutrino oscillation based on Lorentz invariance violation in noncommutative field theory is discussed. It is found that the previous studies about massless neutrino oscillation within deformed canonical anticommutation relations should satisfy the condition of new Moyal product and new nonstandard commutation relations. Furthermore, comparing the Lorentz invariant violation parameters A in the previous studies with new Moyal product and new nonstandard commutation relations, we find that the orders of magnitude of noncommutative parameters (Lorentz invariant violation parameters A) is not self-consistent. This inconsistency means that the previous studies of Lorentz invariance violation in noncommutative field theory may not naturally explain massless neutrino oscillation. In other words, it should be impossible to explain neutrino oscillation by Lorentz invariance violation in noncommutative field theory. This conclusion is supported by the latest atmospheric neutrinos experimental results from the super-Kamiokande Collaboration, which show that no evidence of Lorentz invariance violation on atmospheric neutrinos was observed.

  10. Strongly enhanced effects of Lorentz symmetry violation in entangled Yb+ ions

    CERN Document Server

    Dzuba, V A; Safronova, M S; Porsev, S G; Pruttivarasin, T; Hohensee, M A; Häffner, H

    2015-01-01

    Lorentz symmetry is one of the cornerstones of modern physics. However, a number of theories aiming at unifying gravity with the other fundamental interactions including string field theory suggest violation of Lorentz symmetry [1-4]. While the energy scale of such strongly Lorentz symmetry-violating physics is much higher than that currently attainable by particle accelerators, Lorentz violation may nevertheless be detectable via precision measurements at low energies [2]. Here, we carry out a systematic theoretical investigation of the sensitivity of a wide range of atomic systems to violation of local Lorentz invariance (LLI). Aim of these studies is to identify which atom shows the biggest promise to detect violation of Lorentz symmetry. We identify the Yb+ ion as an ideal system with high sensitivity as well as excellent experimental controllability. By applying quantum information inspired technology to Yb+, we expect tests of LLI violating physics in the electron-photon sector to reach levels of $10^{-...

  11. 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.

  12. 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.

  13. Reality conditions for Ashtekar gravity from Lorentz-covariant formulation

    Energy Technology Data Exchange (ETDEWEB)

    Alexandrov, Sergei [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, Postbus 80.195, 3508 TD Utrecht (Netherlands)

    2006-03-21

    We study the limit of the Lorentz-covariant canonical formulation where the Immirzi parameter approaches {beta} = i. We show that, formulated in terms of a shifted spacetime connection, which also plays a crucial role in the covariant quantization, the limit is smooth and reproduces the canonical structure of the self-dual Ashtekar gravity. The reality conditions of Ashtekar gravity can be incorporated by means of the Dirac brackets derived from the covariant formulation and defined on an extended phase space which involves, besides the self-dual variables, also their anti-self-dual counterparts.

  14. Lorentz symmetry violation, dark matter and dark energy

    CERN Document Server

    Gonzalez-Mestres, Luis

    2009-01-01

    Taking into account the experimental results of the HiRes and AUGER collaborations, the present status of bounds on Lorentz symmetry violation (LSV) patterns is discussed. Although significant constraints will emerge, a wide range of models and values of parameters will still be left open. Cosmological implications of allowed LSV patterns are discussed focusing on the origin of our Universe, the cosmological constant, dark matter and dark energy. Superbradyons (superluminal preons) may be the actual constituents of vacuum and of standard particles, and form equally a cosmological sea leading to new forms of dark matter and dark energy.

  15. Wigner–Souriau translations and Lorentz symmetry of chiral fermions

    Directory of Open Access Journals (Sweden)

    C. Duval

    2015-03-01

    Full Text Available Chiral fermions can be embedded into Souriau's massless spinning particle model by “enslaving” the spin, viewed as a gauge constraint. The latter is not invariant under Lorentz boosts; spin enslavement can be restored, however, by a Wigner–Souriau (WS translation, analogous to a compensating gauge transformation. The combined transformation is precisely the recently uncovered twisted boost, which we now extend to finite transformations. WS-translations are identified with the stability group of a motion acting on the right on the Poincaré group, whereas the natural Poincaré action corresponds to action on the left.

  16. Quantum-Gravity Induced Lorentz Violation and Dynamical Mass Generation

    OpenAIRE

    Mavromatos, Nick E.

    2010-01-01

    In Ref. [1] (by J. Alexandre) a minimal extension of (3+1)-dimensional Quantum Electrodynamics has been proposed, which includes Lorentz-Violation (LV) in the form of higher-(spatial)-derivative isotropic terms in the gauge sector, suppressed by a mass scale $M$. The model can lead to dynamical mass generation for charged fermions. In this article I elaborate further on this idea and I attempt to connect it to specific quantum-gravity models, inspired from string/brane theory. Specifically, i...

  17. Getting the Lorentz transformations without requiring an invariant speed

    CERN Document Server

    Pelissetto, A

    2015-01-01

    The structure of the Lorentz transformations follows purely from the absence of privileged inertial reference frames and the group structure (closure under composition) of the transformations---two assumptions that are simple and physically necessary. The existence of an invariant speed is \\textit{not} a necessary assumption, and in fact is a consequence of the principle of relativity (though the finite value of this speed must, of course, be obtained from experiment). Von Ignatowsky derived this result in 1911, but it is still not widely known and is absent from most textbooks. Here we present a completely elementary proof of the result, suitable for use in an introductory course in special relativity.

  18. New limit on signals of Lorentz violation in electrodynamics.

    Science.gov (United States)

    Lipa, J A; Nissen, J A; Wang, S; Stricker, D A; Avaloff, D

    2003-02-14

    We describe the results of an experiment to test for spacetime anisotropy terms that might exist from Lorentz violations. The apparatus consists of a pair of cylindrical superconducting cavity-stabilized oscillators operating in the TM010 mode with one axis east-west and the other vertical. Spatial anisotropy is detected by monitoring the beat frequency at the sidereal rate and its first harmonic. We see no anisotropy to a part in 10(13). This puts a comparable bound on four linear combinations of parameters in the general standard model extension, and a weaker bound of < 4 x 10(-9) on three others.

  19. Photon emission and decay from generic Lorentz invariance violation

    Science.gov (United States)

    Martínez-Huerta, H.; Pérez-Lorenzana, A.

    2017-06-01

    One of the most studied approaches in phenomenology to introduce the breaking of Lorentz symmetry is the generic approach. This consist on the modification of the free particle dispersion relation by the addition of an extra power law term of order n on energy or momentum. Using this approach in the photon sector, we have calculated the generic rates for vacuum Cherenkov radiation and photon decay, for any order n, at leading order. Explicit results for the decay and emission rates for the lowest values of n are also presented.

  20. New limits on Planck scale Lorentz violation in QED.

    Science.gov (United States)

    Jacobson, T; Liberati, S; Mattingly, D; Stecker, F W

    2004-07-09

    Constraints on possible Lorentz symmetry violation (LV) of order E/M(Planck) for electrons and photons in the framework of effective field theory (EFT) are discussed. Using (i) the report of polarized MeV emission from GRB021206 and (ii) the absence of vacuum Cerenkov radiation from synchrotron electrons in the Crab Nebula, we improve previous bounds by 10(-10) and 10(-2), respectively. We also show that the LV parameters for positrons and electrons are different, discuss electron helicity decay, and investigate how prior constraints are modified by the relations between LV parameters implied by EFT.

  1. 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.

  2. Lorentz invariant relative velocity and relativistic binary collisions

    Science.gov (United States)

    Cannoni, Mirco

    2017-01-01

    This paper reviews the concept of Lorentz invariant relative velocity that is often misunderstood or unknown in high energy physics literature. The properties of the relative velocity allow to formulate the invariant flux and cross-section without recurring to nonphysical velocities or any assumption about the reference frame. Applications such as the luminosity of a collider, the use as kinematic variable, and the statistical theory of collisions in a relativistic classical gas are reviewed. It is emphasized how the hyperbolic properties of the velocity space explain the peculiarities of relativistic scattering.

  3. 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.

  4. Lorentz-Dirac force from QED for linear acceleration

    Science.gov (United States)

    Higuchi, Atsushi; Martin, Giles D.

    2004-10-01

    We investigate the motion of a wave packet of a charged scalar particle linearly accelerated by a static potential in quantum electrodynamics. We calculate the expectation value of the position of the charged particle after the acceleration to first order in the fine structure constant in the ℏ→0 limit. We find that the change in the expectation value of the position (the position shift) due to radiation reaction agrees exactly with the result obtained using the Lorentz-Dirac force in classical electrodynamics. We also point out that the one-loop correction to the potential may contribute to the position change in this limit.

  5. Fick's Law in a Random Lattice Lorentz Gas

    Science.gov (United States)

    Lefevere, Raphaël

    2015-06-01

    We provide a proof that the stationary macroscopic current of particles in a random lattice Lorentz gas satisfies Fick's law when connected to particles reservoirs. We consider a box on a d + 1-dimensional lattice and when , we show that under a diffusive rescaling of space and time, the probability of finding a current different from its stationary value is exponentially small in time. Its stationary value is given by the conductivity times the difference of chemical potentials of the reservoirs. The proof is based on the fact that in a high dimension, random walks have a small probability of making loops or intersecting each other when starting sufficiently far apart.

  6. Black hole entropy and Lorentz-diffeomorphism Noether charge

    CERN Document Server

    Jacobson, Ted

    2015-01-01

    We show that, in the first or second order orthonormal frame formalism, black hole entropy is the horizon Noether charge for a combination of diffeomorphism and local Lorentz symmetry involving the Lie derivative of the frame. The Noether charge for diffeomorphisms alone is unsuitable, since a regular frame cannot be invariant under the flow of the Killing field at the bifurcation surface. We apply this formalism to Lagrangians polynomial in wedge products of the frame field 1-form and curvature 2-form, including general relativity, Lovelock gravity, and "topological" terms in four dimensions.

  7. Isogeometric Simulation of Lorentz Detuning in Superconducting Accelerator Cavities

    CERN Document Server

    Corno, Jacopo; De Gersem, Herbert; Schöps, Sebastian

    2016-01-01

    Cavities in linear accelerators suffer from eigenfrequency shifts due to mechanical deformation caused by the electromagnetic radiation pressure, a phenomenon known as Lorentz detuning. Estimating the frequency shift up to the needed accuracy by means of standard Finite Element Methods, is a complex task due to the non exact representation of the geometry and due to the necessity for mesh refinement when using low order basis functions. In this paper, we use Isogeometric Analysis for discretising both mechanical deformations and electromagnetic fields in a coupled multiphysics simulation approach. The combined high-order approximation of both leads to high accuracies at a substantially lower computational cost.

  8. Unifying Ghost-Free Lorentz-Invariant Lagrangians

    CERN Document Server

    Li, Wenliang

    2015-01-01

    We present the details of the novel framework for Lagrangian field theories that are Lorentz-invariant and lead to at most second order equations of motion. The use of antisymmetric structure is of crucial importance. The general ghost-free Lagrangians are constructed and then translated into the language of differential forms. The ghost-freeness has a geometric nature. A novel duality is proposed which generalizes the Hodge duality in Maxwell's theory. We discuss how the well-established theories are reformulated and propose many new theories.

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

    Energy Technology Data Exchange (ETDEWEB)

    Holzscheiter, M.H.; ATHENA Collaboration

    1999-03-01

    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.

  10. Lorentz invariant relative velocity and relativistic binary collisions

    CERN Document Server

    Cannoni, Mirco

    2016-01-01

    This article reviews the concept of Lorentz invariant relative velocity that is often misunderstood or unknown in high energy physics literature. The properties of the relative velocity allow to formulate the invariant flux and cross section without recurring to non--physical velocities or any assumption about the reference frame. Applications such as the luminosity of a collider, the use as kinematic variable, and the statistical theory of collisions in a relativistic classical gas are reviewed. It is emphasized how the hyperbolic properties of the velocity space explain the peculiarities of relativistic scattering.

  11. Lorentz-invariant formulation of Cherenkov radiation by tachyons

    Science.gov (United States)

    Jones, F. C.

    1972-01-01

    Previous treatments of Cherenkov radiation, electromagnetic and gravitational, by tachyons were in error because the prescription employed to cut off the divergent integral over frequency is not a Lorentz invariant procedure. The resulting equation of motion for the tachyon is therefore not covariant. The proper procedure requires an extended, deformable distribution of charge or mass and yields a particularly simple form for the tachyon's world line, one that could be deduced from simple invariance considerations. It is shown that Cherenkov radiation by tachyons implys their ultimate annihilation with an antitachyon and demonstrates a disturbing property of tachyons, namely the impossibility of specifying arbitrary Cauchy data even in a purely classical theory.

  12. Lorentz and CPT violation in the hydrogen spectrum

    CERN Document Server

    Adkins, Gregory S

    2013-01-01

    We have studied the effect of hypothetical violations of Lorentz and CPT symmetry by calculating the corrections to the energy levels of hydrogen induced by the Standard-Model Extension (SME). Hydrogen studies are interesting because the energy levels of hydrogen can be measured with great precision and the theory for hydrogen based on the Standard Model (SM) is well understood. We obtained corrections through order \\alpha^2 times the SME parameters for all levels of hydrogen and applied them to determine the SME corrections to the transition frequency for the 2S-1S transition.

  13. Wigner-Souriau translations and Lorentz symmetry of chiral fermions

    CERN Document Server

    Duval, C; Horvathy, P A; Zhang, P -M

    2014-01-01

    Chiral fermions can be embedded into Souriau's massless spinning particle model by "enslaving" the spin, viewed as a gauge constraint. The latter is not invariant under Lorentz boosts; spin enslavement can be restored, however, by a subsequent Wigner-Souriau (WS) translation, analogous to a compensating gauge transformation. The combined transformation is precisely the recently uncovered twisted boost, which we now extend to finite transformations. WS-translations are identified with the stability group of a motion acting on the right on the Poincare group, whereas the natural Poincare action corresponds to action on the left.

  14. Fluctuation formula for nonreversible dynamics in the thermostated Lorentz gas

    Science.gov (United States)

    Dolowschiák, M.; Kovács, Z.

    2002-12-01

    We investigate numerically the validity of the Gallavotti-Cohen fluctuation formula in the two- and three-dimensional periodic Lorentz gas subjected to constant electric and magnetic fields and thermostated by the Gaussian isokinetic thermostat. The magnetic field breaks the time reversal symmetry, and by choosing its orientation with respect to the lattice, one can have either a generalized reversing symmetry or no reversibility at all. Our results indicate that the scaling property described by the fluctuation formula may be approximately valid for large fluctuations even in the absence of reversibility.

  15. Dos Enfoques en el Diseño de un Observador Asintótico para un Proceso Fermentativo Descrito por Ecuaciones Diferenciales Parciales Two Approaches in the Design of an Asymptotic Observer for a Fermentative Process Described by Partial Differential Equations

    Directory of Open Access Journals (Sweden)

    Efrén Aguilar-Garnica

    2006-01-01

    Full Text Available En este artículo, se presentan dos enfoques de diseño de un observador asintótico para un sistema fermentativo descrito por ecuaciones diferenciales parciales (EDP. En el primer enfoque, denominado reducción posterior, se diseña el observador directamente sobre el modelo en EDP y después, tanto el modelo como el observador, son reducidos a un conjunto de ecuaciones diferenciales ordinarias (EDO mediante el Método de Colocación Ortogonal (MCO. En el segundo enfoque, denominado reducción temprana, el modelo en EDP, es inicialmente reducido a EDO, usando también el MCO y luego, el observador asintótico es diseñado para el modelo reducido. El estudio muestra, mediante un análisis de la dinámica del error de estimación para ambos enfoques, que el comportamiento dinámico del observador asintótico es independiente del enfoque de diseño utilizado.This paper presents two approaches for the design of an asymptotic observer for a fermentative process described by partial differential equations (PDE. In the first approach, termed late lumping, the observer is designed for the PDE model and then both the observer and the model are reduced to a set of ordinary differential equations (ODE by means of the Orthogonal Collocation Method (OCM. In the second approach, termed early lumping, the PDE model is initially reduced to an ODE set by using the OCM and then the asymptotic observer is designed for the reduced model. The study demonstrates that by analyzing the estimation error dynamics for both design approaches, the dynamic behavior of the asymptotic observer is fully independent of the design approach used.

  16. Projected Constraints on Lorentz-Violating Gravity with Gravitational Waves

    CERN Document Server

    Hansen, Devin; Yagi, Kent

    2014-01-01

    Gravitational waves are excellent tools to probe the foundations of General Relativity in the strongly dynamical and non-linear regime. One such foundation is Lorentz symmetry, which can be broken in the gravitational sector by the existence of a preferred time direction, and thus, a preferred frame at each spacetime point. This leads to a modification in the orbital decay rate of binary systems, and also in the generation and chirping of their associated gravitational waves. We here study whether waves emitted in the late, quasi-circular inspiral of non-spinning, neutron star binaries can place competitive constraints on two proxies of gravitational Lorentz-violation: Einstein-\\AE{}ther theory and khronometric gravity. We model the waves in the small-coupling (or decoupling) limit and in the post-Newtonian approximation, by perturbatively solving the field equations in small deformations from General Relativity and in the small-velocity/weak-gravity approximation. We assume a gravitational wave consistent wi...

  17. Cosmic censorship in Lorentz-violating theories of gravity

    Science.gov (United States)

    Meiers, Michael; Saravani, Mehdi; Afshordi, Niayesh

    2016-05-01

    Is cosmic censorship special to general relativity, or can it survive a violation of local Lorentz invariance? Recent studies have shown that singularities in Lorentz -violating Einstein-Aether (or Horava-Lifshitz) theories can lie behind a universal horizon in simple black hole spacetimes. Even infinitely fast signals cannot escape these universal horizons. We extend this result, for an incompressible aether, to 3 +1 d dynamical or spinning spacetimes which possess inner Killing horizons, and show that a universal horizon always forms in between the outer and (would-be) inner horizons. This finding suggests a notion of cosmic censorship, given that geometry in these theories never evolves beyond the universal horizon (avoiding potentially singular inner Killing horizons). A surprising result is that there are 3 distinct possible stationary universal horizons for a spinning black hole, only one of which matches the dynamical spherical solution. This motivates dynamical studies of collapse in Einstein-Aether theories beyond spherical symmetry, which may reveal instabilities around the spherical solution.

  18. A test of local Lorentz invariance with Compton scattering asymmetry

    CERN Document Server

    Mohanmurthy, P; Dutta, D

    2016-01-01

    We report on a measurement of the constancy and anisotropy of the speed of light relative to the electrons in photon-electron scattering. We used the Compton scattering asymmetry measured by the new Compton polarimeter in Hall~C at Jefferson Lab to test for deviations from unity of the vacuum refractive index ($n$). For photon energies in the range of 9 - 46 MeV, we obtain a new limit of $1-n < 1.4 \\times 10^{-8}$. In addition, the absence of sidereal variation over the six month period of the measurement constrains any anisotropies in the speed of light. These constitute the first study of Lorentz invariance using Compton asymmetry. Within the minimal standard model extension framework, our result yield limits on the photon and electron coefficients $\\tilde{\\kappa}_{0^+}^{YZ}, c_{TX}, \\tilde{\\kappa}_{0^+}^{ZX}$, and $c_{TY}$. Although, these limits are several orders of magnitude larger than the current best limits, they demonstrate the feasibility of using Compton asymmetry for tests of Lorentz invarianc...

  19. Consistency analysis of a nonbirefringent Lorentz-violating planar model

    Energy Technology Data Exchange (ETDEWEB)

    Casana, Rodolfo; Ferreira, Manoel M.; Moreira, Roemir P.M. [Universidade Federal do Maranhao (UFMA), Departamento de Fisica, Sao Luis, MA (Brazil)

    2012-07-15

    In this work analyze the physical consistency of a nonbirefringent Lorentz-violating planar model via the analysis of the pole structure of its Feynman propagators. The nonbirefringent planar model, obtained from the dimensional reduction of the CPT-even gauge sector of the standard model extension, is composed of a gauge and a scalar fields, being affected by Lorentz-violating (LIV) coefficients encoded in the symmetric tensor {kappa}{sub {mu}{nu}}. The propagator of the gauge field is explicitly evaluated and expressed in terms of linear independent symmetric tensors, presenting only one physical mode. The same holds for the scalar propagator. A consistency analysis is performed based on the poles of the propagators. The isotropic parity-even sector is stable, causal and unitary mode for 0{<=}{kappa}{sub 00}<1. On the other hand, the anisotropic sector is stable and unitary but in general noncausal. Finally, it is shown that this planar model interacting with a {lambda}{phi}{sup 4}-Higgs field supports compact-like vortex configurations. (orig.)

  20. Consistency analysis of a nonbirefringent Lorentz-violating planar model

    Science.gov (United States)

    Casana, Rodolfo; Ferreira, Manoel M.; Moreira, Roemir P. M.

    2012-07-01

    In this work analyze the physical consistency of a nonbirefringent Lorentz-violating planar model via the analysis of the pole structure of its Feynman propagators. The nonbirefringent planar model, obtained from the dimensional reduction of the CPT-even gauge sector of the standard model extension, is composed of a gauge and a scalar fields, being affected by Lorentz-violating (LIV) coefficients encoded in the symmetric tensor κ μν . The propagator of the gauge field is explicitly evaluated and expressed in terms of linear independent symmetric tensors, presenting only one physical mode. The same holds for the scalar propagator. A consistency analysis is performed based on the poles of the propagators. The isotropic parity-even sector is stable, causal and unitary mode for 0≤ κ 00<1. On the other hand, the anisotropic sector is stable and unitary but in general noncausal. Finally, it is shown that this planar model interacting with a λ| φ|4-Higgs field supports compactlike vortex configurations.

  1. 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}}

  2. Abraham-Lorentz-Dirac Equation in 5D Stuekelberg Electrodynamics

    CERN Document Server

    Land, Martin

    2016-01-01

    We derive the Abraham-Lorentz-Dirac (ALD) equation in the framework of the electrodynamic theory associated with Stueckelberg manifestly covariant canonical mechanics. In this framework, a particle worldline is traced out through the evolution of an event $x^\\mu(\\tau)$. By admitting unconstrained commutation relations between the positions and velocities, the associated electromagnetic gauge fields are in general dependent on the parameter $\\tau$, which plays the role of time in Newtonian mechanics. Standard Maxwell theory emerges from this system as a $\\tau$-independent equilibrium limit. In this paper, we calculate the $\\tau$-dependent field induced by an arbitrarily evolving event, and study the long-range radiation part, which is seen to be an on-shell plane wave of the Maxwell type. Following Dirac's method, we obtain an expression for the finite part of the self-interaction, which leads to the ALD equation that generalizes the Lorentz force. This third-order differential equation is then converted to an...

  3. Extended Linear and Nonlinear Lorentz Transformations and Superluminality

    Directory of Open Access Journals (Sweden)

    Dara Faroughy

    2013-01-01

    Full Text Available Two broad scenarios for extended linear Lorentz transformations (ELTs are modeled in Section 2 for mixing subluminal and superluminal sectors resulting in standard or deformed energy-momentum dispersions. The first scenario is elucidated in the context of four diverse realizations of a continuous function f ( v , with 0 ≤ f ( v ≤ 1 and f ( 0 = f ( c = 1 , which is fitted in the ELT. What goes in the making of the ELT in this scenario is not the boost speed v , as ascertained by two inertial observers in uniform relative motion (URM, but v × f ( v . The second scenario infers the preexistence of two rest-mass-dependent superluminal speeds whereby the ELTs are finite at the light speed c . Particle energies are evaluated in this scenario at c for several particles, including the neutrinos, and are auspiciously found to be below the GKZ energy cutoff and in compliance with a host of worldwide ultrahigh energy cosmic ray data. Section 3 presents two broad scenarios involving a number of novel nonlinear LTs (NLTs featuring small Lorentz invariance violations (LIVs, as well as resurrecting the notion of simultaneity for limited spacetime events as perceived by two observers in URM. These inquiries corroborate that NLTs could be potent tools for investigating LIVs past the customary LTs.

  4. Lorentz violation, two-time physics, and strings

    Energy Technology Data Exchange (ETDEWEB)

    Romero, Juan M., E-mail: jromero@correo.cua.uam.mx [Departamento de Matematicas Aplicadas y Sistemas, Universidad Autonoma Metropolitana-Cuajimalpa, Mexico, D.F 01120 (Mexico); Sanchez-Santos, Oscar, E-mail: oscarsanbuzz@yahoo.com.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, Mexico 04510 DF (Mexico); Vergara, Jose David, E-mail: vergara@nucleares.unam.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, Mexico 04510 DF (Mexico)

    2011-10-24

    The aim of this paper is to study the generalization of the relativistic particle recently proposed by Kostelecky. An alternative action for this system is presented, and it is shown that this action can be interpreted as a particle in curved space. Furthermore, the following results are established for the model: (i) there exists a limit where the system has more local symmetries than the usual relativistic particle; (ii) in this limit when Lorentz symmetry is restored, a direct relationship with the two-time physics is determined; (iii) if also Poincare symmetry is recovered, the action of a relativistic bosonic string is obtained. -- Highlights: → We study the generalization of the relativistic particle proposed by Kostelecky. → An alternative action for this system is presented. → There is a limit where the model has more symmetries than the relativistic particle. → When Lorentz symmetry is restored, a relationship with two-time physics is determined. → If Poincare symmetry is recovered, the action of a relativistic string is obtained.

  5. Generalized Lorentz invariance with an invariant energy scale

    CERN Document Server

    Magueijo, J; Magueijo, Joao; Smolin, Lee

    2003-01-01

    The hypothesis that the Lorentz transformations may be modified at Planck scale energies is further explored. We present a general formalism for theories which preserve the relativity of inertial frames with a non-linear action of the Lorentz transformations on momentum space. Several examples are discussed in which the speed of light varies with energy and elementary particles have a maximum momenta and/or energy. Energy and momentum conservation are suitably generalized and a proposal is made for how the new transformation laws apply to composite systems. We then use these results to explain the ultra high energy cosmic ray anomaly and we find a form of the theory that explains the anomaly, and leads also to a maximum momentum and a speed of light that diverges with energy. We finally propose that the spatial coordinates be identified as the generators of translation in Minkowski spacetime. In some examples this leads to a commutative geometry, but with an energy dependent Planck constant.

  6. Photospheric Flows, Lorentz Forces, and Solar-Eruption Initiation

    Science.gov (United States)

    Fisher, George; Kazachenko, Maria

    Eruptive Flares and coronal mass ejections (CMEs) are almost certainly magnetically driven. We discuss the role that the Lorentz force must play in driving an eruption, and how both the radial and horizontal components of this force can be related to changes that occur in observations of the vector magnetic field observed at the photosphere. We then review recent observational work on observed flows in the solar atmosphere, and how these flows might be related to changes in the Lorentz force observed during flares. Flows in magnetized regions of the photosphere also generate electric fields, which can affect the flux of magnetic energy transported across the photosphere and into the chromosphere and corona, and result in changes to the magnetic field there as well. We will discuss how such electric fields are incorporated into models of active-regions, to study the buildup of electric currents and the ejection of plasma in the context of our recently funded project, the ``Coronal Global Evolutionary Model (CGEM)'', a collaboration between UC Berkeley, Stanford University, and the Lockheed Martin Solar and Astrophysics Laboratory.

  7. Amplitude modulated Lorentz force MEMS magnetometer with picotesla sensitivity

    Science.gov (United States)

    Kumar, Varun; Ramezany, Alireza; Mahdavi, Mohammad; Pourkamali, Siavash

    2016-10-01

    This paper demonstrates ultra-high sensitivities for a Lorentz force resonant MEMS magnetometer enabled by internal-thermal piezoresistive vibration amplification. A detailed model of the magneto-thermo-electro-mechanical internal amplification is described and is in good agreement with the experimental results. Internal amplification factors up to ~1620 times have been demonstrated by artificially boosting the effective quality factor of the resonator from 680 to 1.14  ×  106 by tuning the bias current. The increase in the resonator bias current in addition to the improvement in the quality factor of the device led to a sensitivity enhancement by ~2400 times. For a bias current of 7.245 mA, where the effective quality factor of the device and consequently the sensitivity is maximum (2.107 mV nT-1), the noise floor is measured to be as low as 2.8 pT (√Hz)-1. This is by far the most sensitive Lorentz force MEMS magnetometer demonstrated to date.

  8. Aspects of semilocal BPS vortex in systems with Lorentz symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Villalobos, C.H.C.; Silva, J.M.H. da; Hott, M.B. [UNESP, Univ Estadual Paulista, Departamento de Fisica e Quimica, Guaratingueta, SP (Brazil); Belich, H. [Universidade Federal do Espi rito Santo (UFES), Departamento de Fisica e Quimica, Vitoria, ES (Brazil)

    2014-03-15

    The existence is shown of a static self-dual semilocal vortex configuration for the Maxwell-Higgs system with a Lorentz-violating CPT-even term. The dependence of the vorticity upper limit on the Lorentz-symmetry-breaking term is also investigated. (orig.)

  9. Extending the graviton propagator with a Lorentz-violating vector field

    CERN Document Server

    Seifert, Michael D

    2016-01-01

    I discuss progress towards "bootstrapping" a Lorentz-violating gravity theory: namely, extending a linear Lorentz-violating theory of a rank-2 tensor to a non-linear theory by coupling this field to its own stress-energy tensor.

  10. The ambiguity-free four-dimensional Lorentz-breaking Chern-Simons action

    Energy Technology Data Exchange (ETDEWEB)

    Brito, F.A. [Departamento de Fisica, Universidade Federal de Campina Grande, Caixa Postal 10071, 58109-970 Campina Grande, Paraiba (Brazil); Nascimento, J.R.; Passos, E. [Departamento de Fisica, Universidade Federal da Paraiba, Caixa Postal 5008, 58051-970 Joao Pessoa, Paraiba (Brazil); Petrov, A.Yu. [Departamento de Fisica, Universidade Federal da Paraiba, Caixa Postal 5008, 58051-970 Joao Pessoa, Paraiba (Brazil)], E-mail: petrov@fisica.ufpb.br

    2008-06-12

    The four-dimensional Lorentz-breaking finite and determined Chern-Simons like action is generated as a one-loop perturbative correction via an appropriate Lorentz-breaking coupling of the gauge field with the spinor field. Unlike the known schemes of calculations, within this scheme this term is found to be regularization independent.

  11. Relativistic Landau-Aharonov-Casher quantization based on the Lorentz symmetry violation background

    CERN Document Server

    Bakke, K; Silva, E O; 10.1063/1.3597230

    2011-01-01

    Based on the discussions about the Aharonov-Casher effect in the Lorentz symmetry violation background, we show that the analogue of the relativistic Landau quantization in the Aharonov-Casher setup can be achieved in the Lorentz-symmetry violation background.

  12. Relativistic Landau-Aharonov-Casher quantization based on the Lorentz symmetry violation background

    Science.gov (United States)

    Bakke, K.; Belich, H.; Silva, E. O.

    2011-06-01

    Based on the discussions about the Aharonov-Casher effect in the Lorentz symmetry violation background, we show that the analogue of the relativistic Landau quantization in the Aharonov-Casher setup can be achieved in the Lorentz-symmetry violation background.

  13. Search for Lorentz and CPT violation effects in muon spin precession

    NARCIS (Netherlands)

    Bennett, G. W.; Bousquet, B.; Brown, H. N.; Bunce, G.; Carey, R. M.; Cushman, P.; Danby, G. T.; Debevec, P. T.; Deile, M.; Deng, H.; Deninger, W.; Dhawan, S. K.; Druzhinin, V. P.; Duong, L.; Efstathiadis, E.; Farley, F. J. M.; Fedotovich, G. V.; Giron, S.; Gray, F. E.; Grigoriev, D.; Grosse-Perdekamp, M.; Grossmann, A.; Hare, M. F.; Hertzog, D. W.; Huang, X.; Hughes, V. W.; Iwasaki, M.; Jungmann, K.; Kawall, D.; Kawamura, M.; Khazin, B. I.; Kindem, J.; Krienen, F.; Kronkvist, I.; Lam, A.; Larsen, R.; Lee, Y. Y.; Logashenko, I.; McNabb, R.; Meng, W.; Mi, J.; Miller, J. P.; Mizumachi, Y.; Morse, W. M.; Nikas, D.; Onderwater, C. J. G.; Orlov, Y.; Oezben, C. S.; Paley, J. M.; Peng, Q.; Polly, C. C.; Pretz, J.; Prigl, R.; Putlitz, G. zu; Qian, T.; Redin, S. I.; Rind, O.; Roberts, B. L.; Ryskulov, N.; Sedykh, S.; Semertzidis, Y. K.; Shagin, P.; Shatunov, Yu. M.; Sichtermann, E. P.; Solodov, E.; Sossong, M.; Steinmetz, A.; Sulak, L. R.; Timmermans, C.; Trofimov, A.; Urner, D.; von Walter, P.; Warburton, D.; Winn, D.; Yamamoto, A.; Zimmerman, D.; Bennet, G.W.; Ozben, C.

    2008-01-01

    The spin precession frequency of muons stored in the (g-2) storage ring has been analyzed for evidence of Lorentz and CPT violation. Two Lorentz and CPT violation signatures were searched for a nonzero Delta omega(a)(=omega(mu+)(a)-omega(mu-)(a)) and a sidereal variation of omega(mu+)(a). No signifi

  14. Implications of Lorentz violation on Higgs-mediated lepton flavor violation

    CERN Document Server

    López-Osorio, M A; Toscano, J J

    2014-01-01

    The lepton flavor violating decay of the Higgs boson $H\\to l_Al_B$ is studied within two qualitatively different extensions of the Yukawa sector: one renormalizable and the other nonrenormalizable; both incorporating Lorentz violation in a model-independent fashion. These extensions are characterized by Yukawa-like matrices, the former by a constant Lorentz 2-tensor $Y^{AB}_{\\mu \

  15. 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.

  16. Testing Lorentz invariance in the weak interaction using laser-polarized {sup 20}Na

    Energy Technology Data Exchange (ETDEWEB)

    Dijck, Elwin A.; Sytema, Auke; Mueller, Stefan E.; Hoekstra, Steven; Jungmann, Klaus; Noordmans, Jacob P.; Onderwater, Gerco; Pijpker, Coen; Timmermans, Rob G.E.; Willmann, Lorenz; Wilschut, Hans W. [University of Groningen (Netherlands)

    2014-07-01

    Lorentz invariance is one of the fundamental principles underlying our current understanding of nature. In models aiming to unify the Standard Model with (quantum) gravity this symmetry may be broken. Few tests of Lorentz invariance in the weak interaction have been made. We have performed a novel test of rotational invariance by searching for variations in the decay rate of {sup 20}Na nuclei depending on the nuclear spin orientation with respect to a possible Lorentz symmetry breaking background field. Using optical pumping, the nuclei were alternately polarized in opposite vertical directions, while the absolute orientation of the spins changed with the rotation of the Earth. A polarization-dependent Lorentz symmetry violating effect was searched for, putting a 95% confidence limit on the amplitude of sidereal variations in the decay rate asymmetry at < 3 x 10{sup -3}. This result was analyzed in the framework of a recently developed theory that assumes a Lorentz symmetry breaking background field of tensor nature.

  17. The role of singular spinor fields in a torsional gravity, Lorentz-violating, framework

    Science.gov (United States)

    Ferrari, A. F.; Neto, J. A. S.; da Rocha, R.

    2017-05-01

    In this work, we consider a generalization of quantum electrodynamics including Lorentz violation and torsional-gravity, in the context of general spinor fields as classified in the Lounesto scheme. Singular spinor fields will be shown to be less sensitive to the Lorentz violation, as far as couplings between the spinor bilinear covariants and torsion are regarded. In addition, we prove that flagpole spinor fields do not admit minimal coupling to the torsion. In general, mass dimension four couplings are deeply affected when singular—flagpoles—spinors are considered, instead of the usual Dirac spinors. We also construct a mapping between spinors in the covariant framework and spinors in Lorentz symmetry breaking scenarios, showing how one may transliterate spinors of different classes between the two cases. Specific examples concerning the mapping of Dirac spinor fields in Lorentz violating scenarios into flagpole and flag-dipole spinors with full Lorentz invariance (including the cases of Weyl and Majorana spinors) are worked out.

  18. 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.

  19. The role of singular spinor fields in a torsional gravity, Lorentz-violating, framework

    CERN Document Server

    Ferrari, A F; Silva-Neto, J A

    2016-01-01

    In this work, we consider a generalization of quantum electrodynamics including Lorentz violation and torsional-gravity, in the context of general spinor fields as classified in the Lounesto scheme. Singular spinor fields will be shown to be less sensitive to the Lorentz violation, as far as couplings between the spinor bilinear covariants and torsion are regarded. In addition, we prove that flagpole spinor fields do not admit minimal coupling to the torsion. In general, mass dimension four couplings are deeply affected when singular flagpoles spinors are considered instead of the usual Dirac spinors. We also construct a mapping between spinors in the covariant framework and spinors in Lorentz symmetry breaking scenarios, showing how one may transliterate spinors of different classes between the two cases. Specific examples concerning the mapping of Dirac spinor fields in Lorentz violating scenarios into flagpole and flag-dipole spinors with full Lorentz invariance (including the cases of Weyl and Majorana sp...

  20. Obtención de ecuaciones de correlación para estimar las velocidades de las ondas de corte en los suelos de la ciudad de Guayaquil

    OpenAIRE

    Ramirez Calderon, Jenny; Tandazo Ortega, Eddie; Vera Grunauer, Xavier

    2009-01-01

    La presente tesis establece un aporte a los ingenieros consultores y diseñadores, proporcionándoles ecuaciones semiempíricas para la estimación de la velocidad de la onda de corte, adaptadas para los suelos de la ciudad de Guayaquil. Para la realización y obtención del perfil de velocidad de onda de corte se llevó a cabo una campaña de medición de las ondas de superficie generadas por una fuente activa (martillos, bulldozers) de vibraciones aleatorias de alta y baja frecuenc...

  1. Metodos multipaso de longitud de paso variable para la solución numerica de ecuaciones diferenciales ordinarias con problema de valor inicial

    OpenAIRE

    Arohuanca Lagos, Ferdinand Gunard

    1998-01-01

    El objetivo principal de este trabajo es construir integradores que solucionen numéricamente ecuaciones diferenciales ordinarias con problemas de valor inicial. En dichos integradores numéricos, basados en las fórmulas multipaso {ej. fórmulas de Adams, BDF, etc.), se utiliza la técnica de paso variable, la cual permite una mayor precisión. Cabe resaltar que estos métodos son usados cuando la función / de la ecuación difer¬encial y' — f(x,y) es dada de un modo más complicado, pues es menor el ...

  2. Un esquema de volúmenes finitos de alto orden para las ecuaciones de aguas someras con topografía y áreas secas

    OpenAIRE

    Gallardo Molina, José María; Castro Díaz, Manuel Jesús; Parés Madroñal, Carlos

    2007-01-01

    Presentamos un esquema de volúmenes finitos para la resolución de las ecuaciones de aguas someras con término fuente debido a la topografía del fondo. Se trata de un esquema de alto orden, bien equilibrado y capaz de afrontar situaciones en las que aparecen zonas secas. El esquema se ha desarrollado en un marco no conservativo general, y se basa en reconstrucciones hiperbólicas de estados. El tratamiento de situaciones seco/mojado se lleva a cabo mediante la resolución de problemas de Rie...

  3. Comparación de ecuaciones para estimar curvas de lactancia con diferentes estrategias de muestreo en bovinos Angus, Suizo y sus cruzas

    OpenAIRE

    Rodolfo Ramírez Valverde; José Guadalupe García Muñiz; Rafael Núñez Domínguez; Agustín Ruiz Flores; Ma. del Refugio Meraz Alvarado

    2004-01-01

    Los objetivos de este estudio fueron comparar cuatro ecuaciones para estimar curvas de lactancia en vacas Angus, Suizo Europeo y sus cruzas recíprocas, basado en cuatro frecuencias de medición de la producción de leche (PL), y determinar el número mínimo de muestreos para predecir adecuadamente las curvas de lactancia. Los datos de PL (297 lactancias) se colectaron semanalmente hasta 180 días posparto, utilizando la técnica de pesaje de becerros antes y después del amamantamiento. Para cada l...

  4. Vibraciones libres de vigas rotantes utilizando las ecuaciones de movimiento de Kane y el método de los modos asumidos

    OpenAIRE

    Gómez, C. N.; Preidikman, S.; Roccia, B. A.

    2014-01-01

    El diseño de rotores de helicópteros, brazos robóticos, turbinas eólicas y otros sistemas mecánicos que involucran movimientos giratorios, ha motivado numerosos estudios sobre los modos de vibrar de vigas sometidas a movimiento de rotación. En este trabajo, se derivan las ecuaciones de movimiento que gobiernan la dinámica de una viga que está empotrada en uno de sus extremos (viga en voladizo) a una base sometida a un movimiento de rotación con velocidad angular constante. Se considera un mod...

  5. Pocklington's equation and the method of moments applied to the twisted pair transmission line; Ecuacion de pocklington y el metodo de momentos aplicados a la linea de transmision de par torcido

    Energy Technology Data Exchange (ETDEWEB)

    Navarrete, Fernando; Barrera Figueroa, Victor; Sosa Pedroza, Jorge [Instituto Politecnico Nacional, Mexico D.F. (Mexico)

    2003-10-15

    In this work is deduced by two methods Pocklingon's Integro-Differential Equation. In the first method is employed a bent cylindrical conductor, in the second one is used a straight cylindrical conductor. Later the Method of Moment is used to solve the Pocklington equation in order to obtain the impedance matrix equation. This is the base to develop a transmission model in the twisted pair line. [Spanish] En este trabjo la ecuacion integro-diferencial de Pocklington se deduce por dos metodos. En el primeo se usa un alambre cilindrico curvilineo, y en el segundo se emplea un alambre cilindrico recto. Despues se utiliza el metodo de momentos para resolver la ecuacion de Pocklington para obtener la ecuacion de la matriz de impedancia. Esta es la base para desarrollar un modelo para la linea de transmision de par torcido.

  6. Time-Varying Metasurfaces and Lorentz Non-Reciprocity

    CERN Document Server

    Shaltout, Amr; Shalaev, Vladimir

    2015-01-01

    A cornerstone equation of optics, Snell's law, relates the angles of incidence and refraction for light passing through an interface between two media. It is built on two fundamental constrains: the conservation of tangential momentum and the conservation of energy. By relaxing the classical Snell law photon momentum conservation constrain when using space-gradient phase discontinuity, optical metasurfaces enabled an entirely new class of ultrathin optical devices. Here, we show that by eradicating the photon energy conservation constrain when introducing time-gradient phase discontinuity, we can further empower the area of flat photonics and obtain a new genus of optical devices. With this approach, classical Snell relations are developed into a more universal form not limited by Lorentz reciprocity, hence, meeting all the requirements for building magnetic-free optical isolators. Furthermore, photons experience inelastic interaction with time-gradient metasurfaces, which modifies photonic energy eigenstates...

  7. An acoustic spacetime and the Lorentz transformation in aeroacoustics

    CERN Document Server

    Gregory, Alastair Logan; Agarwal, Anurag; Lasenby, Joan

    2014-01-01

    This paper introduces acoustic space-time and Geometric Algebra as a new theoretical framework for modelling aeroacoustic phenomena. This new framework is applied to sound propagation in uniform flows. The problem is modelled by means of transformations that turn the convected wave equation into an ordinary wave equation, in either time-space coordinates or frequency-wavenumber coordinates. The transformations are shown to combine a Galilean transformation with a Lorentz transformation and geometrical and physical interpretations are provided. The Lorentzian frame is the natural frame for describing acoustic waves in uniform flow. A key feature of this frame is that it combines space and time in a way that is best described using a hyperbolic geometry. The power of this new theoretical framework is illustrated by providing simple derivations for two classical aeroacoustic problems: the free-field Greens function for the convected wave equation and the Doppler shift for a stationary observer and a source in un...

  8. Collective Lorentz invariant dynamics on a single "polynomial" worldline

    CERN Document Server

    Kassandrov, Vladimir V; Markova, Nina V

    2015-01-01

    Consider a worldline of a pointlike particle parametrized by polynomial functions, together with the light cone ("retardation") equation of an inertially moving observer. Then a set of apparent copies ("duplicons") of the single pointlike particle defined by the roots of the retardation equation and localized on one and the same worldline will be detected by the observer. We prove that for any "polynomial" worldline the induced collective dynamics of duplicons obeys a whole set of canonical conservation laws (for total momentum, angular momentum and the analogue of mechanical energy). Explicit formulas for the values of total angular momentum and the analogue of total rest energy (rest mass) are obtained; the latter is "self-quantized", i.e. for any worldline takes only integer values. The dynamics is Lorentz invariant though different from the canonical relativistic mechanics. Asymptotically, at large values of the observer's proper time, the duplicons split themselves into pairs ("first phase transition") a...

  9. Cosmic Censorship in Lorentz Violating Theories of Gravity

    CERN Document Server

    Meiers, Michael; Afshordi, Niayesh

    2015-01-01

    Is Cosmic Censorship special to General Relativity, or can it survive a violation of equivalence principle? Recent studies have shown that singularities in Lorentz violating Einstein-Aether (or Horava-Lifhsitz) theories can lie behind a universal horizon in simple black hole spacetimes. Even infinitely fast signals cannot escape these universal horizons. We extend this result, for an incompressible aether, to 3+1d dynamical or spinning spacetimes which possess inner killing horizons, and show that a universal horizon always forms in between the outer and (would-be) inner horizons. This finding suggests a notion of Cosmic Censorship, given that geometry in these theories never evolves beyond the universal horizon (avoiding potentially singular inner killing horizons). A surprising result is that there are 3 distinct possible stationary universal horizons for a spinning black hole, only one of which matches the dynamical spherical solution. This motivates dynamical studies of collapse in Einstein-Aether theorie...

  10. 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...

  11. Low energy Lorentz violation from polymer quantum field theory

    CERN Document Server

    Husain, Viqar

    2015-01-01

    We analyze the response of an inertial two-level Unruh-DeWitt particle detector coupled to a polymer quantized scalar field in four-dimensional Minkowski spacetime, within first-order perturbation theory. Above a critical rapidity $\\beta_c \\approx 1.3675$, independent of the polymer mass scale $M_\\star$, two drastic changes occur: (i) the detector's excitation rate becomes nonvanishing; (ii) the excitation and de-excitation rates are of order $M_\\star$, for arbitrarily small detector energy gap. We argue that qualitatively similar results hold for any Lorentz violating theory in which field modes with spatial momentum $k$ have excitation energy of the form $|k|\\ f(|k|/M_\\star)$ where the function $f$ dips below unity.

  12. Signals for Lorentz Violation in Post-Newtonian Gravity

    CERN Document Server

    Bailey, Q G; Bailey, Quentin G.; Kostelecky, Alan

    2006-01-01

    The pure-gravity sector of the minimal Standard-Model Extension is studied in the limit of Riemann spacetime. A method is developed to extract the modified Einstein field equations in the limit of small metric fluctuations about the Minkowski vacuum, while allowing for the dynamics of the coefficients for Lorentz violation. The linearized effective equations depend on 20 independent coefficients, and they are solved to obtain the post-newtonian metric. The corresponding post-newtonian behavior of a perfect fluid is studied and applied to the gravitating many-body system. Illustrative examples of the methodology are provided using bumblebee models. The implications of the general theoretical results are studied for a variety of existing and proposed gravitational experiments, including lunar and satellite laser ranging, laboratory experiments with gravimeters and torsion pendula, measurements of the spin precession of orbiting gyroscopes, timing studies of signals from binary pulsars, and the classic tests inv...

  13. Lorentz violating p-form gauge theories in superspace

    Science.gov (United States)

    Upadhyay, Sudhaker; Shah, Mushtaq B.; Ganai, Prince A.

    2017-03-01

    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.

  14. Lorentz violation for photons and ultrahigh-energy cosmic rays.

    Science.gov (United States)

    Galaverni, Matteo; Sigl, Günter

    2008-01-18

    Lorentz symmetry breaking at very high energies may lead to photon dispersion relations of the form omega2=k2+xink2(k/MPl)n with new terms suppressed by a power n of the Planck mass MPl. We show that first and second order terms of size |xi1|>orsimilar10(-14) and xi2

  15. Proposed test of Lorentz Invariance using the Gravitational Wave Interferometers

    CERN Document Server

    Melissinos, Adrian C

    2016-01-01

    Current limits on violation of local Lorentz invariance in the photon sector are derived mainly from experiments that search for a spatial anisotropy in the speed of light. The presently operating gravitational wave detectors are Michelson interferometers with long effective arms, 4e5 m, and sensitive to a fringe shift 2e-9. Therefore they can be used to test for a difference in the speed of light in the two arms, as modulated bi-annualy by the orientation of the Earth's velocity with respect to the direction of motion of the local system. A limit can be set on the Robertson-Mansouri-Sexl parameter PMM < 10e-15, as compared to its present limit of PMM < 2e-10, an improvement of five orders of magnitude.

  16. Lorentz effect imaging of ionic currents in solution

    Science.gov (United States)

    Truong, Trong-Kha; Avram, Alexandru; Song, Allen W.

    2008-03-01

    Current functional MRI techniques relying on hemodynamic modulations are inherently limited in their ability to accurately localize neural activity in space and time. To address these limitations, we previously proposed a novel technique based on the Lorentz effect and demonstrated its ability to directly image minute electrical activity with a millisecond temporal resolution in gel phantoms containing conductive wires as well as in the human median nerve in vivo. To better characterize its contrast mechanism and ultimately further improve its sensitivity for in vivo applications, we now apply this technique to image ionic currents in solution, which serve as a better model for neural conduction in biological systems than the electronic currents in conductive wires used in previous phantom studies. Our results demonstrate that ionic currents with durations and current densities on the same order of magnitude as those induced by neuroelectric activity in nerve fibers and in the brain can be detected.

  17. Bounding isotropic Lorentz violation using synchrotron losses at LEP

    Science.gov (United States)

    Altschul, Brett

    2009-11-01

    Some deviations from special relativity—especially isotropic effects—are most efficiently constrained using particles with velocities very close to 1. While there are extremely tight bounds on some of the relevant parameters coming from astrophysical observations, many of these rely on our having an accurate understanding of the dynamics of these high-energy sources. It is desirable to have reliable laboratory constraints on these same parameters. The fastest-moving particles in a laboratory were electrons and positrons at LEP. The energetics of the LEP beams were extremely well understood, and measurements of the synchrotron emission rate indicate that the isotropic Lorentz violation coefficient |κ˜tr-(4)/(3)c00| must be smaller than 5×10-15.

  18. Test of Lorentz invariance with spin precession of ultracold neutrons

    CERN Document Server

    Altarev, I; Ban, G; Bison, G; Bodek, K; Daum, M; Fierlinger, P; Geltenbort, P; Green, K; van der Grinten, M G D; Gutsmiedl, E; Harris, P G; Heil, W; Henneck, R; Horras, M; Iaydjiev, P; Ivanov, S N; Khomutov, N; Kirch, K; Kistryn, S; Knecht, A; Knowles, P; Kozela, A; Kuchler, F; Kuźniak, M; Lauer, T; Lauss, B; Lefort, T; Mtchedlishvili, A; Naviliat-Cuncic, O; Pazgalev, A; Pendlebury, J M; Petzoldt, G; Pierre, E; Pignol, G; Quéméner, G; Rebetez, M; Rebreyend, D; Roccia, S; Rogel, G; Severijns, N; Shiers, D; Sobolev, Yu; Weis, A; Zejma, J; Zsigmond, G

    2009-01-01

    A clock comparison experiment, analyzing the ratio of spin precession frequencies of stored ultracold neutrons and 199Hg atoms is reported. No daily variation of this ratio could be found, from which is set an upper limit on the Lorentz invariance violating cosmic anisotropy field b < 2 * 10^{-20} eV (95% C.L.). This is the first limit for the free neutron. This result is also interpreted as a direct limit on the gravitational dipole moment of the neutron |g_n| < 0.3 eV.c^{-2}.m from a spin-dependent interaction with the Sun. Analyzing the gravitational interaction with the Earth, based on previous data, yields a more stringent limit |g_n| < 3 * 10^{-4} eV.c^{-2}.m.

  19. The electrodeless Lorentz force (ELF) thruster experimental facility

    Science.gov (United States)

    Weber, T. E.; Slough, J. T.; Kirtley, D.

    2012-11-01

    An innovative facility for testing high-power, pulsed plasmoid thrusters has been constructed to develop the electrodeless Lorentz force (ELF) thruster concept. It is equipped with a suite of diagnostics optimized to study the physical processes taking place within ELF and evaluate its propulsive utility including magnetic field, neutral gas, and plasma flux diagnostics, a method to determine energy flow into the plasma from the pulsed power systems, and a new type of ballistic pendulum, which enables thrust to be measured without the need for installing the entire propulsion system on a thrust stand. Variable magnetic fields allow controlled studies of plume expansion in a small-scale experiment and dielectric chamber walls reduce electromagnetic influences on plasma behavior and thruster operation. The unique capabilities of this facility enable novel concept development to take place at greatly reduced cost and increased accessibility compared to testing at large user-facilities.

  20. 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.)

  1. New Limits on Local Lorentz Invariance in Mercury and Cesium

    CERN Document Server

    Peck, S K; Stein, D; Orbaker, D; Foss, A; Hummon, M T; Hunter, L R

    2012-01-01

    We report new bounds on Local Lorentz Invariance (LLI) violation in Cs and Hg. The limits are obtained through the observation of the the spin- precession frequencies of 199Hg and 133Cs atoms in their ground states as a function of the orientation of an applied magnetic field with respect to the fixed stars. We measure the amplitudes of the dipole couplings to a preferred direction in the equatorial plane to be 19(11) nHz for Hg and 9(5) microHz for Cs. The upper bounds established here improve upon previous bounds by about a factor of four. The improvement is primarily due to mounting the apparatus on a rotating table. New bounds are established on several terms in the standard model extension including the first bounds on the spin-couplings of the neutron and proton to the z direction, <7e-30 GeV and <7e-29 GeV, respectively.

  2. Renormalization of a Lorentz invariant doubled worldsheet theory

    CERN Document Server

    Nibbelink, Stefan Groot; Patalong, Peter

    2013-01-01

    Manifestly T-duality covariant worldsheet string models can be constructed by doubling the coordinate fields. We describe the underlying gauge symmetry of a recently proposed Lorentz invariant doubled worldsheet theory that makes half of the worldsheet degrees of freedom redundant. By shifting the Lagrange multiplier, that enforces the gauge fixing condition, the worldsheet action can be cast into various guises. We investigate the renormalization of this theory using a non-linear background/quantum split by employing a normal coordinate expansion adapted to the gauge-fixed theory. The propagator of the doubled coordinates contains a projection operator encoding that half of them do not propagate. We determine the doubled target space equations of motion by requiring one-loop Weyl invariance. Some of them are generalizations of the conventional sigma model beta-functions, while others seem to be novel to the doubled theory: In particular, a dilaton equation seems related to the strong constraint of double fie...

  3. An Off Diagonal Marcinkiewicz Interpolation Theorem on Lorentz Spaces

    Institute of Scientific and Technical Information of China (English)

    Yi Yu LIANG; Li Guang LIU; Da Chun YANG

    2011-01-01

    Let(X,μ)be a measure space.In this paper,using some ideas from Grafakos and Kalton,the authors establish an of diagonal Marcinkiewicz interpolation theorem for a quasilinear operator T in Lorentz spaces Lp,q(X)with p,q∈(0,∞],which is a corrected version of Theorem 1.4.19 in[Grafakos,L.:Classical Fourier Analysis,Second Edition,Graduate Texts in Math.,No.249,Springer,New York,2008]and which,in the case that T is linear or nonnegative sublineaa,P∈[1,∞)and q∈[1,∞),was obtained by Stein and Weiss [Introduction to Fourier Analysis on Euclidean Spaces,Princeton University Press,Princeton,N.J.,1971].

  4. Lorentz violation in the gravity sector: the t puzzle

    CERN Document Server

    Bonder, Yuri

    2015-01-01

    Lorentz violation is a candidate quantum-gravity signal, and the Standard-Model Extension (SME) is a widely used parametrization of such violation. In the gravitational SME sector, there is an elusive coefficient for which no effects have been found. This is is known as the $t$ puzzle and, to date, it has no compelling explanation. In this paper, several approaches to understand the $t$ puzzle are proposed. First, redefinitions of the dynamical fields are studied, which reveal that other SME coefficients can be moved to nongravitational sectors. It is also shown that the gravity SME sector can be treated \\textit{\\`a la} Palatini, and that, in the presence of spacetime boundaries, it is possible to correct its action to get the desired equations of motion. Also, through a reformulation as a Lanczos-type tensor, some problematic features of the $t$ term, that should arise at the phenomenological level, are revealed. Additional potential explanations to the $t$ puzzle are outlined.

  5. Mechanical analogies for the Lorentz gauge, particles and antiparticles

    CERN Document Server

    Dmitriyev, V P

    2000-01-01

    An exact analogy of electromagnetic fields and particles can be found in mechanics of a turbulent ideal fluid with voids. The system is supposed to form a fine dispersion of voids in the fluid. This microscopically discontinuous medium is treated as a continuum. The turbulence is described in terms of the Reynolds stresses. Perturbations of the homogeneous isotropic turbulence are considered. For the high-energy low-pressure turbulence they are usually small. This entails the linearization of the Reynolds equations. The latter appear to be isomorphic to Maxwell's electromagnetic equations. The Lorentz gauge expresses the slight effective compressibility of the medium. A particle can be viewed as a cavity in the medium. A respective antiparticle is modeled with an agglomerate of the medium's material. Microscopically, these correspond to some nonlinear vortex formations in the "vortex sponge".

  6. Diffusion in the two-dimensional nonoverlapping Lorentz gas

    Science.gov (United States)

    James, Corinne P.; Evans, Glenn T.

    1987-10-01

    The self-diffusion coefficient, velocity autocorrelation function, and distribution of collision times for a two-dimensional nonoverlapping Lorentz gas were calculated using molecular dynamics simulation. The systems studied covered a range of densities, from a packing fraction (πNr2/L2) of 0.01 to 0.8. Self-diffusion coefficients were found to agree to all densities with kinetic theory predictions [A. Weijland and J. M. J. van Leeuwen, Physica 38, 35 (1968)] if the radial distribution function (rdf) was taken into account. The density dependence of the decay of the velocity autocorrelation function was qualitatively different from that predicted by kinetic theory. The distribution of collision times was nearly exponential for all but the highest density studied.

  7. Chiral Dynamics of Baryons in a Lorentz Covariant Quark Model

    CERN Document Server

    Faessler, A; Lyubovitskij, V E; Pumsa-ard, K; Faessler, Amand; Gutsche, Th.

    2006-01-01

    We develop a manifestly Lorentz covariant chiral quark model for the study of baryons as bound states of constituent quarks dressed by a cloud of pseudoscalar mesons. The approach is based on a non-linear chirally symmetric Lagrangian, which involves effective degrees of freedom - constituent quarks and the chiral (pseudoscalar meson) fields. In a first step, this Lagrangian can be used to perform a dressing of the constituent quarks by a cloud of light pseudoscalar mesons and other heavy states using the calculational technique of infrared dimensional regularization of loop diagrams. We calculate the dressed transition operators with a proper chiral expansion which are relevant for the interaction of quarks with external fields in the presence of a virtual meson cloud. In a second step, these dressed operators are used to calculate baryon matrix elements. Applications are worked out for the masses of the baryon octet, the meson-nucleon sigma terms, the magnetic moments of the baryon octet, the nucleon charge...

  8. Massive photons from Super and Lorentz symmetry breaking

    CERN Document Server

    Bonetti, Luca; Helayël-Neto, José A; Spallicci, Alessandro D A M

    2016-01-01

    In the context of Standard Model Extensions (SMEs), we analyse four general classes of Super Symmetry (SuSy) and Lorentz Symmetry (LoSy) breaking, leading to {observable} imprints at our energy scales. The photon dispersion relations show a non-Maxwellian behaviour for the CPT (Charge-Parity-Time reversal symmetry) odd and even sectors. The group velocities exhibit also a directional dependence with respect to the breaking background vector (odd CPT) or tensor (even CPT). In the former sector, the group velocity may decay following an inverse squared frequency behaviour. Thus, we extract a massive and gauge invariant Carroll-Field-Jackiw photon term in the Lagrangian and show that the mass is proportional to the breaking vector. The latter is estimated by ground measurements and leads to a photon mass upper limit of $10^{-19}$ eV or $2 \\times 10^{-55}$ kg and thereby to a potentially measurable delay at low radio frequencies.

  9. 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.)

  10. Cosmological background torsion inhomogeneities and Lorentz violation in QED

    CERN Document Server

    Garcia de Andrade, L C

    2003-01-01

    A non-minimal photon-torsion axial coupling in the quantum electrodynamics (QED) framework is considered. The geometrical optics in Riemann-Cartan spacetime is considering and a plane wave expansion of the electromagnetic vector potential is considered leading to a set of the equations for the ray congruence. Since we are interested mainly on the torsion effects in this first report we just consider the Riemann-flat case composed of the Minkowskian spacetime with torsion. It is also shown that in torsionic de Sitter background the vacuum polarisation does alter the propagation of individual photons, an effect which is absent in Riemannian spaces. It is shown that the cosmological torsion background inhomogeneities induce Lorentz violation and massive photon modes in this QED.

  11. Integración de Ecuaciones Diferenciales rígidas de valor de contorno en problemas de combustión con cinética de reacción detallada

    OpenAIRE

    Hahn, W. A.; Wendt, J. O. L.

    2009-01-01

    Modelos detallados de la llama de difusión plana, laminar de jets opuestos requieren la solución de las ecuaciones de conservación de cantidad de movimiento, energía y especies químicas en conjunto con una cinética de reacción química stiff. El problema tiene soluciones autosimilares y se puede resolver mediante integración numérica de un conjunto de ecuaciones diferenciales ordinarias stiff de segundo orden, con condiciones de contorno, cada una de las cuales tiene un punto de torno de...

  12. Relative dynamics and control of spacecraft formations subject to lorentz force perturbations

    Science.gov (United States)

    Abdel-Aziz, Yehia; Shoaib, Muhammad

    A spacecraft that generates an electrostatic charge on its surface in the Earth magnetic field will be subject to a perturbative Lorentz force. The Lorentz force acting on an electrostatically charged spacecraft may provide a useful thrust for controlling a spacecraft’s orbit. We develop Lorentz force as a function of the orbital elements. The orbital perturbations of a charged spacecraft by Lorentz force in the Earth’s magnetic field are investigated using the Gauss variation of the Lagrange planetary Equations. The Earth’s magnetic field is modeled as a tilted dipole. The perturbations in the orbital elements depend on the value of the charge to mass ratio (q/m). The dynamical model of relative motion developed leads to approximate analytical solutions for the motion of a charged spacecraft subject to Lorentz force. The chief spacecraft’s reference orbit is taken to be either circular or elliptical. The deputy spacecraft is capable of accumulating electrostatic charge. The numerical results show that Lorentz force can be used to change the in-track position and plane orbit of the spacecraft. The numerical analysis shows that the target trajectory of the Lorentz spacecraft can be reached by varying the ratio (q/m) in different Low Earth Orbits.

  13. 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.

  14. 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.

  15. Time-delay and Doppler tests of the Lorentz symmetry of gravity

    CERN Document Server

    Bailey, Quentin G

    2009-01-01

    Modifications to the classic time-delay effect and Doppler shift in General Relativity (GR) are studied in the context of the Lorentz-violating Standard-Model Extension (SME). We derive the leading Lorentz-violating corrections to the time-delay and Doppler shift signals, for a light ray passing near a massive body. It is demonstrated that anisotropic coefficients for Lorentz violation control a time-dependent behavior of these signals that is qualitatively different from the conventional case in GR. Estimates of sensitivities to gravity-sector coefficients in the SME are given for current and future experiments, including the recent Cassini solar conjunction experiment.

  16. Lorentz-violating neutral-pion decays in isotropic modified Maxwell theory

    CERN Document Server

    Klinkhamer, F R

    2016-01-01

    We consider an extension of the Standard Model with isotropic nonbirefringent Lorentz violation in the photon sector and specialize to the case of a "fast" photon with a phase velocity larger than the maximum attainable velocity of the fermions. With our conventions, this case corresponds to a negative Lorentz-violating parameter $\\kappa$ in the action. The decay rate of a neutral pion into two photons is calculated as a function of the 3-momentum of the initial pion and the negative Lorentz-violating parameter $\\kappa$ of the final photons.

  17. Searching for photon-sector Lorentz violation using gravitational-wave detectors

    CERN Document Server

    Kostelecky, Alan; Mewes, Matthew

    2016-01-01

    We study the prospects for using interferometers in gravitational-wave detectors as tools to search for photon-sector violations of Lorentz symmetry. Existing interferometers are shown to be exquisitely sensitive to tiny changes in the effective refractive index of light occurring at frequencies around and below the microhertz range, including at the harmonics of the frequencies of the Earth's sidereal rotation and annual revolution relevant for tests of Lorentz symmetry. We use preliminary data obtained by the Laser Interferometer Gravitational-Wave Observatory (LIGO) in 2006-2007 to place constraints on coefficients for Lorentz violation in the photon sector exceeding current limits by about four orders of magnitude.

  18. First Test of Lorentz Violation with a Reactor-based Antineutrino Experiment

    CERN Document Server

    Abe, Y; Anjos, J C dos; Bergevin, M; Bernstein, A; Bezerra, T J C; Bezrukhov, L; Blucher, E; Bowden, N S; Buck, C; Busenitz, J; Cabrera, A; Caden, E; Camilleri, L; Carr, R; Cerrada, M; Chang, P -J; Chimenti, P; Classen, T; Collin, A P; Conover, E; Conrad, J M; Crespo-Anadón, J I; Crum, K; Cucoanes, A; D'Agostino, M V; Damon, E; Dawson, J V; Dazeley, S; Dietrich, D; Djurcic, Z; Dracos, M; Durand, V; Ebert, J; Efremenko, Y; Elnimr, M; Erickson, A; Fallot, M; Fechner, M; von Feilitzsch, F; Felde, J; Fischer, V; Franco, D; Franke, A J; Franke, M; Furuta, H; Gama, R; Gil-Botella, I; Giot, L; Göger-Neff, M; Gonzalez, L F G; Goodman, M C; Goon, J TM; Greiner, D; Haag, N; Habib, S; Hagner, C; Hara, T; Hartmann, F X; Haser, J; Hatzikoutelis, A; Hayakawa, T; Hofmann, M; Horton-Smith, G A; Ishitsuka, M; Jochum, J; Jollet, C; Jones, C L; Kaether, F; Kalousis, L N; Kamyshkov, Y; Kaplan, D M; Katori, T; Kawasaki, T; Keefer, G; Kemp, E; de Kerret, H; Konno, T; Kryn, D; Kuze, M; Lachenmaier, T; Lane, C E; Lasserre, T; Letourneau, A; Lhuillier, D; Lima, H P; Lindner, M; López-Castanõ, J M; LoSecco, J M; Lubsandorzhiev, B K; Lucht, S; McKee, D; Maeda, J; Maesano, C N; Mariani, C; Maricic, J; Martino, J; Matsubara, T; Mention, G; Meregaglia, A; Meyer, M; Miletic, T; Milincic, R; Miyata, H; Mueller, Th A; Nagasaka, Y; Nakajima, K; Novella, P; Obolensky, M; Oberauer, L; Onillon, A; Osborn, A; Ostrovskiy, I; Palomares, C; Pepe, I M; Perasso, S; Perrin, P; Pfahler, P; Porta, A; Potzel, W; Pronost, G; Reichenbacher, J; Reinhold, B; Remoto, A; Röhling, M; Roncin, R; Roth, S; Rybolt, B; Sakamoto, Y; Santorelli, R; Sato, F; Schönert, S; Schoppmann, S; Schwetz, T; Shaevitz, M H; Shrestha, D; Sida, J -L; Sinev, V; Skorokhvatov, M; Smith, E; Spitz, J; Stahl, A; Stancu, I; Stokes, L F F; Strait, M; Stüken, A; Suekane, F; Sukhotin, S; Sumiyoshi, T; Sun, Y; Terao, K; Tonazzo, A; Toups, M; Thi, H H Trinh; Valdiviesso, G; Veyssiere, C; Wagner, S; Watanabe, H; White, B; Wiebusch, C; Winslow, L; Worcester, M; Wurm, M; Yanovitch, E; Yermia, F; Zimmer, V

    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 (SME), we set the first limits on fourteen Lorentz violating coefficients associated with transitions between electron and tau flavor, and set two competitive limits associated with transitions between electron and muon flavor.

  19. Strongly Enhanced Effects of Lorentz-Symmetry Violation in Yb$^+$ and Highly Charged Ions

    CERN Document Server

    Safronova, M S

    2016-01-01

    A Lorentz-symmetry test with Ca$^+$ ions demonstrated the potential of using quantum information inspired technology for tests of fundamental physics. A systematic study of atomic-system sensitivities to Lorentz violation identified the ytterbium ion as an ideal system with high sensitivity as well as excellent experimental controllability. A test of Lorentz-violating physics in the electron-photon sector with Yb$^+$ ions has the potential to reach levels of 10$^{-23}$, five orders of magnitude more sensitive than the current best bounds. Similar sensitivities may be also reached with highly charged ions.

  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. Search for Lorentz and CPT Violation Effects in Muon Spin Precession

    CERN Document Server

    Bennett, G W; Brown, H N; Bunce, G; Carey, R M; Cushman, P; Danby, G T; Debevec, P T; Deile, M; Deng, H; Deninger, W; Dhawan, S K; Druzhinin, V P; Duong, L; Efstathiadis, E; Farley, F J M; Fedotovich, G V; Giron, S; Gray, F E; Grigoriev, D; Grosse-Perdekamp, M; Grossmann, A; Hare, M F; Hertzog, D W; Huang, X; Hughes, V W; Iwasaki, M; Jungmann, K; Kawall, D; Kawamura, M; Khazin, B I; Kindem, J; Krienen, F; Kronkvist, I; Lam, A; Larsen, R; Lee, Y Y; Logashenko, I; McNabb, R; Meng, W; Mi, J; Miller, J P; Mizumachi, Y; Morse, W M; Nikas, D; Onderwater, C J G; Orlov, Y; Ozben, C S; Paley, J M; Peng, Q; Polly, C C; Pretz, J; Prigl, R; zu Putlitz, G; Qian, T; Redin, S I; Rind, O; Roberts, B L; Ryskulov, N; Sedykh, S; Semertzidis, Y K; Shagin, P; Shatunov, Yu M; Sichtermann, E P; Solodov, E; Sossong, M; Steinmetz, A; Sulak, L R; Timmermans, C; Trofimov, A; Urner, D; von Walter, P; Warburton, D; Winn, D; Yamamoto, A; Zimmerman, D

    2007-01-01

    The spin precession frequency of muons stored in the (g-2) precision storage ring has been analyzed for evidence of Lorentz and CPT violation. Two Lorentz and CPT violation signatures were searched for: a nonzero \\Delta\\omega_a =\\omega_a ^\\mu^{+} - \\omega_{a}^\\mu^{-} ; and a sidereal variation of \\omega_{a}^\\mu^{\\pm}. No significant effect is found, and several limits on Lorentz and CPT violating parameters for positive and negative muons are set at the level of \\sim 10^{-23} - 10^{-24} GeV.

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

    CERN Document Server

    Borges, Luiz Henrique de Campos

    2016-01-01

    Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the Hydrogen atom are investigated. It is used standard Rayleigh-Schr\\"odinger perturbation theory in order to obtain the corrections to the the ground state energy and 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 reference Eur. Phys. J. C {\\bf 74}, 2937 (2014), where the Lorentz symmetry is broken in the electromagnetic sector.

  3. Asymptotic states and renormalization in Lorentz-violating quantum field theory

    CERN Document Server

    Cambiaso, Mauro; Potting, Robertus

    2014-01-01

    Asymptotic single-particle states in quantum field theories with small departures from Lorentz symmetry are investigated. To this end, one-loop radiative corrections for a sample Lorentz-violating Lagrangian contained in the Standard-Model Extension (SME) are studied. It is found that the spinor kinetic operator is modified in momentum space by Lorentz-violating operators not present in the original Lagrangian. It is demonstrated how both the standard renormalization procedure as well as the Lehmann-Symanzik-Zimmermann reduction formalism need to be adapted as a consequence of this result.

  4. 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.)

  5. 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

  6. Dinâmica de uma partícula neutra em mecânica quântica não-comulativa e em um regime de quebra da simetria de Lorentz

    OpenAIRE

    Ribeiro Filho, Lincoln Rodrigues

    2008-01-01

    Investigamos alguns fen^omenos qu^anticos, como fases topol ogicas e quantiza c~ao de Landau, em um contexto n~ao-relativ stico da mec^anica qu^antica n~ao-comutativa e em regime de quebra da simetria de Lorentz. Apresentamos esses efeitos como o estudo da mec^anica qu^antica do movimentos de part culas neutras na presen ca de campos eletromagn eticos. Por isso usamos a denomina c~ao \\efeitos an alogos". Sob certas condi c~oes para con gura c~ao dos campos, podemos encontrar...

  7. Testing Lorentz Invariance Using an Odd-Parity Asymmetric Optical Resonator

    CERN Document Server

    Baynes, Fred; Tobar, Michael

    2011-01-01

    We present the first experimental test of Lorentz invariance using the frequency difference between counter-propagating modes in an asymmetric odd-parity optical resonator. This type of test is $\\sim10^{4}$ more sensitive to odd-parity and isotropic (scalar) violations of Lorentz invariance than equivalent conventional even-parity experiments due to the asymmetry of the optical resonator. The disadvantages of odd parity resonators have been negated by the use of counter-propagating modes, delivering a high level of immunity to environmental fluctuations. With a non-rotating experiment our result limits the isotropic Lorentz violating parameter $\\tilde{\\kappa}_{tr}$ to 3.4 $\\pm$ 6.2 x $10^{-9}$, the best reported constraint from direct measurements. Using this technique the bounds on odd-parity and scalar violations of Lorentz invariance can be improved by many orders of magnitude.

  8. The remnant group of local Lorentz transformations in f(T) theories

    CERN Document Server

    Ferraro, Rafael

    2014-01-01

    It is shown that the extended teleparallel gravitational theories, known as f(T) theories, inherit some \\emph{on shell} local Lorentz invariance associated with the tetrad field defining the spacetime structure. We discuss some enlightening examples, such as Minkowski spacetime and cosmological (FRW and Bianchi type I) manifolds. In the first case, we show that the absence of gravity reveals itself as an incapability in the selection of a preferred parallelization at a local level, due to the fact that the infinitesimal local Lorentz subgroup acts as a symmetry group of the frame characterizing Minkowski spacetime. Finite transformations are also discussed in these examples and, contrary to the common lore on the subject, we conclude that the set of tetrads responsible of the parallelization of these manifolds is quite vast and that the remnant group of local Lorentz transformations includes one and two dimensional abelian subgroups of the Lorentz group.

  9. 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].

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

    CERN Document Server

    Rubtsov, Grigory; Sibiryakov, Sergey

    2016-01-01

    We discuss the effect of hypothetical violation of Lorentz invariance at high energies 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.

  11. Implications of Lorentz symmetry violation on a 5D supersymmetric model

    Science.gov (United States)

    García-Aguilar, J. D.; Pérez-Lorenzana, A.

    2017-04-01

    Field models with n extra spatial dimensions have a larger SO(1, 3 + n) Lorentz symmetry which is broken down to the standard SO(1, 3) four-dimensional one by the compactification process. By considering Lorentz violating operators in a 5D supersymmetric Wess-Zumino model, which otherwise conserve the standard four-dimensional Poincaré invariance, we show that supersymmetry (SUSY) can be restored upon a simple deformation of the supersymmetric transformations. However, SUSY is not preserved in the effective 4D theory that arises after compactification when the 5D Lorentz violating operators do not preserve Z2 : y →-y bulk parity. Our mechanism unveils a possible connection among Lorentz violation and the Scherk-Schwarz mechanism. We also show that parity preserving models, on the other hand, do provide well defined supersymmetric KK models.

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

    Science.gov (United States)

    Luo, Cheng-Jian; Kuang, Xiao-Mei; Shu, Fu-Wen

    2017-06-01

    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.

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

    Science.gov (United States)

    Rubtsov, Grigory; Satunin, Petr; Sibiryakov, Sergey

    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.

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

    Directory of Open Access Journals (Sweden)

    L.H.C. Borges

    2016-05-01

    Full Text Available 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. Charged Lifshitz black hole and probed Lorentz-violation fermions from holography

    Directory of Open Access Journals (Sweden)

    Cheng-Jian Luo

    2017-06-01

    Full Text Available 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.

  16. Preliminary Design of a Pendulum Experiment for Searching for a Lorentz-Violation Signal

    CERN Document Server

    Shao, Cheng-Gang; Tan, Yu-Jie

    2016-01-01

    This work mainly presents a preliminary design for a pendulum experiment with both the source mass and the test mass in a striped pattern to amplify the Lorentz-violation signal, since the signal is sensitive to edge effects.

  17. 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.)

  18. Wigner rotations, Bell states, and Lorentz invariance of entanglement and von Neumann entropy

    CERN Document Server

    Soo, C; Soo, Chopin; Lin, Cyrus C. Y.

    2003-01-01

    We compute, for massive particles, the explicit Wigner rotations of one-particle states for arbitrary Lorentz transformations; and the explicit Hermitian generators of the infinite-dimensional unitary representation. For a pair of spin 1/2 particles, Einstein-Podolsky-Rosen-Bell entangled states and their behaviour under the Lorentz group are analysed in the context of quantum field theory. Group theoretical considerations suggest a convenient definition of the Bell states which is slightly different from the conventional assignment. The behaviour of Bell states under arbitrary Lorentz transformations can then be described succinctly. Reduced density matrices applicable to identical particles are defined through Yang's prescription. The von Neumann entropy of each of the reduced density matrix is Lorentz invariant; and its relevance as a measure of entanglement is discussed, and illustrated with an explicit example. A regularization of the entropy in terms of generalized zeta functions is also suggested.

  19. Two-pion exchange NN potential from Lorentz-invariant $\\chi$EFT

    Energy Technology Data Exchange (ETDEWEB)

    Higa, Renato; Robilotta, Manoel; da Rocha, Carlos A

    2006-10-12

    We outline the progress made in the past five years by the Sao Paulo group in the development of a two-pion exchange nucleon-nucleon potential within a Lorentz-invariant framework of (baryon) chiral perturbation theory.

  20. Differential Geometry of Curves and Surfaces in Lorentz-Minkowski space

    OpenAIRE

    2008-01-01

    We review part of the classical theory of curves and surfaces in $3$-dimensional Lorentz-Minkowski space. We focus in spacelike surfaces with constant mean curvature pointing the differences and similarities with the Euclidean space.