3,251 research outputs found

    Non-linear metric perturbation enhancement of primordial gravitational waves

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    We present the evolution of the full set of Einstein equations during preheating after inflation. We study a generic supersymmetric model of hybrid inflation, integrating fields and metric fluctuations in a 3-dimensional lattice. We take initial conditions consistent with Eintein's constraint equations. The induced preheating of the metric fluctuations is not large enough to backreact onto the fields, but preheating of the scalar modes does affect the evolution of vector and tensor modes. In particular, they do enhance the induced stochastic background of gravitational waves during preheating, giving an energy density in general an order of magnitude larger than that obtained by evolving the tensors fluctuations in an homogeneous background metric. This enhancement can improve the expectations for detection by planned gravitational waves observatories.Comment: 5 pages, 4 eps figures, matches Phys. Rev. Lett. versio

    Scattering processes could distinguish Majorana from Dirac neutrinos

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    It is well known that Majorana neutrinos have a pure axial neutral current interaction while Dirac neutrinos have the standard vector-axial interaction. In spite of this crucial difference, usually Dirac neutrino processes differ from Majorana processes by a term proportional to the neutrino mass, resulting in almost unmeasurable observations of this difference. In the present work we show that once the neutrino polarization evolution is considered, there are clear differences between Dirac and Majorana scattering on electrons. The change of polarization can be achieved in astrophysical environments with strong magnetic fields. Furthermore, we show that in the case of unpolarized neutrino scattering onto polarized electrons, this difference can be relevant even for large values of the neutrino energy.Comment: 12 pages, 5 figure

    Non-linear Preheating with Scalar Metric Perturbations

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    We have studied preheating of field perturbations in a 3-dimensional lattice including the effect of scalar metric perturbations, in two generic models of inflation: chaotic inflation with a quartic potential, and standard hybrid inflation. We have prepared the initial state for the classical evolution of the system with vanishing vector and tensor metric perturbations, consistent with the constraint equations, the energy and momentum constraints. The non-linear evolution inevitably generates vector and tensor modes, and this reflects on how well the constraint equations are fulfilled during the evolution. The induced preheating of the scalar metric perturbations is not large enough to backreact onto the fields, but it could affect the evolution of vector and tensor modes. This is the case in hybrid inflation for some values of the coupling gg and the height of potential V01/4V_0^{1/4}. For example with V01/41015V_0^{1/4} \simeq 10^{15} GeV, preheating of scalar perturbations is such that their source term in the evolution equation of tensor and vector becomes comparable to that of the field anisotropic stress.Comment: 15 pages, 12 eps figure

    The scalar sector in the Myers-Pospelov model

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    We construct a perturbative expansion of the scalar sector in the Myers-Pospelov model, up to second order in the Lorentz violating parameter and taking into account its higher-order time derivative character. This expansion allows us to construct an hermitian positive-definite Hamiltonian which provides a correct basis for quantization. Demanding that the modified normal frequencies remain real requires the introduction of an upper bound in the magnitude |k| of the momentum, which is a manifestation of the effective character of the model. The free scalar propagator, including the corresponding modified dispersion relations, is also calculated to the given order, thus providing the starting point to consider radiative corrections when interactions are introduced.Comment: Published in AIP Conf.Proc.977:214-223,200

    The Virtual Environments and Platforms in the Teaching of English

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    Abstract The research aims to highlight the significance of virtual learning environments and platforms in promoting cognitive competencies through interactive learning. The objective is to create effective learning environments by utilizing Virtual Learning Environments and implementing platforms to enhance communicative competencies. The methodology employed for this study includes quantitative and qualitative, descriptive, and predictive approaches, using technological innovation through the implementation of the Schoology platform based on the TPACK model. The results of the study indicate that students exhibit high levels of motivation and discernment toward virtual environments, particularly in English classes. Therefore, selecting appropriate didactic resources and incorporating pedagogical mediation is crucial for optimizing learning outcomes. It is essential to educate students on the significance of learning a foreign language and how it can impact the neural structure of the bilingual brain. Virtual environments facilitate interaction between team members, leading to the creation of new networks and learning environments for the development of language and communicative competencies in another language. Keywords: virtual environments, English teaching, technological innovation, TPACK model. Resumen La investigación se enfoca en la importancia de los entornos y plataformas virtuales de aprendizaje porque permiten la interacción para desarrollar competencias cognitivas, para ello el objetivo consiste en generar ambientes de aprendizaje basados en los Entornos Virtuales de Aprendizaje, mediante la implementación de plataformas y fortalecer las competencias comunicativas, con este fin la metodología tiene un enfoque cuantitativo – cualitativo, de naturaleza descriptiva y predictiva desde la innovación tecnológica con la implementación de plataforma Schoology basados en el modelo TPACK. De acuerdo a los resultados, se evidencia que existe un alto discernimiento y motivación de los estudiantes a la implementación de los entornos virtuales, en particular a las clases de inglés. Para lo cual la necesidad de una mediación pedagógica en la selección de los recursos didácticos podría potencializar aún más el aprendizaje, para ello es fundamental hacer comprender a los estudiantes la relevancia de aprender un idioma extranjero y como este cambia en la estructura neuronal y su trascendencia en un cerebro bilingüe. Por tanto, los entornos virtuales promueven la interacción entre equipos de trabajo con la finalidad de generar nuevas redes y ambientes de aprendizaje, para el desarrollo de competencias lingüísticas y comunicativas en otro idioma. Palabras Clave: entornos virtuales, enseñanza inglesa, innovación tecnológica, modelo TPACK

    Teaching English From the Multiple Intelligences Theory Approach for Bilingualism Development

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    discoveries to understand the functioning and cognitive process of the brain. The study aims to determine strategies based on multiple intelligences and their relationship with cognitive neuroscience to improve English language learning processes. To achieve this, a theoreticalpractical methodological approach was proposed through the review of bibliographic information from researchers whose studies aim to improve mental processes for learning another language. It is worth highlighting the importance of the results where the teacher’s role is to apply the learning strategies and styles in students to promote new cognitive developments, skills, and motivation, despite the fact that students possess different multiple intelligences. In addition, emotional intelligence is strengthened, and the importance of neuroscience in the context of neuroplasticity for learning English in the classroom is understood. For this purpose, strategies are presented for each intelligence. Furthermore, the bilingualism scale is presented in terms of flexibility with non-linguistic rules, producing an effect on other aspects of human knowledge. Additionally, arguments centered on neuroscience have been raised to indicate how the brain learns and its emotional connections, which contribute to linguistic processing, bringing us closer to a basic understanding of the central nervous system to inquire about the relationships between linguistic elements and mechanisms for learning another language. Keywords: multiple intelligences theory, English language teaching, bilingualism, cognitive neuroscience. Resumen Las Inteligencias Múltiples de Gardner ha evolucionado en las teorías sobre la mente, aportando descubrimientos para comprender el funcionamiento y el proceso cognitivo desde el cerebro; para lo cual, el objetivo es determinar las estrategias basados en las inteligencias múltiples y su relación con la neurociencia cognitiva para mejorar los procesos de aprendizaje del idioma inglés, para ello se planteó un enfoque metodológico teórico – práctico a través de la revisión de información bibliográfica de investigadores cuyos estudios buscan mejorar los procesos mentales para el aprendizaje de otro idioma, cabe destacarla importancia de los resultados donde el rol del profesor es aplicar las estrategias y estilos de aprendizaje en los estudiantes para promover nuevos desarrollos cognitivos, habilidades y motivación a pesar que el estudiante posee inteligencias múltiples distintos, además fortalecer la inteligencia emocional y comprender la importancia de la neurociencia en el contexto de la neuroplasticidad para el aprendizaje del inglés en el aula; para este efecto, se presenta estrategias para cada una de las inteligencias, asimismo la escala del bilingüismo en la flexibilidad a la hora de normas no necesariamente lingüísticas, esto produce un efecto sobre otros aspectos del conocimiento humano, además se ha topado argumentos centrados en la neurociencia para indicar como aprende el cerebro y sus conexiones emocionales, mismos que contribuyen al procesamiento lingüístico acercándonos a un conocimiento básico del sistema nervioso central para indagar sobre las relaciones entre los elementos lingüísticos y los mecanismos de aprender otro idioma. Palabras Clave: Teoría de las inteligencias Múltiples, enseñanza del inglés, bilingüismo, neurociencias cognitivas

    Asymfast, a method for convolving maps with asymmetric main beams

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    We describe a fast and accurate method to perform the convolution of a sky map with a general asymmetric main beam along any given scanning strategy. The method is based on the decomposition of the beam as a sum of circular functions, here Gaussians. It can be easily implemented and is much faster than pixel-by-pixel convolution. In addition, Asymfast can be used to estimate the effective circularized beam transfer functions of CMB instruments with non-symmetric main beam. This is shown using realistic simulations and by comparison to analytical approximations which are available for Gaussian elliptical beams. Finally, the application of this technique to Archeops data is also described. Although developped within the framework of Cosmic Microwave Background observations, our method can be applied to other areas of astrophysics.Comment: 9 pages, 4 figures, Phys. Rev. D, in pres
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