7,142 research outputs found

    A Family of Quasi-solvable Quantum Many-body Systems

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    We construct a family of quasi-solvable quantum many-body systems by an algebraic method. The models contain up to two-body interactions and have permutation symmetry. We classify these models under the consideration of invariance property. It turns out that this family includes the rational, hyperbolic (trigonometric) and elliptic Inozemtsev models as the particular cases.Comment: 9 pages, REVTeX4, final versio

    Quasi-exact solvability beyond the SL(2) algebraization

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    We present evidence to suggest that the study of one dimensional quasi-exactly solvable (QES) models in quantum mechanics should be extended beyond the usual \sla(2) approach. The motivation is twofold: We first show that certain quasi-exactly solvable potentials constructed with the \sla(2) Lie algebraic method allow for a new larger portion of the spectrum to be obtained algebraically. This is done via another algebraization in which the algebraic hamiltonian cannot be expressed as a polynomial in the generators of \sla(2). We then show an example of a new quasi-exactly solvable potential which cannot be obtained within the Lie-algebraic approach.Comment: Submitted to the proceedings of the 2005 Dubna workshop on superintegrabilit

    Nonlinear Pseudo-Supersymmetry in the Framework of N-fold Supersymmetry

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    We recall the importance of recognizing the different mathematical nature of various concepts relating to PT-symmetric quantum theories. After clarifying the relation between supersymmetry and pseudo-supersymmetry, we prove generically that nonlinear pseudo-supersymmetry, recently proposed by Sinha and Roy, is just a special case of N-fold supersymmetry. In particular, we show that all the models constructed by these authors have type A 2-fold supersymmetry. Furthermore, we prove that an arbitrary one-body quantum Hamiltonian which admits two (local) solutions in closed form belongs to type A 2-fold supersymmetry, irrespective of whether or not it is Hermitian, PT-symmetric, pseudo-Hermitian, and so on.Comment: 10 pages, no figures; typos correcte

    The classroom of Physical Education and students with disabilities

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    Este estudio versa sobre el proceso de construcción y validación de un instrumento estandarizado cuyo objetivo ha sido analizar la realidad educativa de los docentes de Educación Física en la etapa de primaria ante alumnado con discapacidad motora y derivar del mismo los elementos clave que justifiquen la construcción de un plan de formación permanente del profesorado en este ámbito. El proceso llevado a cabo paso por llevar a cabo en primer lugar un juicio de expertos y expertas para posteriormente someter el borrador de aquí derivado a un pilotaje con un total de 57 docentes de Córdoba. El cuestionario definitivo goza de las suficientes garantías para ser aplicado, analizado e interpretado y ha permitido extraer como dimensiones formativas las siguientes: didáctica de la Educación Física, herramientas didáctico educativas, estrategias de trabajo en el aula, habilidades para el ejercicio de la docentes y recursos tecnológicos

    Silent speech: restoring the power of speech to people whose larynx has been removed

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    Every year, some 17,500 people in Europe and North America lose the power of speech after undergoing a laryngectomy, normally as a treatment for throat cancer. Several research groups have recently demonstrated that it is possible to restore speech to these people by using machine learning to learn the transformation from articulator movement to sound. In our project articulator movement is captured by a technique developed by our collaborators at Hull University called Permanent Magnet Articulography (PMA), which senses the changes of magnetic field caused by movements of small magnets attached to the lips and tongue. This solution, however, requires synchronous PMA-and-audio recordings for learning the transformation and, hence, it cannot be applied to people who have already lost their voice. Here we propose to investigate a variant of this technique in which the PMA data are used to drive an articulatory synthesiser, which generates speech acoustics by simulating the airflow through a computational model of the vocal tract. The project goals, participants, current status, and achievements of the project are discussed below.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Statistical measure of complexity for quantum systems with continuous variables

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    The Fisher-Shannon statistical measure of complexity is analyzed for a continuous manifold of quantum observables. It is probed then than calculating it only in the configuration and momentum spaces will not give a complete description for certain systems. Then a more general measure for the complexity of a quantum system by the integration of the usual Fisher-Shannon measure over all the parameter space is proposed. Finally, these measures are applied to the concrete case of a free particle in a box.Comment: 6 pages, 5 figures. Published versio

    Confinement of electrons in layered metals

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    We analyze the out of plane hopping in models of layered systems where the in--plane properties deviate from Landau's theory of a Fermi liquid. We show that the hopping term acquires a non trivial energy dependence, due to the coupling to in plane excitations, and can be either relevant or irrelevant at low energies or temperatures. The latter is always the case if the Fermi level lies close to a saddle point in the dispersion relation.Comment: 4 pages, 1 eps figur
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