31,702 research outputs found

    On Duffin-Kemmer-Petiau particles with a mixed minimal-nonminimal vector coupling and the nondegenerate bound states for the one-dimensional inversely linear background

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    The problem of spin-0 and spin-1 bosons in the background of a general mixing of minimal and nonminimal vector inversely linear potentials is explored in a unified way in the context of the Duffin-Kemmer-Petiau theory. It is shown that spin-0 and spin-1 bosons behave effectively in the same way. An orthogonality criterion is set up and it is used to determine uniquely the set of solutions as well as to show that even-parity solutions do not exist.Comment: 10 page

    Science with the World Space Observatory - Ultraviolet

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    The World Space Observatory-Ultraviolet (WSO-UV) will provide access to the UV range during the next decade. The instrumentation on board will allow to carry out high resolution imaging, high sensitivity imaging, high resolution (R~55000) spectroscopy and low resolution (R~2500) long slit spectroscopy. In this contribution, we briefly outline some of the key science issues that WSO-UV will address during its lifetime. Among them, of special interest are: the study of galaxy formation and the intergalactic medium; the astronomical engines; the Milky Way formation and evol ution, and the formation of the Solar System and the atmospheres of extrasolar p lanets.Comment: Just one text file (aigomezdecastro.tex). To be published in the proceeding of the conference: "New Quest in Stellar Astrophysics II: UV properties of evolved stellar populations" held in Puerto Vallarta - Mexico, in april 200

    Comment on "Relativistic extension of shape-invariant potentials"

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    This comment directs attention to some fails of the Alhaidari approach to solve relativistic problems. It is shown that his gauge considerations are way off the mark and that the class of exactly solvable relativistic problems is not so enlarged as Alhaidari thinks it is

    Derivation of a multilayer approach to model suspended sediment transport: application to hyperpycnal and hypopycnal plumes

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    We propose a multi-layer approach to simulate hyperpycnal and hypopycnal plumes in flows with free surface. The model allows to compute the vertical profile of the horizontal and the vertical components of the velocity of the fluid flow. The model can describe as well the vertical profile of the sediment concentration and the velocity components of each one of the sediment species that form the turbidity current. To do so, it takes into account the settling velocity of the particles and their interaction with the fluid. This allows to better describe the phenomena than a single layer approach. It is in better agreement with the physics of the problem and gives promising results. The numerical simulation is carried out by rewriting the multi-layer approach in a compact formulation, which corresponds to a system with non-conservative products, and using path-conservative numerical scheme. Numerical results are presented in order to show the potential of the model

    Bound states of bosons and fermions in a mixed vector-scalar coupling with unequal shapes for the potentials

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    The Klein-Gordon and the Dirac equations with vector and scalar potentials are investigated under a more general condition, Vv+Vs=constantV_{v}+V_{s}= \mathrm{constant}. These intrinsically relativistic and isospectral problems are solved in a case of squared hyperbolic potential functions and bound states for either particles or antiparticles are found. The eigenvalues and eigenfuntions are discussed in some detail and the effective Compton wavelength is revealed to be an important physical quantity. It is revealed that a boson is better localized than a fermion when they have the same mass and are subjected to the same potentials.Comment: 3 figure
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