2,306 research outputs found
Two–body Coulomb problems with sources for the J-matrix method
No full textThe two-body Coulomb problem with sources is studied. Close d form solutions are provided for particular non-homogeneities used within the J-matrix method. The results are employed to build analytical solutions having incoming , outgoing and standing wave asymptotic conditions.Fil: Ancarani, L. U.. Université Paul Verlaine-Metz; FranciaFil: Gasaneo, Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; Argentin
Derivatives of any order of the Gaussian hypergeometric function 2F1( a,b,c;z) with respect to the parameters a, b and c
No full textThe derivatives to any order of the Gaussian hypergeometric function 2F1(a, b, c; z) with respect to the parameters a, b and c are expressed in terms of generalizations of multivariable Kampé de Fériet functions. Several properties are presented. In an application to the two-body Coulomb scattering problem, the usefulness of these derivatives is illustrated with the study of the charge dependence of Pollaczek-like polynomials.Fil: Ancaran, L. U.. Université Paul Verlaine-Metz; FranciaFil: Gasaneo, Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; Argentin
Classical structures arising in the autoionization of He
No full textIn this work, a classical mechanics study of the autoionization process induced by ion impact is performed. The electron distribution in momentum space is obtained and compared with the results of the continuum distorted wave quantum theory. Typical structures arising in quantum and classical treatments are identified and compared. Oscillatory profiles for the autoionization spectrum are obtained within the present classical picture, in contrast with existing models which attach them to a purely quantum behavior.Fil: Otranto, Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; ArgentinaFil: Gasaneo, Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; Argentin
Derivatives of any order of the hypergeometric function pFq(a1, ..., ap; b1, ..., bq; z) with respect to the parameters ai and bi
No full textThe derivatives of any order of the general hypergeometric function pFq(a1.....ap; b1.....bq;z) with respect to the parameters a; or bj are expressed, in compact form, in terms of generalizations of multivariable Kampe de Feriet functions. To achieve this, use is made of Babister's solution to nonhomogeneous differential equations for pFq(a1.....ap; b1.....bq;z). An application to Hahn polynomials, which are 3F2 functions, is given as an illustration.Fil: Ancarani, L.U.. Université Paul Verlaine-Metz; FranciaFil: Gasaneo, Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; Argentina. Universidad Nacional del Sur. Departamento de Física; Argentin
Two-body Coulomb problems with sources
No full textThe two-body Coulomb Schrödinger equation with different types of nonhomogeneities are studied. The particular solution of these nonhomogeneous equations is expressed in closed form in terms of a two-variable hypergeometric function. A particular representation of the latter allows one to study efficiently the solution in the asymptotic limit of large values of the coordinate and hence the associated physics. Simple sources are first considered, and a complete analysis of scattering and bound states is performed. The solutions corresponding to more general (arbitrary) sources are then provided and written in terms of more general hypergeometric functions. © 2010 The American Physical Society.Fil: Gasaneo, Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Sur. Departamento de Física; ArgentinaFil: Ancarani, L.U.. Université Paul Verlaine-Metz; Franci
An analytic and parameter-free wavefunction for studying the stability of three-body systems
No full textAn analytic wavefunction is proposed for the ground state of general atomic three-body systems in which two light particles are negatively charged and the third (heavy) is positively charged. By construction the wavefunction (i) has the same analytical form for all systems; (ii) is parameter-free; (iii) is nodeless; (iv) satisfies all two-particle cusp conditions; and (v) yields reasonable ground state energies for several three-body systems, including the prediction of a bound state for H-, D-, T- and Mu-. Simple polynomial fits are provided for certain important subcases, allowing for a rapid estimate of the ground state energy and of the stability of three-body systems.Fil: Ancarani, L. U.. Université Paul Verlaine-Metz; FranciaFil: Gasaneo, Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; Argentin
A special asymptotic limit of a Kampé de Fériet hypergeometric function appearing in nonhomogeneous Coulomb problems
No full textIn the investigation of two-body Coulomb Schrödinger equations with some types of nonhomogeneities, the particular solution can be expressed in terms of a two-variable Kampé de Fériet hypergeometric function. The asymptotic limit of the latter-for both variables being large but their ratio being a bound constant-is required in order to extract relevant physical information from the solutions. In this report the mathematical limit is provided. For that purpose, a particular series representation of the hypergeometric function-in terms of products of Kummer and Gauss functions-is first derived. © 2011 American Institute of Physics.Fil: Ancarani, L.U.. Université Paul Verlaine-Metz; FranciaFil: Gasaneo, Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Sur. Departamento de Física; Argentin
A spectral approach based on generalized Sturmian functions for two- and three-body scattering problems
No full textA methodology based on generalized Sturmian functions is put forward to solve two- and three-body scattering problems. It uses a spectral method which allows for the inclusion of the correct asymptotic behavior when solving the associated driven Schroedinger equation. For the two-body case, we demonstrate the equivalence between the exterior complex scaling (ECS) and the Sturmian approaches and illustrate the latter by using Hulthen Sturmian functions. Contrary to the ECS approach, no artificial cut-off of the potential is required in the Surmian approach. For the three-body scattering problem, the theoretical framework is presented in hyperspherical coordinates and a set of hyperspherical generalized Sturmian functions possessing outgoing asymptotic behavior is introduced. The Sturmian procedure is a direct generalization of the method discussed for the two-body problem; thus, the comparison with the ECS method is similar. For both the two- and three-body cases, Sturmian bases are efficient as they possess the correct outgoing behavior, diagonalize part of the potentials involved and are essentially localized in the region where the unsolved interaction is not negligible. Moreover, with the Sturmian basis, the operator (H − E ) is represented by a diagonal matrix whose elements are simply the Sturmian eigenvalues.Fil: Gasaneo, Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; Argentin
Teléfonos inteligentes: su impacto en las capacidades atencionales de niños y jóvenes
No full textEl valor de un desarrollo tecnológico puede ser medido por su penetración y permanencia en la sociedad. Este trae beneficios, pero también conlleva desventajas. Se revisan aspectos asociados a la incorporación social de los teléfonos celulares inteligentes (TCI) junto con otros dispositivos, haciendo foco en niños y jóvenes. Se analiza su influencia en el desarrollo de capacidades atencionales; se discute el proceso de formación de redes cerebrales de atención y factores implicados, y la relación de la atención con el desempeño en el contexto áulico.Fil: Freije, María Luján. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; ArgentinaFil: Sapognikoff, M.. Clínica Privada Bahiense; ArgentinaFil: Gasaneo, Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; Argentin
Solution for boson-diboson elastic scattering at zero energy in the shape-independent model
No full textWe derive an exact analytic expression for the boson-diboson elastic scattering phase shift in the shape-independent model for positive two-body scattering lengths when the total energy vanishes. A three-body hard-core potential depending upon a hyperradial cutoff parameter R0 is introduced to obtain a finite result. The exact result is compared with adiabatic hyperspherical calculations of the phase shift, and a similar functional dependence on the cutoff parameter is found. The cutoff parameter plays the role of a renormalization constant in that it renormalizes the wave function at vanishing hyperradius.Fil: Macek, J. H.. University of Tennessee; Estados UnidosFil: Ovchinnikov, Serge. University of Tennessee; Estados UnidosFil: Gasaneo, Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Física; Argentin
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