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COLOQUIO HOY
***
Estimados Colegas,
El coloquio de HOY MIERCOLES 2-FEB estará a cargo del
Prof. Roland Lefebvre
Institut des Sciences Mol´eculaires d?Orsay, B?at. 350, Univ. Paris-Sud
(CNRS), 91405 Orsay, France
and U.F.R. de Physique, Universit´e Pierre et Marie Curie, 75321
Paris,France
El titulo de su charla es:
"SOME USES of PAD´E APPROXIMANTS in MOLECULAR PHYSICS"
Abstract
Pad´e approximants constitute a powerful method to make an analytic
representation of a function as a ratio of two polynomials. We first
consider a class of problems where Pad´e methods can be used to extract
information about resonance energies and the associated wave functions, with
an input resulting from a modification of the wave equation, made to ease
the numerical treatment. The examples which are treated correspond either to
the introduction of a so-called optical potential in the wave equation, with
a strong distortion of the results, or to the replacement of the relative
coordinate between two entities by a complex coordinate. In the latter case
Pad´e approximants are used to calculate the unnormalizable wave function of
a resonance. In the second class of problems, Pad´e approximants allow the
detection of the position of a point in a parameter plane at which there is
a failure of the method. This is useful in the context of the theory of
exceptional points where there is a coalescence of two complex resonance
energies, with a merging of the two wave functions into a unique one.
Because this point is a branch point, the Pad´e approximant breaks down.
This failure provides in fact the desired information.
? R. Lefebvre, M. ˇ Sindelka and N. Moiseyev, Phys. Rev. A 72,052704(2005)
? R. Lefebvre and N. Moiseyev, J. Phys. B:At.Mol.Opt. Phys. 43,095401(2010)
? R. Uzdin and R. Lefebvre, J. Phys. B:At.Mol.Opt. Phys. 43,235004(2010)
Esperamos contar con su amable presencia a las 5:30 PM
en el auditorio del Instituto de Ciencias Fisicas de la UNAM- Campus
Morelos.
Atentamente,
Jorge Hernandez Cobos y Angel Romo Uribe.
Organizadores del Colquio del ICF
Dr. Angel Romo-Uribe
Lab de Nanopolimeros y Coloides
Instituto de Ciencias Físicas
Universidad Nacional Autónoma de México
Av. Universidad s/n, Col. Chamilpa
Cuernavaca, Mor. 62210 MEXICO
Tel/Fax. +52-777-329-0880
e-mail: aromo-uribe@xxxxxxxxxxx
Lab website: http://www.fis.unam.mx/laboratorio.php
website: http://www.fis.unam.mx/~aromo-uribe
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