Solitons
Mostrando 25-36 de 60 artigos, teses e dissertações.
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25. Existence and stability of periodic optical solitons / Existencia e estabilidade de solitons opticos periodicos para um sistema de equações do tipo Schrodinger
In this thesis we study the following nonlinear Schrodinger type system ... Note: The complete abstract in available with the full electronic digital thesis or dissertations
Publicado em: 2007
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26. Perturbações temporais em condensados de Bose-Einstein diluídos e vórtice em condensados densos / Time dependent perturbation in dilude Bose Einstein Condensate and vortex in dense condensate.
In this work we studied the soliton interactions between two solitons under time dependent perturbations in a trap potential and interparticule potential. In a dense Bose-Einstein condensate we studied the insertion of kinetic term going beyond the Thomas-Fermi approximation and its effect in critical frequency of vortices formation.
Publicado em: 2007
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27. Acopladores direcionais de fibras Ãpticas com perfis de dispersÃo / Directional optic staple dispersion profile fiber(DPF)
We present a numerical investigation of the propagation and the switching of fundamental solitons in a two-core nonlinear fiber coupler constructed with Dispersion Profile Fiber (DPF). We have shown that appropriate shaping of the DPF profile is quite effective to recover, almost completely, the original switching behavior associated to the lossless situatio
Publicado em: 2007
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28. Soliton dynamics of magnetization driven by a magnetic field in uniaxial anisotropic ferromagnet
We study the nonlinear magnetic excitation in an anisotropic ferromagnet with a magnetic field. In the long wave approximation, the Landau-Lifschitz equation with easy axis anisotropy is transformed into the nonlinear Schrödinger type. By means of a straightforward Darboux transformation we obtain the one- and two-soliton solutions of uniaxial anisotropic f
Brazilian Journal of Physics. Publicado em: 2006-12
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29. Mistura de quatro ondas na propagaÃÃo de pulsos Ãpticos ultra-curtos em fibras com dispersÃo decrescente para sistemas WDM / Mixture of four waves in the propagation of ultra-short optical pulses in fiber wither dispersion decreasing for WDM systems
Serà estudado nesta dissertaÃÃo o comportamento da propagaÃÃo de trÃs tipos de pulsos Ãpticos (Solitons, Quasisolitons e Gaussianos) ultracurtos na regiÃo de 1.55μm e a eficiÃncia de conversÃo destes na geraÃÃo de pulsos por meio do fenÃmeno nÃo-linear de mistura de quatro ondas (FWM) em uma fibra comum e em fibras com dispersÃo decrescen
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 07/12/2005
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30. Solitons in nucleon-nucleus collisions / Solitons em colisões núcleon-núcleo
Assuming that the nucleus can be treated as a perfect fluid we study the conditions for the formation and propagation of Korteweg-de Vries (KdV) solitons in nuclear matter. The existence of these solitons depends on the nuclear equation of state, which, in its turn, depends on the underlying microscopic theory of the nucleon-nucleon interaction and also on t
Publicado em: 2005
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31. Noncommutative solitons and instantons
I review different approaches to the construction of vortex and instanton solutions in noncommutative field theories.
Brazilian Journal of Physics. Publicado em: 2004-12
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32. New developments in the quantization of supersymmetric solitons (kinks, vortices and monopoles)
We discuss the one-loop quantum corrections to the mass M and central charge Z of supersymmetric (susy) solitons: the kink, the vortex and the monopole. Contrary to previous expectations and published results, in each of these cases there are nonvanishing quantum corrections to the mass. For the N = 1 kink and the N = 2 monopole a new anomaly in Z rescues BP
Brazilian Journal of Physics. Publicado em: 2004-12
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33. Considerations on undistorted-progressive X-waves and Davydov solitons, Fröhlich-Bose-Einstein condensation, and Cherenkov-like effect in biosystems
Research in ultrasonography has evidenced the propagation of a peculiar kind of excitation in fluids. Such excitation, dubbed a X-wave, has characteristics resembling that of a solitary-wave type. We reconsider the problem in a medium consisting of a biological material of the like of alpha-helix proteins. It can be shown that in this case is expected an exc
Brazilian Journal of Physics. Publicado em: 2004-06
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34. Scalar fields: from domain walls to nanotubes and fulerenes
In this work we review some features of topological defects in field theory models for real scalar fields. We investigate topological defects in models involving one and two or more real scalar fields. In models involving a single field we examine two different subclasses of models, which support one or more topological defects. In models involving two or mo
Brazilian Journal of Physics. Publicado em: 2002-12
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35. Coherent soliton propagation through doped optical fibers: cloning, breakup, and soliton interactions
Investiga-se numericamente a propagação simultânea de dois pulsos ópticos através de um meio dispersivo não linear dopado, modelado por um sistema ressonante de três níveis, usando-se uma abordagem de equações generalizadas não lineares de Schrödinger. Estas últimas incluem a contribuição das ressonâncias do dopante cuja dinâmica é regida p
Anais da Academia Brasileira de Ciências. Publicado em: 2001-06
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36. GERAÇÃO DE PULSOS ÓPTICOS CURTOS SINTONIZÁVEIS EM COMPRIMENTO DE ONDA UTILIZANDO UM LASER A FIBRA EM ANEL / WAVELENGTH TUNABLE OPTICAL PULSES GENERATION USING FIBER LASERS
Neste trabalho, descreve-se a geração de pulsos ópticos curtos com diferentes taxas de repetição, para aplicações em sistemas de transmissão de sólitons. Para isto foi desenvolvido um laser a fibra em anel operando na terceira janela de comunicações ópticas (em 1.55 mm), capaz de gerar pulsos curtos, utilizando a técnica de mode-locking ativo. N
Publicado em: 2000