Coherent States
Mostrando 25-36 de 66 artigos, teses e dissertações.
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25. AnÃlise e resultados experimentais de sistemas de distribuiÃÃo quÃntica de chaves usando fÃtons isolados e estados coerentes mesoscÃpicos. / Theorical analysis and experimental results of quantum key distribution systems using single-photons and mesoscopic coherent states
In this dissertation it is realized a study about quantum key distribution (QKD) in optical networks. Initially, a review of the theory of quantum key distribution and some of its implementations with strongly attenuated coherent states, as well a review of an optical system for physical encryptation using mesoscopic coherent states are realized. Following,
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 13/09/2006
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26. Coherent properties and rabi oscillations in two-level donor systems
Coherent properties and Rabi oscillations in two-level donor systems, under terahertz excitation, are theoretically investigated. Here we are concerned with donor states in bulk GaAs and GaAs - (Ga, Al)As quantum dots. We study confinement effects, in the presence of an applied magnetic field, on the electronic and on-center donor states in GaAs - (Ga, Al)As
Brazilian Journal of Physics. Publicado em: 2006-06
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27. Frenkel-exciton-polaritons in organic microcavities
We study organic microcavities in the strong coupling regime. The cavity exciton-polariton dispersion relations and quantum states are derived in using a microscopic theory. We consider the two cases of anisotropic organic crystals with one and two molecules per unit cell. In general, the cavity exciton-polaritons are a coherent superposition of both cavity
Brazilian Journal of Physics. Publicado em: 2006-06
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28. Dinâmica de campos térmicos aplicada a análise de distribuições de estado de Fock
We use the formalism of the thermal field dynamics (TFD) to introduce the effect of temperature in states of overlapping of the electromagnetic field. We introduce and analyze the thermal effect in the statistics of the states of overlapping formed for the coherent states and states number. Added to this analysis statistics, we get the distribution of therma
Publicado em: 2006
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29. Correlations and interferences in atomic systems of cold Bose Einstein condensates / Correlações e interferência de sistemas atômicos de Bose-Einstein frios
This work consists of a theoretical study of the coexistance of coupled atomic Bose-Einstein condensates. These mixed condensates can consist of atoms of the same element in different hyperfine internal states. A different situation is that in which an atom in one internal state can ocupate different single particle external states. The similarities and diff
Publicado em: 2006
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30. A methodology applied to selection of taxpayers for audit proposals. / Uma metodologia aplicada à seleção de contribuintes do ICMS para fins de auditoria.
With the advent of the Real Plan, the brazilian states has initiated an improvement process of the management instruments in their tax agencies. It is included among such instruments planning of the tax case, which had been incorporated new systematics for the taxpayer selection of the value added taxes on sales and services (ICMS). This work presents a comb
Publicado em: 2006
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31. AnÃlise e resultados experimentais de sistemas de distribuiÃÃo quÃntica de chaves usando fÃtons isolados e estados coerentes mesoscÃpicos / Theoretical analysis and experimental results of quantum key distribution systems using single-photons and mesoscopic coherent states.
Nesta dissertaÃÃo à realizado um estudo sobre implementaÃÃes de distribuiÃÃo quÃntica de chaves (DQC) em redes Ãpticas. Inicialmente, à feita uma revisÃo da teoria da distribuiÃÃo quÃntica de chaves com fÃtons isolados e de algumas implementaÃÃes com estados coerentes fortemente atenuados, bem como a revisÃo de um sistema Ãptico para encri
Publicado em: 2006
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32. Tratados internacionais sobre direitos humanos: vícios na emenda constitucional 45/2004
This masters degree thesis, which is divided into three chapters, in addition to the introduction and conclusion, encompasses application of international Human Rights treaties in the domestic framework. This study made use of inductive investigation methods; monographic, technical and bibliographical procedures; review of the literature, jurisprudence and I
Publicado em: 2006
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33. Fundamentação antropológico-cultural da religião segundo Paul Tillich: perspectivas pedagógicas abertas frente aos dispositivos legais vigentes
Having in mind the problem with the religious teaching, my reflection is inserted in a historical course of which I have been participating actively since the 1960s. By associating myself with other professionals of the teaching, in both state and national field of action, I reflected with them about the contextual changes, trying to give a new meaning to th
Publicado em: 2006
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34. A função simbolica como um meio para avaliação e intervenção em atendimentos psicopedagogicos : um estudo de caso / The symbolic function as a way for evaluation and intervention in psychopedagogics attendance: a case study
Based on Jean Piaget?s theory, this work is focused on the use of the representation conducts of the symbolic function, which a child presents in his or her preoperational stage of development, as a means to evaluate and to intervene in infants psycho-pedagogical consulting. A case study with a five years old child (hereby called GIL) was conducted between M
Publicado em: 2006
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35. A new form of path integral for the coherent states representation and its semiclassical limit
The overcompleteness of the coherent states basis leads to a multiplicity of representations of Feynman's path integral. These different representations, although equivalent quantum mechanically, lead to different semiclassical limits. Two such semiclassical formulas were derived in [1] for the two corresponding path integral forms suggested by Klauder and S
Brazilian Journal of Physics. Publicado em: 2005-03
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36. Semiclassical propagation of coherent states / Propagação semiclassica de estados coerentes
This thesis addresses di®erent aspects of the semiclassical propagation of coherent states. We have derived a general expression for the propagator connecting these states which, di®erently from previous formulae in the literature, is valid for packets of arbitrary widths. The result, obtained via functional integration, depends on classical trajectories i
Publicado em: 2005