7,626 research outputs found

    Hamiltonian symplectic embedding of the massive noncommutative U(1) Theory

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    We show that the massive noncommutative U(1) theory is embedded in a gauge theory using an alternative systematic way, which is based on the symplectic framework. The embedded Hamiltonian density is obtained after a finite number of steps in the iterative symplectic process, oppositely to the result proposed using the BFFT formalism. This alternative formalism of embedding shows how to get a set of dynamically equivalent embedded Hamiltonian densities.Comment: 16 pages, no figures, revtex4, corrected version, references additione

    Supersymmetrization of the Radiation Damping

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    We construct a supersymmetrized version of the model to the radiation damping \cite{03} introduced by the present authors \cite{ACWF}. We dicuss its symmetries and the corresponding conserved Noether charges. It is shown this supersymmetric version provides a supersymmetric generalization of the Galilei algebra obtained in \cite{ACWF}. We have shown that the supersymmetric action can be splited into dynamically independent external and internal sectors.Comment: 9 page

    Optimized generation of spatial qudits by using a pure phase spatial light modulator

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    We present a method for preparing arbitrary pure states of spatial qudits, namely, D-dimensional (D > 2) quantum systems carrying information in the transverse momentum and position of single photons. For this purpose, a set of D slits with complex transmission are displayed on a spatial light modulator (SLM). In a recent work we have shown a method that requires a single phase-only SLM to control independently the complex coefficients which define the quantum state of dimension D. The amplitude information was codified by introducing phase gratings inside each slit and the phase value of the complex transmission was added to the phase gratings. After a spatial filtering process we obtained in the image plane the desired qudit state. Although this method has proven to be a good alternative to compact the previously reported architectures, it presents some features that could be improved. In this paper we present an alternative scheme to codify the required phase values that minimizes the effects of temporal phase fluctuations associated to the SLM where the codification is carried on. In this scheme the amplitudes are set by appropriate phase gratings addressed at the SLM while the relative phases are obtained by a lateral displacement of these phase gratings. We show that this method improves the quality of the prepared state and provides very high fidelities of preparation for any state. An additional advantage of this scheme is that a complete 2\pi modulation is obtained by shifting the grating by one period, and hence the encoding is not limited by the phase modulation range achieved by the SLM. Numerical simulations, that take into account the phase fluctuations, show high fidelities for thousands of qubit states covering the whole Bloch sphere surface. Similar analysis are performed for qudits with D = 3 and D = 7.Comment: 12 pages, 7 figure

    Distribuição espacial da cultura de café no Estado de São Paulo.

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    Neste trabalho é analisada a distribuição espacial da cultura de café no Estado de São Paulo. O objetivo é subsidiar um plano de estratificação dos municípios produtores para fins de previsão de safra. Os métodos de análise espacial utilizados neste estudo são baseados nas estatísticas de Moran: índice global de associação espacial; índice local de associação espacial; e gráfico de espalhamento de Moran. Estes métodos permitem quantificar a dependência espacial de fenômenos geográficos e determinar a significância estatística dos agrupamentos espaciais. Foram utilizados dados do levantamento da Produção Agrícola Municipal - PAM - de 2004, produzidos pelo Instituto Brasileiro de Geografia e Estatística - IBGE. O programa TerraView foi utilizado no cálculo dos índices e para visualização dos resultados. Os resultados indicam que é importante considerar a localização geográfica dos municípios, pois a produção de café apresentou dependência espacial e foram identificados agrupamentos de municípios com índices de associação espacial significantes. No futuro, será possível comparar a distribuição espacial do café com a de outras culturas agrícolas em São Paulo ou com a da mesma cultura em outros Estados, o que auxiliará no planejamento da estratificação, fase inicial da estimativa de área plantada.bitstream/CNPMA/7431/1/boletim_40.pd

    Noncommutative Metafluid Dynamics

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    In this paper we define a noncommutative (NC) Metafluid Dynamics \cite{Marmanis}. We applied the Dirac's quantization to the Metafluid Dynamics on NC spaces. First class constraints were found which are the same obtained in \cite{BJP}. The gauge covariant quantization of the non-linear equations of fields on noncommutative spaces were studied. We have found the extended Hamiltonian which leads to equations of motion in the gauge covariant form. In addition, we show that a particular transformation \cite{Djemai} on the usual classical phase space (CPS) leads to the same results as of the \star-deformation with ν=0\nu=0. Besides, we will shown that an additional term is introduced into the dissipative force due the NC geometry. This is an interesting feature due to the NC nature induced into model.Comment: 11 page

    Introdução à análise probabilística simplificada da segurança estrutural

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    A análise da segurança de estruturas com vidas úteis diferentes das correntes, de estruturas existentes, de estruturas submetidas a acções invulgares, ou de estruturas reforçadas, é bastante complexa. A abordagem correcta deste problema não pode dispensar a utilização de modelos probabilísticos, que são desconhecidos da maioria dos engenheiros civis. Neste trabalho é apresentada uma breve introdução à análise probabilística simplificada da segurança, dando especial destaque à descrição dos modelos de acções e à análise de exemplos de aplicação
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