Generation of maximally entangled states of qudits using twin photons

We report an experiment to generate maximally entangled states of D-dimensional quantum systems, qudits, by using transverse spatial correlations of two parametric down-converted photons. Apertures with D-slits in the arms of the twin fotons define the qudit space. By manipulating the pump beam correctly the twin photons will pass only by symmetrically opposite slits, generating entangled states between these differents paths. Experimental results for qudits with D=4 and D=8 are shown. We demonstrate that the generated states are entangled states.Comment: 04 pages, 04 figure

A proposal for a first class conversion formalism based on the symmetries of the Wess-Zumino terms

We propose a new procedure to embed second class systems by introducing Wess-Zumino (WZ) fields in order to unveil hidden symmetries existent in the models. This formalism is based on the direct imposition that the new Hamiltonian must be invariant by gauge-symmetry transformations. An interesting feature in this approach is the possibility to find a representation for the WZ fields in a convenient way, which leads to preserve the gauge symmetry in the original phase space. Consequently, the gauge-invariant Hamiltonian can be written only in terms of the original phase-space variables. In this situation, the WZ variables are only auxiliary tools that permit to reveal the hidden symmetries present in the original second class model. We apply this formalism to important physical models: the reduced-SU(2) Skyrme model, the Chern-Simons-Proca quantum mechanics and the chiral bosons field theory. In all these systems, the gauge-invariant Hamiltonians are derived in a very simple way.Comment: Revised version. Title changed for Gauging by symmetries. To appear in IJMP

Propagation of spatially entangled qudits through free space

We show the propagation of entangled states of high-dimensional quantum systems. The qudits states were generated using the transverse correlation of the twin photons produced by spontaneous parametric down-conversion. Their free-space distribution was performed at the laboratory scale and the propagated states maintained a high-fidelity with their original form. The use of entangled qudits allow an increase in the quantity of information that can be transmitted and may also guarantee more privacy for communicating parties. Therefore, studies about propagating entangled states of qudits are important for the effort of building quantum communication networks.Comment: 5 Pages, 4 Figures, REVTeX

A canonical transformation and the tunneling probability for the birth of an asymptotically DeSitter universe with dust

In the present work, we study the quantum cosmology description of closed Friedmann-Robertson-Walker models in the presence of a positive cosmological constant and a generic perfect fluid. We work in the Schutz's variational formalism. If one uses the scale factor and its canonically conjugated momentum as the phase space variables that describe the geometrical sector of these models, one obtains Wheeler-DeWitt equations with operator ordering ambiguities. In order to avoid those ambiguities and simplify the quantum treatment of the models, we introduce new phase space variables. We explicitly demonstrate that the transformation leading from the old set of variables to the new one is canonical. In order to show that the above canonical transformations simplify the quantum treatment of those models, we consider a particular model where the perfect fluid is dust. We solve the Wheeler-DeWitt equation numerically using the Crank-Nicholson scheme and determine the time evolution of the initial wave function. Finally, we compare the results for the present model with the ones for another model where the only difference is the presence of a radiative perfect fluid, instead of dust.Comment: Revtex4, 18 pages, 2 EPS figure

Melhoramento genético de grevílea para produção de madeira em pequenas propriedades

A grevílea (Grevillea robusta Cunn.) é uma espécie arbórea, nativa das regiões costeiras da Austrália, dos Estados de New South Wales e Queensland. Os principais usos desta espécie incluem ornamentação, sombreamento de culturas agrícolas, produção de cobertura morta, apicultura e madeira para usos diversos. O cerne é resistente, de alta durabilidade e de boa qualidade para marcenaria e produção de parquês, peças torneadas, laminados e chapas. As introduções desta espécie em vários países, inclusive no Brasil, feitas em torno de um século atrás, foram com sementes oriundas de poucas árvores matrizes, resultando em uma base genética restrita, que se supõe como a principal causa de problemas generalizados de alta mortalidade, sementes de baixo vigor, alta freqüência de fustes de má forma, com bifurcações e retorcimentos que se verificam nesses plantios. Num esforço para combinar os benefícios da grevílea como quebra-ventos, plantios ornamentais e como fonte alternativa de madeira de alta qualidade, em pequenas propriedades rurais, a Embrapa Florestas reintroduziu novas procedências e progênies com uma base genética ampla e de alto potencial para o melhoramento genético. Com base no exposto, o trabalho de melhoramento teve por objetivo avaliar o comportamento de procedências e progênies ou clones de grevílea para posterior produção de sementes melhoradas. Este trabalho foi conduzido em diferentes locais das Regiões Sul e Sudoeste do Brasil, sempre envolvendo parceiros do nível de empresas estatais de pesquisa, Universidades e outras empresas privadas do segmento florestal. Espera-se disponibilizar conhecimentos sobre a espécie, que permitam aos produtores e empresários florestais obterem alternativas para seus empreendimentos, através da disponibilização de sementes e de técnicas adequadas de cultivo, tornando-a economicamente atraente.bitstream/CNPF-2009-09/39759/1/BPD23.pd

Histopathological and immunohistochemical differentiation of epithelial alterations in vocal nodule comparing to polyps and to laryngeal edema

AIM: To evaluate by histological and immunohistochemical methods the epithelial lesions in vocal nodule and correlate with polyp, laryngeal edema and vocal folds without macroscopic lesions. STUDY DESIGN: Chart review. MATERIAL AND METHOD: In a retrospective analysis of medical records, twenty-six patients, who underwent microsurgical excision of laryngeal inflammatory lesions (nodules, polyps and laryngeal edema), were identified. Vocal folds without macroscopic lesions were obtained from autopsy. To evaluate epithelial lesions, specimens were stained with H&E, PAS, and with antibodies against laminin and collagen type IV. These specimens were analyzed by light microscopy. RESULTS: Lesions diagnosed as nodules showed more collagen type IV and laminin deposition when compared to polyps (p=0,034 and p=0,036, respectively) and to vocal folds without macroscopic lesions (p=0,019 and p=0,021, respectively). Nodules showed basement membranes thicker than polyps on PAS stain (p=0,102). Laryngeal edema could not be differentiated from nodules, polyps or vocal folds without macroscopic lesions by PAS, laminin or collagen type IV stain (p>0,10). CONCLUSION: By histological and immunohistochemical techniques to evaluate epithelium of laryngeal inflammatory lesions we conclude that vocal fold nodule differentiate from polyps on the three techniques used to stain basement membrane (PAS, laminin, collagen IV) and from vocal folds without macroscopic lesions on two techniques used (laminin, collagen IV). Laryngeal edema cannot be differentiated from the others laryngeal lesions, neither from vocal folds without macroscopic lesions, when the techniques before described are used.OBJETIVO: Avaliar, por meio de técnicas histológicas e imunoistoquímicas, o epitélio nos nódulos vocais em relação aos pólipos, ao edema de laringe e às pregas vocais sem lesões macroscópicas. FORMA DE ESTUDO: Clínico retrospectivo. MATERIAL E MÉTODO: Por meio de levantamento de prontuário, foram identificados vinte e seis pacientes com lesões laríngeas inflamatórias (nódulos, pólipos e edema de laringe), que haviam sido submetidos à cirurgia. Pregas vocais sem alterações macroscópicas foram obtidas a partir de autópsia de cadáveres. Para análise do epitélio, foram realizadas colorações pela técnica da hematoxilina-eosina e do ácido periódico de Schiff e técnicas de imunoistoquímica com anticorpos dirigidos contra laminina e colágeno IV. A leitura das lâminas foi realizada por meio de microscopia óptica. RESULTADOS: Houve maior imunoexpressão de laminina e colágeno IV nos nódulos quando comparados aos pólipos (p=0,034 e p=0, 036, respectivamente), assim como quando comparados às pregas vocais sem lesões macroscópicas (p=0,019 e p=0, 021, respectivamente). Nódulos tendem a apresentar maior espessura da membrana basal, quando utilizamos coloração pela técnica do PAS, em relação aos pólipos (p=0,102). O edema de laringe não se diferenciou das demais nas técnicas utilizadas (p> 0,10). CONCLUSÕES: O Nódulo Vocal diferencia-se dos pólipos, nas três técnicas utilizadas para detecção da membrana basal (PAS, laminina, colágeno IV), e das pregas vocais sem lesões macroscópicas em duas das técnicas utilizadas (laminina e colágeno IV). Edema de laringe não se diferencia das demais lesões, nem de pregas vocais sem lesões macroscópicas, quando utilizadas as técnicas anteriormente descritas, para estudo da membrana basal.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de Otorrinolaringologia e Distúrbios da Comunicação HumanaUniversidade de São Paulo Faculdade de OdontologiaUNIFESP, EPM, Depto. de Otorrinolaringologia e Distúrbios da Comunicação HumanaSciEL

Planning, Managing and Monitoring Technological Security Infrastructures

Over the past few decades many different Information Technologies (IT) policies have been introduced, including COSO, ITIL, PMBook, CMM,ISO 2700x, Six Sigma, being COBIT IT (Control Objectives for IT) the framework that encompasses all IT and Information Systems (IS) governance activities at the organization’s level. As part of the applicability of quality services certification (ISO 9001) in all IT services of a public institution, it is presented a case study aimed at planning, managing and monitoring technological security infrastructures. It followed the guidelines for the ISO 2700x family, COBIT, ITIL and other standards and conducted a survey to complement the IT process’s objectives. With regard to an action-research methodology for problem-solving (i.e., a kind of attempt to improve or investigate practice) and according to the issue under analyze, the question is put into the terms, viz. “How can the ISO 2700x, COBIT, ITIL and other guidelines help with the planning, management and monitoring of technological security infrastructures and minimize the risk management of IT and IS?”. Indeed, it may be resolved that it is possible to achieve the goals of planning, managing and monitoring a technological security infrastructure. In the future, we will use Artificial Intelligence based approaches to problem solving such as Artificial Neural Networks and Cased Based Reasoning, to evaluate this issue

Past and future blurring at fundamental length scale

We obtain the $\kappa$-deformed versions of the retarded and advanced Green functions and show that their causality properties are blurred in a time interval of the order of a length parameter $q=1/(2\kappa)$. The functions also indicate a smearing of the light cone. These results favor the interpretation of $q$ as a fundamental length scale below which the concept of a point in spacetime should be substituted by the concept of a fuzzy region of radius $q$, as proposed long ago by Heisenberg.Comment: Essentially, this is the version published in the Phys. Rev. Lett. 105, 211601 (2010). It has 4 pages and contains 2 figure