14,392 research outputs found
Experimental determination of multipartite entanglement with incomplete information
Multipartite entanglement is very poorly understood despite all the
theoretical and experimental advances of the last decades. Preparation,
manipulation and identification of this resource is crucial for both practical
and fundamental reasons. However, the difficulty in the practical manipulation
and the complexity of the data generated by measurements on these systems
increase rapidly with the number of parties. Therefore, we would like to
experimentally address the problem of how much information about multipartite
entanglement we can access with incomplete measurements. In particular, it was
shown that some types of pure multipartite entangled states can be witnessed
without measuring the correlations [M. Walter et al., Science 340, 1205 (2013)]
between parties, which is strongly demanding experimentally. We explore this
method using an optical setup that permits the preparation and the complete
tomographic reconstruction of many inequivalent classes of three- and
four-partite entangled states, and compare complete versus incomplete
information. We show that the method is useful in practice, even for non-pure
states or non ideal measurement conditions.Comment: 12 pages, 7 figures. Close to published versio
Image and Coherence Transfer in the Stimulated Down-conversion Process
The intensity transverse profile of the light produced in the process of
stimulated down-conversion is derived. A quantum-mechanical treatment is used.
We show that the angular spectrum of the pump laser can be transferred to the
stimulated down-converted beam, so that images can also be transferred from the
pump to the down-converted beam. We also show that the transfer can occur from
the stimulating beam to the down-converted one. Finally, we study the process
of diffraction through an arbitrarily shaped screen. For the special case of a
double-slit, the interference pattern is explicitly obtained. The visibility
for the spontaneous emitted light is in accordance with the van Cittert -
Zernike theorem for incoherent light, while the visibility for the stimulated
emitted light is unity. The overall visibility is in accordance with previous
experimental results
Correlações simples e análise de trilha de caracteres relacionados à arquitetura da planta, precocidade e produção de grãos em três gerações de um cruzamento de feijão caupi.
Competição de linhagens de feijão-caupi de porte ereto e crescimento determinado do tipo Canapu no Vale do São Francisco.
Linhagens de feij„o-caupi de porte ereto e crescimento determinado e do tipoëCanapuí foram avaliadas para diversos caracteres, em v·rios ambientesirrigados e de sequeiro do Vale do S„o Francisco, visando ‡ recomendaÁ„o decultivares. As linhagens tipo ëCanapuí foram avaliadas na densidade deplantio de 100.000 plantas/ha, com espaÁamento de 1 m entre linhas,enquanto as linhagens de porte ereto e crescimento determinado foramavaliadas na densidade de plantio de 200.000 plantas/ha, com espaÁamentode 0,5 m entrelinhas, em regime irrigado, no segundo semestre, e desequeiro, no primeiro semestre, nos anos de 2007, 2008 e 2009. Ascultivares controle foram BRS Maratao„, Canapu e BRS Pujante para os doisexperimentos, os quais foram conduzidos no delineamento de blocos ao acasocom trÍs repetiÁ?es. Nas avaliaÁ?es do segundo semestre, quando ocorremas mais altas temperaturas, os genÛtipos Maratao„ e Canapu apresentaramas menores produtividades, nos dois experimentos. Foi observada diferenÁaestatÌstica significativa (p<0,01) para a interaÁ„o genÛtipo*ambiente, paraos dois experimentos. Duas linhagens tipo ëCanapuí e trÍs de porte ereto ecrescimento determinado, de diferentes cores, foram selecionadas paraavaliaÁ„o em macroparcelas em v·rios ambientes, visando ‡ recomendaÁ„ode cultivares para a regi„o do Vale do S„o Francisco.bitstream/item/17894/1/Boletim-de-Pesquisa.pd
Irrigação do cajueiro-anão-precoce na região de Teresina.
bitstream/CPAMN-2009-09/20953/1/CT186.pd
Avaliação da influência do método de síntese na fotoatividade de nanocompósitos de TiO2/CoFe2O4 e TiO2/Fe3O4.
Photocatalysis with semiconductors: a comparative discussion of the photodegradation mechanisms of rhodamine and atrazine.
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