Entropic Entanglement Criteria for Continuous Variables

We derive several entanglement criteria for bipartite continuous variable quantum systems based on the Shannon entropy. These criteria are more sensitive than those involving only second-order moments, and are equivalent to well-known variance product tests in the case of Gaussian states. Furthermore, they involve only a pair of quadrature measurements, and will thus should prove extremely useful the experimental identification of entanglement.Comment: 4 pages, 2 figure

Caracterização de uma amilase de sementes de Libidibia ferrea (Mart. ex. Tul.).

Caracterizar uma amilase de extratos aquosos de sementes de L. ferrea quanto à estabilidade térmica e massa molecular

Inibidores de papaina e tripsina em frações proteicas de sementes de Libidibia ferrea (Mart. ex Tul.).

Verificar a inibição da papaína e da tripsina por frações protéicas de sementes de Libidibia ferreae seu perfil eletroforético

Ensaio alternativo para triagem de extratos protéicos com atividade celulolítica.

Este comunicado apresenta uma metodologia de difusão radial em gel de agarose (DRGA) desenvolvida por Teather e Wood (1982), modificada por Rehman et al. (2009), e adaptada no Laboratório de Bioquímica da Embrapa Caprinos e Ovinos para avaliar a atividade celulolítica em extratos proteicos de microrganismos ruminais. A técnica baseia-se na difusão radial, em gel de agarose, das proteínas da amostra analisada. O gel contém o substrato específico para celulase, a carboximetilcelulose, que pode ser corada com o corante vermelho congo.bitstream/item/31686/1/UMT-Cot112.pd

Experimental investigation of the dynamics of entanglement: Sudden death, complementarity, and continuous monitoring of the environment

We report on an experimental investigation of the dynamics of entanglement between a single qubit and its environment, as well as for pairs of qubits interacting independently with individual environments, using photons obtained from parametric down-conversion. The qubits are encoded in the polarizations of single photons, while the interaction with the environment is implemented by coupling the polarization of each photon with its momentum. A convenient Sagnac interferometer allows for the implementation of several decoherence channels and for the continuous monitoring of the environment. For an initially-entangled photon pair, one observes the vanishing of entanglement before coherence disappears. For a single qubit interacting with an environment, the dynamics of complementarity relations connecting single-qubit properties and its entanglement with the environment is experimentally determined. The evolution of a single qubit under continuous monitoring of the environment is investigated, demonstrating that a qubit may decay even when the environment is found in the unexcited state. This implies that entanglement can be increased by local continuous monitoring, which is equivalent to entanglement distillation. We also present a detailed analysis of the transfer of entanglement from the two-qubit system to the two corresponding environments, between which entanglement may suddenly appear, and show instances for which no entanglement is created between dephasing environments, nor between each of them and the corresponding qubit: the initial two-qubit entanglement gets transformed into legitimate multiqubit entanglement of the Greenberger-Horne-Zeilinger (GHZ) type.Comment: 15 pages, 14 figures; only .ps was working, now .pdf is also availabl