Generation of Closed Timelike Curves with Rotating Superconductors

The spacetime metric around a rotating SuperConductive Ring (SCR) is deduced from the gravitomagnetic London moment in rotating superconductors. It is shown that theoretically it is possible to generate Closed Timelike Curves (CTC) with rotating SCRs. The possibility to use these CTC's to travel in time as initially idealized by G\"{o}del is investigated. It is shown however, that from a technology and experimental point of view these ideas are impossible to implement in the present context.Comment: 9 pages. Submitted to Classical and Quantum Gravit

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

Biogas production from dairy cattle manure, under organic and conventional production systems.

The purpose of this study was to evaluate the production of biogas, as well as the biogas production potential resulting from the anaerobic biodigestion of dairy cattle manure under organic (CMOS) and conventional (CMCS) production system. Also, the concentration of thermotolerant coliforms was evaluated after the biodigestion process. Therefore, bench biodigesters prototypes were supplied with CMOS and CMCS for 30 weeks. The experimental design was completely randomized with four repetitions for each treatment. Analysis of total solids (TS), volatile solids (VS), biogas production potential, most probable number (MPN) of thermotolerant coliforms were made. The cumulative biogas production was 6.18 L and 11.15 L, when using the CMOS and CMCS, respectively. Average biogas production potential of CMCS were 0.2; 2.6 and 2.9 L kg-1 substrate, ST and SV added, respectively and for CMOS 0.1; 1.4 and 1.9 L kg-1substrate, ST and SV added, respectively. After the anaerobic biodigestion process of CMOS and CMCS, it was observed that the concentrations of thermotolerant coliforms were well below than the limit established by law

Optimal teleportation with a noisy source

We establish the optimal quantum teleportation protocol for the realistic scenario when both input state and quantum channel are afflicted by noise. In taking these effects into account higher fidelities are achieved. The optimality of the proposed protocol prevails even when restricted to a reduced set of generically available operations.Comment: 4 pages, 2 figure

Métodos de superação de dormência em Piptadenia adiantoides (SPRENG.) J.F. MACBR. (Fabaceae:Mimosoideae).

O objetivo deste trabalho foi avaliar os tratamentos mais eficazes na promoção da germinação de sementes de P. adiantoides, propor sua utilização como alternativa para o reflorestamento e proporcior novas informações sobre a espécie Piptadenia adiantoides