5,977 research outputs found

    Universality of weakly bound dimers and Efimov trimers close to Li-Cs Feshbach resonances

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    We study the interspecies scattering properties of ultracold Li-Cs mixtures in their two energetically lowest spin channels in the magnetic field range between 800 G and 1000 G. Close to two broad Feshbach resonances we create weakly bound LiCs dimers by radio-frequency association and measure the dependence of the binding energy on the external magnetic field strength. Based on the binding energies and complementary atom loss spectroscopy of three other Li-Cs s-wave Feshbach resonances we construct precise molecular singlet and triplet electronic ground state potentials using a coupled-channels calculation. We extract the Li-Cs interspecies scattering length as a function of the external field and obtain almost a ten-fold improvement in the precision of the values for the pole positions and widths of the s-wave Li-Cs Feshbach resonances as compared to our previous work [Pires \textit{et al.}, Phys. Rev. Lett. \textbf{112}, 250404 (2014)]. We discuss implications on the Efimov scenario and the universal geometric scaling for LiCsCs trimers

    Five-Dimensional QED, Muon Pair Production and Correction to the Coulomb Potential

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    We consider QED in five dimensions in a configuration where matter is localized on a 3-brane while foton propagates in the bulk. The idea is to investigate the effects of the Kaluza-Klein modes of the photon in the relativistic regime, but in low energy, and in the nonrelativistic regime. In the relativistic regime, we calculate the cross section for the reaction e++eμ++μe^+ + e^- \to \mu^+ + \mu^-. We compare our theoretical result with a precise measurement of this cross section at s=57.77\sqrt{s}=57.77 GeV. As result, we extract a lower bound on the size of the extra dimension. In the nonrelativistic regime, we derive the contribution for the Coulomb potential due to the whole tower of the Kaluza-Klein excited modes of the photon. We use the modified potential to calculate the Rutherford scattering differential cross section.Comment: minor changes, three new refs. added, to appear in IJMP

    Universal three-body recombination and Efimov resonances in an ultracold Li-Cs mixture

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    We study Efimov resonances via three-body loss in an ultracold two-component gas of fermionic 6^6Li and bosonic 133^{133}Cs atoms close to a Feshbach resonance at 843~G, extending results reported previously [Pires \textit{et al.}, Phys. Rev. Lett. 112, 250404 (2014)] to temperatures around 120~nK. The experimental scheme for reaching lower temperatures is based upon compensating the gravity-induced spatial separation of the mass-imbalanced gases with bichromatic optical dipole traps. We observe the first and second excited Li-Cs-Cs Efimov resonance in the magnetic field dependence of the three-body event rate constant, in good agreement with the universal zero-range theory at finite temperature [Petrov and Werner, Phys. Rev. A 92, 022704 (2015)]. Deviations are found for the Efimov ground state, and the inelasticity parameter η\eta is found to be significantly larger than those for single-species systems

    Pollination efficiency of P. juliflora (SW) DC in Petrolina, Pernambuco.

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    This research study aims, therefore, at defining the reproductive sysrern and the possible causes for the low fruit output per inflorescence, i.e. the low pollination efficiency

    Cork biomass biocomposites: lightweight and sustainable materials

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    Chapter 17. Cork biomass biocomposites: lightweight and sustainable materials.The authors would like to thank to the financial support from the Portuguese Foundation for Science and Technology (FCT) for the fellowship grant of Emanuel M. Fernandes (SFRH/BPD/96197/2013), “Fundo Social Europeu”- FSE and “Programa Diferencial de Potencial Humano POPH”.info:eu-repo/semantics/publishedVersio

    On the width of the last scattering surface

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    We discuss the physical effects of some accelerated world models on the width of the last scattering surface (LSS) of the cosmic microwave background radiation (CMBR). The models considered in our analysis are X-matter (XCDM) and a Chaplygin type gas. The redshift of the LSS does not depend on the kind of dark energy (if XCDM of Chaplygin). Further, for a Chaplygin gas, the width of the LSS is also only weakly dependent on the kind of scenario (if we have dark energy plus cold dark matter or the unified picture).Comment: 10 pages, 1 figure, 2 tables, accepted to IJMP

    Zoom-in-Net: Deep Mining Lesions for Diabetic Retinopathy Detection

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    We propose a convolution neural network based algorithm for simultaneously diagnosing diabetic retinopathy and highlighting suspicious regions. Our contributions are two folds: 1) a network termed Zoom-in-Net which mimics the zoom-in process of a clinician to examine the retinal images. Trained with only image-level supervisions, Zoomin-Net can generate attention maps which highlight suspicious regions, and predicts the disease level accurately based on both the whole image and its high resolution suspicious patches. 2) Only four bounding boxes generated from the automatically learned attention maps are enough to cover 80% of the lesions labeled by an experienced ophthalmologist, which shows good localization ability of the attention maps. By clustering features at high response locations on the attention maps, we discover meaningful clusters which contain potential lesions in diabetic retinopathy. Experiments show that our algorithm outperform the state-of-the-art methods on two datasets, EyePACS and Messidor.Comment: accepted by MICCAI 201
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