4,697 research outputs found

    Entanglement of two individual atoms using the Rydberg blockade

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    We report on our recent progress on the manipulation of single rubidium atoms trapped in optical tweezers and the generation of entanglement between two atoms, each individually trapped in neighboring tweezers. To create an entangled state of two atoms in their ground states, we make use of the Rydberg blockade mechanism. The degree of entanglement is measured using global rotations of the internal states of both atoms. Such internal state rotations on a single atom are demonstrated with a high fidelity.Comment: Proceeding of the 19th International Conference on Laser Spectroscopy ICOLS 2009, 7-13 June 2009, Hokkaido, Japa

    Electromagnetic Simulation and Design of a Novel Waveguide RF Wien Filter for Electric Dipole Moment Measurements of Protons and Deuterons

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    The conventional Wien filter is a device with orthogonal static magnetic and electric fields, often used for velocity separation of charged particles. Here we describe the electromagnetic design calculations for a novel waveguide RF Wien filter that will be employed to solely manipulate the spins of protons or deuterons at frequencies of about 0.1 to 2 MHz at the COoler SYnchrotron COSY at J\"ulich. The device will be used in a future experiment that aims at measuring the proton and deuteron electric dipole moments, which are expected to be very small. Their determination, however, would have a huge impact on our understanding of the universe.Comment: 10 pages, 10 figures, 4 table

    E2 properties of nuclei far from stability and the proton-halo problem of 8B

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    E2 properties of A=6--10 nuclei, including those of nuclei far from stability, are studied by a (0+2)ω(0+2)\hbar\omega shell-model calculation which includes E2 core-polarization effects explicitly. The quadrupole moments and the E2 transition strengths in A=6--10 nuclei are described quite well by the present calculation. This result indicates that the relatively large value of the quadrupole moment of 8^8B can be understood without introducing the proton-halo in 8^8B. An interesting effect of the 2ω2\hbar\omega core-polarization is found for effective charges used in the 0ω0\hbar\omega shell model; although isoscalar effective-charges are almost constant as a function of nucleus, appreciable variations are needed for isovector effective-charges which play important roles in nuclei with high isospin-values.Comment: (LaTeX, 23 pages

    Substance Misuse Education for Physicians: Why Older People are Important.

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    This perspective article focuses on the need for training and education for undergraduate medical students on substance-related disorders, and describes initiatives undertaken in the United Kingdom (UK), Netherlands, United States (US), and Norway to develop the skills, knowledge, and attitudes needed by future doctors to treat patients adequately. In addition, we stress that in postgraduate training, further steps should be taken to develop Addiction Medicine as a specialized and transverse medical domain. Alcohol use disorder is a growing public health problem in the geriatric population, and one that is likely to continue to increase as the baby boomer generation ages. Prescription drug misuse is a major concern, and nicotine misuse remains problematic in a substantial minority. Thus, Addiction Medicine training should address the problems for this specific population. In recent years, several countries have started an Addiction Medicine specialty. Although addiction psychiatry has been a subspecialty in the UK and US for more than 20 years, in most countries it has been a more recent development. Additional courses on addiction should be integrated into the curriculum at both undergraduate and postgraduate levels, as well as form part of the continuous training of other medical specialists. It is recommended that further research and mapping of what is currently taught in medical programs be undertaken, so as to enhance medical education in addiction and improve treatment services

    Influence of anisotropic conductivity of the white matter tissue on EEG source reconstruction a FEM simulation study

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    The aim of this study was to quantify the influence of the inclusion of anisotropic conductivity on EEG source reconstruction. We applied high-resolution finite element modeling and performed forward and inverse simulation with over 4000 single dipoles placed around an anisotropic volume block (with an anisotropic ratio of 1:10) in a rabbit brain. We investigated three different orientation of the dipoles with respect to the anisotropy in the white matter block. We found a weak influence of the anisotropy in the forward simulation on the electric potential. The relative difference measure (RDM) between the potentials simulated with and without taking into account anisotropy was less than 0.009. The changes in magnitude (MAG) ranged from 0.944 to 1.036. Using the potentials of the forward simulation derived with the anisotropic model and performing source reconstruction by employing the isotropic model led to dipole shifts of up to 2 mm, however the mean shift over all dipoles and orientations of 0.05 mm was smaller than the grid size of the FEM model (0.6 mm). However, we found the source strength estimation to be more influenced by the anisotropy (up to 7-times magnified dipole strength)

    Reliability analysis of water distribution systems using graph decomposition

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    Water supply utilities are increasingly being confronted with growing maintenance requirements in order to provide a reliable and cost efficient operation of the water distribution system in order to deliver high standard drinking water. One specific challenge is to find a satisfactory compromise between the contradictory objectives of saving investment cost and meeting the increasing expectations of customers. A valuable tool for the planner is reliability analysis of the system that for instance provides information about the importance of each particular pipe in determining the total reliability of the system. This information can be used to decide which pipes should be replaced next or potentially duplicated to reduce the risk of system isolation. Since structural (topological) reliability only considers the connectivity of the network a new approach for the calculation of structural hydraulic reliability is presented in this paper. The algorithmic implementation is based on a decomposition method of the network graph that greatly enhances both the calculation of pure structural reliability as well as structural hydraulic reliability.Jochen Deuerlein, Andreas Wolters, Dietmar Roetsch and Angus R. Simpso
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