9,988 research outputs found

    Spontaneous electromagnetic superconductivity and superfluidity of QCDxQED vacuum in strong magnetic field

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    It was recently shown that the vacuum in the background of a strong enough magnetic field may become an electromagnetic superconductor due to interplay between strong and electromagnetic forces. The superconducting ground state of the QCDxQED sector of the vacuum is associated with magnetic-field-assisted emergence of quark-antiquark condensates which carry quantum numbers of charged rho mesons (i.e., of electrically charged vector particles made of lightest, u and d, quarks and antiquarks). Here we demonstrate that this exotic electromagnetic superconductivity of vacuum is also accompanied by even more exotic superfluidity of the neutral rho mesons. The superfluid component -- despite being electrically neutral -- turns out to be sensitive to an external electric field as the superfluid may ballistically be accelerated by a test background electric field along the magnetic-field axis. In the ground state both superconducting and superfluid components are inhomogeneous periodic functions of the transversal (with respect to the axis of the magnetic field) spatial coordinates. The superconducting part of the ground state resembles an Abrikosov ground state in a type-II superconductor: the superconducting condensate organizes itself in periodic structure which possesses the symmetry of an equilateral triangular lattice. Each elementary lattice cell contains a stringlike topological defect (superconductor vortex) in the charged rho condensates as well as three superfluid vortices and three superfluid antivortices made of the neutral rho condensate. The superposition of the superconductor and superfluid vortex lattices has a complicated "kaleidoscopic" pattern.Comment: 6 pages, 2 figures. Talk given at Sixth International Conference on Quarks and Nuclear Physics QNP2012, April 16-20, 2012, Ecole Polytechnique, Palaiseau, Franc

    Phonon spectrum of QCD vacuum in magnetic-field-induced superconducting phase

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    In the background of a sufficiently strong magnetic field the vacuum was suggested to become an ideal electric conductor (highly anisotropic superconductor) due to an interplay between the strong and electromagnetic forces. The superconducting ground state resembles an Abrikosov lattice state in an ordinary type--II superconductor: it is an inhomogeneous structure made of a (charged vector) quark-antiquark condensate pierced by vortices. In this paper the acoustic (phonon) vibrational modes of the vortex lattice are studied at zero temperature. Using an effective model based on a vector meson dominance, we show that in the infrared limit the longitudinal (transverse) acoustic vibrations of the vortex lattice possess a linear (quadratic) dispersion relation corresponding to type I (type II) Nambu--Goldstone modes.Comment: 12 pages, 3 figures; v2: minor changes, published versio

    That\u27s the Tune They Play in Dixie Land (My Home Sweet Home)

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    https://digitalcommons.library.umaine.edu/mmb-vp/6551/thumbnail.jp

    When a Fellow Has A Sweethear, Life\u27s a Song

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    https://digitalcommons.library.umaine.edu/mmb-vp/5754/thumbnail.jp

    If You Are No One\u27s Sweetheart : Is There Any Chance for Me?

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    https://digitalcommons.library.umaine.edu/mmb-vp/1822/thumbnail.jp

    Somewhere there is Someone I\u27d like to know

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    https://digitalcommons.library.umaine.edu/mmb-vp/6181/thumbnail.jp

    Seeking out and building monopolies, Rothschild strategies in non ferrous metals international markets (1830-1940)

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    The aim of this article is to analyse the strategies employed by the Rothschilds until 1940 to limit competition in the non ferrous international market. We will study how they opted for rigid demand products of highly concentrated supply which were favourable to market control (mercury, nickel, lead and copper and sulphur) by assuming administrative monopolies (mercury from Spanish Almadn Mines) or through control of the leading businesses of the respective markets (Le Nickel, Pearroya and Rio Tinto). We will also analyse how the family was able to gain worldwide monopolies, or if not, how they promoted collusive oligopolies with the competition in any number of forms in their quest to maintain profitability and to flee from any competition.International Raw material markets, Cartels, Rothschild, mining, Non-ferrous metals.

    Reactive Turing Machines

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    We propose reactive Turing machines (RTMs), extending classical Turing machines with a process-theoretical notion of interaction, and use it to define a notion of executable transition system. We show that every computable transition system with a bounded branching degree is simulated modulo divergence-preserving branching bisimilarity by an RTM, and that every effective transition system is simulated modulo the variant of branching bisimilarity that does not require divergence preservation. We conclude from these results that the parallel composition of (communicating) RTMs can be simulated by a single RTM. We prove that there exist universal RTMs modulo branching bisimilarity, but these essentially employ divergence to be able to simulate an RTM of arbitrary branching degree. We also prove that modulo divergence-preserving branching bisimilarity there are RTMs that are universal up to their own branching degree. Finally, we establish a correspondence between executability and finite definability in a simple process calculus

    Electronic fraud detection in the U.S. Medicaid Healthcare Program: lessons learned from other industries

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    It is estimated that between 600and600 and 850 billion annually is lost to fraud, waste, and abuse in the US healthcare system,with 125to125 to 175 billion of this due to fraudulent activity (Kelley 2009). Medicaid, a state-run, federally-matchedgovernment program which accounts for roughly one-quarter of all healthcare expenses in the US, has been particularlysusceptible targets for fraud in recent years. With escalating overall healthcare costs, payers, especially government-runprograms, must seek savings throughout the system to maintain reasonable quality of care standards. As such, the need foreffective fraud detection and prevention is critical. Electronic fraud detection systems are widely used in the insurance,telecommunications, and financial sectors. What lessons can be learned from these efforts and applied to improve frauddetection in the Medicaid health care program? In this paper, we conduct a systematic literature study to analyze theapplicability of existing electronic fraud detection techniques in similar industries to the US Medicaid program
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