2,025 research outputs found

    Gravitating monopoles in SU(3) gauge theory

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    We consider the Einstein-Yang-Mills-Higgs equations for an SU(3) gauge group in a spherically symmetric ansatz. Several properties of the gravitating monopole solutions are obtained an compared with their SU(2) counterpart.Comment: 7 pages, Latex, 3 figure

    The 1-soliton in the SO(3) gauged Skyrme model with mass term

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    The solitons of the SO(3) gauged Skyrme model with no pion-mass potential were studied in Refs. {nl,jmp}. Here, the effects of the inclusion of this potential are studied. In contrast with the (ungauged) Skyrme model, where the effect of this potential on the solitons is marginal, here it turns out to be decisive, resulting in very different dependence of the energy as a function of the Skyrme coupling constant.Comment: new title, typos corrected, LaTeX, 8 pages, 4 figure

    Infinite Games with Uncertain Moves

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    International audienceWe study infinite two-player games where one of the players is unsure about the set of moves available to the other player. In particular, the set of moves of the other player is a strict superset of what she assumes it to be. We explore what happens to sets in various levels of the Borel hierarchy under such a situation. We show that the sets at every alternate level of the hierarchy jump to the next higher level

    Gravitating dyons and the Lue-Weinberg bifurcation

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    Gravitating t'Hooft-Polyakov magnetic monopoles can be constructed when coupling the Georgi-Glashow model to gravitation. For a given value of the Higgs boson mass, these gravitating solitons exist up to a critical value of the ratio of the vector meson mass to the Planck mass. The critical solution is characterized by a degenerate horizon of the metric. As pointed out recently by Lue and Weinberg, two types of critical solutions can occur, depending on the value of the Higgs boson mass. Here we investigate this transition for dyons and show that the Lue and Weinberg phenomenon is favorized by the presence of the electric-charge degree of freedom.Comment: RevTeX, 6 pages, 8 figure

    Rhythmic Oxygen Levels Reset Circadian Clocks through HIF1 alpha

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    This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordThe mammalian circadian system consists of a master clock in the brain that synchronizes subsidiary oscillators in peripheral tissues. The master clock maintains phase coherence in peripheral cells through systemic cues such as feeding-fasting and temperature cycles. Here, we examined the role of oxygen as a resetting cue for circadian clocks. We continuously measured oxygen levels in living animals and detected daily rhythms in tissue oxygenation. Oxygen cycles, within the physiological range, were sufficient to synchronize cellular clocks in a HIF1α-dependent manner. Furthermore, several clock genes responded to changes in oxygen levels through HIF1α. Finally, we found that a moderate reduction in oxygen levels for a short period accelerates the adaptation of wild-type but not of HIF1α-deficient mice to the new time in a jet lag protocol. We conclude that oxygen, via HIF1α activation, is a resetting cue for circadian clocks and propose oxygen modulation as therapy for jet lag.Israel Science FoundationEuropean Research CouncilFeinberg Graduate School, Weizmann Institute of ScienceBritish Heart FoundationEuropean Union, Seventh Framework Programm

    Particle-like solutions to higher order curvature Einstein--Yang-Mills systems in d dimensions

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    We consider the superposition of the first two members of the gravitational hierarchy (Einstein plus first Gauss-Bonnet(GB)) interacting with the superposition of the first two members of the SO(±)(d)SO_{(\pm)}(d) Yang--Mills hierarchy, in dd dimensions. Such systems can occur in the low energy effective action of string theory. Particle-like solutions %for the systems with only an Einstein term, and with only a GB term, in dimensions d=6,8d=6,8 are constructed respectively. Our results reveal qualitatively new properties featuring double-valued solutions with critical behaviour. In this preliminary study, we have restricted ourselves to one-node solutions.Comment: 10 pages, 11 figure

    Ion-beam-hydrogenated amorphous silicon

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    A kaufman ion-beam source has been used to study the rehydrogenation and postdeposition hydrogenation of amorphous silicon. In the rehydrogenation study, hydrogen atoms were implanted into glow-dischargedeposited amorphous silicon materials in which the hydrogen content had been driven out by heating. In the posthydrogenation study, amorphous silicon samples with no hydrogen content detectable by infrared absorption and no photoconductivity were used as the starting material. These materials were deposited by thermal CVD, magnetron sputtering, or RF glow discharge

    The Faraday Quantum Clock and Non-local Photon Pair Correlations

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    We study the use of the Faraday effect as a quantum clock for measuring traversal times of evanescent photons through magneto-refractive structures. The Faraday effect acts both as a phase-shifter and as a filter for circular polarizations. Only measurements based on the Faraday phase-shift properties are relevant to the traversal time measurements. The Faraday polarization filtering may cause the loss of non-local (Einstein-Podolsky-Rosen) two-photon correlations, but this loss can be avoided without sacrificing the clock accuracy. We show that a mechanism of destructive interference between consecutive paths is responsible for superluminal traversal times measured by the clock.Comment: 6 figure

    High-level software-pipelining in LLVM

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    Software-pipelining is an important technique for increasing the instruction level parallelism of loops during compilation. Currently, the LLVM compiler infrastructure does not offer this optimization although some target specific implementations do exist. We have implemented a high-level method for software-pipelining within the LLVM framework. By implementing this within LLVM's optimization layer we have taken the first steps towards a target independent software-pipelining method
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