669 research outputs found

    Fabricating plasmonic components for nanophotonics:[invited]

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    We report on experimental realization of different metal-dielectric structures that are used as surface plasmon polariton waveguides and as plasmonic metamaterials. Fabrication approaches based on different lithographic and deposition techniques are discussed

    Magnetoluminescence

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    Pulsar Wind Nebulae, Blazars, Gamma Ray Bursts and Magnetars all contain regions where the electromagnetic energy density greatly exceeds the plasma energy density. These sources exhibit dramatic flaring activity where the electromagnetic energy distributed over large volumes, appears to be converted efficiently into high energy particles and gamma-rays. We call this general process magnetoluminescence. Global requirements on the underlying, extreme particle acceleration processes are described and the likely importance of relativistic beaming in enhancing the observed radiation from a flare is emphasized. Recent research on fluid descriptions of unstable electromagnetic configurations are summarized and progress on the associated kinetic simulations that are needed to account for the acceleration and radiation is discussed. Future observational, simulation and experimental opportunities are briefly summarized.Comment: To appear in "Jets and Winds in Pulsar Wind Nebulae, Gamma-ray Bursts and Blazars: Physics of Extreme Energy Release" of the Space Science Reviews serie

    Distributed phase-covariant cloning with atomic ensembles via quantum Zeno dynamics

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    We propose an interesting scheme for distributed orbital state quantum cloning with atomic ensembles based on the quantum Zeno dynamics. These atomic ensembles which consist of identical three-level atoms are trapped in distant cavities connected by a single-mode integrated optical star coupler. These qubits can be manipulated through appropriate modulation of the coupling constants between atomic ensemble and classical field, and the cavity decay can be largely suppressed as the number of atoms in the ensemble qubits increases. The fidelity of each cloned qubit can be obtained with analytic result. The present scheme provides a new way to construct the quantum communication network.Comment: 5 pages, 4 figure

    Enamel remineralization via poly(amido amine) and adhesive resin containing calcium phosphate nanoparticles

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    Objectives:The objective of this study was to investigate enamel remineralization using salivary statherin pro-tein-inspired poly(amidoamine) dendrimer (SN15-PAMAM) and adhesive containing nanoparticles of amor-phous calcium phosphate (NACP) in a cyclic artificial saliva/demineralizing solution for thefirst time.Methods:The enamel shear bond strengths of NACP adhesives were measured compared to commercial adhesive(Scotchbond Multi-Purpose, 3 M). Adhesive disks containing NACP were tested for calcium (Ca) and phosphorus(P) ions release. Four groups were tested: (1) enamel control, (2) enamel with NACP, (3) enamel with SN15-PAMAM, and (4) enamel with SN15-PAMAM + NACP. The specimens were treated with cyclic artificial saliva/demineralizing solution for 28 days. The remineralized enamel specimens were examined by surface and cross-sectional hardness test.Results:NACP adhesive yielded a similar shear bond strength to commercial control (Scotchbond Multi-Purpose,3 M). NACP adhesive released high levels of Ca and P ions. At 28 days, the enamel hardness of SN15-PAMAM +NACP group was 2.89 ± 0.13 GPa, significantly higher than that of control group (1.46 ± 0.10 GPa) (p< 0.05).SN15-PAMAM + NACP increased the enamel cross-sectional hardness at 28 days; at 25μm, enamel cross-sectional hardness was 90 % higher than that of control group (p< 0.05).Significance:The novel SN15-PAMAM + NACP adhesive method could achieve 90 % higher enamel reminer-alization of the artificial caries than the control under acid challenge for thefirst time. This method is promisingfor use after tooth cavity preparation, or as a coating on enamel with white spot lesions (WSLs) for prevention, toreduce secondary caries, prevent caries procession and protect tooth structures

    Lower limit on the neutralino mass in the general MSSM

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    We discuss constraints on SUSY models with non-unified gaugino masses and R_P conservation. We derive a lower bound on the neutralino mass combining the direct limits from LEP, the indirect limits from gmuon, bsgamma, Bsmumu and the relic density constraint from WMAP. The lightest neutralino (mneutralino=6GeV) is found in models with a light pseudoscalar with MA<200GeV and a large value for tanβtan\beta. Models with heavy pseudoscalars lead to mneutralino>18(29)GeV for tanβ=50(10)\tan\beta=50(10). We show that even a very conservative bound from the muon anomalous magnetic moment can increase the lower bound on the neutralino mass in models with mu<0 and/or large values of tanβ\tan\beta. We then examine the potential of the Tevatron and the direct detection experiments to probe the SUSY models with the lightest neutralinos allowed in the context of light pseudoscalars with high tanβ\tan\beta. We also examine the potential of an e+e- collider of 500GeV to produce SUSY particles in all models with neutralinos lighter than the W. In contrast to the mSUGRA models, observation of at least one sparticle is not always guaranteed.Comment: 37 pages, LateX, 16 figures, paper with higher resolution figures available at http://wwwlapp.in2p3.fr/~boudjema/papers/bound-lsp/bound-lsp.htm

    Observation of the ϕ(1680)\phi(1680) and the Y(2175) in e+eϕπ+πe^+ e^- \to \phi\pi^+\pi^-

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    The cross sections for e+eϕπ+πe^+ e^- \to \phi\pi^+\pi^- and e^+ e^- \to \phi \fzero are measured from threshold to s=3.0\sqrt{s}=3.0 GeV\hbox{GeV} using initial state radiation. The analysis is based on a data sample of 673 fb1^{-1} collected on and below the Υ(4S)\Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ee^+e^- collider. First measurements are reported for the resonance parameters of the ϕ(1680)\phi(1680) in the ϕπ+π\phi\pi^+\pi^- mode: m=(1689±7±10)m=(1689\pm 7\pm 10) MeV/c2c^2 and Γ=(211±14±19)\Gamma=(211\pm 14\pm 19) MeV/c2c^2. A structure at s=2.1GeV/c2\sqrt{s}=2.1 \hbox{GeV}/c^2, corresponding to the so called Y(2175), is observed; its mass and width are determined to be 2079±1328+792079\pm13^{+79}_{-28} MeV/c2c^2 and 192±2361+25MeV/c2192\pm23^{+25}_{-61} \hbox{MeV}/c^2, respectively.Comment: 11 pages, 6 figures. Add one plot. Accepted by Phys.Rev.D(RC

    Measurement of CP asymmetry in Cabibbo suppressed D0 decays

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    We measure the CP-violating asymmetries in decays to the D0 -> K+K- and D0 -> pi+pi- CP eigenstates using 540 fb^{-1} of data collected with the Belle detector at or near the Upsilon(4S) resonance. Cabibbo-favored D0 -> K-pi+ decays are used to correct for systematic detector effects. The results, A_{CP}^{KK} = (-0.43 +- 0.30 +- 0.11)% and A_{CP}^{pipi} = (+0.43 +- 0.52 +- 0.12)%, are consistent with no CP violation.Comment: Submitted to Phys. Lett.

    Study of B0ˉD()0π+π\bar{B^{0}} \to D^{(*)0} \pi^+ \pi^- Decays

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    We report on a study of B0ˉD()0π+π\bar{B^{0}} \to D^{(*) 0} \pi^+ \pi^- decays using 29.1 fb1^{-1} of e+ee^{+}e^{-} annihilation data recorded at the Υ(4S)\Upsilon(4S) resonance with the Belle detector at the KEKB storage ring. Making no assumptions about the intermediate mechanism, the branching fractions for Bˉ0D0π+π\bar{B}^0 \to D^0 \pi^+ \pi^- and Bˉ0D0π+π\bar{B}^0 \to D^{* 0} \pi^+ \pi^- are determined to be (8.0±0.6±1.5)×104(8.0 \pm 0.6 \pm 1.5) \times 10^{-4} and (6.2±1.2±1.8)×104 (6.2 \pm 1.2 \pm 1.8) \times 10^{-4} respectively. An analysis of B0ˉD0π+π\bar{B^{0}} \to D^{0} \pi^+ \pi^- candidates yields to the first observation of the color-suppressed hadronic decay Bˉ0D0ρ0\bar{B}^0 \to D^0 \rho^0 with the branching fraction (2.9±1.0±0.4)×104(2.9 \pm 1.0 \pm 0.4) \times 10^{-4}. We measure the ratio of branching fractions B(B0ˉD0ρ0)/B(B0ˉD0ω){\mathcal B}(\bar{B^0} \to D^0 \rho^0) / {\mathcal B}(\bar{B^0} \to D^0 \omega) = 1.6 ±\pm 0.8.Comment: 13 pages, LaTex, 4 figures, submitted to Phys. Lett.
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