9,103 research outputs found

    Nuclear Magnetic Resonance Implementation of a Quantum Clock Synchronization Algorithm

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    The quantum clock synchronization algorithm proposed by I. L. Chuang (Phys. Rev. Lett, 85, 2006(2000)) has been implemented in a three qubit nuclear magnetic resonance quantum system. The effective-pure state is prepared by the spatial averaging approach. The time difference between two separated clocks can be determined by reading out directly through the NMR spectra.Comment: 13 pages, 5 figure

    Systematic study of breakup effects on complete fusion at energies above the Coulomb barrier

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    A large number of complete fusion excitation functions of reactions including the breakup channel were measured in recent decades, especially in the last few years. It allows us to investigate the systematic behavior of the breakup effects on the complete fusion cross sections. To this end, we perform a systematic study of the breakup effects on the complete fusion cross sections at energies above the Coulomb barrier. The reduced fusion functions F(x) are compared with the universal fusion functions which are used as a uniform standard reference. The complete fusion cross sections at energies above the Coulomb barrier are suppressed by the breakup of projectiles. This suppression effect for reactions induced by the same projectile is independent of the target and mainly determined by the lowest energy breakup channel of the projectile. There holds a good exponential relation between the suppression factor and the energy corresponding to the lowest breakup threshold.Comment: 10 pages, 9 figures; Fig. 9 and related discussions modifie

    Scattering by a contact potential in three and lower dimensions

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    We consider the scattering of nonrelativistic particles in three dimensions by a contact potential Ω2δ(r)/2μrα\Omega\hbar^2\delta(r)/ 2\mu r^\alpha which is defined as the a0a\to 0 limit of Ω2δ(ra)/2μrα\Omega\hbar^2\delta(r-a)/2\mu r^\alpha. It is surprising that it gives a nonvanishing cross section when α=1\alpha=1 and Ω=1\Omega=-1. When the contact potential is approached by a spherical square well potential instead of the above spherical shell one, one obtains basically the same result except that the parameter Ω\Omega that gives a nonvanishing cross section is different. Similar problems in two and one dimensions are studied and results of the same nature are obtained.Comment: REVTeX, 9 pages, no figur

    Influence of Advertisement Message on Fitbar Billboard Towards Brand Awareness and Its Implication to Brand Image

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    The assumption that snacks could cause problem in diet and bodyweight, makes this study interesting. Because this product, Fitbar, appears on the market as a healthy snack that is contrary to this assumption. This product is about to prove that there is a healthy and tasty snack as snacks. Marketing communications through advertising billboards with the media aims to reach the target market. Fitbar billboard ads convey the message content in the form of information about the attributes and benefits of products such as nutritional content and product slogans. This study uses path analysis techniques to determine the effect of variable X (advertisement message) to variable Y (brand awareness) and its implications on the variable Z (brand image). The results showed that the content of the message components such as message structure, message display, message format, and the source of the message have contributed in the formation of brand awareness, which further on has implications on brand image. Influence on brand awareness message content is equal to 0.609. The effect of variable X (message) and Y (brand awareness) to variable Z (brand image) amounted to 0,365. Therefore, the use of billboards media in conveying the message to the target market of Fitbar products is to build brand awareness and the implications for brand image

    Nonlinearity and hysteresis of resonant strain gauges

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    Nonlinearity and hysteresis effects of electrostatically activated, voltage driven resonant microbridges have been studied theoretically and experimentally. It is shown, that, in order to avoid vibration instability and hysteresis to occur, the choices of the ax. and d.c. driving voltages and of the quality factor of a resonator, with a given geometry and choice of materials, are limited by a hysteresis criterion. The limiting conditions are also formulated as hysteresis-free design rules. An expression for the maximum attainable figure of merit is also given. Experimental results, as obtained from electrostatically driven vacuum-encapsulated polysilicon microbridges, are presented and show good agreement with the theory

    Quantized spin excitations in a ferromagnetic microstrip from microwave photovoltage measurements

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    Quantized spin excitations in a single ferromagnetic microstrip have been measured using the microwave photovoltage technique. Several kinds of spin wave modes due to different contributions of the dipole-dipole and the exchange interactions are observed. Among them are a series of distinct dipole-exchange spin wave modes, which allow us to determine precisely the subtle spin boundary condition. A comprehensive picture for quantized spin excitations in a ferromagnet with finite size is thereby established. The dispersions of the quantized spin wave modes have two different branches separated by the saturation magnetization.Comment: 4 pages, 3 figure

    Proton-Antiproton Annihilation in Baryonium

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    A possible interpretation of the near-threshold enhancement in the (ppˉ)(p\bar{p})-mass spectrum in J/ψγppˉJ/\psi{\to}\gamma p{\bar p} is the of existence of a narrow baryonium resonance X(1860). Mesonic decays of the (ppˉ)(p\bar{p})-bound state X(1860) due to the nucleon-antinucleon annihilation are investigated in this paper. Mesonic coherent states with fixed GG-parity and PP-parity have been constructed . The Amado-Cannata-Dedoder-Locher-Shao formulation(Phys Rev Lett. {\bf 72}, 970 (1994)) is extended to the decays of the X(1860). By this method, the branch-fraction ratios of Br(Xη4π)Br(X\to \eta 4\pi), Br(Xη2π)Br(X\to \eta 2\pi) and Br(X3η)Br(X\to 3\eta) are calculated. It is shown that if the X(1860) is a bound state of (ppˉ)(p\bar{p}), the decay channel (Xη4π)X\to \eta 4\pi) is favored over (Xη2π)(X\to \eta 2\pi). In this way, we develop criteria for distinguishing the baryonium interpretation for the near-threshold enhancement effects in (ppˉ)(p\bar{p})-mass spectrum in J/ψγppˉJ/\psi{\to}\gamma p{\bar p} from other possibilities. Experimental checks are expected. An intuitive picture for our results is discussed.Comment: 19 pages, 3 figure

    Vacuum polarization for neutral particles in 2+1 dimensions

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    In 2+1 dimensions there exists a duality between a charged Dirac particle coupled minimally to a background vector potential and a neutral one coupled nonminimally to a background electromagnetic field strength. A constant uniform background electric current induces in the vacuum of the neutral particle a fermion current which is proportional to the background one. A background electromagnetic plane wave induces no current in the vacuum. For constant but nonuniform background electric charge, known results for charged particles can be translated to give the induced fermion number. Some new examples with infinite background electric charge are presented. The induced spin and total angular momentum are also discussed.Comment: REVTeX, 7 pages, no figur
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