9,643 research outputs found

    Inverse Avalanches On Abelian Sandpiles

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    A simple and computationally efficient way of finding inverse avalanches for Abelian sandpiles, called the inverse particle addition operator, is presented. In addition, the method is shown to be optimal in the sense that it requires the minimum amount of computation among methods of the same kind. The method is also conceptually nice because avalanche and inverse avalanche are placed in the same footing.Comment: 5 pages with no figure IASSNS-HEP-94/7

    Analysis of Two-Body Decays of Charmed Baryons Using the Quark-Diagram Scheme

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    We give a general formulation of the quark-diagram scheme for the nonleptonic weak decays of baryons. We apply it to all the decays of the antitriplet and sextet charmed baryons and express their decay amplitudes in terms of the quark-diagram amplitudes. We have also given parametrizations for the effects of final-state interactions. For SU(3) violation effects, we only parametrize those in the horizontal WW-loop quark diagrams whose contributions are solely due to SU(3)-violation effects. In the absence of all these effects, there are many relations among various decay modes. Some of the relations are valid even in the presence of final-state interactions when each decay amplitude in the relation contains only a single phase shift. All these relations provide useful frameworks to compare with future experiments and to find out the effects of final-state interactions and SU(3) symmetry violations.Comment: 28 pages, 20 Tables in landscape form, 4 figures. Main changes are: (i) some errors in the Tables and in the relations between the quark-diagram amplitudes of this paper and those of Ref.[10] are corrected, (ii) improvements are made in the presentation so that comparisons with previous works and what have been done to include SU(3) breaking and final-state interactions are more clearly stated; to appear in the Physical Review

    Comments on the Quark Content of the Scalar Meson f0(1370)f_0(1370)

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    Based on the measurements of (Ds+,D+)f0(1370)π+(D_s^+,D^+)\to f_0(1370)\pi^+ we determine, in a model independent way, the allowed ssˉs\bar s content in the scalar meson f0(1370)f_0(1370). We find that, on the one hand, if this isoscalar resonance is a pure nnˉn\bar n state [ nnˉ(uuˉ+ddˉ)/2]n\bar n\equiv(u\bar u+d\bar d)/\sqrt{2} ], a very large WW-annihilation term will be needed to accommodate Ds+f0(1370)π+D_s^+\to f_0(1370)\pi^+. On the other hand, the ssˉs\bar s component of f0(1370)f_0(1370) should be small enough to avoid excessive Ds+f0(1370)π+D_s^+\to f_0(1370)\pi^+ induced from the external WW-emission. Measurement of f0(1370)f_0(1370) production in the decay Ds+K+Kπ+D_s^+\to K^+K^-\pi^+ will be useful to test the above picture. For the decay D0f0(1370)Kˉ0D^0\to f_0(1370)\bar K^0 which is kinematically barely or even not allowed, depending on the mass of f0(1370)f_0(1370), we find that the finite width effect of f0(1370)f_0(1370) plays a crucial role on the resonant three-body decay D0f0(1370)Kˉ0π+πKˉ0D^0\to f_0(1370)\bar K^0\to\pi^+\pi^-\bar K^0.Comment: 12 pages, 2 figure

    Imaging radar observations and nonlocal theory of large-scale plasma waves in the equatorial electrojet

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    International audienceLarge-scale (l ~ 1 km) waves in the daytime and night-time equatorial electrojet are studied using coherent scatter radar data from Jicamarca. Images of plasma irregularities within the main beam of the radar are formed using interferometry with multiple baselines. These images are analyzed according to nonlocal gradient drift instability theory and are also compared to nonlinear computer simulations carried out recently by Ronchi et al. (1991) and Hu and Bhattacharjee (1999). In the daytime, the large-scale waves assume a non-steady dynamical equilibrium state characterized by the straining and destruction of the waves by shear and diffusion followed by spontaneous regeneration as predicted by Ronchi et al. (1991). At night, when steep plasma density gradients emerge, slowly propagating large-scale vertically extended waves predominate. Eikonal analysis suggests that these waves are trapped (absolutely unstable) or are nearly trapped (convectively unstable) and are able to tunnel between altitude regions which are locally unstable. Intermediate-scale waves are mainly transient (convectively stable) but can become absolutely unstable in narrow altitude bands determined by the background density profile. These characteristics are mainly consistent with the simulations presented by Hu and Bhattacharjee (1999). A new class of large-scale primary waves is found to occur along bands that sweep westward and downward from high altitudes through the E-region at twilight

    Good Quantum Convolutional Error Correction Codes And Their Decoding Algorithm Exist

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    Quantum convolutional code was introduced recently as an alternative way to protect vital quantum information. To complete the analysis of quantum convolutional code, I report a way to decode certain quantum convolutional codes based on the classical Viterbi decoding algorithm. This decoding algorithm is optimal for a memoryless channel. I also report three simple criteria to test if decoding errors in a quantum convolutional code will terminate after a finite number of decoding steps whenever the Hilbert space dimension of each quantum register is a prime power. Finally, I show that certain quantum convolutional codes are in fact stabilizer codes. And hence, these quantum stabilizer convolutional codes have fault-tolerant implementations.Comment: Minor changes, to appear in PR

    Multilayer framework for vehicle-to-grid operation

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    In recent years, electric vehicles (EVs) have been widely accepted by general publics due to their low emissions. Particularly, those EVs which are able to be connected to power grid have earned lots of attention. In this paper, a multilayer framework is newly proposed for vehicle-to-grid operation. In this framework those gridable EVs can serve as resources to provide their capacity and energy service or as loads to be charged directly. The corresponding aggregator works as a smart controller for the framework, which is responsible for forming aggregations of gridable EVs and determining which vehicle to be a resource or a load. Cost-emission analysis is carried out based on this framework. Hence, operation cost and emissions can be reduced by using these gridable EVs. © Copyright 2011 IEEE - All Rights Reserved.published_or_final_versionThe 2010 IEEE Vehicle Power and Propulsion Conference (VPPC), Lille, France, 1-3 September 2010. In Proceedings of VPPC, 2010, p. 1-

    Two-Body Cabibbo-Suppressed Charmed Meson Decays

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    Singly-Cabibbo-suppressed decays of charmed particles governed by the quark subprocesses csusˉc \to s u \bar s and cdudˉc \to d u \bar d are analyzed using a flavor-topology approach, based on a previous analysis of the Cabibbo-favored decays governed by csudˉc \to s u \bar d. Decays to PPPP and PVPV, where PP is a pseudoscalar meson and VV is a vector meson, are considered. We include processes in which η\eta and η\eta ' are produced.Comment: 18 pages, latex, 2 figures, to be submitted to Phys. Rev.

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    Quantum Convolutional Error Correction Codes

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    I report two general methods to construct quantum convolutional codes for quantum registers with internal NN states. Using one of these methods, I construct a quantum convolutional code of rate 1/4 which is able to correct one general quantum error for every eight consecutive quantum registers.Comment: To be reported in the 1st NASA Conf. on Quantum Comp., uses llncs.sty, 12 page

    Final-State Phases in Charmed Meson Two-Body Nonleptonic Decays

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    Observed decay rates indicate large phase differences among the amplitudes for the charge states in DKˉπD \to \bar K \pi and DKˉπD \to \bar K^* \pi but relatively real amplitudes in the charge states for DKˉρD \to \bar K \rho. This feature is traced using an SU(3) flavor analysis to a sign flip in the contribution of one of the amplitudes contributing to the latter processes in comparison with its contribution to the other two sets. This amplitude may be regarded as an effect of rescattering and is found to be of magnitude comparable to others contributing to charmed particle two-body nonleptonic decays.Comment: 19 pages, latex, 4 figures, to be submitted to Phys. Rev.
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