165,603 research outputs found

    Model-checking branching-time properties of probabilistic automata and probabilistic one-counter automata

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    This paper studies the problem of model-checking of probabilistic automaton and probabilistic one-counter automata against probabilistic branching-time temporal logics (PCTL and PCTL∗^*). We show that it is undecidable for these problems. We first show, by reducing to emptiness problem of probabilistic automata, that the model-checking of probabilistic finite automata against branching-time temporal logics are undecidable. And then, for each probabilistic automata, by constructing a probabilistic one-counter automaton with the same behavior as questioned probabilistic automata the undecidability of model-checking problems against branching-time temporal logics are derived, herein.Comment: Comments are welcom

    Neutrino Flavor Ratio on Earth and at Astrophysical Sources

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    We present the reconstruction of neutrino flavor ratios at astrophysical sources. For distinguishing the pion source and the muon-damped source to the 3σ\sigma level, the neutrino flux ratios, R≡ϕ(νμ)/(ϕ(νe)+ϕ(ντ))R\equiv\phi(\nu_\mu)/(\phi(\nu_e)+\phi(\nu_\tau)) and S≡ϕ(νe)/ϕ(ντ)S\equiv\phi(\nu_e)/\phi(\nu_\tau), need to be measured in accuracies better than 10%.Comment: 3 pages, 8 figures. Talk presented by T.C. Liu in ERICE 2009, Sicily

    Andreev Edge State on Semi-Infinite Triangular Lattice: Detecting the Pairing Symmetry in Na_0.35CoO_2.yH_2O

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    We study the Andreev edge state on the semi-infinite triangular lattice with different pairing symmetries and boundary topologies. We find a rich phase diagram of zero energy Andreev edge states that is a unique fingerprint of each of the possible pairing symmetries. We propose to pin down the pairing symmetry in recently discovered Na_xCoO_2 material by the Fourier-transformed scanning tunneling spectroscopy for the edge state. A surprisingly rich phase diagram is found and explained by a general gauge argument and mapping to 1D tight-binding model. Extensions of this work are discussed at the end.Comment: 4 pages, 1 table, 4 figure

    Concrete: Potential material for Space Station

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    To build a permanent orbiting space station in the next decade is NASA's most challenging and exciting undertaking. The space station will serve as a center for a vast number of scientific products. As a potential material for the space station, reinforced concrete was studied, which has many material and structural merits for the proposed space station. Its cost-effectiveness depends on the availability of lunar materials. With such materials, only 1 percent or less of the mass of a concrete space structure would have to be transported from earth
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