36,430 research outputs found

    Two monotonic functions involving gamma function and volume of unit ball

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    In present paper, we prove the monotonicity of two functions involving the gamma function Γ(x)\Gamma(x) and relating to the nn-dimensional volume of the unit ball Bn\mathbb{B}^n in Rn\mathbb{R}^n.Comment: 7 page

    Axiomatic Foundations for the Principle of Entropy Increase

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    We show that the principle of entropy increase may be exactly founded on a few axioms valid not only for quantum and classical statistics, but also for a wide range of statistical processes.Comment: 8 page

    Electromagnetic Scattering and Statistic Analysis of Clutter from Oil Contaminated Sea Surface

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    In order to investigate the electromagnetic (EM) scattering characteristics of the three dimensional sea surface contaminated by oil, a rigorous numerical method multilevel fast multipole algorithm (MLFMA) is developed to preciously calculate the electromagnetic backscatter from the two-layered oil contaminated sea surface. Illumination window and resistive window are combined together to depress the edge current induced by artificial truncation of the sea surface. By using this combination, the numerical method can get a high efficiency at a less computation cost. The differences between backscatters from clean sea and oil contaminated sea are investigated with respect to various incident angles and sea states. Also, the distribution of the sea clutter is examined for the oil-spilled cases in this paper

    All-optical Imprinting of Geometric Phases onto Matter Waves

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    Traditional optical phase imprinting of matter waves is of a dynamical nature. In this paper we show that both Abelian and non-Abelian geometric phases can be optically imprinted onto matter waves, yielding a number of interesting phenomena such as wavepacket re-directing and wavepacket splitting. In addition to their fundamental interest, our results open up new opportunities for robust optical control of matter waves.Comment: 5 pages, 2 figures, to appear in Phys. Rev.

    Normal approximation for nonlinear statistics using a concentration inequality approach

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    Let TT be a general sampling statistic that can be written as a linear statistic plus an error term. Uniform and non-uniform Berry--Esseen type bounds for TT are obtained. The bounds are the best possible for many known statistics. Applications to U-statistics, multisample U-statistics, L-statistics, random sums and functions of nonlinear statistics are discussed.Comment: Published at http://dx.doi.org/10.3150/07-BEJ5164 in the Bernoulli (http://isi.cbs.nl/bernoulli/) by the International Statistical Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm

    Experimental demonstration of phase-remapping attack in a practical quantum key distribution system

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    Unconditional security proofs of various quantum key distribution (QKD) protocols are built on idealized assumptions. One key assumption is: the sender (Alice) can prepare the required quantum states without errors. However, such an assumption may be violated in a practical QKD system. In this paper, we experimentally demonstrate a technically feasible "intercept-and-resend" attack that exploits such a security loophole in a commercial "plug & play" QKD system. The resulting quantum bit error rate is 19.7%, which is below the proven secure bound of 20.0% for the BB84 protocol. The attack we utilize is the phase-remapping attack (C.-H. F. Fung, et al., Phys. Rev. A, 75, 32314, 2007) proposed by our group.Comment: 16 pages, 6 figure
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