24,020 research outputs found

    Classical and quantum interference in multiband optical Bloch oscillations

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    Classical and quantum interference of light propagating in arrays of coupled waveguides and undergoing multiband optical Bloch oscillations (BOs) with negligible Zener tunneling is theoretically investigated. In particular, it is shown that Mach-Zehnder-like interference effects spontaneously arise in multiband BOs owing to beam splitting and subsequent beam recombination occurring in one BO cycle. As a noteworthy example of quantum interference, we discuss the doubling of interference fringes in photon counting rates for a correlated photon pair undergoing two-band BOs, a phenomenon analogous to the manifestation of the de Broglie wavelength of an entangled biphoton state observed in quantum Mach-Zehnder interferometry.Comment: 11 pages, 4 figure

    Reverse and dual Loomis-Whitney-type inequalities

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    Various results are proved giving lower bounds for the mmth intrinsic volume Vm(K)V_m(K), m=1,…,n−1m=1,\dots,n-1, of a compact convex set KK in Rn{\mathbb{R}}^n, in terms of the mmth intrinsic volumes of its projections on the coordinate hyperplanes (or its intersections with the coordinate hyperplanes). The bounds are sharp when m=1m=1 and m=n−1m=n-1. These are reverse (or dual, respectively) forms of the Loomis-Whitney inequality and versions of it that apply to intrinsic volumes. For the intrinsic volume V1(K)V_1(K), which corresponds to mean width, the inequality obtained confirms a conjecture of Betke and McMullen made in 1983

    Damage in Fiber Bundle Models

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    We introduce a continuous damage fiber bundle model that gives rise to macroscopic plasticity and compare its behavior with that of dry fiber bundles. Several interesting constitutive behaviors are found in this model depending on the value of the damage parameter and on the form of the disorder distribution. In addition, we compare the behavior of global load transfer models with local load transfer models and study in detail the damage evolution before failure. We emphasize the analogies between our results and spinodal nucleation in first-order phase transitions.Comment: 9 pages, 13 figures (ps, eps
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