16,056 research outputs found

    Experimental realization of a broadband illusion optics device

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    We experimentally demonstrate the first metamaterial "illusion optics" device - an "invisible gateway" by using a transmission-line medium. The device contains an open channel that can block electromagnetic waves at a particular frequency range. We also demonstrate that such a device can work in a broad frequency range.Comment: 9 pages, 5 figure

    The Photonic Band theory and the negative refraction experiment of metallic helix metamaterials

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    We develop a theory to compute and interpret the photonic band structure of a periodic array of metallic helices for the first time. Interesting features of band structure include the ingenuous longitudinal and circularly polarized eigenmodes, the wide polarization gap [Science 325, 1513 (2009)], and the helical symmetry guarantees the existence of negative group velocity bands at both sides of the polarization gap and band crossings pinned at the zone boundary with fixed frequencies. A direct proof of negative refraction via a chiral route [Science 306, 1353 (2004)] is achieved for the first time by measuring Gooshanchen shift through a slab of three dimensional bona fide helix metamaterial

    Avalanche to streamer transition in particle simulations

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    The avalanche-to-streamer transition is studied and illustrated in a particle model. The results are similar to those of fluid models. However, when superparticles are introduced, numerical artifacts become visible. This underscores the need of models that are hybrid in space

    Azimuthal distributions of radial momentum and velocity in relativistic heavy ion collisions

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    Azimuthal distributions of radial (transverse) momentum, mean radial momentum, and mean radial velocity of final state particles are suggested for relativistic heavy ion collisions. Using transport model AMPT with string melting, these distributions for Au + Au collisions at 200 GeV are presented and studied. It is demonstrated that the distribution of total radial momentum is more sensitive to the anisotropic expansion, as the anisotropies of final state particles and their associated transverse momentums are both counted in the measure. The mean radial velocity distribution is compared with the radial {\deg}ow velocity. The thermal motion contributes an isotropic constant to mean radial velocity
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