252 research outputs found

    Scattering of surface plasmon polaritons by one-dimensional inhomogeneities

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    The scattering of surface plasmons polaritons by a one-dimensional defect of the surface is theoretically studied, by means of both Rayleigh and modal expansions. The considered defects are either relief perturbations or variations in the permittivity of the metal. The dependence of transmission, reflection and out-of-plane scattering on parameters defining the defect is presented. We find that the radiated energy is forwardly directed (with respect to the surface plasmon propagation) in the case of an impedance defect. However, for relief defects, the radiated energy may be directed into backward or forward (or both) directions, depending on the defect width.Comment: 10 pages, 5 figures, corrected typos, some minor modifications in figures. Accepted in Phys. Rev.

    Disordered and Frustrated Magnetization in Coated MnFe₂O₄ Nanoparticles Prepared by Microwave Plasma Synthesis

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    Disordered and frustrated magnetization of different surface coated (Cr2O3, Co3O4, ZrO2, and SiO2) MnFe2O4 nanoparticles have been studied using SQUID-magnetometry. Magnetic measurements, such as ZFC/FC and ac-susceptibility evidence surface spin-glass behavior. ZFC/FC curves were also compared with numerical simulation to get information about effective anisotropy constants. Frequency dependent ac susceptibility results were analyzed by using Arrhenius, Vogel Fulcher and dynamic scaling laws to further confirm the spin-glass behavior. It is observed that the strength of surface spins disorder and frustration strongly depends upon the type of the coating material. All these analyses signify that disordered and frustrated surface magnetization in MnFe2O4 nanoparticles greatly depend on the type of the surface coating materials and are useful for controlling the nanoparticle’s magnetism for different practical applications

    Effect of anisotropy and destructuration on behavior of Haarajoki test embankment

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    This paper investigates the influence of anisotropy and destructuration on the behavior of Haarajoki test embankment, which was built by the Finnish National Road Administration as a noise barrier in 1997 on a soft clay deposit. Half of the embankment is constructed on an area improved with prefabricated vertical drains, while the other half is constructed on the natural deposit without any ground improvement. The construction and consolidation of the embankment is analyzed with the finite-element method using three different constitutive models to represent the soft clay. Two recently proposed constitutive models, namely S-CLAY1 which accounts for initial and plastic strain induced anisotropy, and its extension, called S-CLAY1S which accounts, additionally, for interparticle bonding and degradation of bonds, were used in the analysis. For comparison, the problem is also analyzed with the isotropic modified cam clay model. The results of the numerical analyses are compared with the field measurements. The simulations reveal the influence that anisotropy and destructuration have on the behavior of an embankment on soft clay

    Measurements in two bases are sufficient for certifying high-dimensional entanglement

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    High-dimensional encoding of quantum information provides a promising method of transcending current limitations in quantum communication. One of the central challenges in the pursuit of such an approach is the certification of high-dimensional entanglement. In particular, it is desirable to do so without resorting to inefficient full state tomography. Here, we show how carefully constructed measurements in two bases (one of which is not orthonormal) can be used to faithfully and efficiently certify bipartite high-dimensional states and their entanglement for any physical platform. To showcase the practicality of this approach under realistic conditions, we put it to the test for photons entangled in their orbital angular momentum. In our experimental setup, we are able to verify 9-dimensional entanglement for a pair of photons on a 11-dimensional subspace each, at present the highest amount certified without any assumptions on the state.Comment: 11+14 pages, 2+7 figure
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