8,764 research outputs found

    Nonlocality without inequality for spin-s system

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    We analyze Hardy's non-locality argument for two spin-s systems and show that earlier solution in this regard was restricted due to imposition of some conditions which have no role in the argument of non-locality. We provide a compact form of non-locality condition for two spin-s systems and extend it to n number of spin-s particles. We also apply more general kind of non-locality argument still without inequality, to higher spin system.Comment: 6 page

    Effect of non-magnetic impurities on the magnetic states of anatase TiO2_2

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    The electronic and magnetic properties of TiO2_2, TiO1.75_{1.75}, TiO1.75_{1.75}N0.25_{0.25}, and TiO1.75_{1.75}F0.25_{0.25} compounds have been studied by using \emph{ab initio} electronic structure calculations. TiO2_2 is found to evolve from a wide-band-gap semiconductor to a narrow-band-gap semiconductor to a half-metallic state and finally to a metallic state with oxygen vacancy, N-doping and F-doping, respectively. Present work clearly shows the robust magnetic ground state for N- and F-doped TiO2_2. The N-doping gives rise to magnetic moment of \sim0.4 μB\mu_B at N-site and \sim0.1 μB\mu_B each at two neighboring O-sites, whereas F-doping creates a magnetic moment of \sim0.3 μB\mu_B at the nearest Ti atom. Here we also discuss the possible cause of the observed magnetic states in terms of the spatial electronic charge distribution of Ti, N and F atoms responsible for bond formation.Comment: 11 pages, 4 figures To appear J. Phys.: Condens. Matte

    Nonlocality without inequality for almost all two-qubit entangled state based on Cabello's nonlocality argument

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    Here we deal with a nonlocality argument proposed by Cabello which is more general than Hardy's nonlocality argument but still maximally entangled states do not respond. However, for most of the other entangled states maximum probability of success of this argument is more than that of the Hardy's argument.Comment: 9 pages, 1 figur

    Shear-strain-induced Spatially Varying Super-lattice Structures on Graphite studied by STM

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    We report on the Scanning Tunneling Microscope (STM) observation of linear fringes together with spatially varying super-lattice structures on (0001) graphite (HOPG) surface. The structure, present in a region of a layer bounded by two straight carbon fibers, varies from a hexagonal lattice of 6nm periodicity to nearly a square lattice of 13nm periodicity. It then changes into a one-dimensional (1-D) fringe-like pattern before relaxing into a pattern-free region. We attribute this surface structure to a shear strain giving rise to a spatially varying rotation of the affected graphite layer relative to the bulk substrate. We propose a simple method to understand these moire patterns by looking at the fixed and rotated lattices in the Fourier transformed k-space. Using this approach we can reproduce the spatially varying 2-D lattice as well as the 1-D fringes by simulation. The 1-D fringes are found to result from a particular spatial dependence of the rotation angle.Comment: 14 pages, 6 figure

    Local ionospheric electrodynamics associated with neutral wind fields at low latitudes: Kelvin-Helmholtz billows

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    International audienceThe Gadanki radar observation of plasma irregularities bearing the signature of Kelvin-Helmholtz billows above 100 km altitude raises the question of the electrodynamical mechanism that would allow the structures to drift with the neutral wind. We show that for locally varying neutral wind fields with the right geometry at night, multiple Hall effects in the electron gas lead to a situation where ions, electrons, and neutrals move together along the component of the wind that changes most rapidly in space. The species must not move together along all directions, however. If this were the case the plasma would be stable and a radar would be unable to observe the wind field. We discuss the stability of the plasma itself for Es layers affected by the Kelvin-Helmholtz wind field and show that a variety of factors have to be taken into account beyond the study of the zeroth order mechanism
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