3,238 research outputs found

    Phase transitions and spin excitations of spin-1 bosons in optical lattice

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    We investigate ground state properties of spin-1 bosonic system trapped in optical lattice with extended standard basis operator (SBO) method. For both ferromagnetic (U20U_20) systems, we analytically figure out the symmetry properties in Mott-insulator and superfluid phases, which would provide a deeper insight into the MI-SF phase transition process. Then by applying self-consistent approach to the method, we include the effect of quantum and thermal fluctuations and derive the MI-SF transition phase diagram, which is in quantitative agreement with recent Monte-Carlo simulation at zero temperature, and at finite temperature, we find the underestimation of finite-temperature-effect in the mean-field approximation method. If we further consider the spin excitations in the insulating states of spin-1 system in external field, distinct spin phases are expected. Therefore, in the Mott lobes with n=1n=1 and n=2n=2 atoms per site, we give analytical and numerical boundaries of the singlet, nematic, partially magnetic and ferromagnetic phases in the magnetic phase diagrams.Comment: 14 pages, 6 figure

    4-Chloro­anilinium tetra­fluoro­borate 18-crown-6 clathrate

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    In the title compound, C6H7ClN+·BF4 −·C12H24O6, the complete cation is generated by crystallographic mirror symmetry, with two C atoms and the N and Cl atoms lying on the mirror plane. The complete crown ether is also generated by mirror symmetry, as is the anion (in which the B and two F atoms lie on the mirror plane). The –NH3 + group of the cation inserts into the crown-ether ring and forms bifurcated N—H⋯(O,O) hydrogen bonds. The H atoms of the –NH3 + group were modelled as disordered across the mirror plane

    Sequential Classification of Hyperspectral Images

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    Hyperspectral imaging has become increasingly popular in applications such as agriculture, food, and environment. Rich spectral information of hyperspectral images leads to new possibilities and new challenges in data processing. In this chapter, we consider the hyperspectral classification problems in consideration of sequential data collection, which is a frequent setting in industrial pushboom imaging systems. We present related techniques including data normalization, dimension reduction, classification, and spatial information integration and the way to accommodate these techniques to the context of sequential data collecting and processing. The propose scheme is validated with real data collected in our laboratory. The methodology of result assessment is also presented
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