1,876 research outputs found

    National input-output table of Brazil

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    This paper reports on the basic information about the Brazilian input-output tables. First part presents the history of constructing I-O tables in Brazil, starting from the non-official table of 1959. The second part illustrates some basic features of the last table with the reference year of 2005. It also articulates the issues concerning the integration of the table into 2005 BRICS International Input-Output Table.Brazil; Input-Output; Tables

    Quasi-classical path integral approach to supersymmetric quantum mechanics

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    {}From Feynman's path integral, we derive quasi-classical quantization rules in supersymmetric quantum mechanics (SUSY-QM). First, we derive a SUSY counterpart of Gutzwiller's formula, from which we obtain the quantization rule of Comtet, Bandrauk and Campbell when SUSY is good. When SUSY is broken, we arrive at a new quantization formula, which is found as good as and even sometime better than the WKB formula in evaluating energy spectra for certain one-dimensional bound state problems. The wave functions in the stationary phase approximation are also derived for SUSY and broken SUSY cases. Insofar as a broken SUSY case is concerned, there are strong indications that the new quasi-classical approximation formula always overestimates the energy eigenvalues while WKB always underestimates.Comment: 13 pages + 5 figures, complete paper submitted as postscript file, to appear in Phys. Rev.

    Single-photon-driven high-order sideband transitions in an ultrastrongly coupled circuit quantum electrodynamics system

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    We report the experimental observation of high-order sideband transitions at the single-photon level in a quantum circuit system of a flux qubit ultrastrongly coupled to a coplanar waveguide resonator. With the coupling strength reaching 10% of the resonator's fundamental frequency, we obtain clear signatures of higher-order red and first-order blue-sideband transitions, which are mainly due to the ultrastrong Rabi coupling. Our observation advances the understanding of ultrastrongly-coupled systems and paves the way to study high-order processes in the quantum Rabi model at the single-photon level.Comment: Accepted in Physical Review A. 12 pages, 6 figure

    Epitaxial Co2Cr0.6Fe0.4Al thin films and magnetic tunneling junctions

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    Epitaxial thin films of the theoretically predicted half metal Co2Cr0.6Fe0.4Al were deposited by dc magnetron sputtering on different substrates and buffer layers. The samples were characterized by x-ray and electron beam diffraction (RHEED) demonstrating the B2 order of the Heusler compound with only a small partition of disorder on the Co sites. Magnetic tunneling junctions with Co2Cr0.6Fe0.4Al electrode, AlOx barrier and Co counter electrode were prepared. From the Julliere model a spin polarisation of Co2Cr0.6Fe0.4Al of 54% at T=4K is deduced. The relation between the annealing temperature of the Heusler electrodes and the magnitude of the tunneling magnetoresistance effect was investigated and the results are discussed in the framework of morphology and surface order based of in situ STM and RHEED investigations.Comment: accepted by J. Phys. D: Appl. Phy

    Magnetism and superconductivity in McM_{c}Ta2_{2}S2_{2}C (M = Fe, Co, Ni, and Cu)

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    Magnetic properties of McM_{c}Ta2_{2}S2_{2}C (MM = Fe, Co, Ni, Cu) have been studied using SQUID DC and AC magnetic susceptibility. In these systems magnetic M2+M^{2+} ions are intercalated into van der Waals gaps between adjacent S layers of host superconductor Ta2_{2}S2_{2}C. Fe0.33_{0.33}Ta2_{2}S2_{2}C is a quasi 2D XYXY-like antiferromagnet on the triangular lattice. It undergoes an antiferromagnetic phase transition at TNT_{N} (= 117 K). The irreversible effect of magnetization occurs below TNT_{N}, reflecting the frustrated nature of the system. The AF phase coexists with two superconducting phases with the transition temperatures Tcu=8.8T_{cu} = 8.8 K and Tcl=4.6T_{cl} = 4.6 K. Co0.33_{0.33}Ta2_{2}S2_{2}C is a quasi 2D Ising-like antiferromagnet on the triangular lattice. The antiferromagnetic phase below TN=18.6T_{N} = 18.6 K coexists with a superconducting phase below Tcu=9.1T_{cu} = 9.1 K. Both Ni0.25_{0.25}Ta2_{2}S2_{2}C and Cu0.60_{0.60}Ta2_{2}S2_{2}C are superconductors with TcuT_{cu} (=8.7= 8.7 K for Ni and 6.4 K for Cu) and TclT_{cl} (= 4.6 K common to McM_{c}Ta2_{2}S2_{2}C). Very small effective magnetic moments suggest that Ni2+^{2+} and Cu2+^{2+} spins are partially delocalized.Comment: 15 pages, 17 figures, and 3 table

    On the Path Integral in Imaginary Lobachevsky Space

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    The path integral on the single-sheeted hyperboloid, i.e.\ in DD-dimensional imaginary Lobachevsky space, is evaluated. A potential problem which we call ``Kepler-problem'', and the case of a constant magnetic field are also discussed.Comment: 16 pages, LATEX, DESY 93-14
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