567,701 research outputs found

    Reply on the ``Comment on `Loss-error compensation in quantum- state measurements' ''

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    The authors of the Comment [G. M. D'Ariano and C. Macchiavello to be published in Phys. Rev. A, quant-ph/9701009] tried to reestablish a 0.5 efficiency bound for loss compensation in optical homodyne tomography. In our reply we demonstrate that neither does such a rigorous bound exist nor is the bound required for ruling out the state reconstruction of an individual system [G. M. D'Ariano and H. P. Yuen, Phys. Rev. Lett. 76, 2832 (1996)].Comment: LaTex, 2 pages, 1 Figure; to be published in Physical Review

    Single-phase heat transfer improved by helical inserts in tubes

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    Helical-vane insert creates a single, well defined helical flow passage resulting in more reliable predictions and extrapolations of the thermal and hydraulic performance. Insert core houses instrumentation which does not disturb the flow

    Electronic transport properties of (fluorinated) metal phthalocyanine

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    The magnetic and transport properties of the metal phthalocyanine (MPc) and F16_{16}MPc (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn and Ag) families of molecules in contact with S-Au wires are investigated by density functional theory within the local density approximation, including local electronic correlations on the central metal atom. The magnetic moments are found to be considerably modified under fluorination. In addition, they do not depend exclusively on the configuration of the outer electronic shell of the central metal atom (as in isolated MPc and F16_{16}MPc) but also on the interaction with the leads. Good agreement between the calculated conductance and experimental results is obtained. For M = Ag, a high spin filter efficiency and conductance is observed, giving rise to a potentially high sensitivity for chemical sensor applications.Comment: 8 pages (two-column), 8 figure

    Modular Invariance on the Torus and Abelian Chern-Simons Theory

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    The implementation of modular invariance on the torus as a phase space at the quantum level is discussed in a group-theoretical framework. Unlike the classical case, at the quantum level some restrictions on the parameters of the theory should be imposed to ensure modular invariance. Two cases must be considered, depending on the cohomology class of the symplectic form on the torus. If it is of integer cohomology class nn, then full modular invariance is achieved at the quantum level only for those wave functions on the torus which are periodic if nn is even, or antiperiodic if nn is odd. If the symplectic form is of rational cohomology class nr\frac{n}{r}, a similar result holds --the wave functions must be either periodic or antiperiodic on a torus rr times larger in both direccions, depending on the parity of nrnr. Application of these results to the Abelian Chern-Simons is discussed.Comment: 24 pages, latex, no figures; title changed; last version published in JM

    Vector Mesons and Baryon Resonances in Nuclear Matter

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    We calculate the effect of many-body interactions in nuclear matter on the spectral function of ρ\rho and ω\omega meson. In particular, we focus on the role played by baryon resonances in this context.Comment: 4 pages, 4 figures, to be published in proceedings of the Third International Conference on Perspectives on Hadronic Physics, 7 - 11 May 2001, Miramare-Trieste, Ital

    Smooth representations and sheaves

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    The paper is concerned with `geometrization' of smooth (i.e. with open stabilizers) representations of the automorphism group of universal domains, and with the properties of `geometric' representations of such groups. As an application, we calculate the cohomology groups of several classes of smooth representations of the automorphism group of an algebraically closed extension of infinite transcendence degree of an algebraically closed field.Comment: 20 pages, final versio

    Fuchsian groups of the second kind and representations carried by the limit set

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    We compute the cohomology of a Fuchsian group of the second kind with coefficients in the hyperfunction vectors of the principal series representations of SL(2,R)SL(2,R) supported on the limit set.Comment: 22 pages, LATE
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