Browsing by Subject "Coherent light"

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    Coherent and incoherent transport through T-shaped double quantum dots
    (Elsevier B.V., 2008) Moldoveanu, V.; Ţolea, M.; Tanatar, Bilal
    We investigate the measurement induced dephasing of the Fano effect in the electronic transport through a double quantum dot mesoscopic interferometer coupled to a charge detector. The current and the differential conductance are computed within the Keldysh formalism, taking into account of the inelastic processes due to the dot-detector interaction. We show that the visibility of the Fano lineshape is reduced by applying a finite bias on the charge detector.
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    Existence of a metallic phase in a 1D Holstein-Hubbard model at half filling
    (Elsevier B.V., 2007) Krishna, P. M.; Chatterjee, A.
    The one-dimensional half-filled Holstein-Hubbard model is studied using a series of canonical transformations including phonon coherence effect that partly depends on the electron density and is partly independent and also incorporating the on-site and the nearest-neighbour phonon correlations and the exact Bethe-ansatz solution of Lieb and Wu. It is shown that choosing a better variational phonon state makes the polarons more mobile and widens the intermediate metallic region at the charge-density-wave-spin-density-wave crossover recently predicted by Takada and Chatterjee. The presence of this metallic phase is indeed a favourable situation from the point of view of high temperature superconductivity.
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    Linear algebraic theory of partial coherence: discrete fields and measures of partial coherence
    (SPIE, 2003-08) Özaktaş, Haldun M.; Yüksel, S.; Kutay, M. A.
    We present a linear algebraic theory of partial coherence which allows precise mathematical definitions of concepts such as coherence and incoherence. This not only provides new perspectives and insights, but also allows us to employ the tools of linear algebra in applications. We define a scalar measure of the degree of partial coherence of an optical field which is zero for complete incoherence and unity for full coherence.
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    Progressive refinement radiosity on ring-connected multicomputers
    (ACM, 1993-10) Çapın, Tolga K.; Aykanat, Cevdet; Özgüç, Bülent
    The progressive refinement method is investigated for parallelization on ring-connected multicomputers. A synchronous scheme, based on static task assignment, is proposed, in order to achieve better coherence during the parallel light distribution computations. An efficient global circulation scheme is proposed for the parallel light distribution computations, which reduces the total volume of concurrent communication by an asymptotical factor. The proposed parallel algorithm is implemented on a ring-embedded Intel's iPSC/2 hypercube multicomputer. Load balance quality of the proposed static assignment schemes are evaluated experimentally. The effect of coherence in the parallel light distribution computations on the shooting patch selection sequence is also investigated.
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    Technique for reconstructing a surface shape for measuring coordinates
    (OSA, 2006) Sainov, V. K.; Kharizanova, Z. I.; Stoikova, E. V.; Özaktaş, Haldun M.; Onural, Levent
    This paper describes a method of projecting interference fringes as one of the most accessible techniques for measuring the coordinates of objects and scenes that can be used when solving inverse problems in dynamic holographic display, where the coordinates need to be measured in order to compute diffraction structures when reconstructing three-dimensional images. A comparative analysis is presented of the experimental results obtained with successive projections of interference patterns with two different periods, using a Mach-Zehnder interferometer in coherent light and a micromirror projector with digital generation of fringes in white light. The use of the method is limited by the size of the objects and scenes. The possibilities of using more refined methods, including the holographic approach to phase reconstruction, are discussed. © 2006 Optical Society of America.