4,192 research outputs found

    Electro-optic characteristics of CdTe at 3.39 and 10.6 ”

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    The physical characteristics of high resistivity CdTe which are relevant to its use for electro-optic modulation have been investigated at 3.39 and 10.6 ”. The unclamped electro-optic characteristic n0^3r41 of CdTe was found to be 12 × 10^–11 m/V and the absorption coefficient is 0.006 cm^–1. Our measurements indicate that CdTe will be a very important material for electro-optic modulation in the infrared

    Comments on Critical Electric and Magnetic Fields from Holography

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    We discuss some aspects of critical electric and magnetic fields in a field theory with holographic dual description. We extend the analysis of arxiv:1109.2920, which finds a critical electric field at which the Schwinger pair production barrier drops to zero, to the case of magnetic fields. We first find that, unlike ordinary weakly coupled theories, the magnetic field is not subject to any perturbative instability originating from the presence of a tachyonic ground state in the W-boson spectrum. This follows from the large value of the 't Hooft coupling \lambda, which prevents the Zeeman interaction term to overcome the particle mass at high B. Consequently, we study the next possible B-field instability, i.e. monopole pair production, which is the S-dual version of the Schwinger effect. Also in this case a critical magnetic field is expected when the tunneling barrier drops to zero. These Schwinger-type criticalities are the holographic duals, in the bulk, to the fields E or B reaching the tension of F1 or D1 strings respectively. We then discuss how this effect is modified when electric and magnetic fields are present simultaneously and dyonic states in the spectrum can be pair produced by a generic E - B background. Finally, we analyze finite temperature effects on Schwinger criticalities, i.e. in the AdS-Schwarzshild black hole background.Comment: 33 pages, 4 figures; v2: refs added; v3: typos corrected, to appear on JHE

    Frequency response of intracavity laser coupling modulation

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    A resonant energy coupling between the atomic system and the oscillating optical mode leads to severe output distortion in intracavity laser coupling modulation. This anomalous behavior, which places a lower limit on the modulation frequency, is investigated in a case of a CO2 laser and compared with theoretical predictions

    Evidence of Non-Markovian Behavior in the Process of Bank Rating Migrations

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    This paper estimates transition matrices for the ratings on financial institutions, using an unusually informative data set. We show that the process of rating migration exhibits significant non-Markovian behavior, in the sense that the transition intensiFinancial institutions, macroeconomic variables, capitalization, supervision, transition intensities

    Bank Failure: Evidence from the Colombia Financial Crisis

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    This paper identifies the main bank specific determinants of bank failure during the financial crisis in Colombia using duration analysis. Using partial likelihood estimation, it shows that the process of failure of financial institutions during that period can be explained by differences in financial health and prudence across institutions. The capitalization ratio is the most significant indicator explaining bank failure. Increases in this ratio lead to a reduction in the hazard rate of failure at any given moment in time. Of special relevance, this ratio exhibits a non-linear component. Our results thus provide empirical support for existing regulatory practice. Other important variables explaining bank failure dynamics are bank's size and profitability.

    The Coherence of Primordial Fluctuations Produced During Inflation

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    The behaviour of quantum metric perturbations produced during inflation is considered at the stage after the second Hubble radius crossing. It is shown that the classical correlation between amplitude and momentum of a perturbation mode, previously shown to emerge in the course of an effective quantum-to-classical transition, is maintained for a sufficiently long time, and we present the explicit form in which it takes place using the Wigner function. We further show with a simple diffraction experiment that quantum interference, non-expressible in terms of a classical stochastic description of the perturbations, is essentially suppressed. Rescattering of the perturbations leads to a comparatively slow decay of this correlation and to a complete stochastization of the system.Comment: LaTeX (7 pages

    The balance in the museum

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    Thermal conductive connection and method of making same Patent

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    Thermal conductive, electrically insulated cleavable adhesive connection between electronic module and heat sin
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