51 research outputs found

    Effect of resonances on the transport properties of two-dimensional disordered systems

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    We study both analytically and numerically how the electronic structure and the transport properties of a two-dimensional disordered system are modified in the presence of resonances. The energy dependence of the density of states and the localization length at different resonance energies and strengths of coupling between resonances and random states are determined. The results show, that at energy equals to the resonance energy there is an enhancement in the density of states. In contrast, the localization length remains unaffected from the presence of the resonances and is similar to the one of the standard Anderson model. Finally, we calculate the diffusion constant as a function of energy and we reveal interesting analogies with experimental results on light scattering in the presence of Mie resonances.Comment: 4 pages, 4 figures, accepted in Phys. Rev. B (2000

    Resonant tunneling of electromagnetic waves through polariton gaps

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    We consider resonant tunneling of electromagnetic waves through an optical barrier formed by dielectric layers with the frequency dispersion of their dielectric permiability. The frequency region between lower and upper polariton branches in these materials presents a stop band for electromagnetic waves. We show that resonance tunneling through this kind of barriers is qualitatevely different from tunneling through other kind of optical barriers as well as from quantum mechanic tunneling through a rectangular barrier. We find that the width of the resonance maxima of the transmission coeffcient tends to zero as frequency approach the lower boundary of the stop band in a very sharp non-analytical way. Resonance transmission peaks give rise to new photonic bands inside the stop band if one considers periodical array of the layers.Comment: 8 pages, 5 figure

    Incentivizing Irreversible Investment

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    Are Institutions Informed About News?

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    This paper combines daily buy and sell institutional trading volume with all news announcements from Reuters. Using institutional order flow (buy volume minus sell volume) we find a variety of evidence that institutions are informed. Institutional trading volume predicts the occurrence of news announcements. Institutional order flow predicts (i) the sentiment of the news; (ii) the stock market reaction on news announcement days; (iii) the stock market reaction on crisis news days; and (iv) earnings announcement surprises. These results suggest that significant price discovery related to news stories occurs through institutional trading prior to the news announcement date

    The performance of optimally diversified firms Reconciling theory and evidence

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    Also available via the InternetAvailable from British Library Document Supply Centre-DSC:3597.9512(no 3546) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo
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