709 research outputs found

    Fano versus Kondo Resonances in a Multilevel "Semi-Open" Quantum Dot

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    Linear conductance across a large quantum dot via a single level e_0 with large hybridization to the contacts is strongly sensitive to quasi-bound states localized in the dot and weakly coupled to e_0. It oscillates with the gate voltage due to interference of the Fano type. At low temperature and Coulomb blockade, Kondo correlations damp the oscillations on an extended range of gate voltage values, by freezing the occupancy of the e_0 level itself. As a consequence, antiresonances of Fano origin are washed out. The results are in good correspondence with experimental data for a large quantum dot in the semi-open regime.Comment: 4 eps figures, RevTex format, revised version, to appear in Phys. Rev. Letter

    On Type IIA geometries dual to N = 2 SCFTs

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    We provide explicit solutions of Type IIA supergravity which are believed to be dual to N = 2 superconformal four dimensional gauge theories. These explicit solutions are based on the general ansatz for such a type of backgrounds introduced by Gaiotto and Maldacena.Comment: 23 pages, 10 figures; minor corrections, references correcte

    Open Semiclassical Strings and Long Defect Operators in AdS/dCFT Correspondence

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    We consider defect composite operators in a defect superconformal field theory obtained by inserting an AdS_4 x S^2-brane in the AdS_5 x S^5 background. The one-loop dilatation operator for the scalar sector is represented by an integrable open spin chain. We give a description to construct coherent states for the open spin chain. Then, by evaluating the expectation value of the Hamiltonian with the coherent states in a long operator limit, a Landau-Lifshitz type of sigma model action is obtained. This action is also derived from the string action and hence we find a complete agreement in both SYM and string sides. We see that an SO(3)_H pulsating string solution is included in the action and its energy completely agrees with the result calculated in a different method. In addition, we argue that our procedure would be applicable to other AdS-brane cases.Comment: 22 pages, 1 figure, LaTeX, minor corrections and references added. v3) some new results added. shortened and accepted version in PR

    A new, universal Series Hybrid Cascaded H-Bridge Converter for Power-Hardware in the Loop Emulation

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    A standardized and modular power electronics platform for academic research on advanced grid-connected converter control and microgrids

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    This paper introduces a multifunctional converter platform rated at 30kW. Individual units allow research on advanced grid-connected converter control, while their interconnection enables isolated microgrid investigations. The standardized and modular design allows simple reconfiguration of the system for different setups, for which multiple measurements are presented

    Causal effects of PetroCaribe on sustainable development: a synthetic control analysis

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    We examine the causal effects of the energy subsidy programme PetroCaribe in the three dimensions of sustainable development: economic, social and environmental. We use the synthetic control method to construct a counterfactual and compare it to the outcomes of the beneficiary countries and thus estimate the magnitude and direction of the PetroCaribe effect. PetroCaribe had a positive effect on economic growth in most of the beneficiary countries; however, this economic boost was not followed by an improvement in social development. Environmentally, PetroCaribe did not negatively or positively impact the environmental quality of the member countries, in the sense that we do not find a significant effect on the trend of urn:x-wiley:14636786:media:manc12275:manc12275-math-0001 emissions per capita

    Superstring Scattering from O-planes

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    We write the vertex operators of massless NS-NS and RR states of Type II superstring theory in the presence of Orientifold p-planes. They include the usual vertex operators of Type II theory and their images. We then calculate the two-point functions of these vertex operators at the projective plane PR_2 level. We show that the result can be written in the Veneziano-type formulae, with the same kinematic factor that appears in the D_p-branes amplitudes. While the scattering amplitudes with the usual vertex operators are not gauge invariant, the above amplitudes are invariant. From the amplitude describing scattering of two NS-NS states off the O-plane, we find the low energy effective action of O-planes. The result shows a relative factor 2^{p-6} between couplings to O-planes and to D-branes at (\alpha')^2 order.Comment: 22 pages, no figure, latex file, v2: minor corrections, version to appear in Nucl. Phys.
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