904 research outputs found

    Electron-electron interactions in antidot-based Aharonov-Bohm interferometers

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    We present a microscopic picture of quantum transport in quantum antidots in the quantum Hall regime taking electron interactions into account. We discuss the edge state structure, energy level evolution, charge quantization and linear-response conductance as the magnetic field or gate voltage is varied. Particular attention is given to the conductance oscillations due to Aharonov-Bohm interference and their unexpected periodicity. To explain the latter we propose the mechanisms of scattering by point defects and Coulomb blockade tunneling. They are supported by self-consistent calculations in the Hartree approximation, which indicate pinning and correlation of the single-particle states at the Fermi energy as well as charge oscillation when antidot-bound states depopulate. We have also found interesting phenomena of anti-resonance reflection of the Fano type.Comment: 12 pages, 8 figure

    Continued development of a detailed model of arc discharge dynamics

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    Using a previously developed set of codes (SEMC, CASCAD, ACORN), a parametric study was performed to quantify the parameters which describe the development of a single electron indicated avalanche into a negative tip streamer. The electron distribution function in Teflon is presented for values of the electric field in the range of four-hundred million volts/meter to four billon volts/meter. A formulation of the scattering parameters is developed which shows that the transport can be represented by three independent variables. The distribution of ionization sites is used to indicate an avalanche. The self consistent evolution of the avalanche is computed over the parameter range of scattering set

    Rompimiento de la Simetria Electrodebil y la Fisica del Higgs: Conceptos Basicos

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    Presentamos una introduccion a los conceptos basicos del rompimiento de la simetria electrodebil y la fisica del Higgs dentro del Modelo Estandar y sus extensiones supersimetricas. Se presenta tambien una breve perspectiva general de mecanismos alternativos del rompimiento de la simetria. Ademas de las bases teoricas, se discute el estado actual de la fisica experimental del Higgs y sus implicaciones para futuros experimentos en el LHC y en colisionadores lineales e+e-.Comment: Spanish text, including full English translation. Published in the Proceedings of the XI Mexican School on Particles and Fields, Xalapa, Veracruz, Mexic

    Non equilibrium dynamics of isolated disordered systems: the classical Hamiltonian p-spin model

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    We study the dynamics of a classical disordered macroscopic model completely isolated frorn the environment reproducing, in a classical setting, the ‘quantum quench’ protocol. We show that, depending on the pre and post quench parameters, the systern approaches equilibrium, succeeding to act as a bath on itself, or remains out of equilibrium, in two different ways. In the latter one, the systern stays confined in a metastable state in which it undergoes stationary dynamics characterised by a single temperature. In the other, the systern ages and its dynamics are characterised by two temperaturas associated with observations rnade at short and long time differences (high and low frequencies). The parameter dependence of the asymptotic states is rationalised in terrns of a dynamic phase diagram with one equilibrium and two out of equilibrium phases. Aspects of pre-thermalisation are observed and discussed. Similarities and differences with the dynamics of the dissipative model are also explained.Facultad de Ciencias Exacta
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