904 research outputs found
Electron-electron interactions in antidot-based Aharonov-Bohm interferometers
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
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
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
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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