DEPARTAMENTO SISTEMAS COMPLEJOS Y ALTAS ENERGÍAS

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https://nuclea.cnea.gob.ar/handle/20.500.12553/5208

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Examinando DEPARTAMENTO SISTEMAS COMPLEJOS Y ALTAS ENERGÍAS por Materia "PROCESOS GAUSSIANOS"

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  • Miniatura
    ÍtemAcceso Abierto
    Backbone structure of the Edwards-Anderson spin-glass model
    (Amer Physical Soc, 2013-10) Romá, Federico José; Risau-Gusman, S.
    We study the ground-state spatial heterogeneities of the Edwards-Anderson spin-glass model with both bimodal and Gaussian bond distributions. We characterize these heterogeneities by using a general definition of bond rigidity, which allows us to classify the bonds of the system into two sets, the backbone and its complement, with very different properties. This generalizes to continuous distributions of bonds the well-known definition of a backbone for discrete bond distributions. By extensive numerical simulations we find that the topological
    structure of the backbone for a given lattice dimensionality is very similar for both discrete and continuous bond distributions. We then analyze how these heterogeneities influence the equilibrium properties at finite temperature and we discuss the possibility that a suitable backbone picture can be relevant to describe spin-glass phenomena.
  • Miniatura
    ÍtemAcceso Abierto
    Directed transport induced by α-stable Lévy noises in weakly asymmetric periodic potentials
    (American Physical Society, 2013-02) Risau Gusman, Sebastian Luis; Ibáñez, Santiago Agustín; Bouzat, Sebastian
    We study the motion of a particle in spatially periodic potentials with broken mirror symmetry under the influence of white α-stable Lévy noises. We consider both time-independent and fluctuating potentials. We focus on cases in which the spatial asymmetry of the potential is due not to a difference between the distances from an absolute minimum to the absolute maximum on its left and to the absolute maximum on its right but only to the curvatures of the potential profiles. The analysis is performed using the fractional Fokker-Planck formalism. Consistent results from Langevin simulations are also presented. We analyze the influence of the symmetry properties of the potentials in combination with the fluctuating characteristics of the system in the determination of the current. We find different situations in which both the absolute value and the direction of the current depend not only on the properties of the potential but also on the parameters characterizing the α-stable Lévy noise. Among other features, we analyze the case of supersymmetric potentials. In particular, we show that a static supersymmetric potential produces no current, and we analyze the conditions for observing a nonvanishing current when the potential fluctuates between different supersymmetric profiles.