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Wio H.S.,Institute Fisica Of Cantabria Uc And Csic | Deza R.R.,CONICET | Revelli J.A.,CONICET | Escudero C.,Autonomous University of Madrid
Acta Physica Polonica B | Year: 2013

We discuss a tentative path-integral approach to numerically follow the scaling properties of the mean rugosity (and other typical averages) of an interface whose growth is described by the Kardar-Parisi-Zhang equation. It resorts to functional minimization and a cellular automata-like algorithm, and can be regarded as a kind of importance-sampling approach. This method is intended to predict the crossover time as a function of the coefficient of the nonlinear term, through the comparison of the weight of the different terms in the "stochastic action".

Wio H.S.,Institute Fisica Of Cantabria Uc And Csic | Revelli J.A.,National University of Cordoba | Escudero C.,University Aut Of Madrid | Deza R.R.,CONICET | De La Lama M.S.,Max Planck Institute
AIP Conference Proceedings | Year: 2011

Starting from a variational formulation of the Kardar-Parisi-Zhang (KPZ) equation, we point out some strong constraints and consistency tests, to be fulfilled by real-space discretization schemes. In the light of these findings, the mainstream opinion on the relevance of Galilean invariance and the fluctuation - dissipation theorem (peculiar of 1D) is challenged. © 2011 American Institute of Physics.

Dell'Erba M.G.,CONICET | Izus G.G.,CONICET | Deza R.R.,CONICET | Wio H.S.,Institute Fisica Of Cantabria Uc And Csic
European Physical Journal D | Year: 2011

The nonequilibrium Ising-Bloch front bifurcation of the FitzHugh-Nagumo model with nondiffusing inhibitor provides a beautiful instance of an extended bistable system made up of propagating (Bloch) fronts. Moreover, these fronts are chiral and parity-related, and the barrier between them is nonetheless but a stationary Ising front. By means of numerical simulation in the neighborhood of this bifurcation, we demonstrate the existence of stochastic resonance in the transition between Bloch fronts of opposite chiralities, when an additive noise is included. The signal-to-noise ratio is numerically observed to scale with the distance to the critical point. This scaling law is theoretically characterized in terms of an effective nonequilibrium potential. © 2010 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.

Wio H.S.,Institute Fisica Of Cantabria Uc And Csic
Journal of Physics: Conference Series | Year: 2010

We analyze the stochastic resonance response in an extended system, considering different transport/coupling mechanisms: diffusion, KPZ, and also include the possibility of a non-local interaction. Our aim, since these mechanisms correspond to different forms of coupling of resonant units leading to an extended system, is to obtain information about the way to optimize the system's response to weak signals. To reach such a goal, we exploit the knowledge of the so called "non-equilibrium potential" for the above indicated situations. © 2010 IOP Publishing Ltd.

Wio H.S.,Institute Fisica Of Cantabria Uc And Csic | Revelli J.A.,Institute Fisica Of Cantabria Uc And Csic | Deza R.R.,CONICET | Escudero C.,ICMAT CSIC UAM UC3M UCM | De La Lama M.S.,Institute Fisica Of Cantabria Uc And Csic
EPL | Year: 2010

Strong constraints are drawn for the choice of real-space discretization schemes, using the known fact that the KPZ equation results from a diffusion equation (with multiplicative noise) through a Hopf-Cole transformation. Whereas the nearest-neighbor discretization passes the consistency tests, known examples in the literature do not. We emphasize the importance of the Lyapunov functional as natural starting point for real-space discretization and, in the light of these findings, challenge the mainstream opinion on the relevance of Galilean invariance. © 2010 EPLA.

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