Horacio S. Wio

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Previous works have shown numerically that the response of a " stochastic res-onator " is enhanced as a consequence of spatial coupling. Also, similar results have been obtained in a reaction-diffusion model by studying the phenomenon of stochastic resonance (SR) in spatially extended systems using nonequilib-rium potential (NEP) techniques. The knowledge(More)
We analyze a simple opinion formation model consisting of two parties, A and B, and a group I, of undecided agents. We assume that the supporters of parties A and B do not interact among them, but only interact through the group I, and that there is a nonzero probability of a spontaneous change of opinion (A I, B I). From the master equation, and via van(More)
We study the effect of finite size population in Galam's model [Eur. Phys. J. B 25, 403 (2002)] of minority opinion spreading and introduce neighborhood models that account for local spatial effects. For systems of different sizes N , the time to reach consensus is shown to scale as ln N in the original version, while the evolution is much slower in the new(More)
We have analyzed the phenomenon of stochastic resonance in a double well potential driven by a colored non Gaussian noise. Using a path-integral approach we have obtained a consistent Markovian approximation that enables us to get, through the two state theory, analytical expressions for the signal-to-noise ratio, nding an enhancement of this quantity when(More)
– We introduce stochastic driving in the Sznajd model of opinion spreading. This stochastic effect is meant to mimic a social temperature, so that agents can take random decisions with a varying probability. We show that a stochastic driving has a tremendous impact on the system dynamics as a whole by inducing an order-disorder nonequilibrium phase(More)
Here we present a study of stochastic resonance in an extended FitzHugh-Nagumo system with a field dependent activator diffusion. We show that the system response (here measured through the output signal-to-noise ratio) is enhanced due to the particular form of the non-homogeneous coupling. Such a result supports previous ones obtained in a simpler scalar(More)
A recently introduced lattice model, describing an extended system which exhibits a reentrant ͑symmetry-breaking, second-order͒ noise-induced nonequilibrium phase transition, is studied under the assumption that the multiplicative noise leading to the transition is colored. Within an effective Markovian approximation and a mean-field scheme it is found that(More)
We study the kinetics for the search of an immobile target by randomly moving searchers that detect it only upon encounter. The searchers perform intermittent random walks on a one-dimensional lattice. Each searcher can step on a nearest neighbor site with probability α, or go off lattice with probability 1 − α to move in a random direction until it lands(More)
Recent massive numerical simulations have shown that the response of a " stochastic resonator " is enhanced as a consequence of spatial coupling. Similar results have been analytically obtained in a reaction-diffusion model, using nonequilibrium potential techniques. We now consider a field-dependent diffu-sivity and show that the selectivity of the(More)
We study an extended system that without noise shows a monostable dynamics, but when submitted to an adequate multiplicative noise, an effective bistable dynamics arises. The stochastic resonance between the attractors of the noise-sustained dynamics is investigated theoretically in terms of a two-state approximation. The knowledge of the exact(More)