R. Deza | Searcharxiv

arXiv1999

Enhancement of Stochastic Resonance in distributed systems due to a selective coupling

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 diffusivity and show that the "selectivity" of the coupling is more efficient for achieving stochastic-resonance enhancement than its overall value in the constant-diffusivity case.

cond-mat.stat-mech↗

arXiv1997

Disordering effects of color in nonequilibrium phase transitions induced by multiplicative noise

The model introduced by Van den Broeck, Parrondo and Toral [Phys. Rev. Lett.73, 3395 (1994)] -- leading to a second-order-like noise-induced nonequilibrium phase transition which shows reentrance as a function of the (multiplicative) noise intensity $σ$-- is investigated beyond the white-noise assumption. Through a Markovian approximation and within a mean-field treatment it is found that -- in striking contrast with the usual behavior for equilibrium phase transitions -- for noise self-correlation time $τ>0$, the stable phase for (diffusive) spatial coupling $D\to\infty$ is always the disordered one. Another surprising result is that a large noise "memory" also tends to destroy order. These results are supported by numerical simulations.

cond-mat↗