Resonance Induced by Repulsive Links

Abstract

In nonlinear systems, the right amount of noise can amplify the response to a weak periodic signal, by a phenomenon known as stochastic resonance 1 . It was shown that the same constructive role can be played by any source of disorder 2 We study an Ising model in a network with disorder induced by the presence of both attractive and repulsive links. The system is subjected to a sub-threshold periodic signal, and the goal is to see how the response is enhanced for a given fraction of repulsive links. This can model a network of spinlike neurons with excitatory and inhibitory couplings. By means of numerical simulations, we find that there is an optimal probability of repulsive links, such that the coherent response is maximal, and we propose a mechanism to explain this resonance.