Noise-induced macroscopic bifurcations in populations of globally coupled maps

Abstract

Populations of globally coupled identical maps subject to additive, independent noise are studied in the regimes of strong coupling. Contrary to each noisy population element, the mean field dynamics undergoes qualitative changes when the noise strength is varied. In the limit of infinite population size, these macroscopic bifurcations can be accounted for by a deterministic system, where the mean-field, having the same dynamics of each uncoupled element, is coupled with other order parameters. Different approximation schemes are proposed for polynomial and exponential functions and their validity discussed for logistic and excitable maps.