Transition to stochastic synchronization in spatially extended systems - art. no. 036226

Spatially extended dynamical systems, namely coupled map lattices, driven b y additive spatio-temporal noise are shown to exhibit stochastic synchroniz ation. In analogy with low-dimensional systems, synchronization can be achi eved only if the maximum Lyapunov exponent becomes negative for sufficientl y large noise amplitude. Moreover, noise can suppress also the nonlinear me chanism of information propagation, which may be present in the spatially e xtended system. An example of phase transition is observed when both the li near and the nonlinear mechanisms of information production disappear at th e same critical value of the noise amplitude. The corresponding critical pr operties cannot be estimated numerically with great accuracy, but some gene ral argument suggests that they could be ascribed to the Kardar-Parisi-Zhan g universality class. Conversely, when the nonlinear mechanism prevails on the linear one, another type of phase transition to stochastic synchronizat ion occurs. This one is shown to belong to the universality class of direct ed percolation.