When noise decreases deterministic diffusion

Dynamical noise, acting homogeneously in each time step, can enhance the st ability of an unstable fixed point. However, if dynamical noise is added lo cally in state space, additional clear enhancement can be achieved, if this restriction is chosen properly. A systematic analysis of the influence of local and global dynamical noise on the residence time of an unstable state is presented, and optimal parameters for the stabilizing mechanisms are di scussed. As a consequence. it is demonstrated that local dynamical noise ca n yield increased localization in deterministic diffusion models. [S1063-65 1X(99)08203-3].