Chaos-nonchaos phase transitions induced by external noise in ensembles ofnonlinearly coupled oscillators - art. no. 026210

Nonlinear dynamical behaviors of ensembles of nonlinearly coupled oscillato rs subjected to external noise are studied on the basis of nonlinear Fokker -Planck equations. The effects of two kinds of noise, the Langevin noise an d the noise introduced in the coupling strength, are investigated, and phas e transitions involving chaos-nonchaos bifurcations are found to occur as t he noise level is changed. An H theorem is proposed for the nonlinear Fokke r-Planck equation to ensure stability of the Gaussian type solution that is approached for large times.