Route to noise-induced synchronization in an ensemble of uncoupled chaotic systems.

We investigate the route to synchronization in an ensemble of uncoupled chaotic oscillators under common noise. Previous works have demonstrated that, as the common-noise amplitude is increased, both chaotic phase synchronization and complete synchronization can occur. Our study reveals an intermediate state of synchronization in between these two types of synchronization. A statistical measure is introduced to characterize this noise-induced synchronization state and the dynamical origin of the transition to it is elucidated based on the Lyapunov dimension of the set formed by all oscillator states.