Emergence of multiple time scales in coupled oscillators with plastic   frequencies
  A coupled-phase oscillator model where each oscillator has an angular velocity that varies due to the interaction with other oscillators is studied. This model is proposed to deepen the understanding of the relationship between the coexistence and the plasticity of time scales in complex systems. It is found that initial conditions close to a one cluster states self-organize into multiple clusters with different angular velocities. Namely, hierarchization of the time scales emerges through the multi-clustering process in phases. Analyses for the clusters solution, the stability of the solution and the mechanism determining the time scales are reported. 
Masashi Tachikawa and Koichi Fujimoto