Noise-Enhanced Multistability in Coupled Oscillator Systems

We study nonequilibrium phenomena in a globally coupled oscillator system with a third harmonic pinning force in the presence of an additive noise and a fluctuating interaction. The system shows a subcritical saddle-node bifurcation from an asymmetric state to a symmetric state at a critical noise intensity leading to multistable states. The fluctuating interaction increases the critical noise intensity and thus enhances the multistability drastically. We show phase diagrams and discuss the nature of the phase transition.