Enhancement of deterministic stochastic resonance in coupled chaotic systems

We show that deterministic stochastic resonance (DSR) can be enhanced by coupling of chaotic oscillators. We study periodic-forced chaotic oscillators coupled to each other. One oscillator phase and periodic force phase are synchronized with each other when the force strength is larger than a critical value. When we set the force strength below the critical value, the phase synchronization occasionally fails. We can observe a quick jump in phase difference between one oscillator and periodic force. In this study, we focus on this phase slip and consider one forced chaotic oscillator as a resonator using the phase slips. When we consider coupled resonators, the coupling strength becomes a bifurcation parameter that has a critical point between asynchronous and synchronous phase slip state. Increases in coupling strength leads to a higher degree of phase slip synchronization. The coupling helps to synchronize the slips with a cooperative effect. Therefore, it can enhance the coincident response to the signal. Optimal coupling strength maximizes the resonance response. This enhancement provides some advantages for signal detection applications using DSR. It is considered that intrinsic fluctuations are important for information processing in biological system. This coupled system may be useful for a model study of neural information processing.