Aperiodic stochastic resonance in a system of coupled chaotic oscillators

Noise-free aperiodic stochastic resonance is investigated numerically in a system of two coupled chaotic Rossler oscillators. The aperiodic input sign al is obtained from a different chaotic system and applied either to one of the parameters of one oscillator or added to the coupling term. When the c oupling constant is decreased the oscillators lose synchronization via attr actor bubbling. The output signal is analyzed which reflects the sequence o f synchronized (laminar) phases and non-synchronized bursts in the time evo lution of the oscillators. The correlation function between the input and o utput signals shows maximum as a function of the coupling constant. The dep endence of the correlation function on the mean frequency of oscillations o f the input signal and on the parameter mismatch between the oscillators is very complex. The correlation increases non-monotonically with decreasing frequency, and the parameter mismatch can cause that the output and input s ignals are anticorrelated.