"Stochastic resonance and synchronization in a multistable system"
A.S. Kovaleva (IKI)
Abstract:
For
a class of multistable systems excited by a periodic signal and noise, the
improvement of the output signal-to noise ratio (SNR) can be achieved by
the apparently paradoxical means of increasing the input noise intensity.
The effect is known as stochastic
resonance (SR). In a mathematically rigorous sense, this notion is
still poorly understood. A hypothesis accepted has been associated with
the synchronization phenomenon. The system dynamics has been taken to be
discrete: a particle exhibits instant random switching between the stable
states, with some degree of coherence with the signal. However, following
SR theory, the output spectrum is a sum of a flat wide-band spectrum of
the Lorentzian type and a discrete spectrum with a peak at the signal
frequency; no coherence between the switching rate and the signal
frequency is implicit in this result. On
the other hand, some experimental and simulation results exhibit
synchronization for some input SNR.
We
determine stochastic resonance and synchronization conditions in a
bistable system subject to a weak periodic signal and noise.
We
demonstrate that these phenomena are not contradictory and can be
interpreted as the limit cases of modulated hopping dynamics corresponding
to the low and high input SNR, respectively. A
boundary between the domains of stochastic resonance and synchronization
is found as a function of the system and excitation parameters.