Stochastic resonance in monostable overdamped systems

We consider the response of an overdamped nonlinear oscillator driven by additive Gaussian white noise to an additive weak harmonic forcing in the context of stochastic resonance (SR). We show that, in addition to the previously reported mechanisms, there exists another type of SR, which can occur even when the system is monostable. If the system is multistable, SR of this new type can coexist with the conventional SR in an appropriate frequency range. Further immediate extensions include stochastic anti- and multi-resonance in overdamped monostable systems.