(a) σ = 0.05 |

(b) σ = 0.1 |

(c) σ = 0.15 |

(d) σ = 0.05 |

(e) |

(f) |

Figure 8: (a–c) Time series illustrating the evolution of a variable in a double well potential, subjected to a weak periodic signal and to white noise fluctuations for a noise intensity of (a) σ = 0.05, (b) σ = 0.1, and (c) σ = 0.15. (d) Power spectrum of (a). (e) Signal-to-noise ratio as a function of the noise intensity showing a maximum at . (f) Residence time distribution for the region for σ = 0.05. |