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Electronic analog experiments on escape over a fluctuating potential barrier are performed for the case when the fluctuations are caused by Ornstein-Uhlenbeck noise (OUN). In its dependence on the relation between the two OUN parameters (the correlation time tau and noise strength Q) the nonmonotonic variation of the mean escape time T as a function of tau can exhibit either a minimum (resonant activation), or a maximum (inhibition of activation), or both these effects. The possible resonant nature of these features is discussed. We claim that T is not a good quantity to describe the resonancelike character of the problem. Independently of the specific relation between the OUN parameters, the resonance manifests itself as a maximal lowering of the potential barrier during the escape event, and it appears for tau of the order of the relaxation time toward the metastable state.

The problem of an escape over a fluctuating potential barrier is considered. The results of the analogue electronic experiment confirm the predictions about the dependence of the occurrence of the phenomena of resonant activation and inhibition of activation on the relation between the barrier noise parameters. We propose a new interpretation of the noise-induced resonance in this problem. A simple theoretical description valid for any correlation time is given.

The thermal activation over a potential barrier in a stochastically modified system is analyzed. If colored noise perturbs the potential one can observe the famous resonant activation phenomenon. We compare this effect with the results caused by correlated fluctuations of the temperature. For high potential barrier stochastic variations of temperature lead to resonant activation as well. However, for low-barrier or barrierless evolution this effect disappears. We formulate an analytical condition separating these cases and present a physical interpretation of both types of behavior.