Experimental investigation of resonant activation

We experimentally investigate the escape from a metastable state over a flu ctuating barrier of a physical system. The system is switching between two states under electronic control of a dichotomous noise. We measure the esca pe time and its probability density function as a function of the correlati on rate of the dichotomous noise in a frequency interval spanning more than four frequency decades. We observe resonant activation, namely a minimum o f the average escape time as a function of the correlation rate. We detect two regimes in the study of the shape of the escape time probability distri bution: (i) a regime of exponential and (ii) a regime of nonexponential pro bability distribution.