DIRECT MEASUREMENTS OF RELAXATION-TIME SCALES IN JOSEPHSON-JUNCTIONS

We describe an experimental method for obtaining a direct measurement of the lifetime tau(d) of the zero-voltage state in Josephson junction s operating at temperatures around 1 K (thermal regime). The range of tau(d) covered by this method runs typically from 10(-3) to 10(-6) sec . The comparison of the experimental results with the theoretical pred ictions is also a test of the effective temperature of the junction. T he possibility of extending the procedure for the determination of oth er time-scales, such as those involved in quantum-Zeno effect and trav ersal time, are discussed.