Possible new effects in superconductive tunnelling

It is shown that the effect of an exponentially correlated noisy source on the escape times of a Josephson junction depends upon the noise correlation time. A careful analysis reveals that two effects are preeminent: the increase of the stability (as measured by the average escape time from the metastable state) and the increase of the extreme events in the tails of the escape time distribution. The changes occur if the noise correlation exceeds the characteristic time of the Josephson junction. As the superconducting device is very fast, with a characteristic time easily below the nanosecond, the device is responsive even to very short noise correlation. We speculate that it is thus possible to estimate in situ noise correlation with a superconducting Josephson junction through the measurements of the escapes, without a high-frequency sampling of the noise. Moreover, as the superconducting circuit can be cooled as much as necessary, the device offers the further advantage to be intrinsically very quiet.