Voltage noise, multiple phase-slips, and switching rates in moderately damped Josephson junctions

Abstract

We study the voltage noise properties including the statistics of phase-slips and switching rates in moderately damped Josephson junctions by using a novel efficient numerical approach that combines the matrix continued-fraction method with the full counting statistics. By analyzing the noise results obtained for the resistively and capacitively shunted junction (RCSJ) model we identify different dominating components; namely, the thermal noise close to equilibrium (small-current-bias regime), the shot noise of (multiple) phase-slips in the intermediate range of biases, and the switching noise for yet higher bias currents. We extract thus far inaccessible characteristic rates of phase-slips in the shot-noise regime as well as the escape and retrapping rates in the switching regime as functions of various junction parameters. The method can be extended and applied to other experimentally relevant Josephson junction circuits as well as to optical trap setups.