Direct lifetime measurements and interactions of charged defect states in submicron Josephson junctions

We have measured the emission and capture time of individual electron traps residing within the tunneling barrier of very small-area (<0.05 <>m2) Josephson junctions. The voltage-bias dependence of the times is consistent with a simple nonequilibrium model in which the bias enhances the rate for electrons to tunnel into the trap from one side of the barrier and exit out the other. Some junctions show clear evidence of interactions between traps, and for certain bias conditions the noise displays predominantly series kinetics.