Resistance steps in underdamped Josephson-junction arrays.

The response of N×N underdamped Josephson-junction arrays to dc-current bias and dc-voltage bias is studied numerically. The current-voltage (I-(V)) relation reveals a substantial hysteresis. If a dc-current bias is applied to inhomogeneous underdamped arrays (i.e., arrays with a random distribution of junction critical currents), the I-(V) curve exhibits many (but no more than N) steplike increases of resistance, in agreement with experiments of Tighe, Johnson, and Tinkham