Document 
Eur. Phys. J. B 34, 3-8 (2003)
DOI: 10.1140/epjb/e2003-00190-7
Synchronization of underdamped Josephson-junction arrays
G. Filatrella1, N. Falsig Pedersen2, C. John Lobb3 and P. Barbara41 Coherentia/INFM Unit Salerno and Science Faculty, University of Sannio, 82100 Benevento, Italy
2 Department of Electrical Power Engineering, The Technical University of Denmark, 2800, Lyngby, Denmark
3 Center for Superconductivity Research, Department of Physics, University of Maryland, College Park, MD 20742 USA
4 Department of Physics, Georgetown University, Washington, DC 20057 USA
filatrella@unisannio.it
(Received 11 April 2003 Published online 23 July 2003)
Abstract
Our recent experiments show that arrays of underdamped Josephson junctions radiate coherently only above a threshold number
of junctions switched onto the radiating state. For each junction, the radiating state is a resonant step in the current-voltage
characteristics due to the interaction between the junctions in the array and an electromagnetic cavity. Here we show that
a model of a one-dimensional array of Josephson junctions coupled to a resonator can produce many features of the coherent
behavior above threshold, including coherent radiation of power and the shape of the array current-voltage characteristic.
The model also makes quantitative predictions about the degree of coherence of the junctions in the array. However, in this
model there is no threshold; the experimental below-threshold region behavior could not be reproduced.
74.50.+r - Tunneling phenomena; point contacts, weak links, Josephson effects.
85.25.-j - Superconducting devices.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2003