Eur. Phys. J. B 34, 3-8 (2003)
https://doi.org/10.1140/epjb/e2003-00190-7

Synchronization of underdamped Josephson-junction arrays

¹ 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

Corresponding author: ^a 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.