The mechanism of synchronization of Josephson arrays coupled to a cavity

Josephson junctions arrays can synchronize to achieve interesting levels of narrow line width radiation in the microwave region. We have numerically investigated the mechanism that leads to such a synchronous state for disordered arrays strongly coupled to a high-Q resonator. We have found that the array undergoes a sharp transition from a state where the junctions are essentially oscillating at the unperturbed frequencies to one where they oscillate at the same frequency.

The transition occurs above a threshold number of active junctions, in agreement with previous experimental and theoretical results.