Modulated Time Delays, Synchronized Josephson Junctions in High-Temperature Superconductors and Chaotic Terahertz Waves

We make the first report on chaos synchronization between Josephson junctions governed by a central junction, when the coupling time between the driving junction and driven junctions is modulated. The results are compared with the case of constant coupling time delays between the junctions. We establish that synchronization is quite robust to the modulation of the coupling time delays, including chaotically modulated delay times. Synchronized Josephson junctions can serve as a terahertz wave generators with enough power for practical applications in diverse scientific fields.