Dr. Ziyi Zhao: Superconducting Switches for Modular Quantum Networks

Superconducting Switches for Modular Quantum Networks

Abstract:
Josephson-junction-based superconducting circuits enable coherent control of microwave signals at cryogenic temperatures, providing a foundation for modular quantum networks. This talk presents superconducting microwave switches that provide rapid, low-loss, and scalable routing of microwave signals, establishing a versatile building block for the modular quantum networks. The architecture integrates a tunable inductor bridge (TIB) as the switch, a seam-free 2D-3D interface that couples the TIB to high-Q cavities, and a current-controlled TIB that implements a persistent- current switch to realize “set-and-forget” control. Our switch achieves a broadband 20-dB on/off ratio, 200 pW power handling, and 600 MHz modulation bandwidth. Combining the TIB with the 2D-3D interface, we show designs and preliminary results of a small two-module quantum network.

Bio:
Ziyi Zhao is a postdoc in the Lehnert Lab at Yale University. He received his Ph.D. in Physics from the University of Colorado Boulder under the supervision of Prof. Konrad Lehnert. His research focuses on superconducting microwave circuits and Josephson-junction-based devices for modular quantum networks, including superconducting microwave switches, low-loss interfaces between planar circuits and 3D cavities, and efficient control schemes for scalable cryogenic systems. His work spans device design, cryogenic microwave measurements, and circuit/electromagnetic modeling.