Date and Time:  24-Nov-2023  2pm

Speaker: Xiaoyue Jin, Guest Researcher, National Institute of Standards and Technology, USA

Host: Fei Yan ( BAQIS）

Title: A Versatile Parametric Coupler for Two-Qubit Gates and Beyond

Venue: Room 320

Abstract: 

Parametric coupling is a powerful technique for generating tunable interactions between superconducting circuits using only microwave tones. Here, we present a highly flexible parametric coupling scheme demonstrated with two transmon qubits, which can be employed for multiple purposes, including the removal of residual ZZ coupling and the implementation of driven swap or swap-free controlled-Z (cZ) gates. Our fully integrated coupler design is only weakly flux tunable, cancels static linear coupling between the qubits, avoids internal coupler dynamics or excitations, and operates with rf-pulses. We show that residual ZZ coupling can be reduced with a parametric dispersive tone down to an experimental uncertainty of 5.5~kHz. Additionally, randomized benchmarking reveals that the parametric swap cZ gate achieves a fidelity of 99.4\% in a gate duration of 60~ns, while the dispersive parametric swap-free cZ gate attains a fidelity of 99.5\% in only 30~ns. We believe this is the fastest and highest fidelity gate achieved with on-chip parametric coupling to date. We further explore the dependence of gate fidelity on gate duration for both p-swap and p-swap-free cZ gates, providing insights into the possible error sources for these gates. Overall, our findings demonstrate a versatility, precision, speed, and high performance not seen in previous parametric approaches. Finally, our design opens up new possibilities for creating larger, modular systems of superconducting qubits.

About the Speaker:

Xiaoyue Jin is a skilled experimental physicist with expertise in quantum control and operations, particularly in the development and optimization of two-qubit gates between superconducting qubits. He holds a Master of Science degree from Peking University and a Dr. rer. nat. degree from Erlangen University, Germany, graduating with summa cum laude. He later moved to the US and worked as a postdoctoral associate at Massachusetts Institute of Technology. Jin joined National Institute of Standards and Technology (NIST) Boulder, Colorado in 2015, and works first as a Physicist, and later as a Guest Researcher until now. Jin currently also serves as the Chief Quantum Scientist at Tabor Electronics, an Israel-based electronics company focusing on FPGA-based DDS systems as a quantum solution.