Fast Qubit Frequency Tuning Approaches for High-Fidelity CZ Gates in Superconducting Circuits

High-fidelity single-qubit and two-qubit gates are foundational components in the realization of practical quantum computing applications. Achieving high gate fidelities in quantum processors based on superconducting circuits face formidable challenges in achieving the requisite gate fidelities, necessitating precise control and calibration procedures. Among these challenges, maintaining flexibility in the qubit idling frequencies to mitigate the effects of parasitic two-level systems and crosstalk during single-qubit gates, while simultaneously ensuring high-fidelity two-qubit gates, stands out as a critical concern. Fast qubit frequency tuning during two-qubit gates offers a practical and readily implementable solution to the aforementioned challenge [1]. Here, we present a comparative analysis of different approaches for tuning qubit frequencies during a controlled-Z gate operation. We systematically evaluate and compare different implementations, highlighting their respective advantages and disadvantages. By investigating different approaches, we provide insights into the trade-offs involved in achieving high-fidelity gates in superconducting quantum processors.

[1] Y.Sung et al., Phys. Rev. X, 11, 021058 (2021)