Control-Signal Crosstalk in Flip-Chip Superconducting Quantum Processors*

We present recent results on the crosstalk performance of our multi-qubit processors. The processors are fabricated based on the quantum-compatible flip-chip technology demonstrated in Ref.[1]. The choice of device architecture (fixed-frequency transmons, frequency-tunable couplers) requires multiple control lines, carrying both DC and/or RF signals, routed in proximity to each other and in a way that is scalable to larger processors. For such a routing scheme to be scalable, the total crosstalk has to be low enough. We will discuss how far we are from this goal and what we have done to reach our level of performance.

[1] Kosen, Li, et al. Quantum Sci. and Technol. 7, 035018 (2022)

*We acknowledge the use of support and resources from Myfab Chalmers for device fabrication, Qiskit Metal for the chip design toolkit. We are grateful for the discussion with A. Aggarwal, L. Chayanun, and T. Vethaak.