Precision frequency tuning of tunable transmon qubits using alternating-bias assisted annealing

Superconducting quantum processors are one of the leading platforms for realizing scalable fault-tolerant quantum computation (FTQC). Overcoming the reproducibility limits in superconducting qubit fabrication for precision Hamiltonian targeting and optimization remains a long-standing goal to avoid frequency collision and enable high fidelity two-qubit gate at scale. In this work, we demonstrate precision trimming (𝜎=7.7MHz) of the maximum |0〉 → |1〉 transition frequency (𝑓_max⁰¹) of tunable transmon qubits using alternating-bias assisted annealing (ABAA) while maintaining high qubit coherence. [1, 2] We ABAA-trim a series of high qubit-count quantum processors to optimized Hamiltonians and demonstrate consistent >99% median 2-qubit gate fidelity. [1] We explore the rich device dynamics during and after ABAA and discuss pathways toward improving trimming precision and throughput.

[1] Wang, X., Howard, J., Sete, E. A., ... & Pappas, D. P. (2024). Precision frequency tuning of tunable transmon qubits using alternating-bias assisted annealing. arXiv preprint arXiv:2407.06425.

[2] Pappas, D. P., Field, M., Kopas, C. J., Howard, J. A., Wang, X., ... & Mutus, J. Y. (2024). Alternating-bias assisted annealing of amorphous oxide tunnel junctions. Communications Materials, 5(1), 150.