Characterization of control in a superconducting qutrit using randomized benchmarking

We characterize control of a qutrit implemented in the lowest three energy levels capacitively shunted flux-biased superconducting circuit. Randomized benchmarking over Clifford group yields an average fidelity 98.89±0.05%. For selected subset group, we perform quantum process tomography and observe behavior repeated gate sequences. Each is generated using only two-state rotations via method applicable to any unitary. find that errors are due primarily decoherence have significant contribution from level shifts. This work demonstrates high-fidelity outlines avenues for future on optimal qudits.Received 6 September 2020Revised 10 2021Accepted 14 2021DOI:https://doi.org/10.1103/PhysRevResearch.3.L042007Published by American Physical Society under terms Creative Commons Attribution 4.0 International license. Further distribution this must maintain attribution author(s) published article's title, journal citation, DOI.Published SocietyPhysics Subject Headings (PhySH)Research AreasQuantum benchmarkingQuantum computationQuantum controlQuantum gatesQuantum tomographyPhysical SystemsJosephson junctionsSuperconducting qubitsTechniquesNumerical approximation & analysisCondensed Matter, Materials Applied PhysicsQuantum Information