• MIT team develops two fast control techniques for fluxonium qubit. • Achieves world-record single-qubit fidelity of 99.998%, surpassing previous benchmarks in quantum computing. • Builds on prior 99.92% two-qubit gate fidelity demonstrated by MIT in superconducting systems. • Techniques mitigate decoherence and control imperfections, key obstacles in quantum scaling. • Collaboration spans MIT Physics, RLE, EECS, and Google Quantum AI. • Findings published in PRX Quantum, advancing superconducting qubit performance for scalable quantum processors.

Article Summaries:

  • MIT researchers have achieved a world‑record single‑qubit fidelity of 99.998 % on a fluxonium superconducting qubit by introducing two novel control techniques. The methods, detailed in a PRX Quantum paper, mitigate counter‑rotating errors that arise when gates are executed rapidly, thereby reducing decoherence. One technique employs circularly polarized microwave drives, while the second-though not fully described here-further suppresses unwanted dynamics. The work complements last year’s 99.92 % two‑qubit gate fidelity from the same group. Senior authors include David Rower, Leon Ding, and William D. Oliver, underscoring the collaboration across MIT’s physics, electrical engineering, and quantum systems departments.

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