# RIKEN-led team keeps silicon spin qubit gates above 99.9% with all five qubits driven at once

Canonical page: https://technooptimist.io/stories/riken-led-team-keeps-silicon-spin-qubit-gates-above-99-9-with-all-five-77cf3573
Date: 17 Oct 2026
About: [RIKEN](https://technooptimist.io/companies/riken.md)
Original source: https://quantumcomputingreport.com/riken-demonstrates-high-fidelity-simultaneous-control-of-silicon-spin-qubits-above-99-9-threshold/

Researchers from RIKEN, National Taiwan University, ETH Zurich and TU Delft drove all five qubits of a silicon spin array through one shared microwave line. Gate fidelity stayed at or above 99.9% in simultaneous operation, a level the article says meets the minimum for 2D surface-code error correction. The results cover single-qubit gates only, and the work was published in Nature Physics.

## Key facts

- Parallel driving used to pull fidelity down from above 99.9% to about 99.5%; the team traced most of the loss to microwave-induced phase shifts.
- They compensate by measuring the phase buildup between each pair of qubits, which takes N(N-1) calibration measurements.
- A single qubit driven alone reached 99.993% to 99.998%; with five driven together, the lowest qubit reached at least 99.90%.
- Idle silicon spins lose their phase far faster (T2* about 10 microseconds) than driven ones (about 100 microseconds), so simultaneous gates matter for error correction.
- No simultaneous two-qubit gate fidelities or full error-correction runs are reported; the faster gates with integrated nanomagnets are projections.

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