Researchers achieve simultaneous control of multiple silicon qubits

RIKEN Achieves 99.9% Multi-Qubit Control

On October 25, 2026, RIKEN researchers showed they could run five silicon qubits simultaneously with 99.9% accuracy. They fixed a hidden error source called the AC Stark shift that blurs qubit phases during shared microwave pulses. Instead of calibrating every qubit combination, the team used pairwise calibrations to cancel unwanted phase shifts. When tested individually, each qubit reached a gate fidelity above 99.99%, with one hitting 99.999%. Even with three qubits active, fidelity stayed above 99.99%, and all five qubits stayed at 99.9%. Remaining errors stem from drive-induced decoherence, which the authors say could improve with better device design. The breakthrough shows shared microwave control lines can scale silicon processors without sacrificing precision. This paves a path toward larger quantum computers built with existing semiconductor manufacturing techniques.