Summary
Bruce Kane’s 1998 vision for silicon-based quantum computing just hit a major milestone. A team in China at SZIQA and SUSTech, led by Dapeng Yu and Yu He, has demonstrated the first universal logical gate operations in a silicon quantum processor. Using five phosphorus nuclear spins in isotopically purified silicon, they encoded two logical qubits, executed a full universal gate set that includes the non-Clifford T gate, and ran a variational quantum eigensolver to compute the ground-state energy of a water molecule. It is the first time any silicon platform has operated at the logical level, reported in Nature Nanotechnology.
Built with STM lithography, the device places five phosphorus atoms with atomic precision in 28Si and shares a single electron across them. The nuclear spins serve as qubits, while the shared electron mediates multi-qubit interactions through hyperfine coupling, enabling native high-connectivity multi-controlled Z-type gates. Single-qubit control uses NMR pulses, and multi-qubit gates use ESR transitions conditioned on nuclear configurations.
Why it matters for quantum security: this is encoded logical computation on silicon, a path that aligns with existing semiconductor supply chains and the prospect of mass manufacturing. It is not a near-term cryptographic threat, but it raises the tempo for PQC migration and crypto agility programs. With China now demonstrating logical-level silicon operations, CISOs should track progress metrics that matter for timelines, such as logical qubit counts, error rates, and manufacturability, while accelerating PQC deployment and key management modernization.
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See the original article at: https://postquantum.com/quantum-research/silicon-logical-operations-first/