Summary
Silicon quantum computing is not one thing. This piece breaks it into three distinct bets that share a material but diverge in physics, control, fabrication, and scaling strategy. Each leverages silicon’s strengths that matter for scale-up: industry-compatible tooling, tiny ~50 nm qubits, and long coherence times made possible by 28Si isotopic purification.
One path highlighted is atomically precise donor qubits. Here, individual phosphorus atoms are placed in silicon and used as nuclear or electron spin qubits. Donors positioned a few nanometres apart can share a single electron, forming a tightly coupled register with native multi-qubit connectivity via the hyperfine interaction. The upside is strong coherence and compact, locally connected logic. The challenge is extreme placement precision at the atomic scale.
For cyber leaders, the takeaway is timing and manufacturability. These three silicon bets, including quantum dots and a foundry-driven route, trade off control fidelity, device uniformity, and production readiness. The approach that first achieves fault-tolerant scale will shape quantum risk timelines. Track how quickly each turns fab compatibility into reproducible, error-corrected systems to calibrate PQC migration, side-channel considerations, and supply chain plans.
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See the original article at: https://postquantum.com/quantum-computing/silicon-three-approaches-compared/