Silicon Quantum Computing looks back on 25 years of atomic-precision qubits

[JudgmentDay10]

Michelle Simmons and Ludwik Kranz of Silicon Quantum Computing have written a comment piece in Nature Nanotechnology reviewing 25 years of phosphorus in silicon qubits. Quantum Computing Report covered it. It traces the story from Bruce Kane's 1998 proposal to the commercial products SQC is building today

The core technique involves placing individual phosphorus atoms in silicon using a scanning tunnelling microscope. What started as painstaking lab work has become an automated industrial process. SQC now places atoms with 0.13 nanometre accuracy, at a rate of hundreds of thousands of qubit registers a day

The performance figures are strong. Using isotopically purified silicon-28, the platform reports single qubit gate fidelities above 99.99 percent, two qubit fidelities above 99.9 percent and coherence times beyond 30 seconds. Milestones include an 11 qubit multi register processor and analogue simulators with 15,000 quantum dots

SQC is already putting analogue simulators and quantum feature generators into classical computing and AI pipelines. Looking ahead, the authors say full fault tolerance now depends on industrial 3D integration with control electronics made in standard foundries. They argue silicon's relatively forgiving temperature budget could allow hundreds of thousands of physical qubits inside a single dilution refrigerator

This is a company written perspective, so it naturally presents SQC's approach in a positive light. But the 25 year journey from a theoretical proposal to automated atom placement is a remarkable achievement for Australian science. Simmons has led that work from the start

Could atom by atom manufacturing beat other qubit platforms in the long run? And what do you think is the biggest remaining challenge for silicon qubits?

Silicon Quantum Computing Traces 25-Year Roadmap to Atomic-Precision Manufacturing in Nature Nanotechnology - Quantum Computing Reportquantumcomputingreport.com