A University of Sydney quantum physicist has developed a new approach to quantum error correction that could significantly reduce the number of physical qubits required to build large-scale, fault-tolerant quantum computers. The study, co-authored by Dr. Dominic Williamson from the School of Physics, is titled "Low-overhead fault-tolerant quantum computation by gauging logical operators" and published in Nature Physics.
The work was done while Dr. Williamson was on a sabbatical working at global technology firm IBM in California. Elements of the new design have been integrated into IBM's plan to build large-scale quantum computing.
"We're at a point where theory and experiment are beginning to align," Dr. Williamson said. "The big question now is how to design quantum computers that can be scaled efficiently to solve useful problems. Our work provides a promising blueprint."
At the heart of the new approach to reduce quantum errors is the application of gauge theory. This effectively allows a system to keep track of global activity—such as across a "quantum hard drive"—without forcing specific quantum states to collapse at the locality of individual qubits.
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