A Sydney researcher’s “blueprint” for quantum computing error correction developed while on an industry placement at IBM has been adopted by the global tech giant. In a paper published last week in Nature Physics, University of Sydney School of Physics’s Dr Dominic Williamson and IBM researcher Theodore Yoder outlined a new approach to quantum error correction that may speed up the journey to developing reliable quantum computers. Williamson completed this research while on a sabbatical working with IBM’s Quantum Information Theory and Error Correction group in California. The new approach has now been integrated into IBM’s long-term plan to build the world’s first large-scale, fault-tolerant quantum computer by 2029. ‘Theory and experiment are beginning to align’ Quantum computing utilises the ‘superposition’ and ‘destructive inference’ of matter in a quantum state, allowing for new forms of computing to solve problems across industries, beyond the scope of classical computers. Quantum computing promises huge advantages, but the fragile nature of quantum states mean that even the most minor issue can collapse a superposition into a classical state, removing the quantum advantage. “Any unintended interaction with the environment can destroy the very quantum effects that give [quantum computers] their power,” Williamson said. Williamson and Yoder’s research has detailed a new approach to error correction, which aims to overcome this fragility using so-called ‘gauge theory’. This effectively allows a system to keep track of global activity, like across a “quantum hard drive”, without forcing specific quantum states to collapse at the individual qubit level. “Gauge theory introduces additional degrees of freedom that track global properties without forcing the system into a definite local state,” Williamson said. “We realised a similar idea could be used to process logical quantum information. “A gauge is just a mathematical construct that provides a set of local coordinates for any