A Sydney researcher describes a dangerous future for quantum computing

A University of Sydney quantum physicist has developed a new quantum error correction technique that could dramatically reduce the number of physical qubits needed to build large-scale, fault-tolerant computers.

The study, written by Dr Dominic Williamson from the School of Physics, was published in Natural Physics. This work was done while Dr. Williamson was on sabbatical at the global technology firm IBM in California.

Parts of the new design are included in IBM’s plan to build a supercomputer quantum computer.

Dr Williamson said: “We are at a point where theory and experiment are starting to agree.” “The big question now is how to make quantum computers that can be scaled well to solve important problems. Our work provides a promising blueprint.”

At the heart of the new approach to reducing quantum errors is the use of gauge theory. This allows the system to keep track of global activity – like a ‘quantum hard drive’ – without forcing certain quantum states to collapse into individual qubits.

TRANSLATION MAKONE

Quantum computers promise revolutionary advances in cryptography, materials science, chemistry and complex systems. They will do this by using ‘superposition’ and ‘destructive information’ of matter at the quantum level, creating new computing techniques to solve problems beyond the scope of traditional computers.

But this power comes at a cost. Quantum states are fragile. Even a small interaction with the surrounding environment can destroy the highest level in the old state, canceling the quantum advantage. Overcoming this weakness is one of the main challenges in building important quantum technologies.

“Quantum computers do calculations in a very different way to classical machines,” said Dr Williamson, DECRA Fellow in the Quantum Science Group at the University of Sydney. But any unplanned interaction with the environment can destroy the effects that give them their power.

Quantum error correction solves this challenge by redesigning how quantum information is stored and processed. Instead of shielding the quantum bits, or qubits directly, information is embedded in multiple physical qubits in a way that allows errors to be detected and corrected without disrupting the computer.

A qubit is like a transistor in an old computer, it acts like a ‘switch’. While such switches can be turned on or off in classical systems, the qubit exists at the output level, or higher level, which allows for a wide variety of computing algorithms.

The problem of storing information across qubits is more: the number of additional qubits and the processing required to protect the information. Historically, this issue has grown faster than the size of the computer itself, rendering large machines unusable.

Recent theoretical developments have changed that picture, introducing “quantum hard drives” designs where the cost of storing mass information grows only in proportion to the amount of information stored.

Dr Williamson’s new work tackles the next big challenge: how to make sense of this well-preserved quantitative information without losing those benefits.

CORPORATE GAUGE

The research draws inspiration from lattice gauge theory in physics: a framework that links local interactions with global conservation laws.

“The Gauge concept introduces some degrees of freedom that track global properties without forcing the system into a particular local area,” said Dr Williamson. “We realized that the same concept can be used to process logical quantum information.

“Gauge is a mathematical construct that provides local coordinates for any defined system we study,” Dr Williamson said. “What’s good for us is that the gauge theory allows for changes in the coordinate system in the local area, while the essential physical properties of the system remain unchanged.

“This is a concept that is deeply embedded in our understanding of the Standard Model of particle physics and the field theory,” said Dr Williamson. “We have taken this concept and applied it to quantum computers, providing an efficient way to reduce errors while using minimal computing power.”

In the new design, an intelligent processor system is combined with an active quantum memory. Artificial ‘gauge-like’ degrees of freedom are introduced to measure global content without collapsing the localized quantum state. These components are organized using highly interconnected mathematical structures known as graph graphs, which enable efficient scaling.

The result is a flexible architecture for optimized quantum computing that maintains the efficiency of next-generation memory architectures while increasing performance.

UPGRADED WORK WITH IBM

Dr. Williamson did this work during an industrial placement with the Quantum Information Theory and Error Theory group at IBM in California. Design features have long been included in IBM’s long-term roadmap for building fault-tolerant mainframes.

As companies and research centers around the world race to develop scalable quantum devices, different error correction strategies are competing to be the dominant design. Dr. Williamson’s research offers a way to significantly reduce the amount of equipment needed.

CONFIRMED photo of Dr. Williamson and a copy of the paper at this link.

CONVERSATION

Dr. Dominic Williamson | dominic.williamson@sydney.edu.au | +61 435 439 145

CLAIM QUESTIONS

Marcus Strom | Information consultant | marcus.strom@sydney.edu.au | + 61 474 269 459

INVESTIGATION

Williamson, D. and Yoder, T. ‘Low-overhead fault-tolerant quantum computation by gauging logic operators’ (Natural Physics 2026). DOI:10.1038/s41567-026-03220-8

EXPLANATION

The researchers declare no competing interests. This research was funded by IBM.