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A truly useful quantum computer must be able to run any algorithm, with the same versatility an ordinary laptop offers. Physicists have now shown a new way to give a quantum computer exactly that flexibility, harnessing the capabilities of exotic quantum particles called non-Abelian anyons.
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A team of scientists from the University of Chicago Pritzker School of Molecular Engineering (UChicago PME), Harvard, Stony Brook University and Quantinuum built and tested a complete toolkit of operations using non-Abelian anyons, proving for the first time the broad utility of this approach.
"We demonstrated a so-called universal gate set—meaning that if you store information in these emergent versions of quarks, and you move them around, you can do any quantum computation you might want to do," said Ruben Verresen, assistant professor of molecular engineering at UChicago PME and a co-author of the new study published in Nature.
The approach not only has the potential to lead to a general-purpose quantum computer but also suggests a path to reliability. Quantum computers generally depend on error-correction techniques, spreading data across many physical qubits to guard against mistakes. But these error-correcting codes typically do not, on their own, provide all the operations needed for universal quantum computing on the protected data. Instead, engineers use specially prepared "magic states" built through a resource-intensive distillation process that consumes a large share of the qubits in a machine. The new work suggests that non-Abelian anyons can sidestep that process.
"Non-Abelian codes are a dark horse in the race to quantum error correction," said Henrik Dreyer, managing director and scientific lead at Quantinuum's Munich office and a co-author of the study. "In this work we show the first universal gate set in a non-Abelian code, which demonstrates that fault-tolerant computations can in principle be done without resorting to magic state distillation or cultivation, which are the most expensive operations in standard quantum error correction codes."
Where braiding anyons fell short
Ordinary qubits store information in a binary on-or-off state, or some in-between combination of the two. Non-Abelian anyons are different. They don't exist as standalone particles in nature; researchers create them with quantum circuits that link many ordinary qubits into one large, entangled state that behaves like an entirely new kind of particle, with its own internal rules.
"The way I think about these codes is they're creating little universes—alternative universes, but ones that reflect some of the properties of our own," Verresen said.
Non-Abelian anyons each carry an internal state that changes whenever two anyons are moved, or braided, around each other. The order in which they are braided matters (that's what non-Abelian means), giving them the potential to encode quantum information in ways ordinary particles can't. Because their state is spread across many entangled qubits rather than sitting in any one place, these anyons are unusually well protected from the small disturbances that trip up ordinary qubits. In addition, their braiding can double as a computational gate.
In 2024, a team that included Verresen used a Quantinuum trapped-ion computer to create anyons based on a symmetry group called D4—the rotations and reflections that leave a square unchanged—marking the first demonstration of this kind of non-Abelian order on quantum hardware. But braiding those anyons alone didn't allow every operation a computer needs.
"In that work, we didn't demonstrate that those emergent forces were enough to do quantum computation," Verresen said. "That particular universe we created was not powerful enough."
Fusion makes the difference
In the new paper, the team turned to a different type of symmetry called S3—the rotations and mirror-image flips that leave an equilateral triangle unchanged—and built its anyons on Quantinuum's H2 trapped-ion processor, entangling 54 qubits. Unlike D4, S3's structure had the right properties for universal computation, but only if braiding was also paired with a second tool: fusion, in which two anyons are merged together and the outcome is read out as a measurement. The idea had been proposed theoretically in 2003 by Carlos Mochon, then a student of John Preskill at Caltech. However, turning that abstract proposal into a concrete protocol for quantum hardware required substantial further theoretical and experimental work.
The team used pairs of these anyons to encode "topological qutrits," which have three levels of quantum information compared with the two levels encoded by standard qubits. By braiding and fusing these qutrits in different combinations, the researchers demonstrated three operations—one entangling gate from braiding and two distinct types of measurement from fusion—that, combined, can in principle reach any quantum operation, including ones that weren't accessible through braiding alone. In addition to their potential applications, the new states can shed light on basic properties of physics.
"It is gratifying to see ideas we have spent our Ph.D. work thinking about realized in the lab, and it has been made possible by remarkable advances in quantum hardware over the past few years," said Anasuya Lyons and Chiu Fan Bowen Lo, graduate students at Harvard University in the group of Ashvin Vishwanath who helped lead the work.
Moving toward error correction
The team also showed that the non-Abelian anyons could be used to prepare a magic state directly through topological operations—sidestepping the costly distillation process used in most quantum systems.
However, in the current paper, Verresen and colleagues didn't carry out active error correction. Instead, they tested individual computational building blocks to show they work and verified that they had created a magic state that matched theoretical predictions.
"So far, we've ignored the question of error correction. Here, it's more like a proof of principle," Verresen said.
Combining this approach with error correction is the natural next step, he added—one that could eventually make non-Abelian anyons a practical foundation for large-scale, fault-tolerant quantum computers. Verresen is already collaborating with other PME researchers to develop new ways of stabilizing non-Abelian quantum memories.
More information: Chiu Fan Bowen Lo et al, Universal gates from braiding and fusing anyons on quantum hardware, Nature (2026). DOI: 10.1038/s41586-026-10709-y
Provided by University of Chicago
This story was originally published on Phys.org.
