Oxford’s One-in-6.7-Million Qubit Leap Could Redefine Quantum Computing

Oxford University Ion Trap Chip — A rendering of the Oxford University team’s ion trap chip. Credit: Dr. Jochen Wolf and Dr. Tom Harty

Oxford scientists have set a world record for quantum precision, achieving just one error in 6.7 million operations using microwave-controlled ions.

This advancement could drastically shrink the size and cost of future quantum computers.

Record-Breaking Quantum Accuracy

Physicists at the <span class="glossaryLink" aria-describedby="tt" data-cmtooltip="

University of Oxford

The University of Oxford is the oldest university in the English-speaking world and one of the most prestigious institutions globally. It has a distinguished record in scientific innovation, from early astronomical observations to modern vaccine development. Oxford is a leader in quantum computing, AI ethics, and biomedical research, with dozens of cutting-edge departments and institutes. Its global collaborations include CERN, WHO, and the UN.

” data-gt-translate-attributes=”[{"attribute":"data-cmtooltip", "format":"html"}]” tabindex=”0″ role=”link”>University of Oxford have set a new world record for how accurately a quantum bit, or qubit, can be controlled. They achieved the lowest error rate ever measured in a quantum logic operation: just 0.000015 percent. That’s only one error in 6.7 million operations! That’s nearly ten times better than the previous record, which was also set by the same team a decade ago.

To put it into perspective, you’re more likely to be struck by lightning this year (1 in 1.2 million) than for one of Oxford’s quantum gates to make a mistake.

Oxford Clarendon Laboratory Researchers With Experimental Equipment — The Oxford researchers with the experimental equipment, in the Clarendon Laboratory, Department of Physics, University of Oxford. From left to right: Dr. Mario Gely, Molly Smith, Aaron Leu. Credit: Adam Martinez

Toward Practical Quantum Computing

The findings, published recently in <span class="glossaryLink" aria-describedby="tt" data-cmtooltip="

Physical Review Letters

<em>Physical Review Letters (PRL)</em> is a prestigious peer-reviewed scientific journal published by the American Physical Society. Launched in 1958, it is renowned for its swift publication of short reports on significant fundamental research in all fields of physics. PRL serves as a venue for researchers to quickly share groundbreaking and innovative findings that can potentially shift or enhance understanding in areas such as particle physics, quantum mechanics, relativity, and condensed matter physics. The journal is highly regarded in the scientific community for its rigorous peer review process and its focus on high-impact papers that often provide foundational insights within the field of physics.

” data-gt-translate-attributes=”[{"attribute":"data-cmtooltip", "format":"html"}]” tabindex=”0″ role=”link”>Physical Review Letters, are a major advance towards having robust and useful quantum computers.

“As far as we are aware, this is the most accurate qubit operation ever recorded anywhere in the world,” said Professor David Lucas, co-author on the paper, from the University of Oxford’s Department of Physics. “It is an important step toward building practical quantum computers that can tackle real-world problems.”

To perform useful calculations on a quantum computer, millions of operations will need to be run across many qubits. This means that if the error rate is too high, the final result of the calculation will be meaningless. Although error correction can be used to fix mistakes, this comes at the cost of requiring many more qubits. By reducing the error, the new method reduces the number of qubits required and consequently the cost and size of the quantum computer itself.

Oxford University New Ion Trap Chip — Photograph of the Oxford University team’s ion trap chip. Credit: Dr. Jochen Wolf and Dr. Tom Harty

Fewer Qubits, Smaller Machines

Co-lead author Molly Smith (Graduate Student, Department of Physics, University of Oxford), said: “By drastically reducing the chance of error, this work significantly reduces the infrastructure required for error correction, opening the way for future quantum computers to be smaller, faster, and more efficient. Precise control of qubits will also be useful for other quantum technologies such as clocks and quantum sensors.”

This unprecedented level of precision was achieved using a trapped calcium ion as the qubit (quantum bit). These are a natural choice to store quantum information due to their long lifetime and robustness. Unlike the conventional approach, which uses lasers, the Oxford team controlled the quantum state of the calcium ions using electronic (microwave) signals.

Oxford Clarendon Laboratory Researchers — The Oxford authors of the study in front of their experiment, in the Clarendon Laboratory, Department of Physics, University of Oxford. From left to right: Professor David Lucas, Molly Smith, Dr. Koichiro Miyanishi, Dr. Mario Gely, Aaron Leu. Credit: Molly Smith

Microwaves Over Lasers

This method offers greater stability than laser control and also has other benefits for building a practical quantum computer. For instance, electronic control is much cheaper and more robust than lasers, and easier to integrate in ion trapping chips. Furthermore, the experiment was conducted at room temperature and without magnetic shielding, thus simplifying the technical requirements for a working quantum computer.

The previous best single-qubit error rate, also achieved by the Oxford team, in 2014, was 1 in 1 million. The group’s expertise led to the launch of the spinout company Oxford Ionics in 2019, which has become an established leader in high-performance trapped-ion qubit platforms.

The Bigger Challenge Ahead

Whilst this record-breaking result marks a major milestone, the research team caution that it is part of a larger challenge. Quantum computing requires both single- and two-qubit gates to function together. Currently, two-qubit gates still have significantly higher error rates—around 1 in 2000 in the best demonstrations to date—so reducing these will be crucial to building fully fault-tolerant quantum machines.

Reference: “Single-Qubit Gates with Errors at the 10−7 Level” by M. C. Smith, A. D. Leu, K. Miyanishi, M. F. Gely and D. M. Lucas, 12 June 2025, Physical Review Letters.
DOI: 10.1103/42w2-6ccy

The experiments were carried out at the University of Oxford’s Department of Physics by Molly Smith, Aaron Leu, Dr. Mario Gely and Professor David Lucas, together with a visiting researcher, Dr. Koichiro Miyanishi, from the University of Osaka’s Centre for Quantum Information and Quantum Biology.

The Oxford scientists are part of the UK Quantum Computing and Simulation (QCS) Hub, which was a part of the ongoing UK National Quantum Technologies Programme.

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