By cutting single-qubit gate errors to one in 6.7 million, Oxford reduces quantum computer error-correction overhead and paves the way for smaller, more efficient devices.
Physicists at the University of Oxford have recorded the most accurate control of a quantum bit to date, clocking just one mistake in 6.7 million single-qubit operations—an error rate of 0.000015 percent. The advance, nearly ten times better than the group’s previous world record set a decade ago, will appear this week in Physical Review Letters under the title “Single-qubit gates with errors at the 10⁻⁷ level.”
To illustrate how rare such misfires now are, Oxford notes that a person is more likely to be struck by lightning in a given year (1 in 1.2 million) than for one of the team’s quantum logic gates to err. That leap in reliability tackles one of the thorniest barriers between today’s lab-scale devices and practical quantum computers.
Accuracy that trims the hardware bill
Useful quantum machines must run millions of operations across large arrays of qubits. If the per-gate error is too high, a final answer dissolves into noise. Error-correction codes can rescue the calculation, but every “logical” qubit needs clusters of extra qubits to police mistakes, driving up cost, size, and complexity.
“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,” said Molly Smith, graduate student in Oxford’s Department of Physics and co-lead author of the study.
Microwaves, not lasers, and no deep-freeze lab
The record was set on a single trapped calcium ion, a qubit valued for its long lifetime and inherent robustness. Unlike the conventional laser pulses in many trapped-ion experiments, the Oxford group steered the ion’s quantum state with precisely tuned microwave signals. Electronic control proved cheaper and intrinsically more stable than laser hardware, and it integrates neatly with ion-trap chips.
Equally important, the gate operated at room temperature without magnetic shielding, eliminating the cryogenic or isolation systems that often complicate quantum prototypes. Those practical gains, the researchers argue, matter as much as the raw error figure when the goal is a deployable processor.
The experiment was carried out by Smith, Aaron Leu, Dr Mario Gely, and Professor David Lucas, with visiting researcher Dr Koichiro Miyanishi from Osaka University’s Centre for Quantum Information and Quantum Biology. All are members of the UK Quantum Computing and Simulation Hub, part of the National Quantum Technologies Programme.
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Two-qubit gates: the remaining bottleneck
A fully capable quantum computer needs both single- and two-qubit gates working together. While the Oxford team’s single-qubit error now sits near one in seven million, the best two-qubit gates worldwide still generate errors roughly once every 2,000 operations. Driving that figure down to the same 10⁻⁷ realm remains the next critical challenge to fault-tolerant quantum hardware.
For now, the new single-qubit benchmark redefines what “high fidelity” means in quantum logic and offers a clearer engineering path, which is fewer qubits devoted to policing errors, simpler control electronics, and room-temperature operation that could help shrink quantum systems from specialized labs to practical devices.
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Kaif Shaikh Kaif Shaikh is a journalist and writer passionate about turning complex information into clear, impactful stories. His writing covers technology, sustainability, geopolitics, and occasionally fiction. Kaif's bylines can be found in Times of India, Techopedia, and Kitaab. Apart from the long list of things he does outside work, he likes to read, breathe, and practice gratitude.
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