Quantinuum claims world record in quantum error correction

Quantinuum says it has set a world record in quantum error correction on its Helios computer, reporting a logical fidelity of 99.9995%.

That equates to five errors in one million operations, according to the company, and marks its second claimed error-correction breakthrough in two months.

Lower error rates

The latest study used a "color code" within Quantinuum's error-correction architecture on the same Helios hardware used for a previous record in September. The company says the new error rate was 10 times lower than its earlier result and 100 times lower than the best published result from other hardware approaches, which it attributed to Google Quantum AI's superconducting system.

Quantum computing groups have focused heavily on error correction because quantum states are fragile and prone to faults. The ability to reduce logical error rates while scaling systems is widely seen as a central step towards useful fault-tolerant machines.

Quantinuum says the study showed logical errors fell exponentially as code distance increased. Code distance measures how many physical qubits are needed to protect quantum information as error correction scales. Each tested increase reduced the remaining logical errors by a factor of 12, the company says.

The latest work follows a separate September demonstration in which Quantinuum used a Helix code on the same machine to show logical memory and computation results. Together, the two studies highlight the company's ability to test different error-correction codes on one hardware platform and compare trade-offs in accuracy, efficiency and speed.

On Helios, the Helix code used 10 physical qubits per logical qubit, while the color code used up to 37. Quantinuum says the color code delivered lower logical error rates.

Fault-tolerance roadmap

Dr Rajeeb Hazra, Chief Executive Officer of Quantinuum, linked the result to the company's longer-term roadmap.

"With this result, we've proven that we have the error-correction architecture and trapped-ion technology required to achieve universal fault-tolerance. We have reduced error rates tenfold in rapid succession using a different code on the same commercial hardware, demonstrating the flexibility of our error-correction architecture. We've crossed the threshold necessary for exponential improvements in accuracy, reinforcing our path to Apollo and how we can help users unlock commercial value from quantum at scale," said Hazra.

Quantinuum builds trapped-ion quantum computers and has argued that the approach can support strong hardware accuracy alongside flexible error-correction schemes. In this case, it says the architecture combines AI decoders, all-to-all qubit connectivity, high-fidelity physical operations and hardware-level error correction.

The company also says the framework allows adaptive syndrome extraction, which adjusts error-checking measurements during computation, and chain-mapping, which links codes designed for different computational tasks. It argues that, together with real-time decoding, these methods offer several ways to reduce errors and the physical resources needed.

External assessment

Outside researchers have long regarded practical error correction as one of the field's hardest technical barriers. Robin Blume-Kohout, Co-Director of Sandia National Laboratories' Quantum Performance Lab, who was not involved in the study, said the findings represented an important advance.

"This is a significant milestone that quantum computing researchers have been working toward for many years. The paper demonstrates real, serious performance gains from quantum error correction – a logical qubit nearly 100 times better than its component physical qubits. A scaled-up version of this system could reach the reliability required for useful fault-tolerant computation at a feasible size – less than a million physical qubits – which improves the outlook for practical quantum computing. These findings go a long way to retire one of the field's central technical risks," said Blume-Kohout.

The result comes as quantum hardware companies compete to show that their preferred systems can move beyond laboratory experiments into large-scale computation. Rival groups are pursuing different architectures, including superconducting, trapped-ion and photonic systems, and each approach faces its own trade-offs in qubit quality, scaling and engineering complexity.

Apollo targets

Quantinuum says its accuracy performance is now within the target range for Apollo, its planned universal fault-tolerant quantum computer. The company has about 800 employees and operations in the United States, the United Kingdom, Germany, Japan, Qatar and Singapore.