British-American firm Quantinuum says a new error correction result supports its plans to deliver a universal fault-tolerant quantum computer by 2029. On its existing Helios trapped-ion system, the company achieved a logical fidelity of 99.9995 percent, equivalent to five errors per million operations in the reported experiment. The error rate is a hundred times lower than the best result so far, which was reported by Google Quantum AI on a superconducting system. Credit: Quantinuum The experiment used a quantum error-correcting ‘color code,’ which spreads one logical qubit’s information across multiple physical qubits. The name refers to a mathematical layout with regions assigned different colors, organizing the checks used to detect errors. These checks reveal patterns that allow a decoder to identify corrections without directly measuring and destroying the encoded quantum information. As Quantinuum increased the code distance, a measure of how many physical errors the code can withstand, each tested step reduced logical errors by a factor of twelve. The color code used up to 37 physical qubits per logical qubit, compared with ten for the company’s earlier Helix code, trading additional qubits for greater accuracy. Quantinuum says the result puts accuracy within the target range of its future fault-tolerant, multiple-thousand-qubit system called Apollo. Scaling the hardware and reliably executing a full range of computations remain necessary steps.