Quantinuum, whose Helios processor demonstrated that trapped-ion quantum computers can be scaled to substantially larger qubit counts without sacrificing the high accuracy for which ion-based systems are known.

Published in Nature on June 17, Helios is a 98-qubit trapped-ion quantum processor built using Quantinuum's quantum charge-coupled-device architecture.

Trapped ions have historically achieved some of the highest quantum-gate fidelities in the industry, but scaling them has been challenging. Unlike fixed superconducting qubits, ions must be trapped, transported and manipulated with extremely precise electromagnetic and laser controls.

Helios addresses this problem through a system using barium-137 ions, a rotatable ion-storage ring and multiple quantum-operation regions connected through a junction. This allows ions to be physically rearranged so that the processor maintains effectively all-to-all qubit connectivity.

Nature reports average error probabilities of roughly 2.5 × 10⁻⁵ for single-qubit gates and 7.9 × 10⁻⁴ for two-qubit gates across the operating regions.

That combination of scale and precision allowed Helios to execute random quantum circuits that the researchers reported as operating beyond practical classical simulation, establishing a new complexity frontier for trapped-ion systems.

The achievement matters because quantum-computing architectures frequently face a trade-off between quantity and quality. Some platforms can produce very large numbers of qubits but struggle with error rates, while highly accurate technologies can be difficult to scale.

Helios provides evidence that trapped ions may be able to push both dimensions simultaneously.

However, 98 physical qubits remain far below the scale expected for large fault-tolerant applications, which could eventually require thousands or millions of physical qubits depending on the architecture.

The June result therefore does not solve quantum scaling—but it substantially strengthens the case that trapped-ion systems remain serious contenders in the race toward fault-tolerant quantum computing.