Quantinuum Helios 98 量子位元量子電腦 Nature 實證：超越 99.99% 閘極保真度

On June 17, 2026, Ransford et al. (Quantinuum and Sandia National Laboratories) published a peer-reviewed paper in Nature titled "A 98-qubit trapped-ion quantum computer with all-to-all connectivity" (DOI: 10.1038/s41586-026-10676-4), accompanied by a News & Views article . The results establish Helios as Quantinuum's largest and most reliable quantum computer to date and demonstrate that trapped-ion technology can match superconducting-circuit qubit counts while maintaining substantially lower error rates .

Gate fidelities

• Single-qubit gate fidelity: 99.9975% (average infidelity of 2.5 × 10⁻⁵)
• Two-qubit gate fidelity: 99.921% (average infidelity of 7.9 × 10⁻⁴)
• State preparation and measurement (SPAM) fidelity: 99.967% (average infidelity of 3.3 × 10⁻⁴)

The paper states that none of these infidelities are fundamentally limited and are likely able to be improved further .

QCCD architecture, tuning-fork trap, and all-to-all connectivity

Helios is based on a quantum charge-coupled device (QCCD) architecture implemented on a 2D surface electrode trap . Key design features:

• Uses individual ¹³⁷Ba⁺ hyperfine qubits as the information carriers
• All-to-all connectivity is enabled by a rotatable ion storage ring that connects two quantum operation regions via a junction
• Ions are physically transported between spatially separated memory and logic zones — qubits flow through the processor like bits in a classical CPU, with dedicated memory structures, data buses, and logic units
• The tuning-fork-style trap junction allows ions to be routed to any gate zone, enabling arbitrary qubit pair interactions

This transport-based architecture yields an average depth-1 time of 55 ms per circuit layer across all 98 qubits .

Encoding of error-corrected logical qubits

The Helios system demonstrated multiple scales of logical qubit encoding:

• 94 logical qubits with error detection and 48 logical qubits with full error correction were extracted from the 98 physical qubits, achieving better-than-break-even performance
• With 50 error-detected logical qubits, Helios ran the largest encoded simulation of quantum magnetism to date
• A separate technical report from Mitsubishi Electric (published the same day) evaluated the Quantum Fourier Transform on up to 12 logical qubits encoded in the Steane code on Helios

The Nature paper used mid-circuit measurements (nondestructive readout) — a capability essential for active error correction — and Sandia contributed a new benchmarking methodology specifically to measure the performance of these measurements .

Independent validation

• Sandia National Laboratories independently evaluated and certified the Helios system, supplying new benchmarking tools and co-authoring the paper . Sandia's Quantum Performance Laboratory has a long-standing Cooperative Research and Development Agreement with Quantinuum (renewed in May 2026) .
• Europe's JUPITER exascale supercomputer: The available evidence contains no mention of JUPITER validating Helios. This claim is uncorroborated by the sources retrieved. It may refer to a separate classical simulation comparison or a future validation step, but it is not documented in the Nature paper or related news coverage.

Broader implications

• Helios is the first 100-qubit-class trapped-ion quantum computer and demonstrates that trapped-ion systems can achieve superconducting-circuit-scale qubit counts (≈100) while maintaining 10–100× lower error rates
• The system operates well beyond the reach of classical simulation, as confirmed by random circuit sampling benchmarks
• The component-level infidelities are predictive of system-level performance, meaning the error model is reliable and scalable
• The results support the DOE's goal of fault-tolerant quantum computing and mark a "new frontier of fidelity and complexity for quantum computers"