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Two-qubit gate fidelity (2Q fidelity)

How often an operation on two qubits gives the right result. 99.9% means about one error in a thousand operations.

When results can be compared

Best, median and average values differ a lot; so do single pairs and whole-chip figures. Compare only like with like.

Where it comes from

Standard measure in quantum computing.

Type
Measurement, component level
Unit
%
Better is
Higher
Applies to
gate-based machines

Results

Set-up: mean. Only these results are compared with each other.
Machine ValueSet-upPublishedMeasured byGradeRecord
Quantinuum Helios 99.921% mean 17 Jun 2026 Maker B r-000017
Quantinuum H2 99.843% mean 2025 Maker B r-000023
Google Willow 99.67% mean 9 Dec 2024 Maker B r-000005
Google Willow 99.86% mean 9 Dec 2024 Maker B r-000006
QuEra Computing Harvard–MIT rubidium atom array 99.54% mean 11 Oct 2023 Maker B r-000032
Set-up: single pair. Only these results are compared with each other.
Machine ValueSet-upPublishedMeasured byGradeRecord
IonQ Oxford Ionics two-qubit prototype 99.9916% single pair 20 Oct 2025 Maker B r-000031
Atom Computing Ytterbium atom array 99.4% single pair 21 May 2025 Maker B r-000037
Set-up: statistic not stated. Only these results are compared with each other.
Machine ValueSet-upPublishedMeasured byGradeRecord
Infleqtion Cesium atom array 99.35% statistic not stated 25 Aug 2025 Maker B r-000038
IonQ Tempo 99.9% statistic not stated – Maker C r-000027
Set-up: median. Only these results are compared with each other.
Machine ValueSet-upPublishedMeasured byGradeRecord
IQM Quantum Computers Emerald 99.5% median 5 Aug 2025 Maker C r-000047
Rigetti Computing Ankaa-3 99.5% median 23 Dec 2024 Maker C r-000040
IonQ Forte 99.536% median 7 Nov 2024 Maker B r-000030
IQM Quantum Computers Garnet 99.5% median 22 Aug 2024 Maker B r-000044
Rigetti Computing Cepheus-1-108Q 98.82% median – Maker B r-000041