What is the lowest quantum gate error rate ever demonstrated?
As of March 2026, the lowest demonstrated two-qubit gate error rate is 0.0003 (0.0300%), set on trapped-ion hardware in July 2024. Per-platform records: Neutral Atom 0.00136, Superconducting 0.000519, Trapped-Ion 0.0003. Every figure links to the primary paper.
Why the two-qubit error rate matters
The two-qubit gate error rate is the single most important hardware figure of merit for fault tolerance: error correction only suppresses errors when the physical rate is below the code's threshold (1.4% for the surface code, 0.58% for the leading qLDPC code). All 3 tracked platforms are now below the surface-code threshold, fidelity is no longer the gating factor for error correction; scale is.
Record error rates halve roughly every 1.5 years (neutral atom), 1.8 years (superconducting), 5.8 years (trapped-ion) on log-linear fits of the record series. These are extrapolations of record data points, not predictions.
Compute it yourself
Every number on this page is computed from the same open model that powers the interactive calculator and the MCP server for AI assistants.
GET https://www.quantum-expectations.com/api/fit-historic-series?seriesType=fidelity&hardwareType=Trapped-Ion