MilestoneQuantum advantageDisputed

IBM and partners claim quantum advantage with built-in accuracy checks

Jul 30, 2026

On July 30, 2026, IBM announced three preprints, with the University of Chicago, Qedma and Algorithmiq, that it says show quantum advantage: calculations beyond leading classical methods, each with a way to check the answers. The flagship ran a 70-qubit encoded circuit on IBM hardware.

Why it matters

Showing that a quantum computer beats classical ones on a task whose answers can be checked is a key test on the road to useful machines. IBM opened the results to public challenge, and one was quickly matched classically.

On Aug. 13, 2026, a preprint by Manabe, Gu and Pan reported computing the exact outputs of the original 70-qubit IBM–UChicago circuit on 256 GPUs in 37.3 minutes. IBM's authors acknowledged it and revised the paper with a layout that blocks that shortcut. The Qedma and Algorithmiq results were not covered.

Jay Gambetta · Bill Fefferman · IBM · UChicago · Qedma · Algorithmiq

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