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Verdict night

IBM named a date for the first verified quantum advantage. On that date the Ledger scores it, in public, against a test written down months earlier.

What was said

IBM anticipates that the first cases of verified quantum advantage will be confirmed by the wider community by the end of 2026.

IBM, press release of 12 November 2025. The full record and the claim in the Ledger.

The test, fixed in advance

The test is IBM’s own words: confirmed by the wider community, not announced by IBM. The Ledger froze the exact criteria on 23 September 2026, before anyone knew how the year would end. They are quoted below from the record, not paraphrased.

Loading the criteria from the record.

How the night will go

1. The clock. The deadline is 31 December 2026, with a grace period of 30 days for evidence that was already in flight. A verdict can therefore land on the night or as late as 30 January 2027. The page will say which.
2. The sources. The desk reads the places named in the record: IBM’s newsroom, the arXiv quant-ph listing, and the Quantum Advantage Tracker run by IBM with Algorithmiq, the Flatiron Institute and BlueQubit.
3. The question for each claimed case. Has a party that is neither IBM nor an author of the result confirmed it, and does a published classical reproduction still stand on the date? Those two facts decide between the three outcomes.
4. Two keys. Whoever logged the claim does not resolve it, and a second person writes the verdict. The reasoning and every source are published with it, and the claimant may respond on the record.

What would move it

• An independent group, or a peer-reviewed paper, stating that the best classical methods it tried cannot match an IBM result.
• A classical simulation that reproduces a claimed case. That has happened to earlier advantage claims, which is why the test has a clause for it.
• A case that is still in open dispute at the deadline, which is the partial outcome by definition.

The latest dated check-ins are listed below, straight from the record.

Put your own number on it

Before the night, you can record what you think will happen as three probabilities that add to 100. The Ledger keeps them, scores them with a Brier score once the verdict exists, and shows you your own calibration on The Standing. Make your forecast in the Ledger. Forecasts need an account, which is not switched on yet; the claim and its test are public either way.

This page reads the claim record at load time. If the record says the claim has resolved, the page shows the published verdict and its reasoning instead of the countdown. It never carries a verdict of its own.