Microsoft's Majorana 1 quantum chip may not have done what Microsoft said it did.
In February 2025, Microsoft unveiled the Majorana 1 processor and declared it a breakthrough built on a new class of hardware called topological qubits — which the company pitched as the future building blocks of practical quantum computing. Now, a peer-reviewed article published in Nature on Wednesday challenges that claim. Henry Legg, a physicist at the University of St Andrews, reanalyzed Microsoft's own data and concluded the company's researchers did not conclusively demonstrate that the underlying technology actually worked as described.
The timing is uncomfortable. Microsoft announced the Majorana 2 chip at its Build conference earlier this month, doubling down on the same topological qubit roadmap that Legg's paper now puts in doubt. If the foundational evidence for Majorana 1 doesn't hold up to peer scrutiny, the entire lineage of chips built on it inherits that uncertainty — and so does whatever Microsoft told investors and partners about its quantum timeline.
This is not the first time a major tech company's quantum milestone has drawn skeptical follow-up from academics; Google's 2019 "quantum supremacy" claim sparked a prolonged dispute with IBM over methodology. The pattern suggests that quantum computing announcements, especially those timed to product cycles, deserve more skepticism than the press release cadence usually invites.