Overview
- A peer-reviewed 'Matters Arising' by Henry Legg published Wednesday in Nature argues Microsoft did not demonstrate a topological qubit and that signals the company labeled as evidence can be explained by noise or trivial device effects.
- Legg identifies specific software flaws he says affected Microsoft’s results, including a hardcoded filter that hid alternative regions, an array-reversal error that misapplied bias voltages, and omitted raw transport data that showed disorder rather than a clear topological gap.
- Microsoft formally rebutted the critique in Nature and said it stands by its measurements and 2029 roadmap, noting ongoing DARPA evaluation and claiming its tune-up code is a practical tool that does not change the physical interpretation of the capacitance signals.
- The dispute follows earlier problems in Microsoft-linked Majorana research, including two prior retractions and editorial flags, and Majorana 2’s published performance claims—such as parity lifetimes averaging about 20 seconds—remain unverified by independent labs.
- If Legg’s concerns hold, they would undercut Microsoft’s foundational physics for topological qubits, slow confidence in the company’s commercialization timeline, and increase pressure for open data, independent replication, and clearer standards for quantum claims.