The company has been touting its quantum technology for years, but some experts say those claims simply aren’t valid.
By Joseph Howlett edited by Claire Cameron

Majorana 2, a next-generation quantum chip built with Microsoft Discovery’s agentic AI. Photo by John Brecher for Microsoft.
John Brecher for Microsoft
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A leading quantum computing expert is criticizing Microsoft’s claims that it has a “topological qubit,” arguing in a new paper that the company has failed to demonstrate the technology.
Henry Legg, a physicist at the University of St Andrews, says the “topological qubit”, a quantum information store that could theoretically maintain higher fidelity than any other in existence, could simply be noise.
The comment was published today in Nature“Questions Raised” the journal’s venue for formal criticism of its published articles. Legg’s response targets Microsoft’s most recent version Nature article, published earlier this month, but it’s just the latest in a series of criticisms leveled at Microsoft’s Quantum division from other researchers in the field.
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The company was forced to retract some earlier peer-reviewed papers. And in the new commentary, Legg claims that their most recent Nature the paper may also be defective. In a response also published today by Naturea member of Microsoft’s Quantum team says their measurements support the claim that they have produced a topological qubit.
In a statement to Scientific AmericanChetan Nayak, technical researcher and Microsoft corporate vice president, Quantum Hardware, said: “We remain committed to our results and our roadmap. Ultimately, success lies in delivering a scalable quantum computer. We are confident in our ability to execute on our roadmap and proud of our continued engagement with DARPA, which has propelled Microsoft into the final phase of its quantum benchmarking initiative after independently evaluating our results (those in the public domain and owners) with a team of highly qualified experts Skepticism and rigor are hallmarks of the scientific process, which we value and have supported by various academics. We participated in the dialogue and our thorough rebuttal was accepted and published by. Nature.”
The review, which Microsoft knew was in preparation for Nature for some time – lands on the heels of the company’s unveiling of the “Majorana 2” chipand an updated timeline for producing “scalable and practical quantum computing” by the end of the decade. “They simply can’t sell the 2029 roadmap as credible to the public when the underlying physics isn’t there,” Legg says.
“The ‘Matters Arising’ painfully shows that the newspaper in Nature has no scientific value,” says Sergey Frolov, a physicist at the University of Pittsburgh who was not involved in either paper. “And that it will probably have to be retracted, like the other paper. Nature Microsoft-related documents.
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