For years, Microsoft has claimed breakthroughs in quantum computing. Now, a UK-based physicist has published a paper in the journal Nature arguing that the tech giant's research is flawed.
Dr Henry Legg, a long-term critic, said a software tool Microsoft used to check its own data contained coding errors and was not sufficiently accurate. He also said the company had still not proved it had created a theoretical quasi-particle called Majorana, which is central to its approach.
“UK physicist Dr Henry Legg publishes paper in Nature questioning Microsoft's quantum computing claims, citing coding errors.”
"Last year Microsoft claimed they had built the equivalent of a precision Swiss watch," Legg said. "However when I opened the case to examine the mechanism, I found what looked like a chaotic jumble of mismatched parts. Something was making noise, but it didn't look like the breakthrough Microsoft had claimed."
Microsoft has consistently stood by its conclusions despite scepticism from experts. Dr Chetan Nayak, Technical Fellow and Corporate Vice President, Quantum Hardware at Microsoft, said: "At the end of the day, success is the delivery of a scalable quantum computer. Scepticism and rigour are hallmarks of the scientific process, which we appreciate and have supported from various academics."
Nayak added that Microsoft's thorough rebuttal was accepted and published by Nature. In that response, the company stated that the software Legg referred to did not "interpret" the measurements which led to its conclusions.
Legg also accused Microsoft of not sharing enough data for other scientists to scrutinise. Microsoft said it was sharing all of its data with the US defence agency Darpa for independent arbitration but claimed some of it was too commercially sensitive to publish more widely.
Legg's paper critiqued research Microsoft published in 2025. Since then, Microsoft has released a second generation of its Majorana chip, which it says is 1,000 times more reliable than the previous one. The company has invested heavily in the race to build quantum computers, which work very differently to traditional machines and are said to have the potential to solve difficult global challenges.