A new paper says Microsoft exaggerated its claims a year ago

A Critique published in Nature Wednesday calls Microsoft’s groundbreaking “breakthrough” quantum computing chip Majorana 1 into question. Microsoft unveiled the chip in February 2025 and said it contained a new technology known as a topological qubit. Topological qubits, they said, will be the “building blocks” of their future quantum computers. Microsoft announced the next generation Majorana 2 chip at Build earlier this month.

But in a peer-reviewed article, Henry Legg, a physicist at the University of St Andrews, reviewed Microsoft’s data on their device and said that the company’s researchers had not predicted a working qubit in the first place.

Proponents of quantum computing predict that the technology will advance new drug discovery, encryption, and machine learning. Companies like Google and IBM they have already demonstrated systems far superior to Majorana 1 or 2, although at present, no one has gotten any kind of computer to do anything useful. But Microsoft said that Majorana 1, and later Majorana 2, paved their way to a more efficient computer.

Microsoft’s design, unique among computer companies, involves a tiny wire, thinner than a human hair, made of semiconductor indium arsenide bonded to a superconductor. Theory predicts that the electrons in this wire behave as a group called a Majorana particle, which the chip is called. Microsoft wants to put more information on the Majorana particle. (A topological qubit is a Majorana particle like a transistor and silicon.)

Proponents of Majorana particles think they are promising because the theory predicts that when made into topological qubits, Majorana particles should have fewer computational errors than competing devices, such as the supercomputers pioneered by IBM. This suggests that ultimately, fewer topological qubits are needed to reach an efficient quantum computer.

That is, if Microsoft actually makes Majorana stuff. “They have not shown conclusively that they have Majoranas,” Legg said Seaside. “You can’t make money if you don’t have Mr. Majorana.”

In Legg’s rebuttal, he writes that what Microsoft says is the signature of Majorana particles could come from the formation of quantum dots, which contain electrons, in the device. Quantum dots may not be useful in building a quantum computer. They also write that Microsoft chose their data.

The Microsoft team issued a statement of objection Nature contradicting Legg’s interpretation of their data. Legg’s criticism “does not raise a serious scientific problem with our findings,” the Microsoft team wrote. Legg “didn’t create a model that would fit what we know,” Chetan Nayak, lead scientist for Microsoft’s quantum team, said. Seaside.

Legg first posted his critique on the online physics arXiv on March 11, 2025, within a month of Microsoft’s Majorana 1 announcement. It took a year Nature doing peer review and publishing his article.

Meanwhile, on June 2, Microsoft announced a new chip, Majorana 2, containing what it claims is the next generation of its topological qubits. The company says it can build a “supercomputer” by 2029. “We 100% stand behind our results,” Nayak said. Seaside. “We are standing our ground. We are standing behind our long-standing commitment to scientific challenges and dialogue.”

Legg says the company’s version of Majorana 2, which Microsoft wrote in a non-peer-friendly document, has some similarities. problems he said a year ago. “None of this (manual) solves the problems many scientists have with the company’s previous claims,” ​​Legg said. Seaside.

Correction, June 24: The original story of this story was misrepresented the original publication date of Legg’s critique. It was posted on March 11, 2025, not February 26, 2025.