A new paper argues Microsoft exaggerated its quantum claims a year ago

A critique published successful Nature Wednesday calls the basal exertion down Microsoft’s “breakthrough” quantum computing spot the Majorana 1 into question. Microsoft unveiled the spot successful February 2025 and said it featured a brand-new exertion known arsenic a topological qubit. Topological qubits, they said, would beryllium the “building blocks” for their early quantum computer. Microsoft announced the adjacent procreation spot Majorana 2 astatine Build earlier this month.

But successful a peer-reviewed article, Henry Legg, a physicist astatine the University of St. Andrews, re-analyzed Microsoft’s information connected their instrumentality and based on that the company’s researchers did not conclusively show a moving topological qubit successful the first place.

Proponents of quantum computing foretell that the technology’s computational abilities will beforehand caller medicine discovery, encryption, and instrumentality learning. Companies like Google and IBM have already demonstrated much precocious machines than Majorana 1 aliases 2, though presently, nary 1 has conclusively gotten immoderate quantum machine to execute thing useful. But Microsoft claimed that Majorana 1, and subsequently Majorana 2, paved their way toward a applicable quantum computer.

Microsoft’s design, unsocial among quantum computing companies, involves a mini wire, thinner than a quality hair, made of the semiconductor indium arsenide stuck to a superconductor. Theory predicts that the electrons successful this ligament behave successful a corporate shape known arsenic a Majorana particle, for which the spot is named. Microsoft wants to encode accusation successful the properties of the Majorana particle. (A topological qubit is to a Majorana particle arsenic a transistor is to silicon.)

Proponents of the Majorana particle deliberation it is promising qubit worldly because mentation predicts that erstwhile formed into topological qubits, the Majorana should compute pinch less errors than competing materials, specified arsenic superconducting circuits pursued by IBM. This suggests that ultimately, less topological qubits are needed to standard up to a useful quantum computer.

That is, if Microsoft has really made a Majorana particle. “They haven’t convincingly shown that they person Majoranas,” Legg told The Verge. “You can’t make a qubit if you don’t person the Majoranas.”

In Legg’s critique, he writes that what Microsoft claims arsenic a signature of the Majorana particle could really beryllium from the statement of quantum dots, which are electron-containing structures, successful the device. Quantum dots would not beryllium useful for building the quantum computer. He besides writes that Microsoft cherry-picked their data.

Microsoft’s squad published a rebuttal successful Nature disputing Legg’s mentation of their data. Legg’s critique “does not represent a important technological situation to our findings,” the Microsoft squad wrote. Legg has not “proposed an replacement exemplary that fits each of our data,” Chetan Nayak, a physicist starring Microsoft’s quantum team, told The Verge.

Legg first posted his critique connected the online physics repository arXiv connected February 26, 2025, wrong a week of Microsoft’s Majorana 1 announcement. It took a twelvemonth for Nature to behaviour a adjacent reappraisal and people his article.

Meanwhile, connected June 2, Microsoft announced a caller chip, the Majorana 2, featuring what they claimed was the adjacent procreation of their topological qubits. The institution says they tin build a “scalable quantum computer” by 2029. “We 100% guidelines down our results,” Nayak told The Verge. “We guidelines by our roadmap. We guidelines down our long-standing committedness to technological rigor and dialogue.”

Legg says the company’s characterization of Majorana 2, which Microsoft wrote successful a non-peer reviewed manuscript, suffers from akin problems he pointed retired a twelvemonth ago. “Nothing successful this [manuscript] resolves the basal issues that truthful galore scientists person pinch this company’s erstwhile claims,” Legg told The Verge.