A critique printed in Nature Wednesday calls the fundamental expertise behind Microsoft’s “breakthrough” quantum computing chip the Majorana 1 into query. Microsoft unveiled the chip in February 2025 and mentioned it featured a brand-new expertise generally known as a topological qubit. Topological qubits, they mentioned, could be the “constructing blocks” for his or her future quantum pc. Microsoft introduced the subsequent technology chip Majorana 2 at Construct earlier this month.
However in a peer-reviewed article, Henry Legg, a physicist on the College of St Andrews, reanalyzed Microsoft’s knowledge on their machine and argued that the corporate’s researchers didn’t conclusively display a working topological qubit within the first place.
Concept predicts that the electrons on this wire behave in a collective sample generally known as a Majorana particle, for which the chip is known as.
Proponents of quantum computing predict that the expertise’s computational skills will advance new drugs discovery, encryption, and machine studying. Firms like Google and IBM have already demonstrated extra superior machines than Majorana 1 or 2, though presently, nobody has conclusively gotten any quantum pc to carry out something helpful. However Microsoft claimed that Majorana 1, and subsequently Majorana 2, paved their path towards a sensible quantum pc.
Microsoft’s design, distinctive amongst quantum computing corporations, includes a tiny wire, thinner than a human hair, fabricated from the semiconductor indium arsenide caught to a superconductor. Concept predicts that the electrons on this wire behave in a collective sample generally known as a Majorana particle, for which the chip is known as. Microsoft desires to encode info within the properties of the Majorana particle. (A topological qubit is to a Majorana particle as a transistor is to silicon.)
Proponents of the Majorana particle suppose it’s promising qubit materials as a result of idea predicts that when fashioned into topological qubits, the Majorana ought to compute with fewer errors than competing supplies, resembling superconducting circuits pursued by IBM. This implies that finally, fewer topological qubits are wanted to scale as much as a helpful quantum pc.
That’s, if Microsoft has truly made a Majorana particle. “They haven’t convincingly proven that they’ve Majoranas,” Legg instructed The Verge. “You may’t make a qubit in case you don’t have the Majoranas.”
In Legg’s critique, he writes that what Microsoft claims as a signature of the Majorana particle might truly be from the formation of quantum dots, that are electron-containing constructions, within the machine. Quantum dots wouldn’t be helpful for constructing the quantum pc. He additionally writes that Microsoft cherry-picked their knowledge.
“You may’t make a qubit in case you don’t have the Majoranas.”
Microsoft’s workforce printed a rebuttal in Nature disputing Legg’s interpretation of their knowledge. Legg’s critique “doesn’t represent a considerable scientific problem to our findings,” the Microsoft workforce wrote. Legg has not “proposed an alternate mannequin that matches all of our knowledge,” Chetan Nayak, a physicist main Microsoft’s quantum workforce, instructed The Verge.
Legg first posted his critique on the net physics repository arXiv on March 11, 2025, inside a month of Microsoft’s Majorana 1 announcement. It took a yr for Nature to conduct a peer evaluation and publish his article.
In the meantime, on June 2, Microsoft introduced a brand new chip, the Majorana 2, that includes what they claimed was the subsequent technology of their topological qubits. The corporate says they will construct a “scalable quantum pc” by 2029. “We 100% stand behind our outcomes,” Nayak instructed The Verge. “We stand by our roadmap. We stand behind our long-standing dedication to scientific rigor and dialogue.”
Legg says the corporate’s characterization of Majorana 2, which Microsoft wrote in a non-peer reviewed manuscript, suffers from comparable issues he identified a yr in the past. “Nothing on this [manuscript] resolves the basic points that so many scientists have with this firm’s earlier claims,” Legg instructed The Verge.
Correction, June twenty fourth: An earlier model of this text misstated the unique date of publication of Legg’s critique. It was posted on March 11, 2025, not February 26, 2025.
