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Microsoft unveils Majorana 1, a chip it says uses topological qubits
Feb 19, 2025
Microsoft announces Majorana 1, a processor it says runs on "topological" qubits and is designed to scale to a million qubits. A companion Nature paper reports a key measurement, but its authors warn the tests do not by themselves show that Majorana particles are present.
Why it matters
Topological qubits are expected to be better protected from noise and easier to scale than other designs, so a working one would matter a lot; the evidence for this chip is still contested.
Physicists questioned the claim: the Nature paper does not establish Majorana modes, and a critique by Henry Legg argues that the test Microsoft relies on to identify the topological phase is unreliable.
Chetan Nayak · Microsoft
Related
Sources (5)
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Microsoft Azure Quantum Blog
Microsoft unveils Majorana 1, the world's first quantum processor powered by topological qubits
“Majorana 1: the world's first Quantum Processing Unit (QPU) powered by a Topological Core, designed to scale to a million qubits on a single chip.”
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Nature
Interferometric single-shot parity measurement in InAs–Al hybrid devices
“We discuss the interpretation of our measurements in terms of both topologically trivial and non-trivial origins.”
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Scientific American (reprinted from Nature)
Microsoft Claims Quantum-Computing Breakthrough—but Some Physicists Are Skeptical
“The paper reports measurements suggesting that the nanowire does indeed harbour an extra electron. These tests "do not, by themselves" guarantee that the nanowire hosts two Majorana quasiparticles, the authors warn.”
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arXiv (Henry F. Legg)
Comment on "InAs-Al hybrid devices passing the topological gap protocol", Microsoft Quantum, Phys. Rev. B 107, 245423 (2023)
“As such, Microsoft Quantum's claim in PRB 107, 245423 (2023) that their devices have a "high probability of being in the topological phase" is not reliable and must be revisited.”
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The Quantum Insider
Major Debate Continues to Swirl Around Majorana Findings
“In a preprint published on arXiv, Henry Legg, a theoretical physicist at the University of St Andrews, argues that Microsoft's topological gap protocol (TGP) — a test for detecting Majoranas — is flawed, casting doubt on the foundation of its qubit approach.”
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