Microsoft's Majorana chips: has it built a topological qubit?
Microsoft says its Majorana chips use a new kind of qubit that resists errors by design, and that a scalable machine could arrive by 2029. The underlying physics is still disputed, and no working topological qubit operations have been published.
- Announced
- Published
- Peer-reviewed
- Independently repeated
- Useful in practice
Verdict: Not yet shown. An ambitious idea with real progress, but the key claim is disputed.
- The claim
- Microsoft says Majorana 1 (2025) is the first chip with a "topological core" of eight qubits, and that Majorana 2 (2026) is a thousand times more reliable and brings a scalable quantum computer forward to 2029.
- What was actually shown
- A peer-reviewed measurement (Nature, February 2025) of the property such qubits would store, made on Microsoft's devices, and a preprint (June 2026) showing that property lasting about 20 seconds in one wire.
- What it doesn't show
- That the devices contain the Majorana states the whole approach depends on. Nature's editors wrote that the 2025 paper isn't evidence of them. No operations on topological qubits, or links between them, have been published.
- Why it matters
- If topological qubits work, they could need far less error correction than any other approach: a genuine shortcut. That's why the claim matters, and why it needs strong evidence.
- What would settle it
- Independent confirmation that the devices host Majorana states, then published operations on, and links between, topological qubits.
What Microsoft claimed
In February 2025, Microsoft announced Majorana 1, calling it the first chip with a "topological core". It said the chip holds eight topological qubits built from a new material it calls a "topoconductor", with a path to a million qubits on one chip. In June 2026 it announced Majorana 2, saying the key property now lasts about 20 seconds, which it describes as a thousand times more reliable, and that this "cut our timeline in half" to a scalable machine by 2029.
Why it would matter
Most quantum computers need many physical qubits to make one reliable, error-corrected qubit. A topological qubit would store information in exotic states, called Majorana zero modes, that are naturally shielded from many errors. If it works, it could be a shortcut past much of the error-correction overhead that every other approach has to pay.
What the evidence shows
The 2025 Nature paper is real and peer-reviewed, but it reports something narrower than the announcement: a way to measure the property a topological qubit would store. In the published peer-review file, Nature's editors said the results don't represent evidence that Majorana zero modes are present. In March 2025, most physicists who saw Microsoft's follow-up data at a major physics conference were unconvinced. In June 2026, Nature published a peer-reviewed critique of the method Microsoft uses to identify these states, together with Microsoft's reply.
Majorana 2's 20-second figure comes from a preprint that hasn't been peer-reviewed, and it measures one wire in a larger device. Critics point out it shows measurements, not operations on qubits or links between them.
Where that leaves things
Microsoft is a serious player: it's in the final stage of DARPA's Quantum Benchmarking Initiative, and it has provided a Majorana 2-based system for DARPA to evaluate. It also supplies error-correction software for other companies' hardware, such as its joint machine with Atom Computing. None of that settles the scientific question at the heart of the topological approach.
Our verdict: not yet shown. The idea is ambitious and the engineering is progressing, but the claim that these chips contain working topological qubits is disputed, and the operations that would prove it haven't been published. We'll update this page as new evidence appears.
Sources
- Microsoft's Majorana 1 chip carves new path for quantum computing, Microsoft, 19 February 2025.
- Peer review file: Interferometric single-shot parity measurement in InAs-Al hybrid devices, Nature, 19 February 2025.
- Physicists are mostly unconvinced by Microsoft's new topological quantum chip, Science News, 27 March 2025
- Majorana 2: Microsoft's scalable quantum processor, Microsoft Quantum, 2 June 2026
- 20 second parity lifetime in an InAs-Pb tetron device, arXiv preprint 2606.03884, 2 June 2026.
- Critique published by Nature challenges Microsoft's quantum computing claims, University of St Andrews, 24 June 2026
- Four more teams enter Quantum Benchmarking Initiative final stage, DARPA, 7 October 2026