Microsoft announced Majorana 2 on June 2, a 12-qubit topological quantum chip using a lead-based superconducting materials stack, claiming a mean qubit lifetime of 20 seconds and a 1,000-fold improvement in parity lifetime over its predecessor. The results were disclosed via arXiv preprint, and multiple independent physicists immediately contested the claims, with University of St. Andrews physicist Henry Legg stating the reported lifetimes reflect classical bit behavior rather than true quantum coherence. A prior Microsoft topological qubit preprint from 2025 remains unpublished after journal investigation.

If the topological approach actually works at scale, Microsoft could eventually put millions of qubits on a single chip, a manufacturing advantage no other approach can match. But that upside only exists if the physics is real, and right now the independent scientific community is saying it cannot reproduce what Microsoft is claiming.

A 12-qubit result announced via preprint rather than peer review, from a company whose prior topological paper is still under journal investigation, is not a breakthrough until independent physicists can reproduce it, and right now they are saying they cannot.

Science News — "Microsoft's quantum chip got an upgrade. Critics are still skeptical" (June 2, 2026): https://www.sciencenews.org/article/microsoft-quantum-chip-upgrade-majorana Scientific American — "Microsoft's upgraded Majorana quantum computing chip fizzles with physicists" (June 2, 2026): https://www.scientificamerican.com/article/microsofts-upgraded-majorana-quantum-computing-chip-fizzles-with-physicists/ Postquantum.com — "Microsoft Majorana 2: 20-Second Qubits, Same Questions" (June 3, 2026, technical breakdown of the Z/X measurement gap): https://postquantum.com/industry-news/microsoft-majorana-2-analysis/ Quantum Zeitgeist — "Majorana Qubit Claims: The Definitive 2026 Microsoft Dispute" (background on how the two papers relate): https://quantumzeitgeist.com/microsoft-majorana-qubit-claims/