Henry Legg, a physicist at the University of St. Andrews, has published a critical commentary in Nature magazine that calls into question Microsoft’s fundamental findings about topological cubits as set out in an article in early 2025. The scientist analyzed the transport data of the corporation and concluded that they did not confirm the presence of a stable superconducting gap necessary for correct interpretation of signals as topological. In his opinion, the fixed effects may have a trivial explanation associated with quantum dots or defects of the device.

Microsoft flatly rejected the criticism, stating that their measurements do not require a priori assumption of the existence of a gap and that the signals they receive are fully consistent with the topological nature of the states. The company’s position was supported by the manager of quantum equipment direction, Chetan Nayak, who emphasized confidence in the chosen road map. It is worth noting that the argument broke out shortly after the presentation of the Majorana 2 chip, which, according to the corporation, shows the cubit’s life span up to 20 seconds. While Legg’s critique does not directly affect the next generation of chips, it questions the basic physical principles on which Microsoft’s entire quantum strategy is built.

The situation is made worse by the opinion of independent experts: physicist Sergei Frolov of the University of Pittsburgh suggested that Microsoft’s original article in Nature was reviewable. In the meantime, the corporation continues to develop its direction actively, with support from DARPA under the US2QC program, which aims to create a commercially viable quantum computer by 2033. Amid these discussions, other market players such as D-Wave are also presenting their ambitious fault-resistant quantum system roadmaps.