Boffin Claims Microsoft's 'Quantum Leap' Is Invalid Due To 'Basic Python Errors'

A peer-reviewed Nature critique argues that Microsoft's 2025 Majorana quantum-computing breakthrough -- and its claim that it could enable "a truly meaningful quantum computer not in decades, as some have predicted, but in years" -- is fundamentally flawed. According to Dr Henry Legg, a lecturer at the University of St Andrews, the claims were undermined by omitted data, selective plotting, and basic Python errors that concealed alternative results. Microsoft, for its part, says the bugs were minor and stands by its findings and roadmap. The Register reports: "Last year they claimed to be years, not decades from a 'topological quantum supercomputer,'" Legg told The Register in an email. "My feeling is that they are centuries, not decades away. If it works at all -- and, based on what I have seen, the most likely scenario is that it doesn't work." Based on his analysis of the research Microsoft published in 2025, Legg argues that the company's claims about finding and being able to control the elusive Majorana particle to build a topological superconductor do not withstand scrutiny. "I demonstrate that Microsoft's tune-up software is flawed and that coding errors resulted in incorrect statements to peer reviewers," said Legg. "Raw data, which was omitted from the original paper, also appears to indicate Microsoft's devices contain considerable disorder and are not compatible with the existence of a topological gap. In other words, the prerequisites for Microsoft's claims do not appear to be met, but this was obscured because this data did not appear in the original publication." Essentially, Microsoft has proposed a Topological Gap Protocol (TGP) that can be used to detect the phase transition deemed to be a prerequisite for conducting quantum calculations using Majorana particles. Legg argues that based on his analysis of underlying transport data (measurements of particle change) -- omitted from the original publication -- Microsoft chose to focus on results that supported its thesis and ignored data that could be interpreted as a negative result. As he notes in his critique: "The TGP plotting code was set to highlight only the largest purportedly topological region." "The primary consequence was the omission of other regions that passed their tune-up protocol (the TGP)," said Legg. "When peer reviewers asked if other regions existed, Microsoft inaccurately stated that they had investigated the only region passing the protocol within the explored range. This was not correct." Legg also argues that Microsoft mishandled its code. "The code antisymmetrized bias voltage based on array index rather than physical value," his analysis says. In other words, Microsoft's researchers made a basic programming mistake by evaluating the array index -- the number identifying a value's position in an array -- instead of the value to which the index refers. "There were two pretty basic Python programming errors that hid these alternative regions," Legg explained. "Their plotting software was hardcoded with a filter (zbp_cluster_numbers=[1]) that forced it to display only the single largest region, concealing other successful results from their phase maps. Changing this to zbp_cluster_numbers=[1,2] shows already a second region." Legg added: "The TGP software transformed the data by simply reversing a Python array (x[::-1]) based on its index position, ignoring the actual physical bias voltages."

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