Nature published a peer‑reviewed critique that challenges Microsoft’s 2025 claim of a quantum breakthrough using Majorana particles. The paper, authored by University of St Andrews lecturer Henry Legg, argues the company’s topological gap protocol contains basic Python bugs that hide alternative data regions. Legg says the omitted transport data undermines the claimed observation of a topological gap.

Microsoft responded with a rebuttal published in Nature, insisting its results are sound and that the off‑by‑one indexing error is inconsequential. The company highlighted DARPA’s Quantum Benchmarking Initiative endorsement and claimed its Majorana 2 chip, represents a topological quantum processor, though no qubit performance metrics were disclosed. The rebuttal says independent experts reviewed transport and capacitance data and found no contradiction with the reported topological signatures.

Legg maintains the critique is substantive, noting the Python filter forced the analysis to show only the largest region and that the reversed array operation ignored actual bias voltages. Without a clearly demonstrated X‑measurement, the device cannot perform quantum gate operations. The alleged reliability gains pertain to classical bit lifetimes, not quantum computation.