“The detection of a topographical superconducting phase–the basis of proposed topological qubits–is notoriously difficult because trivial states can mimic the signatures expected from a topological superconductor,” Legg wrote.
Microsoft said Majorana 2 can keep quantum information stable for an average of 20 seconds, with some qubits lasting up to a minute. The company said AI helped speed development by identifying promising materials, automating tests, and improving manufacturing. The chip relies on the same topological qubit technology now being questioned by critics. Microsoft argues the approach could produce more reliable quantum computers by reducing the errors that plague today's systems.
Legg argued that previously unpublished transport data underlying Microsoft's results failed to show clear evidence of the superconducting state required to support the company's topological qubit claim. Instead, he said the measurements appeared more consistent with alternative explanations, including quantum dot effects.
Microsoft pushed back on Legg's conclusions.
Bitcoin is considered particularly vulnerable because a quantum attacker could potentially derive private keys from exposed public keys and steal funds. Legg's critique does not rule out that future, but it does challenge the evidence Microsoft cites for reaching it.
