Microsoft Quantum Computing 'Breakthrough' Faces Fresh Challenge

An anonymous reader shares a report: A physicist has cast doubt on a test that underlies a high-profile claim by Microsoft to have created the first 'topological qubits', a long-sought goal of the company's quantum computing effort. The critique comes amid mounting speculation about the validity of Microsoft's claim.

Microsoft announced the breakthrough, which could lead to a quantum computer more resistant to information loss than with other approaches, on 19 February. Without a peer-reviewed paper backing up the claim, some researchers were sceptical. An accompanying paper in Nature described a method to measure the read-out from future topological qubits, but did not offer proof of their existence.

In the latest critique, posted as a preprint, Henry Legg, a theoretical physicist at the University of St Andrews, UK, raises concerns about a test that Microsoft uses to look for Majoranas, so-far undiscovered quasiparticles arising from the collective behaviour of electrons that are needed for the topological qubits to work.

Known as the topological gap protocol (TGP), the test is not mentioned in the 19 February Microsoft announcement. But the company has subsequently indicated to Nature's news team, and in a comment online, that it created the topological qubits using the TGP. 'Since the TGP is flawed, the very foundations of the qubit are not there,' says Legg. Business Insider, separately reports: On February 19, Microsoft unveiled a new quantum processor called Majorana 1. On the same day, Simone Severini, Amazon's head of quantum technologies, emailed CEO Andy Jassy casting doubt on Microsoft's claims, according to a copy of the email obtained by Business Insider.

Severini wrote that Microsoft's underlying scientific paper, released in Nature, 'doesn't actually demonstrate' the claimed achievement and only showed that the new chip 'could potentially enable future experiments.'

Oskar Painter, Amazon's head of quantum hardware, stressed the need to 'push back on BS statements like S. Nadella's,' likely in reference to the Microsoft CEO Satya Nadella's social media post proclaiming major advancements with the Majorana chip. Further reading:
Scientists Question Microsoft's Quantum Computing Claims.

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