Another retraction of the angel particle paper! Microsoft's topological quantum computing is not working again

Majorana fermions, also known as angel particles, are considered to be the best vehicles for implementing topological quantum computers because the antiparticle of a Majorana fermion is itself, making it a very stable state. After decades of searching, several teams have announced the discovery of the angel particle in recent years, but recent frequent withdrawals have cast a shadow over the field of research.

Two key papers published in Nature in 2017 and 2018 by Dutch physicist and former Microsoft employee Leo Kouwenhoven and colleagues on the discovery of angel particles have been retracted, with the 2018 paper explicitly suggesting that they had discovered angel particles. The reasons for the retraction were the same; they hid key data.

Original 2017 paper：

https://www.nature.com/articles/nature23468

Retraction statement：

https://www.nature.com/articles/s41586-022-04704-2

2018 Original paper：

https://arxiv.org/abs/2101.11456 (original Nature article withdrawn)

Withdrawal statement：

https://www.nature.com/articles/s41586-021-03373-x

Not coincidentally, another team was withdrawn from Science today, in a paper published on 21 July 2017 showing that researchers observed chiral Majorana fermions in their experiments. The paper had four corresponding authors, Qinglin He, Xufeng Kou, Shoucheng Zhang and Kanglong Wang, all Chinese scientists.

The retraction statement mentioned that after the publication of the paper, readers who failed to reproduce the findings requested the authors to provide the original data files. Subsequently, the source of the original data was questioned; and an analysis of the original and published data revealed serious irregularities and discrepancies. These issues led the editors of Science to lose confidence in the paper's conclusions, resulting in an editorial retraction.

Original paper：

https://www.science.org/doi/10.1126/science.aag2792

Retraction statement：

https://www.science.org/doi/10.1126/science.adf7575

With this news, many thought that Microsoft, who was at the forefront of the topological quantum computing route, was cool again, but Microsoft didn't reflect too much on this, as they already had an alternative long ago, having parted ways with the Kouwenhoven team.

Today, Microsoft has published a new blog post announcing that their paper on their breakthrough in topological quantum computing is now open for review by all, showing Microsoft's strong confidence.

Pre-printed paper：

https://arxiv.org/abs/2207.02472

The major breakthrough was announced by Microsoft in March this year.

The fidelity, speed and size of topological quantum bits are controlled by a characteristic energy called the topological gap. The prerequisites require reliable generation of the topology of matter and experimental verification that the subcomponents of the quantum bit are in the topological phase and ready for quantum information processing. But this is not straightforward, as the topological phase is characterised by long-range entanglement of ground states, which is not easily accessible to conventional experimental probes.

The Topological Gap Protocol (TGP), proposed by the Microsoft Azure Quantum team last year, solves this difficulty as a standard for determining topological phases from quantum transport measurements. If the protocol can be passed, a topological gap is proven to exist. To do this, they designed a device: a topological superconducting wire with Majorana zero modes at the end. Both ends of the line have a real fermionic operator.

In the end, the Microsoft team measured a topological gap of more than 30 μeV on this device. This is a landmark scientific advance and a key step in the journey to topological quantum computing. Topological quantum computing relies on the fusion and braiding of arbitrons (the two original operations of topological quasiparticles). Topological gaps control the fault tolerance provided by the fundamental state of matter for these operations.

In summary, Microsoft's ability to create and maintain quantum phases through Majorana zero modes and measurable topological gaps removes the biggest obstacle to generating topological quantum bits. Quantum computers based on topological quantum bits are expected to perform more consistently than machines built with other known quantum bits.