Microsoft’s Quantum team’s highly anticipated Majorana fermion study turned out to be wrong. The article, published in Nature in 2018, was met with skepticism.

Machine Heart reports, edited by Du Wei and Devil King.

In March 2018, Dutch physicist and Microsoft employee Leo Kouwenhoven and others reported the observation of a hard-to-find particle, Majorana Fermion.

Paper links: www.nature.com/articles/na…

The Majorana fermion is a fermion whose antiparticle is itself. The particle was named after Italian physicist Ettore Majorana published a paper in 1937 imagining its existence. Many scientists see the particle as one of the best solutions to qubit instability, and it is expected to be used in topological quantum computers.

Microsoft wanted to build a quantum computer with Mayola Fermions, and while IBM and Google were already building good prototypes with more mature technologies, Kouwenhoven’s discovery gave Microsoft hope of catching up. Julie Love, Microsoft’s head of quantum computing business development, has said the company will build a commercial quantum computer “within five years.”

Three years on, however, Microsoft’s 2018 discovery proved to be a failure. In late January, Kouwenhoven and 21 co-authors published a new paper that included more experimental data. In conclusion, they didn’t find Majorana Fermion after all. The authors said in a note that the previous article published in Nature would be retracted because of a “technical error.”

Two physicists in the field say that after they questioned the study, additional data provided by Kouwenhoven’s team showed that the team had removed data points that did not fit its conclusions. “I don’t know what they were thinking,” said Sergey Frolov, a professor at the University of Pittsburgh. “But they skipped over some data that contradicted the thesis. Looking at the more complete data, there’s no doubt that they didn’t find A Mayorana Fermison.”

The 2018 paper claims to have found stronger evidence for the existence of Majorana fermions than Kouwenhoven’s 2012 study. The paper has earned Kouwenhoven and his lab at TU Delft a great reputation. The research project was partially funded by Microsoft, which hired Kouwenhoven in 2016 to study Majorana fermions.

The 2018 paper reported seeing a “zero-bias peak” — a signal of the presence of Majorana fermion — in the current passing through a very low temperature semiconductor line.

Frolov said he saw a number of problems in the unpublished data, including data points that deviated from the main line but were ignored in the paper. If these data points were included, the results were completely different — Majorana fermion did not appear. Frolov’s observation is mentioned in Kouwenhoven’s new paper, published last month, but does not explain why the data points were previously deleted. They acknowledge that trying to test specific theoretical predictions experimentally “may lead to confirmation bias and evidence of false positives.”

Sergey Frolov questioned the study on twitter at twitter.com/spinespress… .

Kouwenhoven did not respond in a statement because the new paper, which reinterprets his findings, is still under peer review. “We believe that quantum computing at scale will help solve some of humanity’s greatest challenges, and we will continue to invest in quantum computing,” he said.

Last March, Nature added an “editorial statement of concern” to the 2018 paper, and a Nature spokesperson recently said it was “working with the authors to address the issues.” A spokesman for TU Delft said an investigation by the university’s Research Integrity Committee had been underway since May 2020 and had not yet been completed. One person familiar with the process said the final report was likely to show that the Delft researchers made mistakes but were not deliberately misleading.

Either way, the issue is a bit of a setback for Microsoft’s quantum computing ambitions. Leading computing companies say Majorana Fermion technology will define the future with new scientific and engineering breakthroughs.

Qubits are the basic information units of quantum computers. Google, IBM and Intel have all demonstrated prototype quantum processors containing about 50 qubits, and companies such as Goldman Sachs and Merck are testing the technology. But useful quantum computing systems may require thousands or even millions of qubits. Much of a quantum computer’s power may have to be dedicated to correcting its own faults.

Microsoft is taking a very different approach, claiming that quantum bits based on Majorana particles are vastly more scalable, making a leap forward. More than a decade later, however, not a single such qubit has been built.

Microsoft’s History with Majorana Fermi

Majorana fermions are named after The Italian physicist Ettore Majorana, who hypothesized in 1937 that particles should exist as their own antiparticles. However, it was not until the 21st century that the Majorana particle was discovered by Kouwenhoven’s laboratory.

Ettore Majorana.

In 2004, Researchers at Microsoft approached Craig Mundie, the company’s director of technology strategy, to say they had a solution to one of the biggest obstacles to quantum computers: the instability of qubits. Since then, Microsoft has been interested in Majorana fermion production.

Using theoretical physics papers, researchers have come up with a way to build more reliable, stable qubits. These so-called topological qubits are built on unusual particles, including Mayorana particles, which can exist inside materials as clusters of electrons at extremely low temperatures.

Microsoft has since assembled a new team of physicists and mathematicians to flesh out the theory and practice of topological quantum computing. The team teamed up with top experimental physicists and funded them to find the particles needed to build the new qubits.

Kouwenhoven is one of the physicists who received the grant. In a 2012 paper published in Science, Signatures of Majorana Fermions in Hybrid Superconductor-Semiconductor Nanowire Devices proposes the “properties” of Majorana particles within nanowire. In 2016, Microsoft stepped up its investment and publicity efforts.

Paper links: science.sciencemag.org/content/336…

Kouwenhoven and Charles Marcus, a top physicist at the University of Copenhagen, were hired as “hunters” for majorana particles. They plan to first detect these particles and then invent more complex devices to control them and make them act like qubits. Todd Holmdahl, who previously led Microsoft’s Xbox gaming hardware, became head of the topological Quantum Computer project. In early 2018, he told Barron’s that Microsoft would implement topological qubits by the end of the year. A month later, the now controversial paper was published.

Microsoft and Google take very different paths to quantum computing

However, while Microsoft is keen to find Majorana particles, its rivals have been steadily building on existing qubit technology. In 2019, Google announced it had achieved quantum Supremacy, developing a 54-qubit computer called Sycamore that could perform in 200 seconds what the world’s fastest supercomputer would achieve in 10,000 years.

Soon after, Microsoft appeared to want to hedge its quantum computing bets by announcing that it would offer other companies access to quantum hardware through its cloud service Azure. Then, according to the Wall Street Journal, Todd Holmdahl left the topological Quantum Computer project after missing an internal deadline.

Google CEO Sundar Pichai and Google’s quantum computer in his Santa Barbara lab.

Since Holmdahl’s departure, Microsoft has been quiet about its expected progress with quantum hardware. Rival companies in quantum computing continue to tout advances in hardware and urge software developers to access lab prototypes over the Internet. Unfortunately, no company seems to be able to produce a working quantum computer in prime time.

The discovery of Majorana fermion is 30 years away?

The questions surrounding Kouwenhoven’s 2018 paper have left a small field of physicists working to detect Majorana particles very hurt, says Sergey Frolov. Good science, he argues, can produce reasonable expectations, not magical ones. In addition, he said, Kouwenhoven’s team should publish the full original experimental data for outside review.

Frolov studied Kouwenhoven’s additional data with Vincent Mourik, a senior research fellow at the University of New South Wales in Australia, who also expressed concerns. Both were Kouwenhoven’s colleagues and were involved in the 2012 paper on Majorana particles.

Sankar Das Sarma, a theoretical physicist at the University of Maryland who has worked with Microsoft researchers, thinks the technology will eventually succeed, but it will take some time.

According to Das Sarma, new theories developed over the past few years show that the method used in 2018 is not in any way certain of the presence of Majorana particles, and that purer materials, more complex experiments and more scientific advances are needed.

How close Microsoft’s qubits are to that goal is unclear. Quantum computing based on Majorana particles may be at a similar stage to the first transistor patent filed in 1926, says Das Sarma. It wasn’t until 1947 that researchers made the first working transistor; It was in the late 1950s that the microsilicon version that enabled the computer industry was developed.

“I don’t see why Majorana fermion can’t exist, or why it exists and can’t be controlled. But it could take 30 years to discover it or control it.” Das Sarma said.

Refer to the link: www.wired.com/story/micro…