Two physicists in the field say extra data Kouwenhoven’s group provided them after they questioned the 2018 results shows the team had originally excluded data points that undermined its news-making claims. “I don’t know for sure what was in their heads,” says Sergey Frolov, a professor at the University of Pittsburgh, “but they skipped some data that contradicts directly what was in the paper. From the fuller data, there’s no doubt that there’s no Majorana.”The 2018 paper claimed to show firmer evidence for Majorana particles than a 2012 study with more ambiguous results that nevertheless won fame for Kouwenhoven and his lab at Delft Technical University. That project was partly funded by Microsoft, and the company hired Kouwenhoven to work on Majoranas in 2016.
Earlier this year, Google artificial intelligence researcher Timnit Gebru sent a Twitter message to University of Washington professor Emily Bender.“This article is a very solid and well-researched piece of work,” says Julien Cornebise, an honorary associate professor at University College London who has seen a draft of the paper.
The 2018 paper reported seeing telltale signatures of the Majorana particles, termed “zero-bias peaks,” in electric current passing through a tiny, supercold wire of semiconductor. One chart in the paper showed dots tracing a plateau at exactly the electrical conductance value that theory predicted.Frolov says he saw multiple problems in the unpublished data, including data points that strayed from the line but were omitted from the published paper. If included, those data points suggested Majorana particles could not be present. Observations flagged by Frolov are visible in the charts in the new paper released last month, but the text does not explain why they were previously excluded. It acknowledges that trying to experimentally validate specific theoretical predictions “has the potential to lead to confirmation bias and effectively yield false-positive evidence.”
In 2017, after the company said it was closing in on the milestone, IBM researchers published results that appeared to move the goalposts.Soon, researchers from Chinese ecommerce company Alibaba, which has its own quantum computing program, released analysis claiming that the device could not do what Google said.
Tweets by Sergey Frolov, a physicist who questioned missing data in the 2018 paper.Microsoft provided a statement attributed to Kouwenhoven saying he could not comment, because the new paper that reinterprets his group’s results is undergoing peer review. “We are confident that scaled quantum computing will help solve some of humanity’s greatest challenges, and we remain committed to our investments in quantum computing,” he said. Nature added an “editorial expression of concern” to the 2018 paper in April last year, and a spokesperson said this week that the journal is “working with the authors to resolve the matter.” A spokesperson for Delft Technical University said an investigation by its research integrity committee, started in May 2020, is not complete. A person familiar with the process says the final report will likely find that researchers at Delft made mistakes but did not intend to mislead.