{"id":86726,"date":"2025-08-21T17:29:06","date_gmt":"2025-08-21T17:29:06","guid":{"rendered":"https:\/\/www.newsbeep.com\/ca\/86726\/"},"modified":"2025-08-21T17:29:06","modified_gmt":"2025-08-21T17:29:06","slug":"controversial-quantum-computing-paper-gets-a-hefty-correction","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ca\/86726\/","title":{"rendered":"Controversial Quantum-Computing Paper Gets a Hefty Correction"},"content":{"rendered":"

A key study claiming to provide evidence of Majorana quasiparticles has received an extensive correction five years after it was published in the journal Science. Two researchers who flagged the paper as problematic say that the correction isn\u2019t sufficient \u2014 triggering the latest dispute in a field dogged by controversy<\/a>.<\/p>\n

For decades, physicists have been compelled by the idea that ultracold electrons in microscopic devices could behave collectively to form quasiparticles resistant to noise \u2014 both environmental perturbations and the inherent atomic jostling that plagues all quantum systems. The resilience of these Majoranas could make them ideal candidates for forming qubits, the informational units in quantum computers that are analogous to bits in classical machines. Studies to prove their existence have come up short, although recent bold claims by technology giant Microsoft have drawn considerable scrutiny<\/a>.<\/p>\n

In September 2018, a team led by Charlie Marcus, a physicist at the University of Copenhagen, who also worked for Microsoft at the time, posted a manuscript to the preprint server arXiv<\/a> that described a fresh approach to generate Majoranas. The researchers made nanowires of indium arsenide surrounded by a shell of aluminium. Applying a small magnetic field, they then measured electrical signals \u201cconsistent\u201d with pairs of Majoranas, one at either end of each wire. A year and a half later, they included theoretical simulations to justify their results, and the study was published in Science.<\/p>\n

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Two physicists \u2014 Sergey Frolov, at the University of Pittsburgh in Pennsylvania, and Vincent Mourik, now at the Research Centre J\u00fclich in Germany \u2014 raised questions about the validity of the data, and in July 2021, Science applied an editorial expression of concern<\/a> to the paper to warn readers of potential problems. Now, Science is lifting that warning, and the authors are issuing a 20-page correction to the paper\u2019s supplementary material. News of the correction was first reported on 31 July by the technology news site The Register<\/a>.<\/p>\n

The authors say they are relieved by the outcome. \u201cIt\u2019s not really correcting any errors,\u201d says co-author Saulius Vaitiek&edot;nas, a physicist at the University of Copenhagen. \u201cWe are summarizing and providing additional information.\u201d Frolov, on the other hand, argues that the data in the paper do not give a full picture of electron behaviour in the team\u2019s devices and calls for retraction. \u201cI do not trust this data,\u201d he says.<\/p>\n

Jake Yeston, an editor at Science who oversees physical-sciences submissions, says that the journal decided not to retract the paper because there was not a \u201cclear, community-grounded view that it\u2019s obviously wrong\u201d. But, Yeston says, the lack of information in the original paper was a problem, and it has now been fixed. \u201cIt shouldn\u2019t be that a reader who wants to know what your protocol was has to go to your lab and talk to you,\u201d he says. \u201cThat should be in the paper.\u201d<\/p>\n

Questioning the data<\/p>\n

Thirteen years ago, Frolov and Mourik were authors on a different study in Science that reported evidence for Majoranas. But excitement around the result faded after researchers discovered that other mundane phenomena could mimic the quasiparticles.<\/p>\n

When the Copenhagen team\u2019s manuscript was posted to arXiv in 2018, Frolov and Mourik were dubious so they requested to see all of the data. E-mails reviewed by Nature show that the Copenhagen group released more data in November 2020. The pair of critics analysed the information provided and concluded that the data were incomplete and contradicted the study\u2019s central claims. An internal inquiry by the university\u2019s physics institute, however, found \u201cno problems with the paper\u201d, and that the Copenhagen team had turned over all of its data. Unsatisfied, editors at Science applied an expression of concern to the paper, and in October 2021, Yeston filed a complaint with the university to request an \u201cindependent, transparent investigation by experts.\u201d<\/p>\n

In June 2022, the university assembled a panel of independent physicists to undertake the effort: Sophie Gu\u00e9ron, at the University of Paris-Saclay; Allan MacDonald, at the University of Texas at Austin; and Pertti Hakonen, at Aalto University in Finland. They travelled to Copenhagen, conducted interviews and examined data from 60 microscopic devices (the original paper included data from 4). Their year-long investigation found no misconduct, but stated that the team\u2019s selection of data led to \u201cconclusions that did not adequately capture the variability of outcomes\u201d. The excluded data, however, did not undermine the paper\u2019s main conclusions, they said.<\/p>\n

One sticking point for Frolov and Mourik continues to be the Copenhagen team\u2019s choice of \u2018tunnelling regime\u2019 \u2014 the range of low electrical conductivities over which the devices were scanned. The Copenhagen researchers said they saw signs of Majoranas persisting \u201cthroughout\u201d their chosen tunnelling regime. But Frolov and Mourik said that the extra data they received showed that the tunnelling regime was much wider, and that the telltale Majorana signs were limited to the smaller tunnelling window.<\/p>\n

Marcus responds that his team first chose a narrow tunnelling regime to avoid noise, then looked for signs of Majoranas. The investigation panel agreed that the criteria for a tunnelling regime made \u201cphysical sense\u201d, but said that including all the voltages would have \u201cgiven a clearer, more faithful, picture of the complex behavior\u201d. The correction includes a lengthy description of the tunnelling regime. \u201cThey just have to be transparent,\u201d Gu\u00e9ron says.<\/p>\n

MacDonald agrees, and hopes that the correction will lead to better standards for data availability.<\/p>\n

Still searching<\/p>\n

No group has replicated the Copenhagen team\u2019s results, although researchers at the Institute of Science and Technology Austria (ISTA) in Klosterneuburg have studied similar nanowires. In papers published in Science and Nature, they described finding quasiparticles with electrical signals resembling those of Majoranas; however, in the end, the particles were found to be mundane and lacking the desired resilience to noise. (Nature\u2019s news team is independent of its journal team.)<\/p>\n

Marcus contends that the ISTA study was not an identical replication of the Copenhagen study, because, for example, it relied on a different chemical to prepare the nanowires. He says that his team would be happy to provide wires for another group to attempt a replication, but so far there have been no takers.<\/p>\n

Much of the uncertainty around the Copenhagen group\u2019s work stems from the messy underlying physical world: disorder from even the smallest imperfection can destroy delicate quantum states and make data selection challenging. \u201cAt present this is a fact of life for all experimental searches for Majorana particles,\u201d the independent panel wrote in its report. \u201cIt is important that authors guard themselves against confirmation bias.\u201d<\/p>\n

Many researchers \u2014 with the exception of some at Microsoft \u2014 have responded to this by moving on from searches for bona-fide Majoranas to looking for phenomena that are less exotic and more stable. Marcus thinks his approach is better than the alternatives, but even he acknowledges the situation: \u201cIt would be perfectly realistic to conclude based on all of the work that people have done that even though this is beautiful physics and completely correct, as far as I\u2019m concerned, it doesn\u2019t really reflect a path forward in designing quantum computers, because it\u2019s just too fragile.\u201d<\/p>\n

This article is reproduced with permission and was first published<\/a> on August 14, 2025.<\/p>\n","protected":false},"excerpt":{"rendered":"A key study claiming to provide evidence of Majorana quasiparticles has received an extensive correction five years after…\n","protected":false},"author":2,"featured_media":86727,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[21],"tags":[49,48,285,61],"class_list":{"0":"post-86726","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-computing","8":"tag-ca","9":"tag-canada","10":"tag-computing","11":"tag-technology"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/86726","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=86726"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/86726\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/86727"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=86726"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=86726"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=86726"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}