Friday, February 23, 2024

Second update to: Evidence of near-ambient superconductivity in a N-doped lutetium hydride

I've been posting occasional updates as I've followed this and other superconductor stories with great interest. This one took an interesting turn with a series of retractions from Nature.


RETRACTED ARTICLE: Room-temperature superconductivity in a carbonaceous sulfur hydride

The editors of Nature have been alerted to concerns regarding the manner in which the data in this paper have been processed and interpreted. Nature is working with the authors to investigate these concerns and establish what (if any) impact they will have on the paper’s results and conclusions. In the meantime, readers are advised to use caution when using results reported therein. 

This is their second retracted paper.

Nature News:

Nature has retracted a controversial paper claiming the discovery of a superconductor — a material that carries electrical currents with zero resistance — capable of operating at room temperature and relatively low pressure.

“They have expressed the view as researchers who contributed to the work that the published paper does not accurately reflect the provenance of the investigated materials, the experimental measurements undertaken and the data-processing protocols applied,” [the retraction report] says, adding that these co-authors “have concluded that these issues undermine the integrity of the published paper”.

“It is at this point hardly surprising that the team of Dias and Salamat has a third high-profile paper being retracted,” says Paul Canfield, a physicist at Iowa State University in Ames and at Ames National Laboratory. Many physicists had seen the Nature retraction as inevitable after the other two, and especially since The Wall Street Journal and Science reported in September that 8 of the 11 authors of the paper — including Salamat — had requested it in a letter to the journal.

One lab says it has partially reproduced Dias and Salamat’s results using a sample provided by the Rochester team. But many others, which tried creating their own samples and running tests, could not. And in the meantime, other causes for concern have arisen. An investigation launched by Physical Review Letters before it retracted its paper by Dias and Salamat found “apparent data fabrication”.

Facing a mutiny by his co-authors, Ranga Dias, the University of Rochester (U of R) physicist embroiled in controversy over his superconductivity research and allegations of scientific misconduct, is set to have a third paper retracted.

If the paper is retracted, it will follow retractions of two other superconducting claims from Dias’s teams: one last month from Physical Review Letters (PRL), and one in September 2022 of a different Nature paper.

In a 14 September email to the co-authors, Nature Senior Editor Tobias Rödel says a postpublication review revealed issues that are “mostly unaddressed.” Rödel added, “We are in absolute agreement with your request that the paper be retracted.”

Questions about the March paper’s results appeared online immediately after its publication. On 2 May, two researchers submitted an anonymous critique of the paper to Nature. These researchers disclosed their identities to Science: They are James Hamlin, a high-pressure experimentalist at the University of Florida, and Brad Ramshaw, an expert in superconductivity at Cornell University.

In their letter to Nature the co-authors allege they had raised concerns about the study prior to publication, but that Dias dismissed them. 

After seeing the postpublication review, the co-authors used their access to the raw data to corroborate Hamlin and Ramshaw’s concerns about the zero-resistance measurement. 

New York Times:

A prominent physics journal on Tuesday retracted a materials science paper that has garnered scrutiny.

The retracted paper did not involve superconductivity, but it added to accusations against Dr. Dias of research misconduct, including the fabrication and falsification of data. 

Nine of the 10 authors of the paper, which was published in Physical Review Letters, agreed to the retraction. Dr. Dias was the lone holdout, and he has maintained that the paper accurately portrays the research findings. However, he said on Tuesday that his collaborators, working in the laboratory of Ashkan Salamat, a professor of physics at the University of Nevada, Las Vegas, introduced errors when producing charts of the data using Adobe Illustrator, software not typically used to make scientific charts.

This took me pretty massively by surprise. I can only speak from my own personal experience, but nobody--I mean nobody--makes charts by hand anymore. We've had programmatic tools to ensure precision for literally decades. Most plots these days are done using scripts that access plotting libraries; for example, I make my plots in Python using matplotlib. I just can't understand what part of the process one would use Adobe Illustrator of all things for--I wish Dr. Dias had elaborated on this more. The problems identified were found in the background subtraction procedure and potentially claims of duplicated data; without commenting on the truth of these allegations, how could one "accidentally" do these things or something similar in Adobe Illustrator of all things? And why would this affect the raw data files that were shared with the investigators and coauthors, which ultimately were found to be flawed as well? 

Nature News:

As part of the investigation, co-author Ashkan Salamat, a physicist at the University of Nevada, Las Vegas, and a long-time collaborator of Dias, supplied what he claimed was raw data used to create figures in the PRL paper. But all four investigators found that the data Salamat provided did not match the figures in the paper.

Ignoring everything else, the raw data didn't match the figures. But Dr. Dias necessarily needs the figures to be correct if his superconductor is legitimate--the figures showed the proof. 

Science News:

A stunning claim of a room-temperature superconductor that grabbed headlines has fizzled. The paper was retracted November 7 from the journal Nature, making for a trio of high-profile retractions for physicist Ranga Dias of the University of Rochester.

The retraction is no surprise to the scientific community, many of whom had expressed hefty skepticism about Dias’ work, following the earlier retractions and many other researchers’ failures to reproduce Dias’ results. 

Compared to the previous retractions, “this is much more worrying,” Boeri says. “This is not just somebody who is doing some honest mistakes.”

Ranga Dias (via Twitter):

Meissner effect on N- doped Lutetium Hydride! 

[mic drop gif]

The Meissner effect is considered the definitive proof of superconductivity!

I look forward to the submission of that result. At the end of the day, everyone only benefits if Dr. Dias is correct and room-temperature superconductivity is achieved. 

Previously on this blog:

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