Mingmin Xiao Xiao from Aofeisi
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The blockbuster paper "First Room Temperature Superconductor" on the cover of Nature was suddenly removed! What is the situation with
? ? ?
You should know that this paper caused a huge sensation in the academic circle at that time. Many well-known scholars such as Cambridge University , Max and the Institute of Max and PLA said that this has a "mileage" meaning.
was rated as one of the top ten scientific breakthroughs in 2020 by Science.
research has discovered the first room temperature superconductor in human history. It can conduct electricity without any resistance at 15℃ at "high temperature":
room temperature superconductor not only accelerates the progress of superconducting magnet-related research such as particle collider , nuclear fusion , etc., but may also truly reduce the power transmission loss in our daily lives.
However, after the paper was released, the doubts became louder and louder: at first, it was just someone who explored the rationality of the experimental data, but later, the authenticity of the experiment began to be suspected. A Wanyin scholar tried to reproduce the experiment 6 times, all of which ended in failure.
BUT, what is even more surprising is the attitude of the nine authors -
They unanimously oppose external doubts and believe that their papers are the result of "experimental and theoretical verification".
Until the paper was withdrawn by Nature, they completely disagree with the reason that "the paper is suspected of manipulating data."
So, what is the core controversial point of this study?
The key data that proves superconducting phenomenon "has doubts"
Let's first look at the reason for withdrawal given by Nature:
In some key data processing steps, (this paper) uses a non-standardized, user-defined program.
Specifically, this program refers to the background subtraction (background subtractions, method for processing noisy background signals) used in the paper to process raw data to generate susceptibility diagrams. The processed data are presented in Figure 2a and Figure 7d of Supplementary Materials.
, but the paper does not explain this background subtraction, so the data validity is also questioned, and we believe that this will weaken the outside world's confidence in the magnetic susceptibility data.
Among them, magnetic susceptibility is one of the important basis for judging whether a material enters a superconducting state.
(Two basiss for the material to enter the superconducting state: magnetic susceptibility under certain conditions, and has complete resistant magnetic properties; resistance suddenly disappears, and has absolute 0 resistance)
Simply put, Nature believes that the authors of the paper used an unusual method when processing the very critical magnetic susceptibility data, but did not explain why this method was used. The two pictures of
questioned are as follows:
△ Figure 2a and 7d
at first glance seem to be fine: Figure 2a shows that under different pressures, when this material reaches different specific temperatures, the magnetic susceptibility will change suddenly, which means it has entered a superconducting state; Figure 7d is the change in the magnetic susceptibility under other pressures.
But if you simply process some data, you will find some strange things.
For example, find the difference for a set of experimental data points (the previous data is subtracted from the next data, which is equivalent to derivation) . Under normal circumstances, data that has been processed differentially usually presents an irregular shape because the noise is irregular.
However, after calculating the difference in the experimental data of this paper, the shape obtained is (almost all present as an integer multiple of 0.16555) :
△ points are very regular
After removing the difference, the data shape has changed drastically compared to the original one:
△ Compared with figures a and b, it looks completely different
Although the authors said that this was their operation to remove background noise, Nature believes that "this method is not convincing."
In addition to Nature, Mikhail Eremets, an experimental physicist at the MaxPhotos Institute of Technology who developed the first superconducting hydride , also tried to reproduce the experiment.
However, he reproduced 6 times, all of which ended in failure (also related to the author's unwillingness to disclose the details of the material, and the specific proportion of the reproduced material may differ from the paper) . The controversial paper, which was reported to be the first room temperature superconductor in humans, was reportedly discovered in just two months after the submission of
.
This is a material composed of hydrogen-sulfur-carbon . It produces a superconducting phenomenon of about 15℃ under the extremely pressure generated by pointed-to-point diamonds.
Specifically, the paper mixes the two hydride together, and then lets the whole mixture recombine under ultra-high pressure.
They chose hydrogen sulfide (a rotten egg odor gas) and methane ( natural gas main component) , and placed these two substances together with the platinum electrode in the diamond anvil.
Diamond anvil is two "point-to-point" diamond . It can generate huge pressure between the two, which can reach millions of atmospheric pressures. When the pressure exceeds 40,000 atmospheric pressures, the researchers irradiated with green laser for several hours to destroy the sulfur-sulfur bonds, thereby forming sulfur-hydrogen compounds.
study found that when the pressure reaches 2.67 million atmospheric pressure, you only need to lower the sample to 15°C and you can see the resistance disappear. This is another important evidence for the material to enter the superconducting state (there is also the magnetic susceptibility) . After the paper
was published, it caused a huge sensation in the academic community at that time.
You should know that low-temperature conditions have always been a huge obstacle to restricting superconductor applications.
It was not until 1987 that Chinese-American physicist Zhu Jingwu discovered the "high temperature superconductor" yttrium barium copper oxygen in the temperature zone of liquid nitrogen (77K, about -196℃) . Superconductors began to be widely used in magnetic levitation, superconductors, nuclear magnetic resonance imaging , mobile phone signal base stations and other fields.
△Full resistant magnetic properties can be used for magnetic levitation
, but without additional cooling room temperature superconductor has always been the ultimate pursuit of scientists. (note that in superconducting, the room temperature is higher than the "high temperature" temperature)
So although this new material requires extremely high voltage conditions to realize superconducting state (about 75% of the core of the earth) . The actual application value is limited, it is still a "mileage event" in the superconducting world. Once the
paper was submitted, it was accepted by Nature and was directly published on the cover only 2 months later.
research results were also selected as one of the top ten breakthrough events in "Physical World" in 2020 and the top ten breakthrough events in Science in 2020.
△Photo source Science Top Ten Breakthroughs in 2020
As of the time of revocation, its number of citations has been 365 times .
With this research, the authors of the paper (from University of Rochester , Intel and University of Nevada Las Vegas ) also won many major awards, and are represented by two corresponding authors .
, one of the corresponding authors, , Ranga Dias, , , (Ranga P.Dias) , is an assistant professor in the Department of Physics, University of Rochester. With his room temperature superconductor, he was selected by Time magazine as one of the 100 most influential innovators in the world and won the CAREER award from the National Science Foundation .
Corresponding author 2 Ashkan Salamat (Ashkan Salamat) , Assistant Professor at the University of Nedahua, Las Vegas. Judging from his homepage, most of the academic news reports in the past two years have been focused on this room temperature superconducting paper.
△Dias (left) and Salamat (right)
It is worth mentioning that Dias and Salamat have established a company for this purpose to develop commercial room temperature superconductors based on existing research results.
However, less than two months after it was published, the paper was caught in a storm of fraud. As time goes by, it not only did not resolve, but instead attracted more doubts from academics.
has been controversial for two years since its publication
If you look at the homepage of this paper, you will find that it has been updated once two months after its publication.
However, as more details are disclosed, the controversy over the paper is getting louder and louder. On August 25, 2021, the core dispute point appeared: the issue about the susceptibility data.
Under such a sound, Nature's paper homepage has successively appeared "three consecutive warnings" and officially withdrew the paper on September 26 this year.
What exactly happened in the middle?
first stood up to question it, Jorge Hessey (Jorge Hirsch) (Jorge Hirsch) (Jorge Hirsch)
The important indicator for the academic circle to measure the influence of scholars h index , which was proposed by him. After the
paper was published, Hesey immediately applied to the team to view the original data, but was repeatedly rejected.
corresponding author Dias said that the research results were applying for patents at the time and the lawyers required the data to be kept confidential for the time being.
This did not stop Hesey from questioning.
In 2021, Hessey questioned the complete antimagnetic and magnetic susceptibility of this superconductor, and wrote his own views, the process of verifying data, and the obstacles encountered in the middle. He wrote the paper and published it on arXiv and Physica C, which quickly caused an uproar.
At this time, the Dias team, who had not responded positively to the question, finally published the paper original data and background signal processing method in November 2021 on arXiv (these contents have not been explained in the paper and supplementary materials before) .
BUT, the research team has suffered more doubts.
on the one hand is a research attitude. Brad Ramshaw, a physicist at Cornell University, said that this means that the process from the original data to the public data is very opaque .
, on the other hand, is the public data itself. Hessey published several more articles on arXiv, claiming that Dias's team used polynomial curve to fit data "a fabrication."
Because his speech was too intense, the question pointed out that the room temperature superconductor may be a scientific scam , so that arXiv and Physica C successively deleted related articles. He was also banned by arXiv and was temporarily unable to publish articles since February this year.
He also complained to the University of Rochester for academic misconduct in Dias' team, but the school said no evidence was found in both investigations.
is at this critical moment, and things have ushered in a critical turning point. condensed matter physicist Dirk van der Marel also took action.
He and Hesey published a new article, again emphasizing that some of the data in the room temperature superconductor paper was artificially processed. Shortly after the article was published, news of Nature's withdrawal process came. Van der Marel said that this encouraged him:
is very happy, not just that we think it has problems.
(of course, Hesey thinks that just withdrawing the article is not enough, because this does not reflect the fact that Dias's team is academic misconduct)
is contrary to the two "anti-counter-killers", but the research team does not think that its achievements are problematic at all. Dias, one of the corresponding authors of
, said they plan to resubmit to Nature without deleting any background information.
corresponding author Saramat pointed out that the key factor in withdrawing the paper lies in the problem of the magnetic susceptibility data, but the zero resistance data is , and it is the main evidence to judge the superconducting achievements in the high voltage field. He also added that neither Hessey nor Van der Marel are high pressure physicists:
I think some of their behavior has risen to personal attacks, and we won't let others throw dirty water on ourselves.
Salamat also said that everyone is welcome to come to their laboratory to observe the research methods of room temperature superconductors. In July, they just released a replica.
(but the independence of this result has also been questioned because the authors of the new result are highly coincident with the previous Nature paper author team...)
One More Thing
room temperature superconductor Dias is also the first author of the first metal hydrogen result in .
Previous research believed that metal hydrogen is likely to be one of the room temperature superconducting materials, but this material must be synthesized under extremely high pressures.
In 2017, Science reported results from the Harvard Isaac Schillera team, Dias was one of the team members.
laboratory cooled the hydrogen sample to a temperature slightly higher than absolute zero. Under extremely high pressure conditions, the hydrogen was compressed with diamond and successfully obtained a small piece of metal hydrogen. This metal hydrogen sample was stored between two tiny diamonds.
However, after the paper was published, the laboratory said that due to operational errors, the metal hydrogen sample had been damaged or disappeared.
Therefore, many scholars doubt whether this metal hydrogen has really existed.
Reference link:
[1]https://www.science.org/content/article/something-seriously-wrong-room-temperature-superconductivity-study-retracted
[2]https://news.ycombinator.com/item?id=32993556
[3]https://www.nature.com/articles/s41586-0 20-2801-z
[4]https://mp.weixin.qq.com/s/TJQ1WCM2vsKeAx2k20FA7g
[5]https://arxiv.org/pdf/2201.07686.pdf
[6]https://www.science.org/content/article/breakthrough-or-bust-claim-room-temperature-superconductivity-draws-fire
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