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LK-99: Phonon bands, Localized Flat Band Magnetism, Models and Chemical Analysis (drive.google.com)
164 points by carabiner on Aug 8, 2023 | hide | past | favorite | 152 comments



As I feared, it is no use at all at this stage to claim anything about LK-99 as every synthesized LK-99 seems different each time. We have to have a thorough analysis on the sample directly provided by Lee and Kim.


> We have to have a thorough analysis on the sample directly provided by Lee and Kim.

Even this sample could be marginal, going by the original paper.

But there has been plenty of "locked" levitation and lots of zero conductance failures. I believe LK-99 a finicky topological superconductor thats going to give researchers headaches for years, not something that will suddenly be a bulk superconductor with just the right synthesis in the coming months.


It seems people are throwing around more and more random physics keywords without any type of evidence. What makes LK-99 a topological superconductor? Topological quantum states and the associated Majorana fermions have only been observed in their bound state so far (and only in highly engineered quantum systems), and there's absolutely no indication that they should exist in that material, at least I don't see how you could postulate that by observing levitation or measuring an IV curve in a bulk sample.


[flagged]


I thought there were rules against using ChatGPT in comments here.

(For the uninitiated, this is a bunch of gibberish with a few science-y keywords for truthiness).


It was clearly a joke, not intended to fool anyone. People have been writing technobabble for at least a century before ChatGPT. https://en.m.wikipedia.org/wiki/Turbo_encabulator


I transgressed and take full responsibility. Couldn’t resist.


Speaking as a layperson and casual observer, I understood some of the words in this thread.


I think you may have been duped by an LLM. I’m glad someone is finding a real use case for it, I just wish it were somewhere else.


I don't think an LLM is capable of this kind of sarcasm (yet).


Levitation with a corner touching the magnet can be accomplished by iron. It's what iron filings do when you put them on a magnet!


There have been multiple videos of tiny LK99 specs completely levitating on single magnets, and resisting motion when pushed, and staying afloat when the magnet is inverted.

That is not possible in any known material. Unless thats an array of very elaborate fakes, its a RT superconductor.

But the simulation papers and conductance tests make me suspect its a topological superconductor that would fail such tests.


> There have been multiple videos of tiny LK99 specs completely levitating on single magnets, and resisting motion when pushed, and staying afloat when the magnet is inverted.

One of those has already been admitted to being outright faked:

https://www.tomshardware.com/news/lk-99-video-fraud-taken-do...


Some additional context here. The author has a further statement, in which he apologizes that the previous video was misleading due to two points: 1. The sample was not LK99. 2. Both the larger piece held by the tweezers and the smaller levitating one were from the same sample. But he also states that no tricks of any kind were used nor the video was edited.

So, some other material levitating itself in seemingly room temperature?

Currently this guy is practically using his real name, with his university and professor exposed. It takes some courage to lie at this point.

link(in Chinese): https://bilibili.com/video/BV1Zh4y1r7XL

======================

Edit: People sometimes speak in convoluted ways. I feel "The sample was not LK99" could have two interpretations here: 1. It is a completely different compound. 2. It is a derivative from LK99 with a different synthesis/doping method.


>Currently this guy is practically using his real name, with his university and professor exposed. It takes some courage to lie at this point.

No, it doesn't. It is a nine second video. Not a research paper. Right now the topic is being hyped up and you might care but next year nobody is going to give a damn about some random video uploaded to bilibili.

Why does everyone on HN pretend that even the smallest of missteps is going to end a reserachers career and therefore even videos with almost no effort put into them, that to feed the rumor mills, are somehow the paragon of truth?


There's a third interpretation: he took an x-ray of both bits of the sample and found that the XRD pattern of the levitating flake didn't match LK99's


I havent seen this video.

I am on mobile now, I will have to go back through my history and check the claims... But one such reproduction is from the Meissner or Bust channel. They have been documenting the production for days, and IIRC they showed full levitation on a single magnet.


I believe you are remembering [1] and it is not a full levitation.

1. https://twitter.com/andrewmccalip/status/1687405505604734978


That video was so obviously not LK-99 I doubt anyone sane was fooled by it (anybody who has played with magnets knows that’s how ferrous metal hangs off of them).

We’ve seen proper levitation of specks that hasn’t been falsified yet.

That said, I believe theory has shown it’s actually possible for a diamagnetic object to fully levitate over a magnet as long as it’s light enough, but unlike a flux-pinned superconductor, it will only levitate over the center of the magnet, as is happening in all the levitation videos.


I have yet to see a video that I would say is 100% unambiguous and from a credible source. Lots of 'maybe's' and a couple where my fraud meter pegged and seems to have broken something inside.


All it would take for me to begin playing much closer attention are a few credible labs saying, “we spent some time on this and we can reproduce it a little bit, sometimes. There’s something up but we’re not ready to throw the weight of our reputation behind it just yet.”

You’d think that with the current excitement and relative simplicity of the apparatus, labs all over would be putting in some weekend hours to muck about.

Consistency might be a problem for fabrication and commercialization.


> labs all over would be putting in some weekend hours to muck about.

That's unfortunately not how science is incentivized.

The lab reproducing this would get exactly zero academic credit. Maybe a day of press fame, but that's it.

On the other hand, once/if this is proven to be real, there would be thousands of labs racing to improve it and cite each other's work.


Are any of those from legit research institutions? I know there have been a bunch of fake hover videos in the past 48 hours.


I haven't seen any such video with a high credibility stance after it, like the author using the real name.


I thought there was just one video of it completely levitating, and that that one was somewhat questionable (having an unclear source, and being deleted by original poster)?

Do you have a link to more than one showing complete levitation?


I recall one showing full levitation (BilliBilli anon poster). If there is a different video, the poster above should link it.


The iris videos were full levitation


Iris photo is completely unconfirmed outside of "Twitter likes her." She said she would make a video over a week ago and never did. Additionally, due to the fleck being confined to a tube, it would not fall afoul of any proofs about ordinary ferromagnetic levitation being impossible.


True. However no internet hottake will be a proof of anything. The fun is over and now it’s time for science to work it’s laborious work. Nothing has been proven, nothing confirmed. But it was fun!


We distinguish between videos and photos in this context.


thank you for providing nuance


Calling it "LK-99" seems to have been a mistake. It gives the impression that the term refers to a well-defined material, perhaps even a mass-produced product like "iPhone 14" or "RTX 4080". This explains all the calls for the original authors to send samples, as if you were ordering from AliExpress.

In reality, what we have is a family of lead-copper-phosphorus-oxygen compounds, each with a different crystal structure, some of which might or might not exhibit interesting properties.

If this hype doesn't fizzle out soon, scientists will probably converge on more neutral, precise terminology to refer to the various configurations in order to avoid talking past one another. Something like β-LK99-Cu-5-7.


Scientists already have well-defined terminology for many of the crystal structures described, the LK-99 is just a shorthand for this synthesis product (and a convenient one at that, for anyone trying to keep up with the latest). I wouldn’t be too concerned!

Part of the reason we’re not using a full formula yet is that we don’t precisely know what it is (or, indeed, if it’s just one thing at all; the linked paper makes a good argument that this will necessarily be a mix of multiple phases if synthesized as-described). Once we know what it is, we can use one of several existing names.


There should be a middle ground somewhere between an unwieldy chemical formula and a catchy product-like name.

For example 3,4-MDMA is a useful shorthand for people who want to be precise as to which isomer they're talking about, but don't want to spell out 3,4-methylene-dioxy-methamphetamine every time.


This is my intuition as well.

Hopefully the controversy doesn't cloud researcher's judgement and cause us to miss out on the technology just because it was way more nuanced than first appeared.

It might also be that everyone loses interest and the original team get the extra time they needed to work in peace and make a comeback.


Unfortunately such bold claims can strongly effect researchers ability to work on this in the future.

The original cold fusion release has had an overhang on any studies of low energy nuclear reactions. Regardless of whether they have any bearing on energy production.

As an example of this, it is obvious and known that metallic lattices can lower the energy barrier of a nuclear reaction. However the underlying physics of how much screening and when is illusive - and their is a high correlation of quackery with any attempts at studying these systems.

https://www1.grc.nasa.gov/space/science/lattice-confinement-...


People always underestimate how much time physical science takes and how small normal steps are.

my favorite xkcd: https://xkcd.com/683/


> Even this sample could be marginal, going by the original paper.

If the sample they claim is superconducting isn't superconducting; why should we assume that this material is a superconductor at all? Because of some vague idea that their prof thought it might be more than 2 decades ago?


That's exactly where I'm coming from here. The original evidence that had people cautiously optimistic has been thoroughly dismantled. It's not showing any unusual or inexplicable signs of superconductivity: no anomalously high diamagnetism, no anomalously low resistivity or IV curves, no heat capacity differences, it lacks a theoretical model, and all anomalous measurements can be completely explained in terms of known or predicted properties of its constituent materials. I don't even need to bring up the lack of credibility of most of the members of the lab, HT Kim's crackpot tendencies, or the fact that Qcentre misrepresented its affiliations for it to be clear that there's nothing to the original paper.

Yet people are arguing "it might still be a superconductor! Just an exotic type that no one can replicate and also doesn't look like a superconductor in any measurements!" Okay, so could any number of other compounds, many of which are far more promising than this one (e.g. some USOs have shown actual definite diamagnetism). Why should we care about this one?


The quality and depth of the analysis here far exceeds the work done by the original Korean team. It is very unlikely the Korean team has successfully manufactured the Cu-doped phase given the thermodynamic mountain required to climb, and its clear anybody attempting to replicate their recipe was essentially producing a random assortment of garbage.

The Korean team needs to disclose any alternative formulations or just accept failure and move on.


Original authors have been working on it for 23 years since they first found the material in 1999. They are part of private institution and have no incentive to rush the disclosure so that other labs can catch on their life's work. Authors already have stated they will publish more information next year. It's pretty arrogant to draw premature conclusions on quick analysis and demand the authors to disclose more information right now, when they are clearly not obligated to anything.


I’ve seen inside of privately funded research that doesn’t have publication requirements and sometimes it is driven by a combination of belief, passion and incompetence which leads to an avoidance of accepting failure. Not saying this is the case with this but please do not elevate private research above public research. There is actually less controls over the quality of private research.


I did not say I consider private research in some sort of higher level than public research. I only said they have no incentive to do full disclosure right now. Without knowing exactly what they know, it is insulting to authors to describe, or even hint, them as avoiding to accept failture. It is simply unwarranted ad-hominem and not contributing anything to academic discussion at this point.


> It is simply unwarranted ad-hominem

When the authors/executives of a private research company are making fraudulent affiliation claims to established corporations and research universities it's actually very warranted to be dismissive of their claims in the absence of supportive evidence. Especially when there is growing evidence suggestive of failure.

This is not the behavior of ethical scientists and suggests malice.

Faking affiliation and refusing to provide supportive evidence both smell like a fundraising scam (i.e. running out of money and need to raise more to continue research seems like the simplest explanation for this behavior).

https://web.archive.org/web/20230806081911/https://koreajoon...


Since when is ad hominem a part of evaluating claims?


Without getting into a philosophical discussion of whether ad hominem is ever appropriate.

This is, in fact, the opposite of ad hominem.

Ad hominem would suggest we are attacking the claim based solely on the author's credibility. In fact, multiple independent replication experiments failed and theoretical models suggest it doesn't work.

So instead of attacking the authors the question is should we be trusting them at their word, and the answer which is reasonably based on credibility seems to be no.


Whether or not authors are credible, instead of the claims, is not a scientific discussion.


The science behind the claims is being scientifically discussed and the preponderance of available evidence provide no experimental or theoretical support.

We're separately discussing the author's credibility as the claims cannot be verified by anyone but the authors. One example of a time we do this is the "disclosures" section of any academic publication.

Are you arguing someone with a conflict of interest and history of making fraudulent arguments should not be placed under heightened scrutiny?

Combining both available evidence and author credibility is completely valid and leads one to the conclusion that this is incorrect until proven otherwise. It's not like we're solely dismissing the claim because the authors have poor credibility.


Preponderance of available evidence is irrelevant to assessing scientific claims of fact.

The original claims only need to be rigorously verified once. As it currently stands the original claims are claimed to have been partially replicated. What's needed now is the rigor.


> Preponderance of available evidence is irrelevant to assessing scientific claims of fact.

The issue is that trying to prove a negative is very hard in this case.

It is similar to me saying that there is a type of cat that floats, although most don't. It is very hard to prove me wrong because even if you find 1M cats that do not float, it doesn't mean that there is a type of cat you missed to find.

All we can say is that we tried to find cats in a thorough way and none of them float.

When that happens, it is often standard to turn the argument over to the one that is claiming that cats float -- prove that you have a cat that floats, rather than relying on me to prove that no cats float.

This is why people are saying we need to do an analysis of the SC sample from LK. If it is super hard to produce, but we can confirm that they made one, then it is true. Otherwise, it is probably best to assume that the claim isn't true.


Nobody is trying to prove a negative here. The initial claim is of a RT superconductor. The claim only needs to be rigorously verified once.

If it can't be verified, it remains an unverified claim, not necessarily a falsehood.


No one in this thread is saying the Korean researchers have a superconductor in their possession has been proven false.

We have an unverified claim of a significant discovery released in a pre-print that was taken on good-faith and replication experiments were attempted.

This has resulted in what can be described as a very thorough and publicized review process by multiple researchers qualified to serve as reviewers. As this was all done in good faith it is effectively analogous to the scientific standard of blinded peer review as no one was considering the author's credibility.

The conclusion of multiple reviews has been the equivalent of "recommend rejection, invitation to resubmit with major revisions". Major revisions being verification of superconductivity in the sample they possess and further details regarding synthesis and yield as what has been described is clearly not working as claimed.

The relevance of author credibility is for a confidence estimation that a superconductor has been discovered at this time. Obviously, if this was Argonne or [peer] one would be more confident than in a private research corporation with a history of claiming false affiliations to notable research institutions. This is not an ad hominem attack, it's a credibility assessment.

The current state is we have a flawed and effectively rejected manuscript making a significant claim. Looking at the authors credibility is an attempt to remain optimistic but this also points to low confidence.


> It's pretty arrogant to draw premature conclusions on quick analysis and demand the authors to disclose more information right now, when they are clearly not obligated to anything.

“Put up or shut up” is a very valid stance in the face of extraordinary claims backed by dodgy evidence. They are not obligated to anything, but then we don’t have to take them seriously. The mere fact that they’ve sat on it for 20 years and don’t have anything solid after seriously working on it for 4 years is strange.

So far, the community has responded as it should, with a proper mixture of excitement and skepticism, which results in renewed interest in lead apatites (which is fine, apatites are great). But when questions keep piling up, “we have the proof but we’re not going to share” is bound to cause some frustration.


Since when live AMA session and twitch demo an requirement for science?

No scientist can do real work if they are constantly distracted by random internet folk like this.


Nobody mentioned any of this. There are several tools commonly used for communications within the scientific community, including peer-reviewed articles, letters, preprints, and conferences. It’s hardly controversial.


Well, it's important to keep this all in context: They did not want to release the paper, even as a preprint, at this point. The infighting in the group necessitated it when someone went off script and threw up the original shoddy paper, forcing them to release their marginally better one.

They had sent out some samples prior to this whole debacle, including to KENTECH (a Korean university focusing on energy technology), but are waiting to send out more samples specifically because they want to get a peer-reviewed article out there before they start sending them out to a broader audience.

I'm not saying LK-99 is a RTAPS, and current evidence seems to indicate it is almost certainly not one, but the broader LK-99 team seems to have been attempting to follow the normal process the whole time.


From my understanding they haven't been actively researching during that time.

It should also be noted that the team most likely did not intend to disclose any information already.

"Currently, two papers concerning LK-99 are available on the preprint service arXiv, which does not conduct peer review, and a related past study was published in the Journal of the Korean Crystal Growth and Crystal Technology in April 2023. Kim has only co-authored one of the arXiv papers, while the other is authored by his colleagues at QERC, some of whom also applied for a patent on LK-99 in August 2022. Both papers present similar measurements, however Kim says that the second paper contains “many defects” and was uploaded to arXiv without his permission. In that paper, the work is described as opening a “new era for humankind”." - From the New Scientist

The "second paper" referenced here is actually the first that was published, in which Young-Wan Kwon is the third author. If Hyun-Tak Kim states that this paper was not published with his permisison it seems like Young-Wan Kwon prematurely published it on arxiv to be the third author. The other paper was submitted by Hyun-Tak Kim just two hours later, listing himself as the third author.

Furthermore, Young-Wan Kwon isn't related to the Q-Centre anymore as he resigned from the function of CTO.


The privately funded work didn't start until 2018 or 2019 I think?

They apparently weren't actively researching that material between 1999 and 2018.


The original Korean team paper was supposedly a rushed job because of inside fight at the research center, so it is expected the quality is poor by default. We still have to wait for a more polished proper research paper from the team to judge whether it is legit or not (APL material is their choice of journal I believe). We can speculate whether the Korean team has achieved superconductivity or they are under delusion based on replication papers published on arxiv, but such papers have never come under the scrutiny of peer review process as well. So I would reserve my conclusion about this at this stage. It is just frivolous to say whether LK-99 is superconductor or not for now.


> but such papers have never come under the scrutiny of peer review process as well.

Except that such pre-prints far outnumber the supportive pre-prints, are from verifiable scientists at reputable institutions, are in agreement with each other, and are not making claims of a shocking scientific breakthrough.

As there is no substantial evidence to support superconductivity claims it's reasonable to dismiss them until said group decides to provide evidence. If you recall the burden of proof is on the one making the claim.

> It is just frivolous to say whether LK-99 is superconductor or not for now.

I don't think it's frivolous given the distraction and resource-sink this has been.


Or Beijing, since they apparently have fully replicated it.

https://arxiv.org/abs/2308.04353

I don't know why so many institutions and scientists are so quick to call it nothing. It feels like hubris to me, the scientists in Korea spent many years on it, if it were so easy to dismiss I don't think that would have continued their research... right?


> The superconducting-like behavior in LK-99 most likely originates from a magnitude reduction in resistivity caused by the first-order structural phase transition of Cu2S

The preprint you are citing is explicitly dismisses the sharp transition seen as being non-superconducting.


Nah, I know. But it still looks like a similar material, no?

Even if it looks unlikely to be superconducting, I still think people should remain level headed about it. They spent a lot of time and effort on it.


Or everyone has to wait for the full paper to be released which supposedly includes some manufacturing steps not included in the leaked paper so that replication can happen properly.

The original samples are now under testing at a national lab in SK.


Well Occam's razor is to rescue. As for now "LK-99 is not superconductor" is the simplest claim consistent with all experimental evidence. That's not awfully specific, but since specifics are not very impactful, people won't rush to clarify it. If anyone (probably original authors) provide something that contradicts this claim then we'll need to revise it


Honestly I'm excited by that. Seems like a big space opened up for exploration. I think over the next few years there will be several types of this composition with varying electro-magnetic properties.


I disagree. I think that given the multiple failed attempts from numerous top tier labs we should say this isn’t a SC unless L&K share their sample and it proves to be.

Replication has failed pretty thoroughly.


> Replication has failed pretty thoroughly

As everyone seems to keep forgetting the original scientists said that less than 10% of their replication attempts was successful.

We don't have 10 replications total let alone 10 based on their exact process which is unknown to everyone except them at this point.

So not sure on what basis you can claim replication has thoroughly failed.


They have been able to replicate the levitation and then shown that it is not due to SC but ordinary ferromagnetism


Stating with confidence that anything has been conclusively shown about it is a sign you’re arguing from a position not based on evidence.

There simply is not enough evidence to say anything yet. Claiming there is means you either don’t understand it or are willfully misrepresenting it. Either way: no.


The evidence that has come out so far against LK99 in the past few days is pretty strong (particularly the paper out of Peking), not conclusive but it would take some very strong results in the other direction to suggest we are seeing anything like superconductivity.

I have worked in the field of characterizing high temperature superconductivity, there appears to be a lot of motivated reasoning going on around this topic. I would love for this to pan out and while I was initially skeptical I thought there could be a chance. I think the evidence of the past two days has been pretty strong for the negative case and I have adjusted my likelihoods significantly downwards in response.


I agree that recent results have been negative. The reason why they were negative when other previous ones were more positive is, however, undetermined.

With a process that seems to be highly variable, and that the original paper had a only 1 in 10 chance of any success PLUS one that seems to be highly change to produce similar results (but unconfirmed if the same) I’m not too surprised at the high variability of the tests so far.

Frankly, I think it’ll be several years before we get anything close to more conclusive results in either direction. The replication results so far have been… enthusiastic but not exactly stringently controlled.


What positive results have their been that are unexplained by the Peking paper?

As far as I am concerned, all of the previous results are entirely consistent with the peking paper, not positive.


Which is a useful data point.

But the wide variety of samples indicates that there isn't convergence yet on what the intended process is. Until that happens any conclusions are just data points - nothing more, nothing less.


The fact that they were able to replicate the original effect (what people thought was flux pinning) that made everyone think it is superconductivity and then conclusively show that it is not superconductivity is pretty strong evidence.


That's exactly what I thought at first. And then I realised that the 'ferromagnetism+diamagnetism' article does not actually provide a mundane explanation of the "half levitation": They estimated that their sample had very strong diamagnetism -- at least the 2nd strongest of any known (non-SC) substance, assuming their sample was pure (but we can assumeit isn't, considering that they just had one tiny flake levitate), so quite possibly the strongest. And superconductivity is a possible cause of diamagnetism.

It still hugely weakens the levitation effect as evidence for SC, but "conclusively show that it is not superconductivity" is not quite true.


There is no meissner effect, so it is not superconductive. I worked in this field, the paper as described is pretty damning. I think your reasoning is motivated.


* multiple successful attempts of levitation/flux pinning.

The hard part is going to be figuring out how to actually isolate the superconducting effect such that it can be tested. We already know the SC effect isn't uniformly spread throughout the ceramic.


eh, most of the synthesized LK-99 out there by the different teams share enough commonalities and seem very promising from the levitation/flux pinning effects.



> let’s invest even more time and resources on what doesn’t look at all like a dud


A dismissal coached by a theoretical physicist (Bernevig [0], the others appear to be students or postdocs) whose job it is to predict superconductors.

At least two reactions come to mind:

1) If his models could predict useful room temperature superconductors, it seems we would have found one already.

2) If his models don’t agree with LK-99 being a superconductor, and it ends up being one, he probably has a lot of revision to do.

I’m not an expert, but doesn’t it seem likely that finding a room temperature superconductor at this point would involve effects or combinations of effects that we don’t have a good theoretical framework for yet?

[0] https://phy.princeton.edu/people/bogdan-bernevig


That's a pretty condescending take on what's evidently a paintakingly put-together theoretical+experimental study, from one of the best condensed matter groups in the world.

Believe it or not, researchers more than any other people love the possibility of previously-undiscovered exotic phenomena; these guys are not coming into this with the agenda of enforcing orthodoxy and stifling a potential discovery. But materials still ought to be consistent with what we know about the laws of physics, and it's totally valid to check this via theory and experiment.


To use an example from a different domain, finance, it is completely fair to be skeptical of models and assume there's huge things they may miss. In that case, we have seen models predict things like "this scenario should only happen once in a billion years" - and then occur a few times on consecutive trading days. "Don't overtrust the model" is practically an object lesson at this point, assuming the 'model' here is actually a model and not a literal restatement of physical laws.


> assuming the 'model' here is actually a model and not a literal restatement of physical laws.

I'm not sure there is a difference. Imhu, what we call "physical laws" are always models. Like, Newton's theory of gravity, which predicts that gravity is inverse to the square of the distance. Then Einstein came along and made a better model with relativity theory. Which cannot be the end of the story, because it is incompatible with quantum mechanics...


Well physicists try to make models that explain everything, so once you do get to the end you have the law. In fundamental physics we haven't gotten there but there's probably examples in other areas where we basically don't think it's gonna change.

In finance nobody thinks they have anything approaching a law, just a regularity that somewhat predicts some phenomenon well enough to make some bucks. There's no suggestion that all the effects are captured.


> so once you do get to the end you have the law

There is no end. Laws are just very very well performing models. But every 'law' breaks down if you violate the assumptions of the model: make things too big/small/hot/cold etc.


> There is no end.

You get to the end of whatever evidence you can gather. If you can explain that, you can't (and don't need) more refinements.


I'd say that the true "laws of physics" are things like conservation of mass-energy, CPT/Lorentz invariance, the principle of least action, and such. There aren't many of them, and they are inputs that constrain the models. The Standard Model, for instance, is designed to respect Lorentz invariance, because as far as we can tell, Lorentz invariance is a True And Unchanging Forever Law Of Reality.

As far as we can tell!


> If his models could predict useful room temperature superconductors, it seems we would have found one already.

This sort of model works like "put these atoms in this configuration, find the favourable energy states, look to see if we see signatures that might indicate superconductivity"

They are not "given the whole infinite number of chemicals and configurations of atoms, tell me which ones are superconducting"


> 1) If his models could predict useful room temperature superconductors, it seems we would have found one already.

How do you arrive at this?


I’m confused how you think it doesn’t follow? Maybe our conception of model is at differing levels?

I’m saying that if their models worked in a predictive way, since they have been established for so long and the value of confirming them is so high, they would have been confirmed by now.


I'm reminded of the story of two economists walking down the street. One of them says there's a $20 bill on the ground. The other dismisses the observation, asserting that if there was a $20 bill on the ground, someone would've picked it up already.


Think by analogy with NP. Finding the solution (the right configuration of matter) is quite difficult compared to analyzing one that's been put in front of you.


Yes, that is fair. However, I was proposing that it followed we would have found one if we could predict it based on the theory, in effect deriving the matter architecture necessary.


> I’m saying that if their models worked in a predictive way, since they have been established for so long and the value of confirming them is so high, they would have been confirmed by now.

So, just run all possible materials through this hypothetical superconductor predictor model, and any that do exist would be found?


Oh, I see the disconnect. In my imaginary high temperature superconductor predictor, it tells you the confluence of factors required to produce zero resistance, and based on that sketch you go find the combinations of atoms that will stay in roughly that configuration and test them.

I understand that we are not there yet and these models only currently exist in piecemeal/can be used in the negative.

My higher-level intended meaning is that since we have so far been fairly unable to theoretically “find” a room temperature superconductor, if one exists it may rely on an effect for which we don’t have a theoretical model, which means that ruling it out based on existing theoretical models sort of just confirms that we don’t understand how it works, if it works.


Is it that easy? There would be some tractable number of arrangements this would spit out, and from there you can work backwards and find all materials that could form these arrangements, and try to synthesize them and see what works? Might be easier said than done.


Then they go on to say

> I’m not an expert, but..


> 1) If his models could predict useful room temperature superconductors, it seems we would have found one already.

No such models exist.


From what I understand of the state of modeling here, it's like verifying primes. It's relatively easy to verify whether a specific number is prime or not, but very difficult to generate a new one. Likewise if you know the specific structure of a material, we can model / characterize it but the search space is so large that it's beyond our capabilities to find new candidates.


> It's relatively easy to verify whether a specific number is prime or not

Only the "not" part is easy


> If his models could predict useful room temperature superconductors, it seems we would have found one already.

A model that can check a given solution is not one that can quickly check the entire solution space. For a pure-CS analogy, this is the very definition of P vs NP.


This version of LK-99 is transparent? Have any of the other groups attempting replication noted the transparency of the material?


I reckon the sample was just thin enough.


Sabine remains skeptical: http://backreaction.blogspot.com/2023/07/lk99-new-room-tempe...

Edit: apologies, meant to link to this more recent update (still skeptical): http://backreaction.blogspot.com/2023/08/superconductor-lk99...


This is from 9 days ago. That said, the case against has only gotten stronger in the intervening time with the Peking paper.



She uploaded her weekly news video yesterday. Seems to remain skeptical but not openly so, simply highlighted that most replication attempts are inconclusive or failed, and commented on some of the new papers (thr DFT theoretical one, 100K SC one...).


"Together, these calculations suggest it is doubtful that Cu enters the structure in meaningful concentrations, despite initial attempts to model LK-99 in this way."

So does this mean all those DFT calculations were useless?


It may mean the structure of LK-99 found by Kim et al is highly metastable. It does not mean the DFT calculations were useless. Also, for clarity, the original DFT calculations by Griffin do not purport to have “verified” superconductivity, but rather just report to have found a band structure (electronic energy levels) which are encouraging.


The DFT calculations were performed on a phase which is not possible to form via the recipe provided by the Korean team, as demonstrated by this latest preprint.

Which raises doubt on what the Korean team actually tested or whether they are withholding alternative recipes.


There's a difference between "can you actually form this structure" and "if you could form this structure, what would it's properties be?"


Think of it in terms of an energy barrier, like someone cycling over Everest. It might be theoretically possible that there's a nice happy superconducting state if you can get things in the right place, but if you've got to cycle over the top of Everest, it might be pretty much impossible to get there.


Reading about this reminds me of carbon nano tubes and graphene: extremely interesting and useful properties but no reliable, reproducible mass manufacturing techniques mean we have no (or only very very limited) real world applications.

I hope LK99 does not end up in the same place...


Well written article, the conclusion is a bummer to me… suggesting again that analysis leads to the ferromagnetic conclusion…

Perhaps the original authors didn’t realize that and got over excited… then fell victim to confirmation bias elsewhere…

I still have some hope!


Bros, it's over: https://news.ycombinator.com/item?id=37058051

The apparent drop in resistivity originally shown by the Koreans can be attributed to the Cu2S phase change. The crystal structure changes with temperature, and that changes its conductivity. The resistivity never becomes zero but drops sharply to near-zero. It's so cleanly explained, I can't believe it's not over so it has to be over.


While structure may play a role, the problem is that many researchers around the world have yet to confirm superconductor properties.


Including original authors


Damn, looks like it's a no then :(


No, it's not a yes. And it could easily stay that way.


I wouldn’t say a “no”, just a failed replication. Though it’s not encouraging


It seems to me there’s also not nothing here too. There seems to me some bits of superconductivity and maybe even if it doesn’t work it will lead to something more.


X link with findings summary (not a superconductor): https://nitter.net/i/status/1689014160477261825


What’s not a superconductor? His sample or all lk99s?


Twitter is where science is done now...


You mean 𝕏 is where science is done now?


People should refuse to help a company to appropriate a letter of the alphabet as a brand for its company.

I think that correcting others and guide them towards such letter contributes to what the company may be desiring.

May be should be the contrary, when one see other referring that company with the letter should be corrected? Or may be, if they success with the appropriation at future, we should gift the company with an noun, like Xdumb, or Xpeculation channel, or so?


They need to drop twitter.com first...


x.com works right now.


The most expensive HTTP 302 of all time, apparently.


There's a lot of value in typing 6 less characters.


It's a redirect to twitter.com


For now..



how'd you get that symbol?


https://www.compart.com/en/unicode/U+1D54F

It's in with the 150,000 characters included in Unicode. Unicode includes like 150 languages going all the way back to cuneiform.


Create text replacements On your Mac, choose Apple menu > System Settings, then click Keyboard in the sidebar. (You may need to scroll down.) ... Click Text Replacements on the right. ... Click the Add button on the left, type the text to replace (such as teh) and its replacement (such as the), then click Add. Click Done.


From X.org


Yes. Has been for a while. Before that, listservs. (OK, they're still with us)

Science is a team sport, and so it is grounded in communication. The faster, the better.


[flagged]


I wouldn't say they fell for anything. The scientific world went on overdrive and tried to verify the finding exactly as it should.

They didn't blindly believe in anything.


Superconductor research is fraught with failures when looking back at previous breakthroughs, it's just history repeating.

Asianometry recently did a video on the history of superconductors where this topic is clearly presented:

https://youtu.be/wUczYHyOhLM


Do you have some special power to know the truth before anyone else?


You see this type of stuff enough it’s all the same.

People are what drive the hype and what motivates people to lie, cheat, etc is the same no matter where you go or what year it is.

Or maybe it’s because I’ve been burned enough times by hype cycles and magical thinking in my youth I have developed some skill for this. You gotta get burned a few times to understand.

of course you need to be careful. Check yourself. I’m not some perma-skeptic or contrarian. But if it quacks like a duck…


I mean when you see it’s the same kind of hype/people as crypto on twitter, that the legitimate experts are doubtful, that the original paper was very poor, that the authors weren’t able to provide more proof, that the field is full of duds…

I don’t know why people were pretending it was anything over 1% chance of being legit


Whoever told you you need special powers to sometimes correctly evaluate things before most of the internet catches up has a unique definition of "special powers."


No, my special power is extreme cynicism, which works 99.99999999% of the time.


Cynics don't create anything new, they can only say No and smear other people's work without lifting a finger.

Creating something new requires to have more positive and optimistic attitude, these people make things happen and make the world a little bit better.


You have to use judgement to figure out what's worth investing your time in.


Diogenes created something new.


I would say that classical cynicism has a very different meaning to the modern usage of the word.


You're not cynical enough about your cynicism. You should assume it'll only work 88.8888% of the time.

It's definitely nowhere near 99%, you're probably falling for some cognitive biases.


No one fell for anything. People are scrambling to try and reproduce the result. I didn't see anyone anywhere claiming to know this is a superconductor except the original authors.




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