Ferromagnetic half levitation of LK-99-like synthetic samples | Hacker News Reader

Ferromagnetic half levitation of LK-99-like synthetic samples

arxiv.org

339 pointsplatz314 comments

Very interesting comments on the paper by Prof. Michael S. Fuhrer https://nitter.net/i/status/1688755932275384320

> But I think they buried the lede a little. Ferromagnetism is novel and unexpected in this material system, and might be interesting. But strong diamagnetism even more so

> Even if the diamagnetic fraction is the entire sample (appears less) then it would be the second-strongest diamagnet known (and pyrolytic graphite's diamagnetism is very anisotropic). In both Bi and graphite, diamagnetism results from unusual band topology. It's not common

> Overall, some evidence that as-synthesized nominally Pb_10-xCu_x(PO4)O ("LK-99") is magnetically quite unusual, with different fractions showing soft ferromagnetism and strong diamagnetism

LK-99 may not be a superconductor, but it will always be super in my heart.

There are 2 things in favor of the Korean team

- Hyun-Tak Kim is unlikely to ruin his career and legacy for something careless and frivolous. But stranger things have happened, so lets assign a 10% probability to give some benefit of doubt to the team.

- The various DFT papers show interesting flat band structures. But DFT is an approximation and also they do not take into account electron electron correlations. So lets assign another 10% probability for this support.

This crude estimate would give a 20% chance of RTSC. Rest has to be resolved by actual demonstrations, primarily from the Korean team themselves, and then from reputed Western researchers/labs.

Repeat after me: Flat bands do not imply superconductivity. DFT calculations cannot be used to predict superconductivity. DFT is a single-particle calculation. Superconductivity is a multi-particle phenomenon.

At most, the preprint(s) you're referring to suggest that maybe (under their unverified assumptions) electron-electron interactions could lead to interesting physics in that material. It provides no evidence for what that physics looks like and says nothing about what temperature these things will occur.

High temperature superconductivity is not well understood and we do not have the theoretical tools to make quantitative predictions about it. At best we run dodgy simulations, squint at the resulting plots, and say "hm, that's interesting".

> Hyun-Tak Kim is unlikely to ruin his career and legacy for something careless and frivolous.

Everyone is suddenly an expert in HT Kim's character who didn't have any idea who he was a month ago.

And this definitely is a sort of "black swan" event in the same sense that major airline crashes are absolutely atypical of normal air travel. Inherently this viral media event is going to involve atypical constituent parts.

The idea that we could have found some of the most overconfident and underqualified material science researchers out there, who could not realize they were committing career suicide, making these claims isn't very paradoxical at all.

Most aircraft maintenance is exceptionally high quality. You're going to find a lot of bad maintenance in the fatal air disasters that hit the headlines. The FAA doesn't approach an air disaster by assuming the good intent of everyone involved with the maintenance of the plane, and that their inherently understanding that lives are in their hands if they make mistakes should necessarily diminish the likelihood of maintenance issues. They assign "0%" significance to that kind of things and instead just investigate what caused the crash. If it was bad maintenance then the operator and/or the mechanic doing the maintenance take the hit to their reputations.

Same thing here.

That's not how probabilities combine.

You are right, but probability estimation of possibly novel phenomena is an ill posed problem.

So either you do not model it at all, or come up with some mental model of what probability you are comfortable with and due to which factors; the factors being more important than the final number.

The exact numbers don’t matter, but your post indicates that you seem to have the wrong mental model of how to adjust your credences. The probability of each factor decreases the overall probability, not increases.

Alright lets do some calculations. Feel free to dissect the assumptions.

K event = Kim says Material L is RTSC

D event = DFT says L is RTSC

S event = L is actually RTSC

we have assumed P(S/K) and P(S/D) are each 0.1, though we could have chosen other numbers for them as well.

We want to estimate P = P(S/(K and D))

P = P((K and D)/S)P(S)/P(K and D)

Assuming Kim and DFT are in the business of making positive predictions, they always get it right when L is actually RTSC.

so P(K/S),P(D/S) and P((K and D)/S) are all taken as 1

hence P = P(S)/P(K and D) = P(S)/(P(K)P(D/K)) = P(S/K)/P(D/K) = 0.1/P(D/K)

(similarly, P = P(S/D)/P(K/D) = 0.1/P(K/D))

But ofcourse we dont know P(D/K) or P(K/D). We could check historical data on how often D aligns with K, a messy exercise at best. Say they dont perfectly align, then the conditionals are less than 1,and P>0.1. Even intuitively when K (or D) gets additional support in the form of D (or K), your P should increase, not decrease.

If we assume D and K align on average, then P(D/K) or P(K/D) is 0.5, and we get P = 0.2.

You may estimate everything above differently, thus getting a different P. You can also come up with your own way of modelling this. I came up with my particular estimate to understand how frequently should i follow the news, and care about the whole thing. You should model it according to your usecase.

What? Your model doesn't make any sense if you don’t know how to combine probabilities.

Furthermore, you can’t just say “I understand things semantically different than everyone else talking about probabilities so when I say the probability of two events happening is 20% I actually mean something completely different and my math works this way I invented to describe why my messy naive intuitions about probability don’t match the reality of how probability works”.

That's not what GP means - even if you assume they're independent variables, 2x 10% probabilities combine to a 1% ('10% of 10%', they multiply, not add) probability of the total outcome, not 20%.

Huh? I think he's saying OR not AND. Why would two separate pieces of evidence make the whole less probable, that makes no sense, whether you spell out the whole thing more formally or not.

So if I find 10 people that claim, each with a 10% likelihood of being true, that the dark side of the moon has a scar that looks like Pikachu, then it’s 100% true?

That doesn’t make sense either. Seems like someone is falling prey to an intuitive fallacy of probability.

The weird model is just wrong in the first place. The commenter we’re discussing conflates the probability of two people saying something with the probability that what they say is true. So yes, you have to model the situation correctly in the first place.

Ok yeah I think maybe I misunderstood the original argument. But those are absolutely not independent (which was probably the repliers point, unless we made the same misreading).

dude you so do not know what you are talking about, the GP is talking about basic conditional probability rules lol

They are only 1% off. They’re trying to say “there are two independent 10% probability events that imply RTSC”.

You can’t add them, but you can multiply 90% by 90% and get an 81% chance of not RTSC, or a 19% chance of RTSC according to this model.

1pp or 5%

I too like to assign probabilities to my vibes. Much more legitimate.

Reminds me of how Data in Star Trek would say things like "There is a 79.85 probability of success".

I mean, maybe it is possible to assign probabilities to future events that you have never seen before, but somehow I doubt it (with 12.88% likelihood).

>but somehow I doubt it

You doubt it? That means you're assigning some underlying probability to the event (not) occurring. Why does it seem strange to you if people are explicit about their priors?

It's not that it's strange, it's that it is transparently silly to claim to precisely quantify in the absence of anything resembling sufficient information for the problem to be treated probabilistically.

How about this? I keep a running probability (e.g. a 32bit float) for the successful outcome of each future event I have absolutely no idea about. At first I make it 50%, but I gradually adjust with each result, such that I aim to minimize my bias. It might sound silly, but at the minimum it would encode some information about the kind of events I'm typically asked to predict. And I do expect it could end up something like 0.5642635 for a particular time in my life.

Ya what if you just don’t know

I think it's the excessive precision that's funny.

I think this culturally comes from lesswrong and it really makes me laugh every time I see it

Yeah, Scott Alexander wrote a whole article about how people should use made up fake statistics instead of simply saying "I don't know"[1].

[1] https://slatestarcodex.com/2013/05/02/if-its-worth-doing-its...

Not always. "I don't know" is identical to saying "I have a uniform prior". In the particular case of LK-99, my prior is perfectly uniform - I know absolutely nothing about the subject matter and almost everything I read on the topic feels way above my head. As I refuse to be influenced by experts (or "experts") until there is some sort of consensus, I have absolutely no good reason to say anything but "I don't know".

It’s the Bayesian way.

Common in tech: “95% of our users wont care if we make the product worse by…”

That's falsifiable though, in a way the other examples are not. You could sample the population of users after the change to the product

> Hyun-Tak Kim is unlikely to ruin his career and legacy for something careless and frivolous.

you came with presumption that this man knows & understands the subject matter. that is a very bold assumption given the mounting evidence against such brief.

> so lets assign a 10% probability

why 10%? not 0.01%? because of his "prof." title or previous publications? Surely that won't change the course of nature I thought?

> and then from reputed Western researchers/labs.

what makes you discount inputs from Russian, Chinese, Japanese researchers?

You seem to have some really wired brief here, get some help I say.

> you came with presumption that this man knows & understands the subject matter. that is a very bold assumption given the mounting evidence against such brief.

Not OP but "this man" has published enough papers on superconductors[0] that yes, he absolutely deserves the benefit of the doubt.

[0]: See e.g. https://scholar.google.com/scholar?hl=de&as_sdt=0%2C5&q=hyun... or https://scholar.google.com/citations?user=_P8mux4AAAAJ&hl=de...

making a few PDFs publicly available doesn't change the course of nature. he is now in the position to fully explain to the world what is going on here as no one seem to be able to reproduce what he claims.

given such facts, it is totally reasonable to question his expertise on the concern subject. you are free to judge people purely based on how much they publish, I totally respect that.

Do you work in the field? Those papers are ridiculous and the “theory” parts literally do not make sense

- Nothing against Russian researchers, but apart from Iris who is somewhat anonymous and doesnt have the required equipment to create good samples, I havent seen anyone from there interested in performing expts on this

- There have already been some retractions from China after the initial replication claims. I get the feeling they have been overeager about this to prove themselves. Maybe if they approach this with cooler heads, they could be depended on more.

- When i said western labs, i spiritually include japan, taiwan, south korean labs in that, since they generally have similar practices and rigor (even if geographically they are in the east)

> When i said western labs, i spiritually include japan, taiwan, south korean labs in that, since they generally have similar practices and rigor

Are you implying that the west is as corrupted as Japan? That is not something I can agree with.

In case you got yourself isolated from daily news for too long, below is just some recent news regarding those common practices in japanese labs.

https://en.wikipedia.org/wiki/Japanese_scientific_misconduct...

most japanese major groups are falsifying their various type of data - just look at recent news since 2015

Hitachi admitted falsifying data on brake testing https://www.asahi.com/ajw/articles/14508789

More fraudulent testing found in Mitsubishi Electric https://www.asahi.com/ajw/articles/14630514

Accounting fraud by Toshiba https://asia.nikkei.com/Business/Companies/Toshiba-s-chairma...

Kobe Steel admits data fraud went on nearly five decades https://www.reuters.com/article/us-kobe-steel-scandal-ceo/ko...

Lets not drag Japan into this. They have very high standards in research despite the few examples you gave here, some of which are not even science related.

As a widely accepted measure of this, you can read about the many nobel laureates from japan.

Anyways lets keep politics out of the discussion. It was not my intent anyway, in case you perceived it that way.

> When i said western labs, i spiritually include japan, taiwan, south korean labs in that, since they generally have similar practices and rigor (even if geographically they are in the east)

It's difficult to communicate with you if you just redefine common expressions however you see fit. It's like saying "by left, I mean right." Just... stop.

We can debate about expressions/terminology, but these three countries are very very closely aligned with the US. Ofcourse its mutually beneficial.

A joke a military contact cracked once is that the only diff between these three and guam, is that guam is officially recognized as US territory.

Make of that what you will.

I've seen this on here before. Guys convincing themselves that they're being rational and you're being emotional - because they put little numbers besides their feelings and perform some calculations to produce a percentage that "proves" their theory about Antivax stuff, Putin/Ukraine or whatever is credible.

It's a shibboleth in rationalist circles who convince themselves/others that they're doing Bayesian inference in their heads.

Anyone who thinks rationality and emotion are mutually exclusive, hasn't understood half of what any of the big names in that area wrote.

Which isn't to say you or the other replies next to mine are wrong — any memes that get shared also get misunderstood, including attempts to be… less wrong.

(Putting numbers on my uncertainty has mainly made me aware that I'm bad at it, which is useful to be aware of even if it doesn't make me better at it).

>their theory about Antivax stuff, Putin/Ukraine or whatever is credible.

Your politics are revealed with your choice of examples here.

Who needs a decision-making mental model when we can just trust what the experts tell us about these things, or maybe "trust your gut"? That's never failed.

> Your politics are revealed

My beliefs and my politics are pretty transparent in my comment history, I'm not trying to avoid them being "revealed" whatsoever.

> Who needs a decision-making mental model when we can just trust what the experts tell us about these things, or maybe "trust your gut"? That's never failed

Not me? I saw people applying the methods we're talking about to convince themselves that the likelihood of their pet conspiracy theory is true is around the same as a coin toss. You can reach bone-headed conclusions if you're determined to do so, whether you use some decision-making mental model or not.

That's a false binary. "I don't have enough information to form an opinion here" and "I feel like that guy's probably full of shit, though" are in no way mutually exclusive.

I agree with the main claim you are making here. That decision-making models are important an aspect to minimizing the chance of failure when considering decisions. Nothing I said is an attempt to contradict your main claim.

> Your politics are revealed with your choice of examples here [Antivax stuff, Putin/Ukraine or whatever is credible].

I understand that antivax has been claimed by the mainstream right (there are antivaxers on the far-left but they have limited influence), but it feels like I'm living in some bizarro world that people see the efficacy of vaccination as being "political." It feels like I'm living a ham-handed allegorical story about dangers of irrationalism.

> Who needs a decision-making mental model when we can just trust what the experts tell us about these things, or maybe "trust your gut"? That's never failed.

I'd argue that trusting your gut or trusting experts are both decision-making models. They both work well within the right context and fail outside those contexts.

* Trusting your gut is often the right option when you have to make an immediate decision and you don't have time to weight the various options. Something weird is happening on the highway ahead of me should I break now? I have 0.3 seconds to decide.

* Trusting the experts works if the experts are experts in that field and that experts in that field have a long track record of correct predictions and the experts are talking to are in fact experts in that field and have access to the level data which has rendered correct predictions in the data. I'd assign a near 100% probability to a statement by an astronomer that tomorrow night will be a full moon over Toronto, I'd be less likely to assign a high probability to a physicist saying that this new experiment they have will detect sterile neutrinos.

Even those fields in which I am an expert in, I weigh the claims of other subject matter experts when I do not have the time to do the necessary reading and work. The biggest problem with trusting experts is determining is a particular "expert" is actually an expert in that field when you are non-expert in that field.

It comes from lesswrong/rationalist circles.

Best to ignore people once you have identified that they are on the wrong side of the Dunning-Kruger curve

No, let's not. I have seen examples here on HN where leading experts in the relevant field have been accused of Dunning-Kruger (I recognized the usernames, the accusers obviously did not). Such accusations are just namecalling and destroy any civilized debate.

> You seem to have some really wired brief here, get some help I say.

I googled "wired brief" and this is what I found:

https://www.ebay.ca/itm/303994118271

Sorry for the typo, statistically you make more typos when you write in a foreign language. feel free to make fun of it, totally fine with me.

It's not my native language either.

Sorry if you felt made fun of.

I swam those a lot.

Coincidently this is the first time of hearing of nitter.net, do I need to open an account there too?

It's just a read-only Twitter mirror.

It "just" makes Twitter readable to the Internet at large.

Also, you can host your own private nitter instance and follow accounts using rss.

https://github.com/zedeus/nitter

"At large" is a strong term given the average person (even the average Twitter reader) doesn't know what it is ;)

I think you misunderstood. Twitter is almost unusable without an account, and the website is very slow. Nitter makes it usable for the majority of us with no twitter accounts, and/or relatively slow devices.

Well, time to make xitter.net then.

Or nix.net

I'd join that.

(my name is Nick)

After reading the r/physics thread on LK-99 [1] I've cooled significantly on the matter.

Basically: people who work in SC think the initial science seems very sloppy and the replication attempts don't come close to what you need to demonstrate a RT SC

[1] https://www.reddit.com/r/Physics/comments/15i3h9d/lk99_megat...

The SNR of this saga is very low. A speck of something floating under a magnetic field on a blurry video is not proof of room temperature superconductivity. We've seen memes, jokes, shitposting, bravado, Soviet fan fiction, play-by-play updates from non-SMEs cooking stuff under improvised conditions. No actual resistance measurement of LK-99 with a 4 point probe.

If this is real, then discoverers found this in 1999, apparently couldn't synthesize with good yield, couldn't analyze rigorously, sat on the discovery for 24 years, were recently rushed to publish half-baked papers, and are now silent. None of this inspires confidence.

LK-99 could hypothetically be the real deal, and I want to believe, but I'm patiently waiting for people who actually know what they're doing to offer experimental evidence.

Adding on to that: the researchers are from a private corporation that falsely claimed partnerships with several South Korean enterprises and universities which have all disavowed any connection, the "Quantum Energy Research Centre" website has gone private[edit: not suspicious as described in comments below] and the co-authors are apparently feuding over project direction with one of them since removed from the paper.

I know nothing about the subject matter but as a curious layperson I've been surprised a pre-print is being taken so seriously with this background and have assumed people much smarter than me interpret the physics as plausible.

> the "Quantum Energy Research Centre" website has gone private

In this particular case however, the website repeatedly hit the daily traffic quota before the closure. So I guess it would be no surprise that the hosting provider [1] forced them to close the website.

[1] The website itself was probably hosted by https://imweb.me/ (the parking page also supports this observation---the asset path and the admin page path matches).

Interesting, so that's the expected parking page for such a situation?

I have no idea how web hosting works in SK and was going off this article, my interpretation was that this was changed after the traffic warning hence why I assumed malice:

While the company’s website previously displayed a message that it has been blocked due to excessive traffic, it has now been shut down altogether as of Thursday with a message saying that it is “under construction."

I guess that's one less red flag.

https://koreajoongangdaily.joins.com/2023/08/03/business/tec...

Edit:

Is the Safari translation of https://imweb.me/price correct in saying unlimited traffic is 24,000 won ($18 USD) per month?

If so, I'll add back that a private company that has discovered a room-temperature superconductor but is skimping out on $18/mo for web hosting does not inspire confidence.

To make my point concrete, compare these 3 Wayback Machine captures:

1. https://web.archive.org/web/20230730033806/https://qcentre.c... when it was still available.

2. https://web.archive.org/web/20230802204310/https://qcentre.c... when it hit the quota. The title and texts roughly translate to: "The access was denied due to the excessive traffic" and "The website you've visited reached the agreed daily traffic limit and thus is automatically made unavailable now. You can connect again when the limit resets on 10 AM [UTC+9]. Please upgrade the version if the traffic repeatedly hits its quota."

3. https://web.archive.org/web/20230805041306/https://qcentre.c... when it was closed down.

All three pages are probably from imweb's own solutions, given its assets and links. So there is no dedicated server or virtual machine instance, everything is on whim of the provider.

> Is the Safari translation of https://imweb.me/price correct in saying unlimited traffic is 24,000 won ($18 USD) per month?

Yes, but you need to read the asterisk: "But atypically large number of connections or DDoS attacks may be limited for the optimal operation of system." It is very frequent that this unstated "limit" is much lower than expected for Korean hosting providers.

Got it. Apologies if it came across like I was questioning you, I'm just trying to understand the only part of this I potentially can (not the physics) and I'm clearly ignorant of how hosting works with SK providers.

I couldn't tell from the Korea JoongAng Daily and Bloomberg articles if this was implying deceitful behavior.

Thanks for taking the time to explain.

>No actual resistance measurement of LK-99 with a 4 point probe.

https://postimg.cc/TyYbv284

http://journal.kci.go.kr/jkcgct/archive/articleView?artiId=A...

Machine translated: https://www.docdroid.net/UiUrs8c/kci-fi002955269-1-pdf

Interview: https://hackmd.io/@sanxiyn/seize-interview

Man I got so many down votes last week for pointing out that like 6 attempts have failed to replicate this miracle thing that a fraudulent paper describes that’s supposedly existed for 24 years now. My point was simply that regardless of whether some combination of the elements described actually exists with roughly the properties described, we don’t know how to make it and neither do the people who published the paper. It should be more clear than ever, now, that there are significant gaps in our understanding of whatever LK-99 is.

Yes, that's what caught my attention too: no actual conductivity measurement, but only magnetic levitation.

Because the levitation is a much better proof. It can only levitate if the resistance is really exactly 0.

While measuring it somehow always adds errors, because the probes themselves have resistance. And then you can't be sure if it's 0 or just really low.

There are measurement configurations that can be used to eliminate contact resistance (such as a van der Pauw measurement). Resistance, and electrical measurement in general, is the true proof - the Meissner effect is secondary and more confusing as, since this paper shows, a small ferromagnetic phase can give rise to the same effects.

You can't completely eliminate contact resistance, and all instruments have a noise floor, so electrical measurements don't constitute "true proof", they are an element of proof among others. The Meissner effect is perfect diamagnetism which can cause levitation and is not like ferromagnetism which only can allow a piece of material to stand up to align itself with field lines (and which is what we've seen so far).

>No actual resistance measurement of LK-99 with a 4 point probe.

You are misinformed. It's in the original Korean paper.

I cooled significantly after watching Asianometry on the history of superconductors:

https://youtu.be/wUczYHyOhLM

The research field is apparently fraught with failures when looking back at previous breakthroughs.

People were saying the initial papers were trash in the first day of their release over a week ago, so that's ancient history and immaterial now. Same with the "replications," they're obviously insufficient when they're generating pieces the size of a pin head that can't be attached to probes. All of us are in a holding pattern waiting for some big lab like Argonne to confirm or deny its SC status.

How would you *deny* the SC status?

Replications keep failing until everyone is pretty sure it's not it. Proving the absence of something is rare to see.

> How would you deny the SC status?

Maybe we should adopt the stance that it’s not a SC by default and have the people asserting that it is prove that it’s a SC.

I think this is functionally equivalent to the status quo?

Not on HN where it’s definitely a SC we just need more time for the miracle to happen, failed replication attempts be damned.

Or even better adopt no stance on truth value and rather adopt a stance on whether there is sufficient evidence to expend further effort.

No need to guess at the truth. Just remain agnostic until you know the truth.

Exactly. That's the only reasonable stance. Everything else is just jumping to conclusions, positive or negative.

Sometimes a decision has to be made though - e.g. is a particular person a murderer.

In most countries, the burden of proof is on the accuser and the accused doesn’t need to proven his or her innocence and is treated as innocent until proven otherwise.

Sure, but science isn't a murder trial, it is entirely evidence based. Show the evidence, if there is none we'll move on and if there is you get a Nobel (in the case of superconductivity at room temperature and ambient pressure).

We (the rest of the world) can't prove a negative, so it is up to the claimant to supply the proof. Given proof it will be believed, no proof then it's a no-op.

With the murder trial you can assume a-priori that there is a murderer, the question then is 'who', not if a murder is possible or not. These are entirely different problems for a logic perspective.

Checking the original samples, for one.

I hope that ultimately it will come to that because I don't think anything else will put this to rest one way or the other (unless it is 100% confirmed/reproduced by another lab). It also seems to be the shortest path to a resolution.

That also adds little value. It would add no information on whether or not the sample is a fluke. We need to understand the material properties and its composition.

If it is a fluke or not doesn't matter. The only thing that matters is whether or not it is real, not how it was made. If it is real then we can expend a fortune on the 'how it was made' question, if it isn't real we can all descend from this holding pattern.

What benefit does that bring?

If the original sample is superconducting, you can perform XRD / other analysis on it to establish a proximate structure and then simulate things / find better methods for synthesis.

Couldn't there be solid evidence that the observed behavior was due to a different effect?

Maybe the original LK-99 sample was contaminated with actual high temperature superconducting impurities.

There is, a combination of strong (but not amazingly strong) diamagnetism at low field strengths and soft ferromagnetism (in floating samples) at high field strengths. Which is exactly what the paper in the link observed while getting the same results everyone else has. The only unambiguous sign of superconductivity was the original resistance graph which can apparently be explained by contact issues with four point probes (you can argue that they must have done many experiments and surely didn't cherrypick just the one where they found "superconductivity", but consider the quality of the rest of the paper...)

Doesn't diamagnetic levitation require a specific arrangement of the permamagnets that is not recreated in these videos?

That's not clear, but either way--as I've told you several times--there has been no credible demonstration of stationary levitation for even very weak uses of the word "credible."

This is explained in Fig. S2 in TFA.

What you'd have to do is 1) create bulk LK-99, 2) prove that that's what you'd created, 3) possibly also show that it's monocrystalline or something, and then 4) show that there's electrical resistance.

The problem is that the stuff is really quite difficult to synthesize reliably. Until that can happen, good luck finding out in either direction!

It's definitely difficult to synthesize reliably when people dismiss any replication attempt that doesn't show superconductivity as a priori not being the right compound.

Heh. But it does sound like it's honestly pretty difficult to make, too.

Cool it down until you DO see a SC transition far below room temperature.

I have been very cautious on any analysis on LK99 - especially my own.

I have mentioned to many people that any potential application of this stuff comes with an 'if it is real'. That IF is doing a lot of heavy lifting and it has to be emphasized.

I want this to be a thing, but it doesn't matter how much you want something to be true, it actually HAS to be true.

A beautiful elegant idea can be crushed by a single ugly dirty truth.

As youtuber John Cadogan says "facts don't care about your feelings".

I personally go by "Carpe Diem", as musician Taylor Swift says.

Now, I don't have this guys credentials, but it sounds very close to "This is not a superconductor as we know them to be". Which almost goes without saying, because if this is a room temperature superconductor in some sense, maybe something quite different is needed to explain it. I think we should be excited for new physics.

No, not at all. Meissner effect is constitutive of SC

> Type-II superconductors do not exhibit a complete Meissner effect.

Are type II superconductors not superconductors to you?

meissner effect != complete meissner effect, but i can see how that would be confusing

there was no meissner effect measured in this substance

Yet somehow those "SC people" issue this opinion without having seen the final paper nor the lab data on the original sample, which is presently being examined as part of the peer review process in SK?

The final paper doesn't mater. If you are in the area, you can skim the paper and look at a few key graphics and tables. Those key graphics and tables should be in the initial draft, because the rest of the article is build around them. Perhaps the final graphs will be prettier, or they will fix some minor errors (like a missing label).

(Sometimes it's more complicated. The initial and final version have bigger changes because the writer realize it's better to select other examples instead of the initial ones. But in this case I guess they don't have too many examples to cherry pick.)

In this case, we have only a rough idea how close the leaked papers are to the final paper, with only one statement from a scientist at the national lab in SK stating that there are additional manufacturing steps in the final version of the paper.

I suspect there's a large difference between what was leaked and what will be formally published.

According to this: https://twitter.com/Andercot/status/1688598313497694208

"...there is a less well-known exception to this rule called Brauenbecker extension which provides a mathematical proof that levitation is possible with a simple diamagnetic in a dipole field so long as the diamagnetic material mass is very small relative to the strength of the magnetic field."

I was very hopeful in the early days and was following the developments eagerly. Unfortunately, now I'm 99% convinced that LK99 is not a superconductor. Hopefully, what we learned from the saga and the momentum will help advanced the field a bit faster.

Maybe a cautionary reminder to not listen to random influencers on Twitter. The expert community was really silent and reserved from the beginning as they've seen such wonder materials many times.

Having worked in that field for many years I'm personally skeptical that there ever will be an ambient-pressure, room-temperature superconductor. The band structure and interactions that need to be present in the material are just one requirement for superconductivity, the other is that the ground state can actually form and won't be destroyed by thermal noise. However, the strong electron-phonon interaction required for (classical) superconductivity also makes the system susceptible to thermal noise, and in my opinion the thermal noise level at 290 K is just too much even for an ideal superconducting material.

I don't see anything bad with this hype cycle :

  - these guys thought they found something
  - turns out it probably wasn't superconductors but it's an still interesting finding
  - there was no fraud and something new was discovered
  - material science got a bit more mainstream exposure

I'd rather see that than another crypto or AI hype cycle

No, it really wasn't that bad.

The annoying part, at least for me as someone who, uh, I guess used to go to a lot of colloquia on this stuff?, is the part you left out: people pre-judged the outcome (of all three phenomena you mention!) and then got really, really cranky with anyone who dared challenge their position.

If you (generic rhetorical you) want to believe that LK99 is going to superconduct, or that Bitcoin is going to the moon, or that AGI is coming next week, that's great. Really, it is! And you're allowed to talk about it, and put your money where your mouth is, and all that. What you're not allowed to do is get mad at people who respectfully disagree with you and point out why your dumb arguments are dumb. And you really, really, really need to pay attention, and not get more hostile, when your position starts to get falsified, as is/was helpfully possible for LK99 (but not so much those others). Do not hold fast to false things.

I understand that this is difficult when the people taking the other side are being equally awful, but such is life. We need to rise above, not get dragged down, lest everything fall into the same cesspools as contemporary politics.

> really cranky with anyone who dared challenge their position.

You could profit from those people, if you are confident in your position, by shorting some of the stocks that shoot up from people's pre-judgments on this matter.

Usually not because as the saying goes: the market can stay irrational longer than you can stay solvent. Most people simply cannot afford to make those bets against the market.

Last time I saw this cycle with EmDrive

  - some guy created EmDrive (2001)
  - author argued for decades that EmDrive violates Newton’s Laws
  - author filled a group of patents, launched a new company "Universal Propulsion Ltd." (2016). But by this point, DOZENS of independent researchers had already proven that EmDrive doesn't create thrust.
  - NASA and DoD and a lot of smaller companies just threw money away testing something that can't even work in theory
  - "there was no fraud" (allegedly), all blamed on measurement errors
  - mainstream exposure was pure hype, it was just electromagnetic/thermal effect, the research has yielded ABSOLUTELY NOTHING new.

This is exactly right. The only difference here is that EmDrive straight up violated a law of physics, whereas high-temp superconductivity was just a matter of degree (pun intended). I was somewhat skeptical of EmDrive, but was very hopeful about LK99. Alas, it was not to be. We'll have to take the slow road to room temperature superconductors.

Since this was an exceedingly short cycle, we were spared one of the negatives. Well, mostly:

  - some folks massively hype this as the "next big thing", extract money from investors and take mindshare away from more promising, but less exciting work

You say it’s a short cycle now. But I bet a non-trivial number of people are still talking about this and trying to get results long after the initial cycle. It took years for cold fusion research to go away.

So what? We can still have labels for fuzzy concepts like “took the world by storm, for 2 weeks”, even if a couple thousand people are still excited about it 2 years later.

It’s the original definition of a meme.

There is no shortage of subjects where exactly that is being tried.

Yes, I only listen to people with handle like "ThePhysicist" or "theMaterialPhyisicist" at hackernews.

I think the point is you can probably ignore everyone who isn't giving a Nobel acceptance speech.

That’s why I personally only listen to the opinions of people with handles like "Planck54", "The1965PhysicsNobel" or "EconNobel94" on hackernews.

Sorry, I couldn’t resist.

N.B. I also tried to find some noteworthy Fields medal winner, but refrained since it appears I don’t know any of them, and that the committee’s choices and motivations have been subject to controversy [0].

[0]: https://www.science.org/content/article/fields-medal-was-nev...

Sure, but every now and then people get into an argument with a Putnam prize winner or the inventor of some Internet Protocol details and find themselves caught out...

I would bet picodollars that rarely happens here…

It happens more often than you think. For example it has happened a bunch of times that people have argued against PostgreSQL core developers about the internals of PostgreSQL.

I know most of their usernames so it is always a great laugh for me.

Hehe. Nice one.

Can you explain how 300K is fundamentally different from 90K?

90K is 20 times above temperature of liquid helium. Is there some law of physics which says that you can go 20x the temperature of liquid helium but not 60x?

It's the relative energy scales in the system that matter. You can e.g. compare the superconducting energy gap to a temperature, for Niobium the gap is around 2.3 meV which corresponds to about 27 K. For high Tc superconductors the story is a bit more complicated but their pseudo gap is 5-8 times higher, hence around 150-200 K. Niobium has a Tc of 10 K, high Tc superconductors (unpressurized) at most 150 K. What's safe to say is that if the temperature becomes significantly higher than the energy gap the superconducting state will be lost as there's thermal tunneling out of the state and it becomes thermodynamically "unfavorable" (this simplifies things). Now there's no reason that we couldn't find a system with a larger energy gap but that gap itself is defined by other properties in the system that have constraints on their own. Fundamentally there's no reason that there couldn't be a system that fulfills all these constraints at room temperature, but there isn't a reason why there should be such a system either. Then again there might be different superconductivity mechanisms that we don't know about yet and that we could exploit, but I think it's not very likely that we'll find a regular material system with these properties because there are not that many crystal lattices to choose from and we've been looking for more than 50 years.

Fwiw 77K is sufficiently cold that wild N2 gas molecules with pretty weak interactions are willing to play nicely with each other and condense...

I think how people define superconductivity varies greatly in discussions.

Wouldn’t be the worst thing if we concentrated our efforts on proving zero resistance first. IMO, a “super conductor” should only be characterized as a material with zero resistance under certain conditions. Everything else should not be a requirement, but more like a side-effect that had been observed to go along (such as diamagnetism through Meisner effect).

Hopefully that will destigmatize future research efforts in both directions, namely towards finding zero resistance materials and those exhibiting diamagnetism.

The worst thing we can do to science is going on a witch hunt. Curiosity powers this discipline. We don’t need for encourage all crazy theories but discouraging that line of thinking entirely will lead to fewer new discoveries.

Fear driven science isn’t science at all.

But the high temp cup rate superconductors don’t follow classical landau theory afaik

Andrew is mistaken, the paper he cites doesn't say that levitation is possible in a dipole field. Brauenbecker showed that diamagnetic levitation was possible at all (e.g. in a quadrupole field), but not in a dipole field.

Stable levitation in a dipole field is still thought to be something only type II superconductors can do, and Andrew should not uncritically repeat what he read on /sci/ - which is one of the only other google results for "Brauenbecker extension" currently (after his tweet).

The best we can hope for is that there is some sort of SC properties that can be investigated further even if this is not the holy grail moment many wanted it to be.

The amount of hyped discussion here on HN based on such scant evidence was astonishing.

Naive question, and I hope someone more knowledgeable than me can enlighten me here;

Why are we even testing for superconductivity with levitation, instead of just checking for current loss/heat loss while conducting?

A magnetic levitation demo indicates a possible Meissner effect (which is refuted here by this paper), and this is so much easier than a resistance measurement, which is a delicate task and susceptible to experimental errors. So levitation is used as a quick "first check", especially when you don't have a full lab setup to do other tests, which are much more complicated (in addition to a levitation test or a resistance measurement, one can also measure its frequency-dependent magnetic susceptibility curve, temperature-dependent specific heat curve, or its Josephson effect).

One cannot measure superconductivity with an ordinary ohmmeter. Electrodes, wires and the ohmmeter itself are resistive, the meter can never show zero ohms. You need to set an experiment up with a current source and a voltmeter to measure the IV curve across the material [1]. Even then, the voltmeter will never show "zero" volt because of noise, which needs to be minimized in the experiment and removed during post-processing. In this case, sample preparation is also problematic as the synthesized material is not uniform. And your measurement is also expected to be temperature-dependent to show the material's transition to a superconductor. It's more involved than seeing it floating on a magnet, to say the least.

[1] It's basically the same 4-wire Kelvin sensing used by all milli-ohmmeters. But to characterize superconductivity, you need to do even better. https://en.wikipedia.org/wiki/Four-terminal_sensing

> One cannot measure superconductivity with an ordinary ohmmeter.

But one can measure electrical resistivity, and if the material's resistivity is much lower than that of ordinary materials, that would be super interesting and valuable, regardless of whether it is a "true" superconductor or not.

If this relatively cheap material had a resistivity around 1/100th that of copper, that would be an engineering breakthrough, and determining that doesn't seem to require a super complicated lab setup.

Do we have an upper bound on LK-99's resistivity, and is that upper bound substantially lower than the resistivity of typical conductors?

I think you are missing the point: a typical ohmmeter would have metal probes, so with a superconductor you would just be measuring the resistance of those probes. Any attempt to overcome that problem probably introduces a lot of chances for error or noise, or require some huge sample of the superconductor.

Zero resistance would be hard to proof this way, but why can't you compare measurements of LK99 with known conductors?

You absolutely can, and as you can see in this paper it is absolutely do-able to measure the resistance of these materials. They measure an insulator with something on the order of 10^6 ohm m. For reference, copper has a resistivity of ~ 10^(-8) ohm m, so there are about 14 orders of magnitude of difference. This does make the contact resistance pretty negligible in this case too.

I have the same thoughts. I think it's because they are not EEs and want to play with the material. A sensing resistor is trivial.

https://www.digikey.com/en/articles/fundamentals-of-current-...

if you were talking about a meter long segment of pure LK99 you'd have a point. But the pieces in question are so small that even if the LK99 were just copper their resistance would be so low that experimental error in a casual test would be substantial compared to the resistance.

Measuring the resistance would also be frustrated by the superconductive material being scattered in the mass separated by highly resistive impurities, making it easy to get a false negative.

Do you have any idea on what the ballpark cost is to do these replication experiments I keep reading about? Or the more complicated experiments you mention?

Asking out of curiosity as I would have assumed it's very expensive but there seem to be many groups of varying sizes doing these and quite quickly which I would have thought would be extremely wasteful but may suggest it's more economically feasible than I had thought.

This question has been asked with near identical or very similar wording in almost every LK-99 submission I've seen over the last week or so... Is there something botnet-y happening? I find it hard to believe anyone reading similar threads could have missed the numerous answers to this and similarly-formed questions that have been offered lately.

It could be the sheer volume of discussion. I've seen a lot of these posts and this is the first time I've read this question.

Maybe it's because I have been obsessively ensuring that I read every comment on every top thread... Some kind of selection bias could be at play...

The top comment on every thread about every new thing on HackerNews is a half-assed debunking of it

I’ve been half assedly following this, not understanding a single word in the papers that keep coming out, not understanding the musings of enthusiasts and professionals

and it looks like I know just as much that its a nothing burger, with maybe some sliver of novelty

we dont have a superconductor, as expected

It’s a natural question when reading about this, like asking why a police officer makes a suspected drunk driver walk a line instead of measuring BAC.

Not everyone reads every (or any!) paper and story.

Maybe it is the most natural question which comes to a lay person like me when it comes to superconducting. Not everyone can be as knowledgeable, or in the loop as you are.

And I assure you that I am no bot. I acquire sustenance, go into low energy states and have a lifetime warranty like all fellow meatbags.

That is exactly what a bot would say... you have to prove you are human by starting a company and making $1M

Wait, you got a lifetime warranty? xD

Yep. It gets void when I die

At least nobody has asked about the real-world technology implications in this thread yet.

now I have to get out my bingo card and ctrl+f "hoverboard" and "maybe purity",

Not all of us read HN every day or follow each discussion. A lot of people don’t read the comments at all.

Exactly. Almost every thread has this query. And surprisingly its always on the top.

Yes, and it is getting a little annoying at this point to be frank.

The samples are super small and not homogeneous, so its tough to get any kind of accurate reading with probes, is my understanding.

Generated samples are too small and powder-like to test for that without a lot of difficulties.

Note: I'm not a physicist. Just my understanding from reading.

Because the production of lk-99 yields a puddle of mess.

https://twitter.com/MarkTyler81/status/1688736978437898240

LK-99 == alchemy RT SC.

So if good old ferromagnetism/diamagnetism is sufficient to explain the half-levitation shown in the video:

How can I build my own half-levitating objects from standard materials?

I've seen the science toys using pyrolytic carbon, but they are nowhere close to the effect from the video. Levitation height with pyrolytic carbon is like 1/20th of what the video demonstrates. The disc in the video looks like it's just about to take off. Can this be replicated with previously known materials at room temperature?

Yes: https://twitter.com/VanGennepD/status/1688052003216261120

This guy goes into detail how he makes a practical fake which demonstrates the same behaviour: it's ground up carbon, superglue and some iron filings on one end.

The pivot point reduces the mass and weights it upright.

I believe (could be wrong) diamagnetic levitation also requires arrangements of several magnets that shapes the magnetic field in a particular way

Go through iron milling residue (that kind that is dust-like at afar, but consist of large flakes) and select some thin and long piece. Put it over a glass, and move a magnet under it. You will see it position itself on a vertical or any angle you want.

But notice that the videos circling the internet show a different behavior. Those are not homogeneous materials, and it's not easy at all to tell what they are actually doing. (But ferromagnetism on LK-99 is surprising by itself.)

> We argue that, together with the pronounced shape anisotropy of the small fragments, the soft ferromagnetism is sufficient to explain the observed half levitation in strong vertical magnetic fields. Our measurements do not indicate the presence of the Meissner effect, nor zero resistance, in our samples, leading us to believe that our samples do not exhibit superconductivity.

What happened to the original LK-99 samples that (allegedly) displayed SC properties?

Were they just thrown in the dustbin, or what?

I haven't seen that question answered or even asked anywhere, but I'm just a layman so maybe I'm not looking in the right places.

There are at least 2 samples definitely produced: one in the original videos and another in the video released by Hyun-Tak Kim via nytimes which definitely look different. It is unclear if the sample sent to KENTECH for the analysis is the first sample or a fresh one. Young-Wan Kwon is also known to have his own sample (confirmed in MML 2023 sightings), but it is unclear whether it's distinct from other samples too.

Interviews with Q-Center folks suggest that the yield is high enough to produce a handful but not large number of samples at once, so there are probably much less than 100 samples available, which might be one of the reasons they were initially hesitant to share samples to others. (There are tons of groups want to get samples, if it's unclear.)

If you cite Korean (or Chinese or Japanese) names, please write them correct. There is no Hyun-Tak Kim, he is called Kim Hyun-Tak. Likewise Kwon Young-Wan.

In Korean it's trivial to detect, in Chinese not so, in Japanese very hard.

These are just how they wrote their own names in arXiv papers [1]. I don't know about Young-Wan Kwon, but Hyun-Tak Kim is a research professor in US university and should have settled on that matter.

After all I'm also Korean and I prefer my name to be written as "Kang Seonghoon" (i.e. the surname first), but I often go pragmatic and use "Seonghoon Kang" instead in order to be consistent with others. I'm very much aware of this issue.

[1] https://arxiv.org/abs/2307.12008 and https://arxiv.org/abs/2307.12037

Ouch. This comment backfired quite badly. Turns out the person being replied to is Korean, the commenter is likely not, and in addition this is how the authors wrote their names themselves.

Yet I do not wish this comment to be snarky. I’m interested in the broader perspective (and I apologize in advance to the parent for using this as an hook). The comment seems common of the present era in which polarization (leading to prejudice against anyone we believe is outside our in-group), and short attention span (leading to drive by/poorly researched comments), combine to low empathy among us. And just to be clear, I’m not putting myself above this, on a bad day this kind of comment could have come from me.

Am I right and things were better on the past on the empathy axis? Or am I exaggerating and getting old?

Just like I want to believe LK99 is RTAPS, I want to believe that you are correct.

But just like with LK99, this might be wishful thinking from me. I am also getting old.

You never write cjk names with firstname first, always surname first. Japanese usually complain, the others just shake their heads silently about the silly westerners.

When the original author writes his/her name american style he/she moved to america, but then he/she changed his firstname also. In this case some citations may started out wrong, as journalists have no idea how to write foreign names, scientists and experts usually do.

the commenter knows how write foreign names, even if some author succumbed to western stupidity.

Seeing mistakes about Korean names in the media is very common. It's a lost cause at this point

I think we're sort of climbing out of a local maximum of entropy. It's gotten better in some ways and worse at others. It'll take some time for everything to settle out.

It's not difficult to detect in Japanese either, because the set of names used for personal and surnames are different. However, both Japanese and non-Japanese alike don't follow any consistent order when writing their names in English, so neither is 'correct'. In fact it could be called a hypercorrection, similarly to using '-san' when addressing Japanese people in English.

It's also easy for chinese names when you know the very limited number of possible surnames. But then you must assume the citator knows some chinese, which they don't.

Japanese is a bit harder as their firstnames are written in myriads of western styles. (e.g. Miu, Miyu, Miyuu, Miju, ... a common female firstname, for "Beauty, Gentleness & Superiority". Mi=Beautiful, Yu=Gentleness, Superiority). Also Miyu can be written in myriads of ways in japanese, with only some being the common female firstname, where yu can also mean Bind, Friend, Eternal, Dream, To exist, Yuzu (a lemon), Sorrow, ...

You need to persist on consistent ordering, even if westerners have no idea and continue ignoring it. Even if everybody writes Itō Mima as Mima Ito, she is still Itō Mima. The prominent Wang Manyu and other chinese table tennis players did establish their correct writing, they just call her Wang Manyu instead of Wang Manyü ("man-yue"), which is equally embarrasing.

You insist on correct gendering, but still write the names wrong.

So instead of learning one fact (x country uses family-given ordering) the reader must learn 1000 facts (whether y name is a family name or given name) about a language they don't know so they can infer which ordering the translation is using.

They were refusing to share them with anyone reputable until today. Today, they said they would share them, so hopefully this will all be over soon (but IMO it's already resolved).

> They were refusing to share them with anyone reputable until today.

This is incorrect (under some definition of "reputable"), because KENTECH [1] has reportedly received samples from Q-Center for the analysis, which started on July (following the MOU on May) and is estimated to finish within 6 months. Whether KENTECH is reputable or not, and whether it should be considered affiliated with Q-Center is of course debatable.

[1] https://www.kentech.ac.kr/

I don't consider a replication attempt with a lab in a commercial relationship with another lab, that has essentially embargoed the results for six months, credible.

Of course, but you don't waste your lab time with useless samples. KENTECH must have seen something to actually allocate resources for the analysis. The recent interview with the vice president of KENTECH said that the initial request was in 2017, when samples were not really reproducible and too impure for analysis, but it was only this year when samples are good enough and can be actually analyzed---if it's just a fake they could have done so in 2017 instead.

Link to where they said that today?

Resolved in which way?

It's not a room temperature ambient pressure superconductor. I should probably bet on it while there's still some value left here, I guess.

Seeing how sure you are of this, you should go all in.

A ferromagnetic oxide featuring copper as the sole transition metal would be very weird. I'm not aware of any examples of the copper block demonstrating ferromagnetism without a more "conventional" ferromagnetic transition metal (from Cr to Ni and cousins).

But ferromagnetism has been demonstrated in black phosphorus:

https://www.sciencedirect.com/science/article/pii/S003810981...

So the most likely explanation for the observation here is that the sample contains black phosphorus. But do all the samples contain black phosphorus?

(Not a scientist, just a hobbyist.)

Red phosphorous is an ingredient in the original paper’s process.

https://patents.google.com/patent/US6110438A/en claims that black phosphorous can be made from red phosphorus using a vacuum and hundreds-of-C temperatures. Both of which people have done.

Seems very possible.

So a completely different compound in a completely different shape.

Yes, but I take it like a rebuttal.

They got the same effect that got everyone excited (half levitation) with a similar material that is ferromagnetic.

Considering that there is a lot of unknowns and randomness regarding the synthesis of LK-99, and that the half levitation effect can be explained by ferromagnetism, to me, it sounds much more likely that the original LK-99 is a ferromagnet rather than a superconductor. Simply because ferromagnets are common, and a room temperature superconductor is an extraordinary claim.

I'd like to be wrong, but for now, it doesn't look good for superconductivity.

This is bad logic. Ferromagnetic explains half levitation but it doesn't explain full levitation. Superconductivity is sufficient to explain full levitation and half levitation.

> Simply because ferromagnets are common

Sure, metal ones are, but Are ceramic ferromagnets (without iron) common? That lone electron in an orbital is pretty important.

> Ferromagnetic explains half levitation but it doesn't explain full levitation

No one reputable has actually demonstrated full levitation, including the original team.

> Sure, metal ones are, but Are ceramic ferromagnets (without iron) common? That lone electron in an orbital is pretty important.

They literally reproduced this behavior with a substance that looks identical to the original LK-99, so while it would be quite unusual, it is clearly possible. Apparently ferromagnetism without any ferromagnetic compounds has been witnessed before, e.g. in ZnO.

Never claimed it was impossible, just that it's rare.

> No one reputable

I don't care about reputability of anyone unless they have a known past of fraud. Gatekeeping in science is lame unless someone makes a claim to break well understood theory or claims to do something technically difficult. RTSC is neither.

Do you think this video is faked?:

https://twitter.com/Andercot/status/1687740396691185664?s=20

> Never claimed it was impossible, just that it's rare.

Okay, so? It's been experimentally verified and it's not some sort of novel behavior. It's even been predicted to occur in PbO before, just not observed until now.

> I don't care about reputability of anyone unless they have a known past of fraud. Gatekeeping in science is lame unless someone makes a claim to break well understood theory or claims to do something technically difficult. RTSC is neither.

RTSC is absolutely something we believe is likely to be difficult, but more importantly none of the replications by either verified labs or scientists willing to put their names on the line, who documented what they were doing, actually worked.

Meanwhile, we have videos like the one you linked, which are posted completely anonymously by someone affiliated with no institution who followed it up with two videos of spinning poop. Many people have demonstrated that it's quite easy to fake a video that looks like this using software like Aftereffects. For you to claim this video is equally trustworthy to replications by credible labs with reputations on the line is certainly a choice you can make! I will not be doing it with you, however.

From the same author: https://twitter.com/andercot/status/1688598313497694208

Video behavior can happen also with a diamagnetic substance.

The Chinese originator of that video has since admitted it's fake.

Still helpful. Now people know this synthesis process and result doesn't have this desired property and the 900 other groups working on this don't need to repeat it.

Different but reproducing the only real current "signature" LK99 behavior anyone's been able to show.

That a definitely non-superconducting material can do something similar is bad news for LK99.

The XRDs are nearly identical. It's a dead horse.

XRD used here only shows crystal lattice information for random orientated polycrystalline. It does not mean the two samples are identical. It does not prove whether they had single crystal or polycrystal.

You will need a four-circle diffractometer to prove two samples are identical, that also only work on single crystal if anyone can make it.

XRD comparison isn't from eyeballing. The fact is, the original papers do not coherently specify "LK-99" because their equations, synth procedure, and subsequent analysis are all incomplete or contradictory. It's like they gave everyone 2 + 2 = 5 and so everyone's been trying to figure out how to get to 5, while also questioning 2 and 5 because the quality of the papers is so poor.

"We do not know the composition or structure of #LK99 with any confidence."

https://twitter.com/Robert_Palgrave/status/16872357567027527...

Yes, but it allows for an Occam's Razor explanation of the observations so far.

My main concern: Where are the original authors and why are they not helping people synthesize the replications?

According to Wikipedia:

> On 3 August 2023, the Korean LK-99 Verification Committee requested a high-quality sample from the original research team. However, the team responded that they would only provide the sample once the review process of their paper, potentially submitted to APL Materials, is completed. This process is expected to take several weeks or months.

These sort of answers do not inspire confidence. That looks like a play for time, why would they connect those two, it's clear they have priority locked in if the sample works out, the peer review of their paper is secondary to the questions of whether or not it is the real deal or not.

> These sort of answers do not inspire confidence.

I'm not anything close to a Materials Engineer, but at least in the (very different) fields in which I've published, it's very standard to not share material (e.g.: plasmids, bacteria, code, or datasets) until you've published.

Pre-prints rarely have code or data available if the authors intend to publish elsewhere (again, in my field).

Ok, that may well be the explanation then. As long as those samples don't go missing...

The whole point is for the samples to not go missing because they will likely need them in rounds of review.

Time for what though? Eventually the world is gonna need to see the samples or we’re just going to assume they never created it to begin with and move on.

I’m not in a big rush, we’ve made it this far without RTSCs.

I am not in material science, but how does sharing a sample of the material not part of the paper review? Anyone can write a paper about things they did to make a material X, but extraordinary claims require extraordinary proof. If I am a top tier material science journal, I would not want to publish a phony SC because I waited to verify their sample.

That's exactly what they say they're doing. They submitted the final paper and the sample(s) to APL for review.

I don't think they have other samples to hand out.

They haven't actually published yet officially... the only papers everyone has their hands on (and which all the replications are based on) were leaked.

So, they're following the process... they've submitted the paper and sample for examination and they're waiting for those results before publishing.

From what I've heard, the chief of the Korean Society of Superconductivity and Cryogenics had personally called LK-99 out as a hoax - which might have been justifiable, given evidences, but it might explain the reluctance by the LK-99 team.

(Assuming the inventors of LK-99 believe it's real, they could be thinking "Why should I give you the honor of being the first outsider to verify the sample, when we could ask anyone else?")

I think we should be careful to throw provocative words like hoax around.

There is no official statement from Korean Society of Superconductivity and Cryogenics saying it is a hoax only that they are still waiting for a sample from the original scientists.

At this point we don't know (a) whether LK-99 is a RT superconductor and if it isn't (b) whether it was simply an error in their research or a conspiracy amongst the scientists to commit fraud. Until we definitively know both I don't see why people should be slandered.

There were a couple of unofficial statements from the Chair of KSSC though. He is now known as the "Mr. Bahahaha" in the Korean internet because he initially dismissed a mail from Q-Center wrongly sent to him by starting his Facebook post---now removed---with "Bahahaha, the era of room-temperature superconductivity is here. Ambient pressure too! Shouldn't my fortune get better?" (translation mine).

The team believes they have made the world's first room temperature superconductor, and they submit the paper to APL Materials (Impact Factor 6.6)?

That's a good question and there is a lot of speculation about that but ultimately we just do not know. There is a whole tree that you can set up to track their reasons, the big branch at the beginning is labeled 'it doesn't work' (which obviously is a bit short on the confirming side, it may still have a 'fraud' and a 'true believers' branch but that's academic) and then from the other branch you get branches which may be labeled as 'they don't know how they did it' and so on.

They weren't ready to publish and then got forced into the lime light by a member of their team going rogue. We should give them some benefit of the doubt due to the circumstances, even if LK-99 turns out not to be a SC, they didn't choose to publish.

Oh I definitely do give them the benefit of the doubt. Regardless of what is going on as long as it eventually works as advertised it's all fine and as long as their samples don't go missing they have a way out that's pretty easy.

Let's hope the growing mountain of evidence against original author claims causes them to move quicker with providing samples to bonafide labs and disclosing the full details of their manufacturing process.

What evidence?

Absence of evidence is not evidence of absence. They haven't even officially released their final version of the paper, and a whole bunch of people who don't have full access to their data being unable to replicate their material well enough to convince the world doesn't reflect at all on the validity of their work.

If the people to whom they have submitted their paper, data, and samples can't replicate it, that will mean something else.

> Absence of evidence is not evidence of absence.

Actually it is when labs all around the world are trying to generate evidence and failing

Then the atom bomb was - for a time - disproven.

Has anyone even seen a ferromagnet stand up like that in a magnetic field?

Yes. https://nitter.net/VanGennepD/status/1688052003216261120

And this new paper finally rigorously explains away all the half-levitation videos. They can no longer be considered any evidence of SC at all.

Not all the replication videos show the sample in the middle, see the Varda sample videos. Constructing something that simulates something else is proof of very little, other than there are other possible explanations. The existence of alternative explanations isn’t a proof the proposed explanation isn’t true.

This paper doesn’t explain away anything yet - they’re conjecturing based on their experience with their sample. Their conjectures are no more credible than the opposing supporting conjectures.

IANAP and I don’t have a horse in the race, and while I’m excited to see if this is true, I don’t believe anything other than there’s a long road of research ahead and nothing will be proven with hottake nitter videos or hottake preprints.

> The existence of alternative explanations isn’t a proof the proposed explanation isn’t true.

But it's proof that the proposed explanation is not a bulletproof proof... Because it could also be any other alternative effect.

That's literally the whole point of it...

> Not all the replication videos show the sample in the middle, see the Varda sample videos

Andrew McCalip himself says this explains everything he's seen.

https://nitter.net/andrewmccalip/status/1688741684316975104#...

You’re reading something entirely different - at the end of a long discussion of sending the samples off for more testing, holding hope it’s a SC but admitting it’s always been a long shot, he notes at the end:

> That said, I think we're getting to the point where magnetic observations may be adding more noise than signal. Yesterday, I did perform the pole flip that was discussed in the last video. Very important to note, however, that ferromagnetism can exhibit pole agnostic behavior too. Check out the excellent video by @vangennepS. nitter.net/vangennepd/statu…. While the amateur magnetics method was fun to try for a screening method, it seems to have too many false positives to be entirely trustworthy.

That’s not at all supportive of “explains everything I’ve seen”

He wrote that other tweet before that paper was put up on arXiv. How does the fact that the one I linked to is a reply to the one you quoted change the plain meaning of his words? I'm trying to understand how I've misinterpreted his tweet but I've got to interpret "Sounds like it explains everything we're seeing" as referring to his own observations too, not (just) other people's.

He's been looking for an explanation of this sort for a while:

"I'm still suspecting it's a magnetic phenomena that's not SC" https://nitter.net/andrewmccalip/status/1687887799872294912

"I don't want to succumb to the echo chamber just yet, it seems weird, but could we explain this another way? Is there a lead compound that exhibits ferromagnetic behavior?" https://nitter.net/andrewmccalip/status/1687497082322788352

My bad, my reader view cut the tweet off and just showed the original.

Still, his phrasing doesn’t indicate it’s over for him, just bordering - perhaps explains everything they’re seeing, but it’s :

* not LK99

* a conjecture

* isolated to magnetic properties that are acknowledged to be novel and don’t rule out messier effect

* ignore other claimed properties like resistivity

Also, something explaining everything you are seeing is again a demonstration of an alternative, as is evinced by the material not being LK99, that claimed LK99 as a ceramic without a reliable method of production with a claimed low production rate (less than 10% of runs claimed by the original authors, with them claiming to have done over 1000 runs to produce their sample).

Again: I think it’s time for science to take the helm and hottakes to take a back seat for a while. I expect we will have something noteworthy either way by the end of the year. By the end of the month conclusions are fun gimmicks. I’m down with fun and love a good gimmick, but I’ll withhold belief in either direction until the original teams paper is released, their claimed sample is analyzed independently, more details of the claimed process are released to allow replication, and any novel properties have a stronger theoretical explanation. It’s extraordinarily unlikely they have found a room temperature super conductors, but not impossible. Regardless, they’ve discovered something novel and that, by definition to any scientist, is interesting.

For the half levitated ferromagnetic sample: isn't there torsional force where that disc touches the magnet?

At this point we have many examples where it's fully levitated.

all the full levitation videos are questionable in origin. I'd even go so far as to call every single one of them fake.

No credible reproduction has featured a levitating sample.

https://arxiv.org/abs/2308.01516

https://nitter.net/altryne/status/1686279028523847680

This is suspect because to balance a magnet like that you’d need to make it very very specifically to make it balance like that. Which means as soon as you flip it, it would not float. In the lk99 samples both sides can float

Just remember, it’s their sample that they theorize it is. A theory/guess does not rule out superconductivity. Their sample if slightly different could also cause these effects. We need more than one and especially a concrete way to make this before testing. The formula isn’t shown in details from the original paper

In the original video he flipped it 360 degrees off the center of the magnet yet it kept the angle it was pointed at. Wouldn't a ferromagnet want to stay orientated with the field of the magnet and flip the other direction when rotated?

That thread above has him flip the magnet and the same thing happens. Note the sample isn't magnetized itself, it's just ferromagnetic so conducts the field so the tip of the sample is the same and the top of the magnet (and this repels). That happens regardless of flipping the magnet.

Not flipping the magnet, rotating the sample. In https://nitter.net/VanGennepD/status/1688052003216261120 (the video with the rubiks cube) at around 20 seconds they rotate the sample around 360 degrees and it stays at the same angle. Normally I'd expect it would stay at the same angle of the magnetic field.

The above twitter thread it looks like he does that too with the ferromagnetic material. He has a long chain of posts although the first post after the original video has him rotate the sample 180 degrees on top of the magnet (still points up) and then again back to the original position. He does have it flop on top of the magnet at some point and has to poke it back upwards but that happens in the original video too so meh. The way the object moves is just too similar imho. It looks like plain old ferromagnetic material of that shape does this.

Out of interest - has this new paper been peer reviewed already?

Lol, so it was all super glue and iron!?

The only evidence of superconductivity is zero resistance. When you have a coil, pump it with current and let it rest for few years. If the current is still the same, it's superconductor.

Rest are just hints.

Oh look, I just found your superconductor! https://www.youtube.com/watch?v=wWpnsMdTrXg

5 years and still has current

not that simple, need to compensate for all external magnetic flux, crystal compression and so on.

We've levitated a living frog in a magnetic field.

Starting to remind me of the logic of the witch test in monty python and the holy grail.

If LK-99 has the same resistance as the weight of a levitating frog, it's a superconductor

What does it mean for an electrical resistance and a weight to be the same?

It means you ought to check the aforementioned monty python bit.

If your sample's resistivity goes down as it warms up, odds are you didn't make the same thing the Koreans did.

Since someone blamed "Soviet fan fiction" in which I did take a part (oops) [1], let's make my opinions explicit. I'm very sure at the moment:

- That the publish of two arXiv papers was accidental and the second paper was only published to claim the proper authorship, thus the exact publish date was never controllable.

- That top-tier Chinese universities do use Bilibili to post early results. This makes very hard to dismiss all Bilibili videos, though probably most would be.

- That you can produce something like the floating rock as seen in the original videos with a synthesis method similar to the paper states.

- That the synthesis method has an extreme variability depending on parameters. No single reproduced LK-99 samples are same.

- Thus, that Q-Center did make something according to this synthesis method as well, but that is probably different to other reproduced samples.

I'm cautiously positive that:

- That LK-99 is not a deliberate fraud. The most probable possibility at the moment is therefore an honest but misguided mistake. I still reserve a nonzero but not large probability (5%) that this is indeed novel to superconductivity.

- That LK-99 indeed has some peculiar properties when synthesis parameters are controlled right. The large variability does suggest singularities in the middle and Q-Center might somehow have gotten the jackpot.

- That at least some authors (notably Hyun-Tak Kim) are clearly distinguishing the superconductivity and superconductor [2]. In the other words, they are aware that LK-99 (supposedly) exhibits superconductivity but might not be considered as a superconductor.

- That there is a Russian group of scientists that claim some relevant knowledge and feel uneasy about the apparent dismissal of it. This might be the most controversial point I like to make, and my relative confidence partly comes from private information (like, I have verified the credential of Iris privately) so you don't have to completely trust me on this.

- That the research group has not settled on a single theoretical explanation. This is probably why all LK-99 papers were different from each other in theory, and also why Young-Wan Kwon became "disgruntled" as Hyun-Tak Kim might have been his substitute.

- That the late professor Tong-Seek Chair is indeed a madman, regardless of the veracity of his theory.

I have suspicions that:

- That the paper is intentionally vague about the synthesis method. This method is notably different from what their international patent describes, and this is AFAIK typical in the material science. Probably the paper describes a low-yield and low-quality but easy method, and their trade secret is an efficient process.

- That Russian scientists and possibly LK-99 folks do have some theory that describes LK-99 better. I had to slightly weaken this point in the previous article because the actual difference was very unclear to me and other proofreaders (we have discovered this during the rewrite to avoid apparent misreadings). I now suspect that there is no actual theoretical difference but different paradigms may have resulted in different blindspots. So the "acceptance" of theory without paradigm may be seen as the fake acceptance to them, possibly explaining their sentiments.

- That China realized this possibility as well and wanted to maximize their leverage, explaining why China universities go crazy about this.

- Therefore, under these assumptions, that Q-Center's apparently suspicious behavior can be fully explained.

I believe all of them needed me no advanced physics knowledge to derive. Any questions about those points are welcomed.

[1] See the original reply https://news.ycombinator.com/item?id=36996337 and the current version https://hackmd.io/@lifthrasiir/lk-99-prehistory for the context.

[2] https://hackmd.io/@sanxiyn/seize-interview

I realized that it might sound like that my points were changed after the fact. I want to make sure that the current replication efforts didn't affect my confidence of these points at all, because the research group has indeed predicted most difficulties in current replications including this (e.g. they thought searching for SC in single crystals hindered the research). The fact that Chair was a sort of madman makes it harder to talk about their intents, and my articles were written to highlight those aspects better.

Does that PDF have a video embedded?

Fun fact: You can even embed JavaScript-controlled 3D models inside PDFs

https://helpx.adobe.com/acrobat/using/adding-3d-models-pdfs-...

Why hasn't the west published anything on this?

Ah damn.

Someone on YouTube mentioned that LK99 is ceramic ie not metal which nullifies many of its potential uses even if it does turn out to be superconducting

YBCO is also not a metal and has also been hard to use, but it has its uses.

Do you have any idea how many crazy things are said by "Someone on YouTube"?

I thought LK-99 looked like bullshit from the start, but the conclusions of this preprint should really be confirmed and there's still a lot they don't understand about the behavior of the sample that should get more fully explained. And there might be something with this material showing semiconductor like behavior that could still prove more mundanely useful.

I knew it was fake, there would have been a huge rise in the stock market. Financial markets would have sniffed this out. The market never lies. If anything, this was an obvious opportunity to short it on prediction markets.

You're saying that, if this had been real, the stock market would have known about it before the scientific community? How exactly?

The markets do predict things but they can't synthesise correct information out of nowhere. Wall Street stock brokers weren't exactly going to sit down and start trying to replicate these results to see if they could cash in on it

Contrary to bored laymen on the internet willing to believe anything for escapism, the stock market usually reflect the outside view base probabilities (~0% in the case of LK-99 being real)

I would rather go with the large number of research groups who have scrambled to try to reproduce the results. They clearly did not estimate the probability to be 0. I don't see how any (correct, informed) predictions from the market could come about before experimental verification.

> The market never lies.

I suppose you weren't paying much attention in 2008.

That was probably the one time the market was being truthful before it all got pumped up again. Nothing to see here, move along!

The market isn't magic, it too would only rise with sufficient repeatable confirmation and indications of viability for mass production and application. After all, we do have knowledge of 'magic' materials like carbon nanotubes and graphene, and yet the stock market hasn't gone crazy over them.

> The market never lies

Whilst this can sometimes be true, e.g. Disney stock decline tied to "go woke go broke", in general this is demonstrably, incredibly false.

The market is based on a mix of widely known facts, speculation, hopes, dreams, fraud, and a bunch of other weird goofy phenomena.

If fake those researchers careers are over. Like, they'll have to go into programming or something. And they've also besmirched the good name of Korea, and their moms are going to beat the shit out of them for fucking up that bad. They've got a LOT to lose if this is fake, which is why I think it's most likely true. But hey, sometimes people just do crazy shit.

The paper was leaked by someone fired from the team months prior. The researchers still active were not satisfied with the state of their paper.

Impossible, wall street has some of the smartest scientists on the planet. They absolutely went through the research and determined it was a fake. Look at the AI boom, nasdaq rallied 40%. Superconductor would have had the same effect

Like how the markets caught on to Covid in early February 2020?

China shutting down, drowning in body bags, yet US markets don't flinch.

squints... can't tell if this is sarcasm. Microstrategy is still trading at like 2x their BTC holdings and so on and so forth, the AI boom is still in-progress and imo the jury is still out on the actual, real-world and $ implications... I think it's sarcasm.

...nothing happened to the markets ~2017 when the transformer architecture (behind the current AI boom) happened. Nor in 2020 when it was pretty obvious shit scales and generalizes well. ONLY when it got built into an actual product (ChatGPT) did the needle start to move.

Same with this, until someone figures out how to make WIRES from LK-99-like-stuff that can be made into useful MAGNETS, it will stay flat.

Markets may be very smart... but they're hyyyyyper-conservative :P (an it makes sense to be so, there's the $$$ powering agriculture and healthcare and pensions floating on the seas of markets nowadays).

Transformers in 2017 basically were just better at computing similarities between blocks of text. OpenAI really did take them and turn them into something new.

"room-temp semiconductors in 2023 were just small blocks of stuff levitating atop magnets without needing to be cooled. XYZ really did manage to produce them into useful shapes that still remain superconductive when you push more than 0.00001 amps through them"

Yea all those geniuses missed COVID completely though. And then the market overreacted in every way possible causing a crash then a rally that compared to nothing we have seen. Not sure the stock market tells us much of anything

Yes but LK-99 is practically unusable in current form if it's a superconductor. There needs to be a lot more material science research before it can be put into utopian use cases that everyone is dreaming about. Recent AI boom brought a lot more finished products which can be immediately put to use.

You know how there was a dotcom boom? Well the AI boom is just a repeat. Those who do not learn from history are doomed to repeat it. Save this comment and revist it in 5 years.

"Those who do not learn from history are doomed to repeat it."

somewhere I read the a good addition to this:

"and those who do know history are doomed to watch it being repeated"

I think you meant to say the REAL market never lies. Because the market obviously lies but the real market is whatever you say it is.

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