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Superconductor news: What’s claimed, and how strong the evidence seems to be

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Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#421

Post by stu255 »

zarzavat wrote: post #413
foven wrote: post #152

Earlier quoted context omitted.

Agreed, this looks bogus. Some suspicious points: In the first paper, they claim to measure zero resistance (on a scale of microvolts), but are very careful not to show full RvT curves - in the second paper, we can still see significant changes below Tc where they include more complete curves. How can the resistance change significantly in the superconducting (zero resistance) state? We can actually see significant n…

> if you just made a groundbreaking discovery like this, wouldn't you care? Hell no! If I had made a discovery of similar magnitude I would have done exactly what they’ve done: push out a rough preprint ASAP to reserve my Nobel prize, then take a deep breath, relax and take my time dotting ‘i’s and crossing ‘t’s for the real paper in Nature. That doesn’t mean they’re correct, but there’s nothing inherently suspicious…

Exactly, they have made a very big claim and made it very easy to replicate / falsify. It takes a few days to produce this stuff.

Their paper is weak on data / results.

This is exactly what you would do if your team genuinely believed you had discovered something monumental.

In poker terms they are "all in" and they want to get called.

That's why it is so interesting. If they had posted lots of extreme results but it needed $10m to replicate then I would be thinking "fraud". It would look like a bluff.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#422

Post by Linosaurus »

blagie wrote: post #281
mlyle wrote: post #223

Earlier quoted context omitted.

> I’ve never understood how this battle could possibly persist, considering that planes can fly upside-down. That's orthogonal. Planes flying upside down still have air flowing faster over the new "top" of the wing than the bottom. Though, a common misunderstanding is that air must be taking the same "time" to go over the top and the bottom. This is not true. You can build a pretty good mental model of flight with ei…

> You can build a pretty good mental model of flight with either simplified mechanism, but you end up underestimating performance by a fair bit. I've never hear of a good mental model built on Bernoulli's Principle. They are either: - Wrong - Give no intuition The key question is /why/ air moves faster on one side, and once you get away from the misconception of same time, I've never heard an intuitive argument. Redi…

> The key question is /why/ air moves faster on one side, and once you get away from the misconception of same time, I've never heard an intuitive argument.

Since the air follows a curved surface instead of straight ahead, you could perhaps apply your intuition for centrifugal force. Momentum sort of pulls the air away from the surface.

I’m not even sure this explanation is wrong.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#423

Post by mromanuk »

MVissers wrote: post #415
RyanAdamas wrote: post #404

What if the team itself did create LK-99 that is a superconductor, but they aren't able to reproduce it and only have the sample left that works. Hence, they aren't able to make more of it to prove their success, but rather decided to release the paper and method so that others can try to reproduce it. Given the amount of interest, they could put hundreds of labs to work trying to recreate what they themselves can't,…

The most likely explanation based on the authors in the two articles is infighting, where one researcher decides to publish an uncomplete manuscript with his name as the third author. He’s omitted from the second author. I do believe they believe they have something nobel-prize worthy. They offered to help with replication in other labs, which is a good sign. Could still be measurement error, we just need to wait unt…

How long does it take to get a replication? I would love to follow up this kind of news, directly from a the researchers doing the work. Is there anyone to follow on twitter to keep posted on this?

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#424

Post by stu255 »

hatsunearu wrote: post #122
carabiner wrote: post #92

Researcher on reddit thinks it's probably spurious measurement artifacts, not superconductivity: > I would say they are not faking it, but instead they just don’t understand what they are looking at. Based on what measurements they are doing, as well as how they are doing them, they do not have a good understanding of the standard processes to characterise a superconductor. Also, based on their analysis/discussion, t…

I'm not a materials scientist but an electronics guy. > 1b) shows the resistivity at some unknown temperature. They are applying current and measuring no potential drop. Just what? First, state the temperature, next measure it as a function of temperature. At the critical temperature the resistance drops to zero. All they have shown is that the contact inputting the current is probably disconnected… this does not pas…

You realise two of the authors (Lee and Kim) discovered this in 1999 (hence LK-99), and only published this paper after a huge fall out within the research team?

This isn't 1 experiment. This is 20 years of research leaking because of a fight over credit.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#426

Post by gus_massa »

amai wrote: post #371

"I am not enough of a solid-state physicist to judge this proposal,..." I stopped reading after this confession of the author. So this text is just as good as a opinion of some other random guy.

The articles about chemistry of this author are very good. I studied a specialty in Chemistry in secondary school (12-18), so I can evaluate most of them but the details are usually above my level. When posted here his post get good comments and I upvote most (all) of his stories.

His conclusions here are similar to the hivemind opinion in the first post https://news.ycombinator.com/item?id=36864624 My takeaway is:

1) It must be confirmed. (And if confirmed it's huge.)

2) The method to make the material are very easy (if you have a good lab)

For me, this post confirm that the chemistry part makes sense. Perhaps there was something weird abut the composition of the ceramic. Perhaps about the method to make it? If he says that it looks fine, for me it's a nice confirmation that it makes sense.

The explanation of the effect using "quantum wells" is more strange. I feel it's suspicious and that it will be explained in a different way in the future. Anyway, I'm neither an expert in superconductivity, so I may be wrong. I don't know his opinion about the "quantum wells" but I guess he also is not an expert in that field to evaluate it.

Superconductivity is a field where the experimental results usually arrive long before the theoretical ones, so assuming this is new material is true, it is possible that we get a lot of new materials in the next 10 years and a good theoretical explanation in 50 years.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#427

Post by jerf »

ddalex wrote: post #377
salty_biscuits wrote: post #356

Earlier quoted context omitted.

You can write out the equations of motion for a bicycle that will very accurately predict the dynamics. You can put these equations into a numerical simulation and predict motion very accurately. You can change the parameters of the model and do simulations with high confidence. Just because there isn't some neat little equation that says exactly what each parameter change is going to do (without doing the simulation…

You are contradicting yourself: > You can write out the equations of motion for a bicycle > there isn't some neat little equation that says exactly what each parameter change is going to do I mean, if you have the equations you can see what each parameter is doing !

Something smaller than may help you grasp this idea: https://www.youtube.com/watch?v=5nW3nJhBHL0

There are things we can characterize to any desired degree of accuracy but that e don't get cute little equations out of... and some of those things are so simple they've been staring you in the face since middle school and you just didn't ever notice their absence from your formula sheets.

This is not the exact same situation being described but it's a similar thing. Being able to put a complex system into a computer and arbitrarily manipulate it still doesn't mean we can extract some simple explanation.

On the other end of the scale, see all the AIs coming out. They're 100% computer artifacts with theoretically no mystery in them whatsoever... but they're just tables of billions of opaque numbers and doing anything with the numbers beyond just running them is amazingly difficult.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#428

Post by glenstein »

akjssdk wrote: post #54
mmastrac wrote: post #12

This is an extremely useful summarization of the original paper. > The authors believe that the modified/strained structure of their material creates a large number of “quantum wells” between particular lead atoms and the adjacent oxygens of the phosphate groups bound to them, in effect making a two-dimensional “electron gas”. They propose that electron tunneling between these quantum wells, which are between 3.7 and…

I don't think the actual proposed superconductivity mechanism is the relevant part of this paper. It is much easier to prove that this is superconducting than to prove why. And in a sense it is a bit less relevant. Although developing a working theory for room temperature is also probably worth a Nobel prize, so I am willing to bet some theorists are also running to their blackboards as we speak.

>I don't think the actual proposed superconductivity mechanism is the relevant part of this paper. It is much easier to prove that this is superconducting than to prove why.

As another commenter has pointed out, the proposal of a new mechanism seems to be extraordinary and novel, and could lead to an explosion of new research, so it does indeed seem to be "relevant" on its merits.

I also don't see this as a case of the "why" being left unexplained. In the history of superconducting it has indeed been the case that new cocktails have led to superconductivity without the underlying why being understood. But the commenter that you're responding to quotes part of the paper that shows an awfully specific mechanism.

I understand the sense in which there can be a "why" that remains to be explained in certain circumstances, even when you have a mechanism. Who do monarch butterflies have the black and orange pattern on their wings? There's a cause and effect answer but there's also a "why" answer. But with superconductivity, the mechanism is the why, unless I'm misunderstanding here. If other forms of superconductivity rely on other mechanisms, there isn't going to be a general why connecting this case to the other cases, but nor is there anything left unexplained just by explaining the "why" of this case by explaining it's extraordinary mechanism.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#429

Post by glenstein »

fnordpiglet wrote: post #318
akjssdk wrote: post #54

Earlier quoted context omitted.

I don't think the actual proposed superconductivity mechanism is the relevant part of this paper. It is much easier to prove that this is superconducting than to prove why. And in a sense it is a bit less relevant. Although developing a working theory for room temperature is also probably worth a Nobel prize, so I am willing to bet some theorists are also running to their blackboards as we speak.

I’m not entirely sure that’s true. A posit in the paper is this is a novel super conducting mechanism and as such if the mechanism is true it’s totally unexplored. That leaves open a huge field of new research. That’s certainly a relevant part of the paper. Super conductivity at room temperature is an amazing breakthrough alone, but if it was with a clever tweak with an existing well established technique that would…

Right. The mechanism itself seems extraordinary. And it seems like that mechanism is exactly the "why", the commenter is claiming is more important.

Moreover, you can have more than one thing about a paper be the "relevant" thing.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#430

Post by PawgerZ »

RyanAdamas wrote: post #404

What if the team itself did create LK-99 that is a superconductor, but they aren't able to reproduce it and only have the sample left that works. Hence, they aren't able to make more of it to prove their success, but rather decided to release the paper and method so that others can try to reproduce it. Given the amount of interest, they could put hundreds of labs to work trying to recreate what they themselves can't,…

I have never worked with super conductors, but I did talk with people who have and read every comment on hacker news. From what I can gather, people already make YBCO superconductors in their garage, and this doesn't seem much different in difficulty. Many people have said that it's simple enough that they expect youtube tutorials on how to make it in a week or two.
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