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LK-99 isn’t a superconductor

nature.com

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Re: LK-99 isn’t a superconductor

#231

Post by exmadscientist »

parker_mountain wrote: post #110
transcriptase wrote: post #88

Earlier quoted context omitted.

Most PhDs are incredibly specific and don’t necessary indicate broad knowledge of a field as a whole. Which is why you should be wary of “experts” making overly broad claims about topics within their field but far outside their area of expertise. Early on during Covid you would see postdoc infectious disease experts on every news channel 3 times daily giving their takes. Some of whom maybe took a 3000 level course in…

> Technically an infectious disease expert but I don’t particularly care what they have to say about Covid over a random person on the street either. I would absolutely care more what they had to say over the rando, especially if they prefaced it with their level experience.

Yeah, uh, I wouldn't.

There was a B- or C-list physics blogger a few years back whose graduate homework I used to grade. (I still remember this one, so that should tell you something.) He got very angry that I gave him zero credit for one particular question. But he:

- did not use the standard/expected approach to this problem

- did not explain what he was doing well enough for me to find him any partial credit (this is not easy!)

- had a pile of impenetrable unnecessary very complex alien math that I wasn't going to try to cut through given that

- his final answer was very, very wrong

- in fact, it was wrong by 26 orders of magnitude

- and he didn't have the skill to notice something was wrong (and, yes, I was lenient with students who noticed final answers were weird even if they couldn't/didn't fix it up)

- also, he was a major asshole (no surprise given that he's complaining about this "indignity") who was

- somehow still causing #MeToo problems in the 21st century despite being under 30 (seriously??)

So if that's who gets held up as "authorities", even minor ones, forgive me if I don't listen too much. I'll choose who I trust.

Re: LK-99 isn’t a superconductor

#232

Post by __MatrixMan__ »

paxys wrote: post #212

[flagged]

Agreed:

> going viral on TikTok isn't the new peer review

Not so sure:

> science is still best done the old fashioned way

It's not surprising that social networks designed to serve ads aren't outperforming scientific journals at deriving scientific consensus. But it would be interesting to see how the journals stack up to a social network that was designed for deriving scientific consensus.

Re: LK-99 isn’t a superconductor

#233

Post by philomath_mn »

rvz wrote: post #172

This only proves that you shouldn't believe such random 'breakthroughs' on the internet, these days. What a shame, but the attention seeking and hype clearly worked and duped many here. Even though they won't admit that they fell for the hype. Be a bit skeptical next time.

> hype clearly worked and duped many here

What was the benefit to those doing the hype? What was the harm to those being "duped"?

I certainly went through periods of waxing and waning belief, but now that the dust is settled I don't think I am any worse for the wear.

It's not like this was a garden variety pump-and-dump or anything like that.

Re: LK-99 isn’t a superconductor

#234

Post by shawabawa3 »

stetrain wrote: post #170
jauco wrote: post #168

(I am very much a layperson) So does this mean that the videos that showed LK-99 hovering but not rotating are fake? Or can you have that static hover effect without being a superconductor?

> In the video, the same edge of the sample seemed to stick to the magnet, and it seemed delicately balanced. By contrast, superconductors that levitate over magnets can be spun and even held upside-down. “None of those behaviors look like what we see in the LK-99 videos,” van Gennep says. > He thought LK-99’s properties were more likely the result of ferromagnetism. So he constructed a pellet of compressed graphite…

That explains the half levitation

A few videos came out of full levitation, but it's pretty certain they are fake

Re: LK-99 isn’t a superconductor

#235

Post by [deleted] »

earthboundkid wrote: post #60
thinkingkong wrote: post #2

It’s disappointing news but the excitement and amount of replication on this paper was pretty fun to witness and experience. To me the most interesting part was everyone talking about potential consequences, uses, the order of magnitude improvements we’d see in certain costs or areas. Pumps, MRIs, power grids, chips, etc. Great reminder what materials science can do to some underlying economics.

The real superconductors were the friends we made along the way.

[deleted]

Re: LK-99 isn’t a superconductor

#236

Post by floxy »

iraqmtpizza wrote: post #178

I don't see how 0.002 ohms per cm could be confused with superconductivity. Is that not orders of magnitude too high? Or there are no instruments which can directly measure resistance more precisely?

The units for resistivity would be ohms*cm (Ohms times a length), not Ohms per cm. Then if you divide by the cross-sectional area of a sample, you would get the resistance per length.

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

Re: LK-99 isn’t a superconductor

#237

Post by sorenjan »

Sixty Symbols released a video about this yesterday, and in it professor Philip Moriarty is less than impressed with the whole ordeal. I haven't been paying attention, I'm too jaded and skeptical and assumed from the start that there was something wrong and much hype about nothing.

Bad Science and Room Temperature Superconductors - Sixty Symbols: https://www.youtube.com/watch?v=zl-AgmoZ5mo

Re: LK-99 isn’t a superconductor

#238

Post by _lqaf »

tysam_and wrote: post #182
okamiueru wrote: post #165

Earlier quoted context omitted.

I think this kind of excitement followed up with "wasn't anything after all" is both dangerous and wrong. When science is done badly (which arguably shouldn't be considered science), which then leads the public to have elevated expectations, only then for science to be done right and disprove and reject the original "findings", public trust in science is ever so slightly damaged.

I think you're conflating PR with the science underneath. PR is something we cannot control -- and avoiding releasing results in a (semi-vain?) attempt to control PR arguably does more harm than releasing them does. The sea makes waves as it will. We can moderate as much as we are able. I think the rest is simply a matter of accepting that things happen as they do out of our control. We can only truly impact ---- and…

Furthermore, preemptively reacting to expected third-party behaviors is doomed.

Journalists are going to write nonsense, hype-filled science articles. PR flacks are going to hype puff newswire blurbs. Why? Because that's what they're paid to do.

You can curse the existence of bad incentives, if you want annoying ideologues to call you a communist.

Or you can hire your own PR flacks. Because worrying about how people will react to what you're doing is PR, and going up against professionals without your own is like going to court without a lawyer.

Or you can just, you know, do science, accept that people suck sometimes, and get on with your life.

Re: LK-99 isn’t a superconductor

#239

Post by masklinn »

djtango wrote: post #132
vecter wrote: post #14

In their preprint, the Korean authors note one particular temperature at which LK-99’s showed a tenfold drop in resistivity, from about 0.02 ohms per centimetre to 0.002 ohms per cm. “They were very precise about it. 104.8ºC,” says Prashant Jain, a chemist at the University of Illinois Urbana–Champaign. “I was like, wait a minute, I know this temperature.” The reaction that synthesizes LK-99 uses an unbalanced recipe…

So they saw a large change in resistivity at 104C but what's not clear from this excerpt is why the Cu2S was a confounding factor, or isnt interesting. Is it that LK99 had impurities of Cu2S and the properties of Cu2S dominated but we already know things about Cu2S?

Per the article, CU2S was well-characterised in the 50s.

The CU2S was a confounding factor because 104C is where it undergoes phase changes, which drastically change its resistivity. So the change in resistivity was from the CU2S impurities, not the LK99 itself. As the tail end of the article notes, when researchers grew a completely pure crystal of LK99 they got a strong insulator (in the mega-ohms).

And as a nearby commenter notes, neither 0.02 ohm-cm nor 0.002 ohm-cm is even a good conductor: typical conductor metals (gold, copper, silver, aluminum) are under 3e-6.

Re: LK-99 isn’t a superconductor

#240

Post by philomath_mn »

throwaway4220 wrote: post #220

“ Derrick van Gennep, a former condensed-matter researcher at Harvard University in Cambridge, Massachusetts, who now works in finance ” This is always sad to see but I get it

Many such cases (most of the quants at my last job had PhDs in Physics or Chemistry)
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