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Electronic Structure of LK-99

arxiv.org

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Re: Electronic Structure of LK-99

#361

Post by DeIonizedPlasma »

fragmede wrote: post #133
RandomBK wrote: post #27

Earlier quoted context omitted.

I'm not a scientist, but personally I expect I'll have two "wow, this is really happening" moments: (1) When there's peer-reviewed replication from a group of reputable labs. (2) When I see the classic superconductor-on-magnetic-track demo, but without liquid nitrogen.

https://nitter.net/lereguy/status/1686363900651151360 is no https://www.youtube.com/watch?v=zPqEEZa2Gis but it's on the way there!

The nitter video could literally be a piece of iron, even a ferromagnetic object will turn like that under the presence of a magnet. It certainly isn't proof that the thing they have there is NOT a superconductor, but you can't use that video as evidence of anything.

Re: Electronic Structure of LK-99

#362

Post by lucideer »

yreg wrote: post #328
lucideer wrote: post #288

For anyone interested in this topic, there's a thread on Twitter that's been garnering some attention: https://nitter.net/Errorreporrt/status/1685835688216821760

Could we please stop giving attention to the obnoxious anonymous Russian troll who's only proof is a photo of a spec of dust in a syringe, who says she 'didnt follow the paper beause she immediately invented a better way to make a room temp superconductor', who says she 'doesnt care about superconductors' and keeps tweeting USSR propaganda? I really don't get how she keeps getting recommended in these hacker news thr…

Not sure if you're implying she's cooked up a few crucibles at home purely for internet attention (nor what the relevance of her political views are here), but regardless the thread is interesting either way as it's generating lot of general interest in replication. This is perhaps a better link: https://eirifu.wordpress.com/2023/07/30/lk-99-superconductor...

Re: Electronic Structure of LK-99

#363

Post by selimthegrim »

objektif wrote: post #339
selimthegrim wrote: post #317

Earlier quoted context omitted.

They may have been throwing a bit of shade around lately but they are by and large reputable scientists barring whatever SDS’s past MA announcement involvement was. It’s more than just him there.

I do not (almost everyone else too) associate "reputable scientist" with University of Maryland. So they should show a bit of humility.

Show me where on the doll they touched you.

Re: Electronic Structure of LK-99

#364

Post by Workaccount2 »

wredue wrote: post #174
dekhn wrote: post #65

Earlier quoted context omitted.

Yes, a combination of fusion, superconductivity, and AGI would indeed be transformative. It's hard to anticipate what the results would look like. Good reading: https://en.wikipedia.org/wiki/Post-scarcity https://en.wikipedia.org/wiki/Kardashev_scale then follow it up with a bit of 1993, https://edoras.sdsu.edu/~vinge/misc/singularity.html and https://web.pa.msu.edu/people/yang/RFeynman_plentySpace.pdf (oh, huh, I ju…

We’re nowhere near AGI dude, even with several breakthroughs. AI today is a glorified search algorithm.

I hate to break it to you, but your brain is also just a glorified search engine.

Re: Electronic Structure of LK-99

#365

Post by adw »

computerfriend wrote: post #332
samhuk wrote: post #282

My ultimate take-away about LK-99 since the start has been that, even if it doesn't turn out to be a holy-grail or whatever, the novel ideas behind the material are incredibly interesting. The idea of causing tiny (~0.5%) crystal lattice shrinkage with cuprate percolation is a really interesting idea. So far, only huge pressures or very low temperatures (i.e. Physics) have been used to cause that shrinkage, therefore…

Physicists were by no means holding the chemists back. Condensed matter is full of chemists, it's the point at which the two subjects meet.

I’ve published in computational solid state. My doctorate is, on paper, in earth sciences (mineral sciences!) and you’re going to find all of the materials science department and a few engineers in the vicinity too. Solid-state is one of those five-way borders in the Benelux countries where everyone speaks three languages.

Re: Electronic Structure of LK-99

#366

Post by adw »

xorbax wrote: post #358
samhuk wrote: post #333

Earlier quoted context omitted.

Indeed. The separation between "Chemistry" and "Physics" completely breaks down when you start dealing with electron behaviours. I've actually got a little tin-foil-hat pet theory that Chemistry is slowly dying as it approaches "completion" of its roots (macroscopic phenomena of matter), and is gradually being subsumed by Physics. To at least a silly layman like me, lots of bleeding-edge Chemistry nowadays reads like…

Chemistry also covers nano/microscale. I'm not sure "macroscopic phenomena of matter" adequately describes it. Computational chemistry tends to be done in collaboratiin between specialists, especially after grad school. You also have to confirm things - you can compute whatever you like, but there's no way to know if your simulation reflects reality without confirmation. And in what way had physics has beaten chemist…

The big software unification driving this has been chemists moving to the (post-)DFT methods the materials people had to use, even for some of their small molecule work. Oversimplifying wildly, a lot of small molecule chemistry is driven by medicine and they started caring a lot about, for example, ab-initio protein models…

As many other people have said, there is no physics or chemistry in solid-state materials; most universities will have multiple groups in this area across three to five different departments (physics, chemistry, materials science, materials engineering, earth sciences).

(The reason materials people were on DFT is that you need to simulate more atoms to model a material. Standard DFT methods scale as O(n^3) with system size, and there are linear-scaling methods like SIESTA and ONETEP; many computational chemistry methods like Configuration Interaction are much worse.)

Re: Electronic Structure of LK-99

#367

Post by cthalupa »

DeIonizedPlasma wrote: post #361
fragmede wrote: post #133

Earlier quoted context omitted.

https://nitter.net/lereguy/status/1686363900651151360 is no https://www.youtube.com/watch?v=zPqEEZa2Gis but it's on the way there!

The nitter video could literally be a piece of iron, even a ferromagnetic object will turn like that under the presence of a magnet. It certainly isn't proof that the thing they have there is NOT a superconductor, but you can't use that video as evidence of anything.

Iron and ferromagnetic objects would not react that way. The key to this showing diamagnetism is the fact that the same points are repelled in the same way regardless of the orientation of the magnet. If it was ferromagnetic, you could have it stand up on it's tip in one polarity and stand up on another portion of the object in the other polarity, but you couldn't make it stand up on it's tip both times.

Re: Electronic Structure of LK-99

#368

Post by marcosdumay »

baq wrote: post #307
weinzierl wrote: post #238

Earlier quoted context omitted.

This is probably a very stupid question, but why is simply measuring resistance not enough to conclusively prove that it is a superconductor. I mean, isn't zero resistance the defining property?

Measuring zero resistance turns out to be quite difficult because your measuring apparatus tends to have some resistance in itself. Perhaps heating it up while it levitates would be a better idea. Put the magnet in an oven together with the sample and bake?

Magnets have an annoying tendency to stop working when they are heated.

And it's ridiculous that I'm saying that on the context of testing a superconductor. But well, here we are.

Re: Electronic Structure of LK-99

#369

Post by marcosdumay »

itsoktocry wrote: post #318
xvector wrote: post #213

Earlier quoted context omitted.

Impact of superconductors: https://threadreaderapp.com/thread/1685088625187495936.html

"1970: Superconducting trains to go from New York to LA in 20 minutes!" 50+ years later the US has how many high speed trains, of any kind?

I guess that's partially missing the point. The main benefit of a superconducting maglev is that it's cheaper to build than a on-rails high-speed train. Specially on problematic terrain (what I understand includes every possible East/West route on the US).

Re: Electronic Structure of LK-99

#370

Post by bradfox2 »

adw wrote: post #365
computerfriend wrote: post #332

Earlier quoted context omitted.

Physicists were by no means holding the chemists back. Condensed matter is full of chemists, it's the point at which the two subjects meet.

I’ve published in computational solid state. My doctorate is, on paper, in earth sciences (mineral sciences!) and you’re going to find all of the materials science department and a few engineers in the vicinity too. Solid-state is one of those five-way borders in the Benelux countries where everyone speaks three languages.

My MSE dept was also colocated with mining engineering. Evolved from the metallurgy dept of a past era. We seemed to have a foot in manufacturing, computational materials, theory and chem lab.
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