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Electronic Structure of LK-99

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Re: Electronic Structure of LK-99

#351

Post by jacquesm »

oxfordmale wrote: post #283
Baeocystin wrote: post #104

Earlier quoted context omitted.

Serious question- I saw the original video, where once they stopped waving the magnet around and held it near the sheet of LK-99, it looked to me like it stayed at a specific standoff distance, with no decay. Assuming no videographic trickery, what else could it be, other than the Meissner effect?

The Meissner effect requires a temperature transition in the diamagnetic behaviour. As you increase the temperature, you would expect a sharp drop with the material falling back on the magnet, and then levitating again once the temperature drops.

Yes, if you know the upper boundary for the temperature up to which the material stays superconducting. But that's a bit of a problem: this material is claimed to be superconducting to very high temperatures. It just could be that it isn't all that easy to reach a temperature where this stuff stops being superconducting. In fact I see no particular reason in physics why it would have to stay below the temperature at which the material disintegrates. So maybe that part of the effects is simply a reflection of the fact that these superconductors that work well below zero are in fact exactly there because they require a cold environment and once you find one that doesn't that whole aspect goes away, it could stay diamagnetic all the way up to its melting point.

Re: Electronic Structure of LK-99

#352

Post by jjk166 »

irthomasthomas wrote: post #227
bluecoconut wrote: post #12

I got my PhD studying band structure of high-tc superconductors (experimentalist, ARPES). These Cu d-d interactions right at the fermi energy give me huge hope. Feels very familiar to other superconductors (re: all the cuprates). (Note: I specifically worked in a lab that was measuring a lot of the d-wave character / gap-energies of various superconductors) All in all, I'm now much more bullish on LK-99 being real su…

I think we're being trolled. Or trawled. Not sure which, yet. But the mention of Salvatore Cezar Pais in the patent should be enough to put this to bed for serious folks. https://news.ycombinator.com/item?id=36967333 In case you aren't familiar with the man's work, here are some highlights of his discoveries over the last decade: Conditional possibility of spacecraft propulsion at superluminal speeds High frequency g…

If something is prior art, you need to include it, regardless of the source. Even fictional descriptions of technologies can be prior art. For example, Samsung used 2001 A Space Odyssey as prior art to invalidate Apple's patent on ipad-like tablets.

Re: Electronic Structure of LK-99

#353

Post by fodkodrasz »

TheSpiceIsLife wrote: post #260
TheSpiceIsLife wrote: post #220

Earlier quoted context omitted.

Not any conductive material, obviously won’t work won’t work, nor magnetic steel / stainless steel alloys.

I meant: obviously iron won’t work.

Could you elaborate why iron pipes wouldn't work?

Re: Electronic Structure of LK-99

#354

Post by shawnz »

pjc50 wrote: post #273
jacquesm wrote: post #209

Earlier quoted context omitted.

Jeffbee in the 1947 edition: The most interesting phenomenon revealed so far is that the solid state electronics people and the rocket fanatics people draw on the same limited global pool of credulity, such that TinkererNews cannot be flooded with both transistor worship and moon travel speculation at the same time. Seriously: if it doesn't interest you, you could simply refrain from commenting and even reading. This…

I think we're all horribly burned out by pop-science. How many battery "breakthroughs" have we seen on here? Meanwhile what actually works is incremental improvement in lithium battery manufacturing. The 1947 Golden Age SF is interesting because the "rocket fanatics" peaked in 1969 and humans haven't gone back to the moon, let alone conquered space. While the transistor succeeded to an extent nobody imagined due to t…

> I think we're all horribly burned out by pop-science.

Speak for yourself, I'm happy to lend my positivity to people who think they might be close to breakthroughs even if they are unlikely moonshots, and you better believe I'll be maximally hyping up my own work if I ever feel like I am close to some kind of breakthrough too. That's part of the fun of being a living thing in this weird physical universe.

Re: Electronic Structure of LK-99

#355

Post by jjk166 »

evergreener wrote: post #344
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…

Is there an intuitive explanation of why shrinkage of a material is beneficial for superconductivity. Naive question, particles physicist by training.

When a material shrinks, it can create immense internal stresses equivalent to what it would experience at extreme pressures. Compare to say a Prince Rupert's drop.

Re: Electronic Structure of LK-99

#356

Post by jboy55 »

JumpCrisscross wrote: post #181
jboy55 wrote: post #148

Earlier quoted context omitted.

Regarding #1, it pains me to see so much hype about this feat. To restate it. We were able to simulate the implosion of the secondary stage of a thermonuclear device in a lab by the means of lasers, to the point that this simulation has ~ 0.001% the efficiency of a real device. We also probably learned a lot about the amplification of x-rays by the casing material that would have been useful during the SDI days of th…

> It was a weapons test, by a weapons lab Beyond a certain point, every energy system is a weapon first. Uncontrolled precedes controlled.

I'm not sure I follow, if I were to define "Energy System" as a system to create or utilize energy, I can think of a half dozen that never were weapons. Solar, Wind, Natural Gas, Coal, Hydro.

If you define energy systems to mean nuclear energy systems, then we only have one, which is fission.

But in the end, this test was specifically designed to test the nuclear weapons stockpile by feeding real data about implosions, by means of ablation by x-rays, back into the computer simulations that have been developed in the last couple of decades.

In review, implosion by ablation of a material by x-rays is the mechanism speculated that the primary fission nuclear device triggers the secondary fusion device in an H-bomb. So, they are not trying to figure out how to produce power or even understand fusion, but they are modeling the characteristics of a specific part of a bomb, so they can know how to test a 50 year old h-bomb without setting one off.

Re: Electronic Structure of LK-99

#357

Post by sjcsjc »

soligern wrote: post #32
redrobein wrote: post #29

Earlier quoted context omitted.

Any conductive material for the tube will have a similar effect. It isn't specific to copper. The moving magnet induces a current in the tube which in turn creates the magnetic field that interacts with the magnet.

Eddy currents

“Eddies,” said Ford, “in the space-time continuum.”

“Ah,” nodded Arthur, “is he? Is he?”

Re: Electronic Structure of LK-99

#358

Post by xorbax »

samhuk wrote: post #333
jhrmnn wrote: post #314

Earlier quoted context omitted.

Condensed matter physics and materials chemistry certainly become inseparable in certain areas

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 chemistry in the case of LK99? They did a post-facto DFT calculation supporting the apparent results, which may or may not be real.

It seems like an illustration of why chemistry is as robust as ever.

Re: Electronic Structure of LK-99

#359

Post by jlokier »

pests wrote: post #350
pjc50 wrote: post #292

Earlier quoted context omitted.

mRNA vaccines are a huge discovery, not quite as powerful as room temperature superconductors but still up there in terms of impact on humanity. And encountered a very different kind of skepticism while ultimately turning out to be not only real but widely deployed with great speed.

Haven't mRNA vaccines been in development for over a decade though?

LK-99 has been in development for longer, 24 years, if you believe a quote copied in many current articles and below. You may have heard before, "it takes years of work to become an overnight success..."

> Lee & Kim had been working on the material on and off since Kim was in graduate school in 1999 (LK-99 geddit?). Lee never makes tenure and is still stuck as an adjunct professor 19 years later. Kim goes off to work in battery materials for a decade plus. 2018 - they get funding from industry for another go at it.

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