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Electronic Structure of LK-99

arxiv.org

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Re: Electronic Structure of LK-99

#131

Post by montecarl »

dekhn wrote: post #36
rsfern wrote: post #28

Earlier quoted context omitted.

Sure it’s post hoc, but these are ab initio calculations, there’s not all that much wiggle room that you could make anything you like come out looking like a superconductor. Plus now I’ve seen three calculations with three different functionals and reasonable convergence criteria and they all find similar electronic structure

Well, then why spend all this time searching in a lab? Instead, run a bunch of simulations until the compounds with properties you desire just sort of pop out as the top hits in your simulations? (I say this as somebody with a decade+ of experience running large ensembles of classical MD simulations, but not so much experience with inorganic DFT)

Crystal structure prediction by itself is a very hard problem. Just given the chemical formula and asking "what is the most stable structure" is a global optimization problem. And this is just for one single composition. It isn't an easy global optimization problem either. You not only have to determine the unit cell vectors, the positions of the atoms in the unit cell, but also the number of atoms in the unit cell needed to represent the structure! Just because you are even given "Pb9Cu(PO4)6O" as the formula finding the most stable structure, let alone the superconducting non-minimum energy state is a huge undertaking. Now expand that to all of chemical space and you can see that it is not that easy!

Edit: Also look at how long these (short pre-print) DFT articles are. These aren't simple calculations to interpret.

Re: Electronic Structure of LK-99

#132

Post by xorbax »

bluecoconut wrote: post #73
SamPatt wrote: post #23

Earlier quoted context omitted.

Thanks for your input. What would you need to see to say "I am 100% convinced this is / isn't real"? And how long would you expect it will be before that occurs?

I'd probably approach 90% confidence with ~2-3 different measurements from different labs showing similar stories. Select from the grab bag of possible experiments that could all collaborate and provide consistency in their stories: specifically things like measuring the critical current, critical magnetic field, high quality electrical resistance in various ways (lots of transport), STM measurements of gaps, ARPES m…

I think a funded and forward-thinking lab with enough postdocs would be trying to grind out a version replacing lead with gold, per the DFT calculations

Few will remember the million replications, but whoever describes a novel version - even if it's no better - will find themselves on equal footing for helping to understand what's happening

Re: Electronic Structure of LK-99

#133

Post by fragmede »

RandomBK wrote: post #27
SamPatt wrote: post #23

Earlier quoted context omitted.

Thanks for your input. What would you need to see to say "I am 100% convinced this is / isn't real"? And how long would you expect it will be before that occurs?

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!

Re: Electronic Structure of LK-99

#134

Post by m3kw9 »

NotYourLawyer wrote: post #59
jeffbee wrote: post #16

The most interesting phenomenon revealed so far is that the room-temperature superconductor people and the generative-LLMs-are-God people draw on the same limited global pool of credulity, such that HN cannot be flooded with both ChatGPT worship and superconductor speculation at the same time.

And together, these two phenomena have just sucked all the energy out of the crypto excitation mode.

Web 3.0 was so exciting with btc at 64k

Re: Electronic Structure of LK-99

#135

Post by xtracto »

refulgentis wrote: post #45
sheepscreek wrote: post #42

Earlier quoted context omitted.

On a related note: I am deeply disappointed by how OpenAI has managed to continually dumb down ChatGPT. I’m sure the shortage of NVIDIA H100s and the demand for their APIs shooting through the roof has something to do with it. Perhaps they’ve switched to a quantized model? Who knows. And yes, LLaMA 2 is awesome. Progress is being made. But it’s slowed down. The novelty’s worn off. Now we’re lacking some fundamental p…

It's not dumber. You can verify this on their models with any prompt you ran at 0.0 when it first came out, I did. It's the exact same model run the same exact way. They've repeatedly confirmed this.

Ooh I have some nice book chapter summaries that ChatGPT generated for me when it first came out. I got them in a Google doc.

If you ask GPT to give you the same thing now, it wont , no matter how hard you try.

That's like hard evidence for me that they've dumbed it down.

Re: Electronic Structure of LK-99

#136

Post by xorbax »

xtracto wrote: post #127
JamisonM wrote: post #113

Earlier quoted context omitted.

> 3. In May we find out apparently our government has recovered alien technologies This is a silly thing to include on the list since it doesn't seem to be true?

What's up with that uh? I read about the swore statements during the depositions, and all the mainstream media news, but for some reason HN had radio silence. Is there something I missed that shows it's all shenanigans?

They (1) claim not to know what the craft are, which somebody told him contained (2) nonhuman biological whatever

It could be a Chinese drone with rat-cell-on-a-chip inside it

The guy's testimony was that somebody told him stuff and it seemed scary. Congress made a dog and pony show that a significant chunk of people attended.

Parse the details, not the overarching fantasy.

The government admitted to doing this in the 70s-90s to keep not-so-strange technology hidden behind The Strange. Trim with Occam.

The ticTac videos aren't interesting if you look at the limitations of perspective and remember that Air Force pilots aren't supreme authorities for objectively assessing parallax and assigning airspeed to all moving objects while flying a fucking cracker attached to a rocket.

Re: Electronic Structure of LK-99

#137

Post by TuringTourist »

xtracto wrote: post #127
JamisonM wrote: post #113

Earlier quoted context omitted.

> 3. In May we find out apparently our government has recovered alien technologies This is a silly thing to include on the list since it doesn't seem to be true?

What's up with that uh? I read about the swore statements during the depositions, and all the mainstream media news, but for some reason HN had radio silence. Is there something I missed that shows it's all shenanigans?

Sworn statements with no evidence don't merit much scrutiny. Especially when it comes to extraordinary claims.

Re: Electronic Structure of LK-99

#138

Post by zarzavat »

xtracto wrote: post #127
JamisonM wrote: post #113

Earlier quoted context omitted.

> 3. In May we find out apparently our government has recovered alien technologies This is a silly thing to include on the list since it doesn't seem to be true?

What's up with that uh? I read about the swore statements during the depositions, and all the mainstream media news, but for some reason HN had radio silence. Is there something I missed that shows it's all shenanigans?

Pics or it didn’t happen. After years of claimed room temp superconductors people believed this one because it had a video of a floating rock. Aliens are an even more extraordinary claim, I’m going to need multiple close up videos before I even start to care.

Re: Electronic Structure of LK-99

#139

Post by calgarymicro »

UberFly wrote: post #35

Several commenters here have mentioned demonstration videos. Does anyone have a link(s) to these? Many thanks.

Try the sources column in this[0] table. You can expand the notes for each entry to read more. There's also this one[1] that's on the front page right now, though its provenance is questionable.

[0]https://forums.spacebattles.com/threads/claims-of-room-tempe...

[1]https://news.ycombinator.com/item?id=36964107

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