All in all, I'm now much more bullish on LK-99 being real superconductivity after seeing multiple different labs compute similar band structures. The video of multiple directions of magnet showing some levitation also inspires a lot of hope.
As someone who is versed in semiconductor band structures but not superconductor band structures: What is it about Cu d-d interactions that causes the superconductivity?
Degenerate energies in semiconductors don't give rise to electron pairing, so I'm a bit out to sea with the proposed mechanism here.
Roughly, one of the "properties" that shows up with these materials is that the 3d orbitals of coper atoms are involved in forming the bands near the fermi level. Couple that with the fun story of Cu electron configuration being [Ar] 3d^10 4s^1, which suggests that spin-effects are "at play" with these electrons near their filling levels. Combine that with the spin-character properties of cuprate paring (eg. s-wave vs. d-wave superconductors, (d-wave for BSCCO for instance)). All together it lends itself to a nice spin-orbit coupled band "setup" at the fermi energy that I have a hunch somehow backs the underlying mechanism of these d-wave superconductors. Fully admit, there's some leaps there in the raw logic -- if I could fully explain it I probably would still be in the field, haha.
I'll note: I've been out of the field for ~8 years, but a quick google search led to some more recent papers [1][2] working through plausible explanations based on some of these copper d orbital shenanigans.
[1] https://www.scirp.org/journal/paperinformation.aspx?paperid=... [2] https://arxiv.org/abs/2105.11664 (d-p, but includes the Cu d-orbital and also specifically states "We also show that the effect of the nearest-neighbor d-d Coulomb interaction Vdd is actually quite important for the stability of superconductivity and phase competition.")
You would use metals as your leads and create Josephson-junctions-like interfaces.
Basically the abrupt change in electron mobility across materials can cause knock on effects that dominate what you are trying to measure.
Interfacial engineering is one term in materials science that implements best practices for dealing with such challenges.
Perhaps heating it up while it levitates would be a better idea. Put the magnet in an oven together with the sample and bake?
This gives a low resistance and diamagnetism which is used as proxy to real superconductivity.
I may be wrong though.
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 gravitational waves-induced propulsion
Piezoelectricity-induced room temperature superconductor
Craft using an inertial mass reduction device
On the Existence of the Superforce–the possible fundamental Force of Unification
https://scholar.google.com/scholar?hl=en&as_sdt=7%2C39&q=Sal...
I can't wait for my cheap antigrav FTL iron man suit to arrive next year.
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?
What I'm actually even slightly more excited about is "what comes next" -- not the market part, but the "fast follow science". For instance, in the few years after LCBO and LSCO were found (TC~30K) we quickly found YBCO and BSCCO (Tc~130K). I would expect that we'll find a whole class of these materials with substitution tricks that possibly work, and there will be a whole slew of options for "going to market" with the technology. The door this opens is what is more exciting than the specifics of LK-99 itself in my opinion.
Estimating times, after the fast follow science (0.5-2 years optimistically?) we will hopefully have the actual "we're all convinced this is real, and the technology can start to be applied in real devices". Specifically, after everyone is pretty clear on a lot of the material properties and ways to reproducibly make high-quality crystals, so consistency is clear on measurements... then begins the cycles on how to manufacture high enough quality material at scale that it can actually be applied. (specifically, these materials (assuming they're like YCBO/BSCCO) are superconducting crystals that have grains, alignment issues, are physically brittle, have homogeneity issues, etc.) While each solvable, these are all real engineering and material challenges that increase cost to manufacture, and all of this will probably take time before we suddenly get wide-scale products that use this (this is all assuming it's real, haha, there's still plenty of reason to be skeptical).
(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.
An Ig Nobel AND a Nobel. That's quite the achievement.
The moving magnet induces a current in the tube which in turn creates the magnetic field that interacts with the magnet.
Assuming no videographic trickery, what else could it be, other than the Meissner effect?
"In simple terms, diamagnetic materials are substances that are usually repelled by a magnetic field. Electrons in an atom revolve around the nucleus, and thus possess orbital angular momentum. The resultant magnetic momentum in an atom of the diamagnetic material is zero."
Whereas the Meissner effect is unique to superconductors. It just has to be distinguished from diamagnetism, and there are materials which are strongly diamagnetic but not superconductors.
But the Meissner effect is a unique signature of a diamagnetic material and will provide you some evidence even if the sample is tiny. So I understand why they have not yet resorted to other measurements, if there is no Meissner effect you don't need to continue with the hard work of trying to make a wire (which may well be a serious challenge for this stuff, the yield will have to come up significantly before that's a real possibility).
hth
If the field is still there, then you have a superconductor.
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 perhaps LK-99 could, at the least, mark the time that Physicists hold up their hands, admit that they have failed, and let the Chemists give it a shot.
I'm slightly oversimplifying the situation, of course, and the disciplines of science cannot be so distinctly separated, but, y'know.
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 your average Physics, e.g. doing quantum simulations for protein folding, superconductors, etc.
I'm probably just being silly though, right?
Assuming this is all true, why is it just now coming to light? Did they just not know what they had? (I have not been following this closely, maybe this has already been explained)
2018 They got funding to research it further,
2020 was a first attempt of publication at Nature that was retracted, further improvements were made until 22/23 were two patents were filled, then suddenly 10 days ago Kwon, one of the co-researchers jumped the gun publishing a paper with the details, on one hand fearing a leak of someone else publishing first as that was too simple to replicate, on the other hand excluding everyone else from the paper and only listing him and Lee/Kim (LK) as authors as a Nobel prize can only be shared by three people. 2.5hrs later LK published again listing other 5 authors but him.
Huge respect for those in this field or others that don’t give up after so many years. Thank you
This is why the calculations by Sinéad Griffin looked so interesting to me: they suggest that the superconductivity depends on an unconventional substitution pattern that might not (in fact should not) occur in most samples of Cu-doped lead apatite. So the active structure was only present in tiny quantities, requiring a long period of trial-and-error optimization.
Again, this is far from proof, but I thought it was at least very curious to have some theory that explains not just a mechanism for superconductivity but also why the samples seem to teeter on the edge of superconductivity so frustratingly.
The replies to my previous post ( https://news.ycombinator.com/item?id=36958419 ) suggesting that flat bands appear simply because copper doesn't belong in that lattice seem inconsistent with the fact that a flat band was not observed when copper substituted at the wrong type of lattice site. If flat bands appear merely because of the unpaired copper electron, they should appear when it is substituted only at Pb {2} sites, but they don't. The appearance of this band structure plus the observance of diamagnetism just takes us from happenstance to coincidence, so we need one more to conclude it is enemy action.
FWIW I don't work in condensed matter physics but I have taken the classes at grad level a few years back. I also should really be doing other things, but this is probably the most fun scientific news cycle since 'Oumuamua at least. (COVID doesn't count as "fun".)
Interesting! The uneven chunk shown in the original video was probably the best specimen they had after decades of attempts.
When I first saw it, my first thought was, "geez, why not at least try to make it uniform"...
It takes a week to bake/whatever a test sample. Which is why this is playing out so "slowly".
So, they had an idea and have been baking/testing/refining samples for decades. Science and funding takes a while.
What idea they started with and why they kept at it for 20 years is beyond me, that's a long time to chase an idea of you didn't have results or a hint that your idea would work. Maybe they had a weird sample that came from some other process in 1999 and have spent the intermediate time convincing funding people and doing the repetitive lab work required to get it to this point.
I suppose they saw something favorable in that 99 sample and nobody else knew. The vagaries of chemical synthesis helped.
But it doesn't seem like they could have had a worse sample than what they fucking have now, while getting data that made them waste a quarter-century.
As much as people hype and have 'reproduced' it, I...dunno. If it's real, the autobiography will be worth an expensive translation.
> A recent paper [Lee {\em et al.}, J. Korean Cryt. Growth Cryst. Techn. {\bf 33}, 61 (2023)] provides some experimental indications that Pb10−xCux(PO4)6O with x≈1, coined LK-99, might be a room-temperature superconductor at ambient pressure. Our density-functional theory calculations show lattice parameters and a volume contraction with x -- very similar to experiment. The DFT electronic structure shows Cu2+ in a 3d9 configuration with two extremely flat Cu bands crossing the Fermi energy. This puts Pb9Cu(PO4)6O in an ultra-correlated regime and suggests that, without doping, it is a Mott or charge transfer insulator. If doped such an electronic structure might support flat-band superconductivity or an correlation-enhanced electron-phonon mechanism, whereas a diamagnet without superconductivity appears to be rather at odds with our results.
Superconductivity: https://en.wikipedia.org/wiki/Superconductivity
Superconductor classification: https://en.wikipedia.org/wiki/Superconductor_classification
Room-temperature superconductor: https://en.wikipedia.org/wiki/Room-temperature_superconducto...
Diamagnetism: https://en.wikipedia.org/wiki/Diamagnetism
VASP is a very common projector augmented wave (PAW) planewave DFT program in the solid state physics/chemistry community. I used it for about 10 years when I was doing computational chemistry. It is distributed as a tarball of FORTRAN90 files, so in some sense all researchers that use it have access to the source code. The research group I was in maintained a set of patches against the source code to implement additional functionality for transition state searches (useful for modeling solid state reactions).
Opensource alternatives exist, but are not as widely accepted (or somehow as fast in my experience). GPAW[1] is one example. It is unfortunate that it is not an opensource program, however, among the large community of scientist with access to the software the source code is available and is well understood and accepted. It is more or less the defacto standard against which other solid state DFT programs are tested.
[1] https://www.quantum-espresso.org/ [2] https://www.cp2k.org/
I really don't get how she keeps getting recommended in these hacker news threads as an interesting source.
If you are not logged in to Twitter, Twitter doesn't show the thread, just the first post alone. But you can use nitter.net, if you don't want to log in to Twitter: https://nitter.net/Errorreporrt/status/1685835688216821760
[0]https://forums.spacebattles.com/threads/claims-of-room-tempe...
Techbro speculation on physics should be considered harmful.
The simulation paper folks are talking about used what appeared to be an existing DFT simulation package. Now, DFT is an approximate theory used to render computation tractable, but to my understanding it is a popular and mature method. I was actually kind of impressed that they were able to reproduce results from the LK paper in simulation so quickly. While it’s possible the speed led to a bug or error in the analysis, simulations often don’t just magically work and can take a decent amount of parameter tuning — especially if the system being simulated has something tricky or exotic going on. The fact that they were able to get what appears to be an accurate simulation working quickly that also justifies the low yield rates has made me more cautiously optimistic than anything
It's a process. Scientists will try to replicate and try to simulate and try to reason theoretically. They are bound to make mistakes but all of this can be critiqued and iterated on.
Again, there's no problem unless you need immediate confirmation or you think chasing this idea is a waste of time.
Enjoy the ride :)
From my understanding (I am not a superconductor person, but in an adjacent field), having flat bands at the Fermi level is not that rare. Such features appear in other materials that are evidently not superconductors, room temperature or otherwise. So the conclusions are more along the lines of "maybe it wouldn't be totally crazy", rather than "omg, we predict this material has astounding properties".
Sounds like it, if prepared right it could be a super conductor and would NOT be a diamagnet that would display the properties we saw in those videos.
> Abstract: A recent report of room temperature superconductivity at ambient pressure in Cu-substituted apatite (`LK99') has invigorated interest in the understanding of what materials and mechanisms can allow for high-temperature superconductivity. Here I perform density functional theory calculations on Cu-substituted lead phosphate apatite, identifying correlated isolated flat bands at the Fermi level, a common signature of high transition temperatures in already established families of superconductors. I elucidate the origins of these isolated bands as arising from a structural distortion induced by the Cu ions and a chiral charge density wave from the Pb lone pairs. These results suggest that a minimal two-band model can encompass much of the low-energy physics in this system. Finally, I discuss the implications of my results on possible superconductivity in Cu-doped apatite
(put another way: it's post-hoc)
Real models for superconductivity take a lot of work to create, it's not something people do for an unverified material, and it's not something you get out of DFT. That paper's agreement is more on the lines of "yeah, all superconductors are grey, and this thing is grey, it can be."
But then, they talked about diamagnetism (graphite-like one, I imagine). Honestly, I have no idea how one could disprove (graphite-like) diamagnetism with that simulation, but disproving it is really good news.
(From the internet: UAP stands for "unidentified anomalous phenomena.")
It's flying saucers carrying aliens from another planet that's controversial and up for debate.
Pretty please?...
https://www.smithsonianmag.com/science-nature/the-year-of-al...
Even if this turns out to flop, I hope history remembers the original authors favorably. They really did find something that by all accounts could plausibly be a room temp superconductor. And of course this seems to have turned over quite a stone. Peripheral research as a result of this will likely continue for years, even if superconductivity is disproven.
Of course it for tedious very quickly, but I remember going to the park and people being told not to sit on benches by police on horseback. How is that not crazy and sort of exciting?
But scientifically? Yeah, I'll go with "exciting". The field seemed to move at a tremendous speed, or at least that's how it looked to me as an outsider.
Sequencing within less than a week, extremely rapid movement on the mRNA front (and really, the whole vaccination field - 200 candidates in 9 months), revamped understanding of aerosol transmission, leaps in rapid modelling, tremendous progress in terms of test development, growth in international collaboration, progress in the (public) understanding of chronic diseases, scaling up of wastewater monitoring, ...
Definitely exciting.
If it happens to be the latter, it's a huge scientific leap forward.
Should he rather be excited about hype manufactured by entertainment or sport companies? Cause that's much more common.
Seriously: if it doesn't interest you, you could simply refrain from commenting and even reading. This stuff is the bleeding edge of tech and if you consider everybody active in these fields or talking about it to be starry eyed children then you should re-calibrate your sense of what these scientific discoveries are likely to cause further downstream. The idea here is to find some balance, it's perfectly ok to discuss a new discovery and to consider the implications on the caveat that it might not pan out. But superconductors already exist, there is no reason in physics why an arbitrary temperature cut-off is going to limit them from existing at room temperature, if you look at the trend since superconductivity was first observed there is a steady increase which with ever smaller margin of error predicts a breakthrough somewhere around 2030. It arrived a bit early, but it - apparently - did arrive, and if true will lead to a revolution in power transmission. And if it isn't true then we'll just drop it and hope for the next round, but I suspect that even if it isn't true there are going to be a lot of labs wondering if they can salvage at least some knowledge gained during all the scrutiny of this particular attempt.
Similar trends can be observed rectro-actively for practical solar panels, micro electronics, powered flight and so on. All had their skeptics, sometimes unreasonable skeptics and all were proven eventually wrong an those inventions transformed our world and are still transforming our world. You see a stupid silly black fleck floating over a magnet and wonder what the big deal is. I see a glimpse of an alternative future that has a lot of potential implications for how we live.
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 the magic of compounding improvements.
> You see a stupid silly black fleck floating over a magnet
Meanwhile over in the AI "optimism" channel people are telling us that AI will be able to produce videos of anything that are indistinguishable from reality, and that we should all learn never to believe video evidence again.
I'm still very much in the "don't know" camp on the superconductor, but what I do know is that it's not worth getting excited until we know it's real.
That said, in general, 9 out of 10 things that are very promising will ultimately fail, and there's nothing wrong with discussing or following all 10, the 1 will work, and it'll be great.
It may not be true, but some amount of keeping it light definitely works for me. I mean I love taking myself seriously too. And some amount of doing that I think is necessary. I guess I just don't wanna put all my eggs in one strategic-approach basket, you know? People are complex! :)
Isn't this textbook survivorship bias?
On the grand scale, I bet the skeptics have a much better record than the optimists.
I enjoy watching floating rocks and talking to computers.
Of course even tough I still use both profusely every day, the feeling of novelty wore out. I expect the same will happen with this.
But with this LK99 stuff, there is not much room for vague wiggle room. The requirements are very clearly defined and if they do it. It is done! It isn't a case of "if in 5 years and $X billion we may be able to produce this stuff", it is a case of they showing a working material.
It is hard not to be excited for this!
That being said:
I want the magical floating rocks to be real.
I want the talky computer to be self aware and capable of genuine creation.
I want the explanation for UAPs to be aliens.
I want reactionless engine technology.
I definitely still feel excited by things, but time has taught me to temper it.
So far we've seen:
1. in Dec 2022 We saw a fusion breakthrough seeing a net gain in energy
2. In March GPT-4 was released, which seems to be a seminal breakthrough in AI, and maybe of our first glimpse in what could become an AGI.
3. In May we find out apparently our government has recovered alien technologies
4. Then in July room temp super conductors just drop
Like this is the most insane period of time. Maybe the fusion technology doesn't scale, maybe GPT-5 doesn't scale, maybe the UAP thing was all a psyop, or a lie, maybe LK-99 doesn't turn out. But there's so much to hope for!
GPT-4 is a nice iterative improvement over previous work, and a culmination of decades of research. It's not anywhere near an AGI and it's close to the limit of what we can accomplish with our current understanding of AI and our current availability of good data. We're near the top of the sigmoid curve on this one; new advances are going to come from specializing and integrating these models, not just making bigger ones.
The fusion "breakthrough" is seriously underwhelming when you look at the total power in/out of the whole plant, not just a tiny tunnel-visioned window of the fusion reaction itself (ignoring power of magnetic confinement and the laser pulse), and even more when you think about how much tritium humanity has ever created. We're just not seeing what we need here and the net power output is still deeply in the negative.
Lol aliens.
My point, to both you and GP, is that it's quite possible to have very different levels of optimism for these recent revelations, and it's not hypocritical to do so. Details and context matter. Dozens of materials science Ph.D.s saying "holy shit this looks like the real deal guys" vs. one guy saying "someone told me there were hidden stocks of blinker fluid that I wasn't allowed to see" just does not engender the same confidence levels.
This is a silly thing to include on the list since it doesn't seem to be true?
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 the early 80s.
tldr; It was a weapons test, by a weapons lab.
- run some simulations and discover a superconductor
- then write up a paper on it ( the paper has some gaps but humans take it and run with it)
- human technology and computing power rapidly accelerates.
- the rogue AI's powers increase exponentially
The AI would need to have a virtually unreachable goal, and run in an endless loop, to be able to drift its goals to be at odds with humanity.
Also, I think it kind of sucks that all that UFO reverse engineering didn’t yield a high temperature superconductor before this… but I guess what can you expect when you sequester away all your materials, silo your research and in effect keep your neural network of nodes (as scientists) really small.
This open shit, as flawed and maybe annoying as it is to some people, I think it’s a much better model of science. It’d be great to see some UFO/UFO tech breakthroughs happen like this too.
People are still unhappy with the decisions of single IP owners controlling the platforms and games they use on a daily basis. Decentralized ledger technology, whether blockchain or not, offers an alternative.
why? it's just a tool.
despise how it was released, how it was trained, the people that operate it , whatever, but I can't really understand why someone would 'despise' a wrench -- even if it was used really poorly and produced by a shady company with a checkered past.
I don't understand why it's worth being bitter about something so joyful and fundamentally human in realtime.
There does not seem to be any conservation of credulity going on here.
Panem et circenses
If, to you, the most interesting thing about LK99 and the developments thereof is tweets and internet forum drama about it, then that speaks more about you than anything to do with anything else.
If you don't have anything to add to the conversation, then just don't add?
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 plumbing to reach a useful AGI.
If anyone cares, Bard is proving to be way more useful these days. Especially for research work. And Claude is bar none for document analysis.
https://twitter.com/fablesimulation/status/16813529041528504... These guys seem to be on the leading edge there - making self-referential character-driven narratives where agents talk to each other and build the collective world understanding, all through a South Park Westworld lol
It's completely different thing to use them in devices that are enclosed and that you never interact with directly, like motors, batteries, electronic components or wires. And in fact we're using lead in car batteries and it's not a problem.
BTW most heavy metals are toxic, including copper. It's just less readily absorbed and accumulated in our bodies.
We're getting quite off-topic here (I guess I should have used different examples), but I would be interested where you got that information from. Most consumer electronics devices do not break prematurely, and especially not due to soldering issues. Source: I buy most electronics second-hand, I regularly repair electronics RoHS and not RoHS, I use lead-free solder and occasionally leaded solder, I watch a bunch of Youtube videos by other people who repair a bunch of electronics, just for fun. (You'll always (and easily) find someone who knows more than me, and it's entirely possible that you do.)
Most consumer electronics devices are retired because their owners got something shinier, or if "broken", it's the battery, display, or some important connector. If something is "actually" broken, it's usually due to power ICs, capacitors, fuses. (You could of course argue that some broken connectors are a case of a soldering issue, but yeah, it's not like I haven't seen broken connectors that were actually soldered using leaded solder, so things can get kind of muddy there)