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Origin of correlated isolated flat bands in LK99

arxiv.org

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Re: Origin of correlated isolated flat bands in LK99

#171

Post by abtinf »

jychang wrote: post #133
abtinf wrote: post #22

Earlier quoted context omitted.

If this material works out and EPA takes that stance, it will be the end of EPA. So they won’t take that stance.

If this material works out and also turns to be massively toxic, then people thinking the way you do is going to cause a lot of lead poisoning. Not fun.

I have not stated a view on whether the hypothetical material of unknown toxicity should be used or not.

I am making a political claim that bureaucrats will behave in certain, highly predictable ways.

If the material proves to be what it claims to be, it will not be banned. At most, it will be highly regulated, as that will preserve and expand government power.

Re: Origin of correlated isolated flat bands in LK99

#172

Post by jacquesm »

radioactivist wrote: post #169

A few comments. 1) This is simulation result using density functional theory. While a standard method for understanding the electronic structure of materials it often does not do so accurately when correlations (electronic interactions) are strong. In this kind of context (where strong interactions are expected to be necessary to give something like high temperature superconductivity) what one is looking for from a D…

> and do not necessarily imply superconductivity, let alone high temperature superconductivity

That's true, but are there superconductors that do not have those flat bands?

If not then it wouldn't be evidence that it is superconducting but it would at least check one more expected property (based on the evidence obtained about superconductors so far).

Re: Origin of correlated isolated flat bands in LK99

#173

Post by jacquesm »

wiz21c wrote: post #128
jacquesm wrote: post #126

Earlier quoted context omitted.

This has been covered in every thread about this stuff so far, maybe read those other threads first and then be more specific?

I admit I didn't read all the threads in detail. I'll give it another try :-)

HN has a search function (bottom of the page, not ideal but the search itself works quite well), type in superconductor, then select order by date. That will give you the stories as posted in reverse order.

Or click here: https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...

Re: Origin of correlated isolated flat bands in LK99

#174

Post by haswell »

threeseed wrote: post #134
dtx1 wrote: post #3

Even if LK99 turns out to be a dud, it's proven that there's a great need and great opportunity for more direct communication from scientist on their experiments via the internet. Live Stream of the Synthesis, Twitter Threads giving life updates of different teams, etc.

Strongly disagree. I don't want scientists to be turned into influencers or D-grade celebrities having to debase themselves on shows like Joe Rogan in order to get funding or justify their work. Or what happened this week on Twitter where the scientist was obsessed with trying to get above 15m views so he could get monetised. It is great to learn more about the scientific process in this ad-hoc manner but I would pre…

There’s a part of me that deeply agrees with you, but I don’t think we need to assume binary extremes here.

LK99 is reinvigorating broader interest in science, and this may be one of the most important things that could possibly happen at a moment in our global history that desperately needs broad support for research and progress. None of this matters if we don’t sort out some pretty major climate/energy problems, and soon.

I agree that it would be problematic for science to become what you describe. What you describe is not some guaranteed outcome of a shift towards more public participation and awareness.

And to be honest, if it does lead to some garbage behavior, that may be a small price to pay for getting the public interested and invested in the process of progress.

Re: Origin of correlated isolated flat bands in LK99

#175

Post by nemo44x »

calf wrote: post #152
yinser wrote: post #76

Earlier quoted context omitted.

I’m currently in a Twitter space with some accounts who know more about this process and this question was answered a few minutes ago. To summarize: no one has yet found a way to “steer” which sites get Cu and which ones don’t. This paper simultaneously makes LK-99 look like the real deal but also points out there may be more, or much more work, to reliably direct the replacement. Someone in the space said “if you fi…

If some third party scoops a more reliable process that would seem unfortunate for the original group.

I don’t think so, not at this point. Their foundational theory and experiments to objectively prove it are more than enough. Anything that follows could be too but it doesn’t diminish what these guys have discovered.

There will be thousands of people working on this now. These guys are the shoulders they all stand on.

Re: Origin of correlated isolated flat bands in LK99

#176

Post by radioactivist »

jacquesm wrote: post #172
radioactivist wrote: post #169

A few comments. 1) This is simulation result using density functional theory. While a standard method for understanding the electronic structure of materials it often does not do so accurately when correlations (electronic interactions) are strong. In this kind of context (where strong interactions are expected to be necessary to give something like high temperature superconductivity) what one is looking for from a D…

> and do not necessarily imply superconductivity, let alone high temperature superconductivity That's true, but are there superconductors that do not have those flat bands? If not then it wouldn't be evidence that it is superconducting but it would at least check one more expected property (based on the evidence obtained about superconductors so far).

> That's true, but are there superconductors that do not have those flat bands?

Yes, many. Most (all?) conventional superconductors. High-Tc iron arsenide superconductors discovered ~15 years ago. DFT (without including Hubbard "U" type corrections) for the cuprate high-Tc superconductors also doesn't indicate show flat bands.

Examples that do have flat bands (or similar physics) include the recently discovered twisted bilayer graphene (still very much actively studied), as well as (morally speaking at least) heavy-fermion superconductors (too many to list).

Superconductivity is a phase of matter than can arise in a variety of different ways depending on the details of the underlying physics. So at least when talking about the microscopic mechanism that stabilizes the superconducting state there isn't any single theory or one set of predictions/properties.

Re: Origin of correlated isolated flat bands in LK99

#177

Post by castis »

regularfry wrote: post #155
0xB31B1B wrote: post #127

Earlier quoted context omitted.

Huge breakthrough. Energy efficiency is just one gain. This also potentially unlocks major gains in quantum computing, fusion energy, tradition computer chip design allowing another 30 years of moore’s law, batteries with zero energy loss leading to ultra dense batteries and electric aviation

Unfortunately the problem with electric aviation isn't the storage tech. Although having superconductors around would make the ground infrastructure nicer, if the current density limit works out.

Whats the problem with electric aviation?

Re: Origin of correlated isolated flat bands in LK99

#178

Post by jacquesm »

radioactivist wrote: post #176
jacquesm wrote: post #172

Earlier quoted context omitted.

> and do not necessarily imply superconductivity, let alone high temperature superconductivity That's true, but are there superconductors that do not have those flat bands? If not then it wouldn't be evidence that it is superconducting but it would at least check one more expected property (based on the evidence obtained about superconductors so far).

> That's true, but are there superconductors that do not have those flat bands? Yes, many. Most (all?) conventional superconductors. High-Tc iron arsenide superconductors discovered ~15 years ago. DFT (without including Hubbard "U" type corrections) for the cuprate high-Tc superconductors also doesn't indicate show flat bands. Examples that do have flat bands (or similar physics) include the recently discovered twist…

> Yes, many.

Thanks!

Re: Origin of correlated isolated flat bands in LK99

#179

Post by flangola7 »

losteric wrote: post #26
caesil wrote: post #7

Out of curiosity, since this seems like a real inflection point toward trending in that direction, if it becomes increasingly likely that LK-99 or similar material is indeed a high-TC superconductor, what will savvy people be positioning themselves to do? What are good investments? What companies will be started, or what will existing companies be pivoting toward?

Posting for Cunningham's law :) * Green energy suddenly becomes way more viable. Megaprojects in the most efficient sites can send energy long-distance and store it with effectively no loss, somewhat mitigating regional variations (especially if we have a high-trust world order where a united global grid is viable). (I read LK99 might have some limitations carrying lots of current but presumably other approaches woul…

Every doctor's office could have an MRI/fMRI machine, brain scans become routine.

Re: Origin of correlated isolated flat bands in LK99

#180

Post by floxy »

jakeinspace wrote: post #170
floxy wrote: post #61

Earlier quoted context omitted.

Most superconducting logic families aren't using transistors at all. They use Josephson junctions, which are just two pieces of superconductor separated by a non-supercondutor. RSFQ (Rapid Single Flux Quantum) uses millivolt-high picosecond-long pulses to represent logic 1 and their absence as logic zero, instead of using voltage level as in CMOS. https://ieeexplore.ieee.org/document/783712 (770 GHz toggle flip-flop…

Are you aware of any obvious issues with manufacturing Josephson junctions using photolithography? Like, would switching to an LK-99 or similar set us back to the 70s in terms of wafer density/size?

You might be interested is this video, which talks about the EDA issues for RSFQ logic:

https://www.youtube.com/watch?v=3O6GpFCIxv0

...and...

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

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