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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

#131

Post by abdela »

u320 wrote: post #106
losteric wrote: post #26

Earlier quoted context omitted.

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…

Transmission losses aren't really a big problem for the grid. Cost, geopolitics, and resiliency matters more. I don't expect superconductors to change much here.

Exactly, NorNed has an efficiency of 95% https://en.m.wikipedia.org/wiki/NorNed

Re: Origin of correlated isolated flat bands in LK99

#132

Post by almostnormal »

bscphil wrote: post #110
u320 wrote: post #106

Earlier quoted context omitted.

Transmission losses aren't really a big problem for the grid. Cost, geopolitics, and resiliency matters more. I don't expect superconductors to change much here.

This seemed likely the case to me as well. I'd be interesting in hearing any counterarguments (or better still, actual studies) concerning distribution efficiencies.

The price for electricity is mainly driven by cost of distribution not production. Reducing losses on distribution would further increase the cost of the expensive part (upgrade to SC net) and decrease the cost of the cheap part.

Storage would help, the cheapest production cannot run continuously.

Re: Origin of correlated isolated flat bands in LK99

#133

Post by jychang »

abtinf wrote: post #22
justrealist wrote: post #15

I really hope this unlocks a class of superconductors and isn't a bizarre oneoff compound, because the EPA of 2023 is not going to let us wire the country with thousands of miles of lead-based ceramic wire.

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.

Re: Origin of correlated isolated flat bands in LK99

#134

Post by threeseed »

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 prefer to let scientists figure out themselves what works best for them rather than it being driven from the unwashed masses.

Re: Origin of correlated isolated flat bands in LK99

#135

Post by j16sdiz »

justrealist wrote: post #15

I really hope this unlocks a class of superconductors and isn't a bizarre oneoff compound, because the EPA of 2023 is not going to let us wire the country with thousands of miles of lead-based ceramic wire.

Lead based materials are still in production .

It just needs proper handling and isolation.

Re: Origin of correlated isolated flat bands in LK99

#136

Post by jacquesm »

nine_k wrote: post #129
u320 wrote: post #106

Earlier quoted context omitted.

Transmission losses aren't really a big problem for the grid. Cost, geopolitics, and resiliency matters more. I don't expect superconductors to change much here.

Transmission losses are a concern because they require building huge, very high-voltage structures. Superconductors could make transmission lines much more compact, sturdy, weatherproof, and less vulnerable to sabotage. You could run a thick armored cable instead of a set of open-air wires on tall towers.

You would no longer need high voltages at all. We only use those to cut down on those very transmission losses because we're trying to reduce the amount of current. So you can drop all of the step-up-step-down stuff. On the down side: a short is then practically unlimited in current.

Re: Origin of correlated isolated flat bands in LK99

#137

Post by j16sdiz »

soligern wrote: post #90
M3L0NM4N wrote: post #71

Earlier quoted context omitted.

Wouldn't the insulation/shielding also contain the lead?

It’s going to be in everything if it’s what they say it is. Landfills are going to be full of lead.

It is still too early to tell.

We don't have reliable process to produce them in large quantity

Re: Origin of correlated isolated flat bands in LK99

#138

Post by nine_k »

jacquesm wrote: post #136
nine_k wrote: post #129

Earlier quoted context omitted.

Transmission losses are a concern because they require building huge, very high-voltage structures. Superconductors could make transmission lines much more compact, sturdy, weatherproof, and less vulnerable to sabotage. You could run a thick armored cable instead of a set of open-air wires on tall towers.

You would no longer need high voltages at all. We only use those to cut down on those very transmission losses because we're trying to reduce the amount of current. So you can drop all of the step-up-step-down stuff. On the down side: a short is then practically unlimited in current.

Exactly the point.

We will still need some step-downs, because current density is limited. But we will need fewer of them, and they won't need the monumental cooling they have now.

Re: Origin of correlated isolated flat bands in LK99

#139

Post by jacquesm »

abdela wrote: post #131
u320 wrote: post #106

Earlier quoted context omitted.

Transmission losses aren't really a big problem for the grid. Cost, geopolitics, and resiliency matters more. I don't expect superconductors to change much here.

Exactly, NorNed has an efficiency of 95% https://en.m.wikipedia.org/wiki/NorNed

No, exactly not. The cost of infra is dominated by the transmission network and that transmission network is very expensive to build and maintain, a superconducting network would have some massive advantages. Besides, the losses are in the 5 to 7% range for a typical grid which may sound great in theory but is still a function of the distance between the generators and the consumers. So you can't really put those where you want them, you put them where you have to in order to minimize the transmission losses or you'll have to live with larger losses. Superconductors for the grid would give far more freedom in siting and would allow all kinds of neat tricks such as transporting solar power across the planet based on the day/night and seasonal cycle and likewise for wind power depending on where it is currently blowing the most.

Generating costs are a small fraction of the final price of electricity, taxes and transportation are the big ones.

If you just look at superconductors as a replacement for any old piece of wire you're going to miss out on a whole bunch of advantages, it is a clear qualitative difference which enables solutions that are entirely undoable today. Yes, there is HVDC, but the lines are expensive and due to the high voltages involved are not easy to interface to or from. They do have some unique advantages, being DC they allow non-synchronized grids to be connected.

Re: Origin of correlated isolated flat bands in LK99

#140

Post by rpep »

tired_and_awake wrote: post #45
bibabaloo wrote: post #30

Earlier quoted context omitted.

If this could be simulated, can you help me understand why we couldn't have used simulation to find promising SC materials to investigate further earlier? Are there just too many permutations to investigate? It seems to my own naive self that if LK99 is the real deal, we mostly just got lucky finding it.

DFT scales horribly so it's phenomenally expensive to run. You have to have some other mechanism for knowing the general atomic layout before entering the DFT realm. Once you know the atomic positions you can then do little perturbation simulations to model phonon dispersions or ask electron density questions.

There are linear scaling DFT codes but they’re not available under open source licensing, only a strange license:

https://onetep.org/

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