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A room-temperature superconductor? New developments

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Re: A room-temperature superconductor? New developments

#771

Post by ben_w »

sorokod wrote: post #476
bluGill wrote: post #397

Earlier quoted context omitted.

The Chinese invented cannons about the time they invented gun power. However by coincidence their forts used stone walls thick enough to resist cannon fire and so it was not really better than the various catapult systems they also had (which also couldn't breach their fort walls). https://acoup.blog/2021/12/17/collections-fortification-part... Goes into this in more detail for a couple paragraphs.

Shooting in steep trajectory, howitzer style, would still be valuable.

You have to know it’s possible, and be able to aim at useful internal targets despite this being well before aerial surveillance photographs and calculus.

My guess is there’s probably a whole bunch of neat things we could build with existing manufacturing tools, that we don’t yet know are even possible, and which the future will have similar discussions about.

Re: A room-temperature superconductor? New developments

#772

Post by pnut »

fragmede wrote: post #558
Workaccount2 wrote: post #304

Earlier quoted context omitted.

All the smart people in the US work in tech and finance. If you have a big ole' brain, why would you take $80k to work in some crumby lab when you can get paid $350k to maintain a login screen from the comfort of your mountain side home.

Because there's more to life than money. For King and Country.

"King" and "Country" sound like paying taxes and dying in a war for profit, i.e., someone else's priorities, no thanks.

Betterment of human existence, preservation of habitable environment, etc, those are bigger than the self.

Re: A room-temperature superconductor? New developments

#774

Post by evgen »

whatshisface wrote: post #732
robot_no_421 wrote: post #653

Earlier quoted context omitted.

You should be measuring that population as a % of their total population. Not sure why you're comparing absolute numbers. China has triple the young people we do, but quadruple the old people that depend on the young people.

Depend on them for what, the cost of a bowl of rice? What is it exactly about 80 year olds that will collapse a country with a brutal government like China has?

You think that a country that has a strong cultural history of venerating their elders is just going to pivot on a dime and decide to put grandma and grandpa onto an iceflow and cut them loose? Those elderly out in the hinterlands are also the people who raised a large fraction of the youth population while their parents were off in Shenzhen pulling shifts at Foxconn.

The other thing to look at in those population distributions, besides the upside-down age distribution, is the absolutely pathological gender imbalance. The number of surplus males under 30 should be keeping Xi Jinping up at night because if there is anything that is going to trigger another revolution it is tens of millions of disaffected young males migrating across the country who eventually get fed up with what they perceive as a dead-end future.

Re: A room-temperature superconductor? New developments

#775

Post by gandik »

carabiner wrote: post #419
gtsnexp wrote: post #338

Failed attempt to replicate: Semiconducting transport in Pb10-xCux(PO4)6O sintered from Pb2SO5 and Cu3P https://arxiv.org/ftp/arxiv/papers/2307/2307.16802.pdf

Good reason to believe what the Chinese synthesized is far way from what the Koreans characterize as LK-99: https://twitter.com/robert_palgrave/status/16863940964101488... They tested a different substance.

I followed your link, but there is nothing there. Perhaps this is why no sane person should be using X for scientific communication at this point.

Re: A room-temperature superconductor? New developments

#776

Post by douglaswlance »

kleer001 wrote: post #484
jtchang wrote: post #418

The ramifications of the inflection point we are currently at is mind boggling. I had a hard time explaining this last night but we may very well be witnessing the beginnings of a technological transformation era much like when the p-n junction was invented. From the 1940s standpoint it would be hard to envision all we had today. - Lossless transport of energy - Batteries that don't take any time to recharge - Faster…

> Can I have my flying car now? I ditto the sentiment. But we don't want literal flying cars. Well, self driven flying cars. Humans have enough problems when they're driving on the ground on ground made for driving.

There are far fewer things to run into in the sky.

Re: A room-temperature superconductor? New developments

#777

Post by PaulHoule »

jtchang wrote: post #418

The ramifications of the inflection point we are currently at is mind boggling. I had a hard time explaining this last night but we may very well be witnessing the beginnings of a technological transformation era much like when the p-n junction was invented. From the 1940s standpoint it would be hard to envision all we had today. - Lossless transport of energy - Batteries that don't take any time to recharge - Faster…

To kill your buzz:

Liquid Nitrogen superconductors shocked the world in 1987 but have hardly changed it. They have some applications but we don't have transoceanic power cables, superconducting supercomputers, MAGLEV trains everywhere, etc.

You could have made the case that the cost of liquid helium cooling put traditional superconductors out of reach for most applications, but liquid nitrogen cooling is not difficult at all. Unlike helium, nitrogen is a renewable resource. Cuprate superconductors have been held back by issues that have had nothing to do with cooling and even if the new room temperature superconductors are for real, it's possible they'll turn out quite like the cuprates.

One strange thing about cuprate superconductors is that the theory is not understood despite being a "holy grail" for more than 35 years. It fits the schema of problems like dark matter, neutrino masses, the matter-antimatter and how energy gets coupled from a quasar accretion disk into a jet... Cases where a devilishly hard problem can go unsolved for the working lifetime of a physicist.

Re: A room-temperature superconductor? New developments

#778

Post by tomxor »

throwawaylinux wrote: post #742
tomxor wrote: post #625

Earlier quoted context omitted.

> CPU heat output is limited by the resistance of the semiconductors. Technically true but not applicable... Super conducting CPUs already exist (at below room temp), and they don't use semiconductors. They don't have an exact transistor equivalent but use digital logic circuits such as Quantum Flux Parametron (QFP) and rapid single flux quantum (RSFQ), which are comprised of Josephson Junctions [0] which are made fr…

> so far demonstrated to 770GHz for one CPU That's not a CPU, it's a simple circuit. From the article, "Simple superconducting logic circuits have been shown to operate at speeds of up to 770 gigahertz." Exotic semiconductor transistors can switch that fast, record being over 800GHz I think. Regular transistors of the type in your phone can probably do around 200-300GHz. Not to say there could not be revolutionary de…

Good catch, I misread that. Clock frequency is ultimately dependent on the longest path of propagation, so it does depend on the circuit, or CPU.

I'd be interested to know from any experts whether there is potential for fundamentally higher switching speed in super conducting circuits. As you suggest, they are not necessarily directly indicative of the clock speed of a specific real world circuit or CPU, especially considering super conductors don't even use transistors and need to use different building blocks for equivalent logic... but as a rough indication based on order of magnitude of switching speed would be interesting.

Re: A room-temperature superconductor? New developments

#779

Post by raducu »

soligern wrote: post #679
fsh wrote: post #516

Earlier quoted context omitted.

None of the things you listed are limited by the conductors in them. The efficiency of high voltage AC power lines is limited by capacitive coupling to ground. Battery charging is limited by the cell chemistry. CPU heat output is limited by the resistance of the semiconductors. Turns out metals (in particular copper) are already incredibly good conductors.

We’re not talking about charging existing batteries but superconductors where you just “trap” large amounts of electricity in the superconductor for future use.

Do you mean superconductors create super capacitors, or how do you want to trap the charge?

Or store in coils, as "magnetic energy"(forgot the name for it)

Re: A room-temperature superconductor? New developments

#780

Post by jacquesm »

XorNot wrote: post #620
jacquesm wrote: post #527

Earlier quoted context omitted.

Yes, it would be upending just about everything because the race would be on to improve on that. Think of it this way: once you show that something is possible at all there will be substantial funding available to improve on it. As long as you can't show that it is possible at all you're on your own. So if it works and that 150 mA is the limit then you can expect a ton of effort to be expended to improve on that and…

The current hypothesis is that most likely whatever they made is not a pure sample of the material which actually superconducts - this is expected, since when you make YBCO superconductors you also tend to get low yields (i.e. ~20%) that actually superconduct. So it could be the whole sample, or it could one micron-sized link of grains of whatever the "real" material is running through the sample.

> The current hypothesis is that most likely whatever they made is not a pure sample of the material which actually superconducts

That has been the hypothesis from day #1.

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