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The first room-temperature ambient-pressure superconductor?

arxiv.org

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Re: The first room-temperature ambient-pressure superconductor?

#791

Post by kolinko »

nvm0n1 wrote: post #761
klodolph wrote: post #689

Earlier quoted context omitted.

The direct impact could be relatively limited, at least for a while. Having a room-temperature superconductor is really awesome, but existing high-temperature superconductors are fragile and expensive. You can make motors, electromagnets, and power grids with much better efficiency—but that’s not so useful if the parts break when you look at them wrong. You’ll still get better magnets and sensors, probably. Maybe eve…

Isn't the big win of superconductors that you can build batteries with them? Like, you just pump them full of power that goes round and round forever with no or trivial losses. I always heard that this was why they were interesting.

It is an option, but there are two downsides: - such a current generates a huge electromagnetic field. So it won't work for a car battery, but may work for grid storage. - price - there is a limit to how much current you can store, and so far this was the limiting factor - i.e. we don't really care about room temperature superconductivity in this case, but we care about the price of materials to build such batteries

Re: The first room-temperature ambient-pressure superconductor?

#792

Post by amai »

See also

- https://en.wikipedia.org/wiki/Room-temperature_superconducto...

Given there have been already around 10-20 claims of room-temperature superconductivity in the past which turned out to be wrong or useless, bayesian reason would imply that this has a maximum of 10% probability that it is true.

Re: The first room-temperature ambient-pressure superconductor?

#793

Post by PaulHoule »

CamperBob2 wrote: post #618
PaulHoule wrote: post #604

Earlier quoted context omitted.

To be specific look at how long it has taken cuprate superconductors to find practical applications https://en.wikipedia.org/wiki/Cuprate_superconductor This was something that people said would change the world when I was in high school and it really hasn't. (For that matter, the fundamental physics is still not very well understood)

Going from 23K to 35K is useful but not a game-changer. Going to 127 C will be, if it works.

They rapidly got up to liquid nitrogen temperatures so when I was in high school we would go to the welding supply shop, bring back liquid nitrogen to the lab, and do the Meissner effect demo

https://www.youtube.com/watch?v=HRLvVkkq5GE

Liquid nitrogen is very easy to handle (ordinary thermos), liquid helium is much more expensive and harder. WHen I was in grad school the one required class was the Physics 510 lab and for that I did an experiment that involved second sound in superfluid helium and that involved cooling stuff down with liquid nitrogen first, then rolling up a huge dewar full of liquid helium, attaching a vacuum pump to get the temperature down to 2K, etc. For all that trouble you get to see

https://www.youtube.com/watch?v=UNpKCYZFfDU

That said, it was a long time before really good superconducting tape for fusion reactor magnets and stuff like that became available.

Re: The first room-temperature ambient-pressure superconductor?

#794

Post by kolinko »

Gud wrote: post #704
TedDoesntTalk wrote: post #658

Earlier quoted context omitted.

How would superconductivity help to reverse climate change? Honest question.

Fusion power require powerful magnets(essentially super conductivity is a requirement). Currently the best contender for commercial fusion is REBCO(see: Commonwealth Fusion Systems). With cheap fusion power, we can begin pumping that CO2 back into the ground and forget about using fossil fuels for energy entirely.

With cheap fusion power we can convert CO2 back into kerosene/fuel, and use it as energy storage.

It would be lovely ironic if in the future we all drove ICE cars, but just fuelled by clean and carbon-neutral gasoline.

Re: The first room-temperature ambient-pressure superconductor?

#796

Post by Roark66 »

sebzim4500 wrote: post #742
CamperBob2 wrote: post #631

Earlier quoted context omitted.

This post is what happens when chemistry sets don't contain anything more hazardous or interesting than marshmallows.

I think it's more that a generation of people grew up with lead paint and that decreased the average IQ so much that you have people suggesting that lead smoke is harmless.

Since when lead emits smoke? You'd have to heat it beyond it's boiling point that is 1750C,while the typical lead casting is done at around 450C.even if you managed to vaporise minute amounts of lead it's going to condense and fall out long before it reaches "your neighbour's house".

I wonder, does everyone that scared of lead own smartphones? (with cadmium in their batteries). Cadmium is very toxic and it boils at under 800C so your average wood flame will vaporise it. But everyone talks about lead.

Why? IMO because lead used to be added to petrol/gas as an anti knock agent. So there was quite a bit of contamination present back in the day. This has been outlawed decades ago, but the collective memory remains.

Re: The first room-temperature ambient-pressure superconductor?

#797

Post by jtbayly »

arjvik wrote: post #584
ChadNauseam wrote: post #579

Earlier quoted context omitted.

> I assume the energy lost as heat occurs due to the "current" going into the and gate having "nowhere else to go" other than to dissapate as heat? Not quite, it's a thermodynamic principle that applies to any way you could possibly compute AND. Basically, the laws of physics are reversible, so your computation must be reversible too. There are 4 possible inputs to an AND gate, so to be reversible there must be 4 pos…

I think we're talking about the same thing, but I explained it absolutely terribly. If we "dump the other output" back into the power source, such as the battery, does that solve the problem of not implicitly dumping it into the environment? Or is it still destroying information?

How will you choose which output is the one with the AND result? You'd need some logic to pick which output was the right one, I assume. Then you've got the same problem again.

Re: The first room-temperature ambient-pressure superconductor?

#798

Post by tomxor »

techdragon wrote: post #699
pezezin wrote: post #682

Earlier quoted context omitted.

I found a Wikipedia article about the topic: https://en.wikipedia.org/wiki/Superconducting_computing Turns out that some research groups have already built superconducting CPU, albeit tiny ones.

I thought there was something out there like this but I wasn’t sure if it had actually built practical devices yet, cool to see where the state of the art has gone since I was last deeply involved in the ASIC & VLSI world. From what I read there I’d expect significant developments based on a number of the technologies outlined in that article if we do indeed have a room temperature superconductor we can build miniatu…

> but there will be a fundamental difference in how small we can make the conductor [...]

Considering how much faster super conductor logic circuits have been demonstrated to be driven [0] it might be worth the trade even with a higher fundamental limit on feature size.

A super conducting chip with far less logic could easily beat CMOS in: (1) Power performance (2) Single threaded performance (where CMOS has stalled) - but interestingly it could still compete in total throughput if the raw frequency is high enough. i.e even though there may be far less logic available compared to the latest and greatest CMOS lithography techniques - if it runs so much faster, less or simpler cores can potentially match or beat the throughput of the more parallel and specialised but slow logic available in CMOS dies.

In short, it could be like taking a step back in time to the simpler, smaller CPU days, but a huge step forward in fundamental frequency. That actually sounds like a nice trade regardless, CPUs are so insanely complex these days.

[0] https://spectrum.ieee.org/superconductor-logic-goes-lowpower

Re: The first room-temperature ambient-pressure superconductor?

#799

Post by tomxor »

nick__m wrote: post #506
mcv wrote: post #459

Earlier quoted context omitted.

CPUs that don't generate heat? That would be pretty awesome.

Superconductivity is not enough for a cpu that doesn't generate heat, you would need a cpu built of reversible logic gate. Thermodynamics requires that when you destroy a bit of information you generate at least 2.9×10−21 J. It's the Landauer's principle.

It turns out that some people are already combining this principle by making adiabatic superconductor microchips!

https://spectrum.ieee.org/new-superconductor-microprocessor-...

I don't think this actually affects the high level opcodes, i.e it's transparent, so long as the circuit implementing them somehow performs charge recovery, the high level programming can still appear to be irreversible (I don't want to think about the potential side channel attacks that causes when you want to zero some bits!).

Re: The first room-temperature ambient-pressure superconductor?

#800

Post by Ajedi32 »

giarc wrote: post #789
rbanffy wrote: post #732

Earlier quoted context omitted.

One thing I can imagine is desktop MRI machines, or, at least, much cheaper and less finicky big MRI machines that don’t take days to chill to operating temperature. Maglevs are also a popular guess - safer, faster, and more power efficient ground mass transport would be a huge thing. Maybe even magnetic rail space launches. And, of course, military applications (the last few examples I mentioned involve acceleration…

Those are two I see mentioned the most often (MRI and maglevs). To be honest though, those are great things to improve (especially the MRI), however, the amount of hype in this thread and on the internet tells me there must be more than just improved MRI and better trains....

I think a big part of the reason there's so much hype around this is that room temperatures superconductors have long been a famous, almost legendary undiscovered material in popsci. Theoretically possible, but with no proof that any such material actually exists. But now not only is this paper claiming that such a material exists, but also that they made some, and it's easy to manufacture and works at temperatures well beyond ambient. Seems almost too good to be true!

So in addition to any immediate practical applications there's also this element of cracking a famous long unsolved problem. It'd be like if we discovered definitive proof that P != NP, or a theoretical basis for FTL communications. Even with no immediate practical applications it'd still be huge news.

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