Best way I've heard the DFT preprint described: "You know those spam pop sci websites where they find a study in which a specific cancer cell is killed by a certain drug and then go to print an article titled ‘SCIENTISTS CURE CANCER’. This is a similar situation." by https://www.reddit.com/user/giantraspberry. The preprint doesn't mean much.
A room-temperature superconductor? New developments
361–370 of 821 posts
Re: A room-temperature superconductor? New developments
#362Earlier quoted context omitted.
People cut cables for copper. Imagine what will happen with cables with gold.
It would be sub-10%* gold content. We're talking about gold doping, specifically substitution in the Pb(1) site, not an alloy. ETA: I was off by an order of magnitude (originally I said sub-1%) because the doping is extensive, and the mass of the lead/gold is a dominant fraction of the total. The formula given in the paper is (subscripts in brackets): Pb[10−x]Cu[x](PO4)[6]O with 0.9 Similarly for Au we would have Pb[…
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Re: A room-temperature superconductor? New developments
#363Failed 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
I would expect to see such failed replications even if LK99 is the real deal. Getting the exact conditions correct for any sort of novel lab science is non-trivial, and often times the crucial variables might not even be measured in initial publications.
People use this fact to try to bash things like cancer research, but it is unfortunately just a fundamental problem of science. Scientific publications are not kernels of distilled truth, they are work-in-progress commits. If we waited to publish until every last detail is known, science discovery would slow to a snails pace and we would miss a ton of discoveries.
Re: A room-temperature superconductor? New developments
#364Earlier quoted context omitted.
Good idea! They wouldn't have been able to do any applications without a voltaic cell, and it would have been a novelty. Like gunpowder in ancient China.
The force of tradition is amazing. Imagine centuries knowing how to make something that explodes violently, and using it for entertainment instead of weapons. Just like how Mesoamerican civilizations invented the wheel, but only used it on children toys and not for transportation. There were no draft animals in the region, but they didn't even make wheelbarrows. https://www.mexicolore.co.uk/aztecs/home/the-concept-of…
Is there a name for this kind of effect?
Re: A room-temperature superconductor? New developments
#365Earlier quoted context omitted.
There are post-quantum-computing encryption schemes [1], thankfully. [1]: https://en.wikipedia.org/wiki/Post-quantum_cryptography
That still leaves all encrypted traffic on the current internet vulnerable to a store-and-decrypt-later attack, which is more concerning the nearer that "later" is.
which is happening in room https://en.wikipedia.org/wiki/Room_641A for decades, all https traffic has been stored, and ones that use rsa (most of them) will retroactively be unveiled once we have shor's algorithm
Re: A room-temperature superconductor? New developments
#366Earlier quoted context omitted.
Japanese and South Korean increasing technical prowess didn't, why would Chinese be any different? China has serious fundamental problems and if you account for its gigantic population - it's seriously underachieving not only compared to US, but even compared to the rest of the developed world. It's fashionable to talk about China taking over, but it's far from guaranteed. China is pretty much confirmed to be falsify…
> it's seriously underachieving not only compared to US, but even compared to the rest of the developed world. This statement would have been viewed as absolutely obvious and ridiculous 2 decades ago. The fact that it even needs to be said now is indicating how fast they are advancing.
They were underachieving for 2 centuries, ceasing to kill their own citizens by millions and imprisoning anybody who tried to think for themselves is enough to grow if you did so for a long time. But it does not make you a new hegemon.
I highly doubt they can preserve their pace of growth for next few decades without significant changes to the regime and liberalization.
Once they return to the mean - they will very likely slow down. Arguably they already did (3% official growth last year + people accusing them of falsifying data for 1-2 percentage points of growth each year would make them already grow slower than some western countries, including the US).
Re: A room-temperature superconductor? New developments
#367I still have a very, very hard time understanding what all of this means. Is there an easy to understand explanation for a room temperature superconductor?
It's a conductor of electricity. But super good at it. i.e. - It has zero resistance to electricity. Currently, the best superconducting materials we can create have to be chilled to near absolute zero, which means designing them to work in liquid helium baths. This is expensive, and difficult. If a material can superconduct at room temperature, now we're talking usage in general purpose consumer goods. As for why we…
It probably has no applications in transmission. Trans losses arent that high; not enough to justify refurbishing the grid.
The electrical resistance per se is actually not that interesting. Certainly not for energy loss. Electronics would benefit, especially CPUs if transistor switching doesn't heat the interconnects above the transition T (the actual cpu is much hotter than the package where the thermocouple is).
High quality (as in high Q) passives would be cool. Think very good capacitors and inductors for filtering. Super cond. caps wouldn't be great for energy dumping since high B fields kill the superconducting effect.
The magnetic properties are more interesting. MRIs w/out crygenic cooling, mag levitation without stabilization.
Apparently there are quantum applications too, but Im not too sure about those but my physicist friend is super excited (in a bad way) for quantum computers now.
If this pans out we're looking at an unexpected revolution.
Re: A room-temperature superconductor? New developments
#368I'm not a scientist but how does this demonstrate anything? It just looks like a magnet is moving some metallic object. Can someone explain like I'm a five year old?
So what's happening is they are demonstrating diamagnetism. Basically when exposed to an external magnetic field, that field induces a response in the material that repels it.
When people think of magnetism, they think of polar charges that either attract or repel other polar charges. Diamagnetism is neat in that regardless of the orientation and polarity of the external field, a diamagnetic material is always repelled.
Now why this matters. All superconductors exhibit diamagnetism, but not all diamagnetic materials are superconductors. So this lends credibility to lk-99 being a potential super conductor because they have been able to show it has one of properties of a superconductor.
But we're still far off from showing it is a superconductor. That will be harder because impurities and other factors can confound the results, so right now the focus is on synthesis and confirming some of the easier properties we expect to see
Re: A room-temperature superconductor? New developments
#369Ha! "Headless Poultry Mode myself".
Re: A room-temperature superconductor? New developments
#370Earlier quoted context omitted.
Is your argument that China’s increasing technical prowess will not inevitably result in the US hegemony ending?
Japanese and South Korean increasing technical prowess didn't, why would Chinese be any different? China has serious fundamental problems and if you account for its gigantic population - it's seriously underachieving not only compared to US, but even compared to the rest of the developed world. It's fashionable to talk about China taking over, but it's far from guaranteed. China is pretty much confirmed to be falsify…
>Japanese and South Korean increasing technical prowess didn't, why would Chinese be any different?
Because while Japan and South Korea are the 51st and 52nd US states, China is a superpower vying to usurp the US as the preeminent world superpower.