Guys, even if everything in this paper is true, the material as it is might have limited applications.
From what they show, the critical field and critical current seem very low. 2500 Oe is like 0.25 Tesla. Even REBCO at 77K is >1T. And 2500 Oe is not even at critical temperature but much lower. From skimming through the article I couldn't find the sample size of the current measurement to get the critical current density, not just current which is meaningless (and around 300 mA).
This means you can't actually push big current through this thing (yet). You can't make a powerful magnet, and you can't make viable power lines, both applications that were the hallmark of "room temperature superconductor revolution".
Of course, maybe one or a few more tweak(s) of the material and boom, it will give high J_c and B_c. I really hope it does, it would be super cool!
You can improve the current density a lot if you can make a single crystal, or at least make your crystal grains larger.
Impure superconductor samples often come out as a spongy mixture of superconducting and non-superconducting bits, the critical current is limited because less then 25% of the cross section is actually carrying current. When I was DIYing YBCO this is what happened most of the time. Every now and then you would get a good one.
edit: Actually if you look at the sample picture in the paper on page 7, it looks like spongy crap. Nobel prize winning spongy crap, but still. I would expect the numbers to improve as better crystal growing methods are found.
Yeah, it’s been a pretty solid trend line, new superconductor, first batch is usually kinda shitty, but proves the basics, refining the mix nails down its exact performance characteristics.
It’s spongy grainy crap indeed… but as long as their analysis holds up to scrutiny and replication… and whoa boy do I bet there are people already trying to replicate this result as I’m typing my reply and reading the rest of the comments…. As long as the results hold up and this isn’t an abnormally low performing superconductor… i have no doubt this is going to win a Nobel prize. This has been the prize for a long time in this whole discipline, and they may have finally nailed it.
We as a species may be on the bring of a revolutionary step forward in what we can achieve in engineering and science. Better instruments and more powerful or sophisticated motors and power systems. It’s heady stuff to think it may happen in my lifetime.
As someone who doesn't follow superconductors, what sorts of things about life/engineering/society would change, how dramatic would it be, and more importantly: which stocks would you pick :)
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 even get new types of circuitry.
Just for comparison—we use silicon for integrated circuits. Not because it has the best performance, but because it’s convenient, it’s readily available, silicon dioxide is a good insulator, etc.
Sensors could be huge I think, even with a material that's a total dud in terms of the superconductor power revolution. I'd be surprised if there wasn't a range of novel sensor approaches that haven't really been explored due to the practicality threshold of low temperature superconductivity.
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
I'm pretty sure you can pick coil geometries that cancel external magnetic fields. There may be some stray fields, but they can be quite modest with tight manufacturing tolerances.
It's an interesting idea worth exploring. The two places where I think feasibility may face challenge is in the energy density gated by critical current density and magnetic field and in raw discharge rate (giant inductors are not known for being able to change their current quickly).
Knowing peak capacity and aging is also tricky since you can't measure critical limits without hitting a quench (a very, very bad scenario). You'll need to maintain healthy margins so you don't have things blowing up on sunny days or after so many charge/discharge cycles.
Back in the 90s or maybe early 2000s, everyone was convinced that silicon was almost dead for high-performance chips like CPUs, and that we'd all be switching to GaAs (gallium arsenide) very soon. Turns out that GaAs wasn't that practical and silicon's limitations could be overcome, so we still use silicon today.
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 of big-ish masses to surreally high velocities, which is popular approach to weaponry).
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.
> Theoretically possible, but with no proof that any such material actually exists.
I wouldn't say that it was necessarily "theoretically possible," for there has never been, and there still isn't, a grand theory of how any given material's atomic/crystalline structure relates to superconductivity. In other words, with no theory of material superconductivity, it was never quite clear what's possible and what isn't. With this new material, though, we might get a lot closer to a working model, if nothing else.
I got into superconductors shortly after the Fukushima disaster, and it was the poster child for superconductors in transmission lines. One of the perks back then was that you could put these reactors that are sensitive to earthquakes and the like out where they are relatively safe from such things. You can also have fewer, higher output power stations, so fewer municipalities have to operate smaller power plants (which tend to be coal or natural gas).
If its economical it will help with losses in the grid over distance. colliders like the LHC and fermi lab could be a lot cheaper to upgrade with room temp superconductors. More reliable too. Would also be a big help fusion reactors. Anything that uses electric motors will also benefit.
The changes introduced by discovery of fire were very gradual. No Internet, no written language at all: any innovation back then could only spread as quickly as humans walked, and would temporarily stop at every significant geographic barrier such as sea.
Compared to the discovery of fire, the changes from room temperature superconductors would be a flash fire.
I totally missed the impact of the internet, you are absolutely correct. Something else that I just noticed buried in the paper is that it can be readily deposited onto a substrate (search for UNIVAC in the paper, page 4). That's an incredibly big deal.
For the idiots in the room (me), could you explain why that’s a big deal? Does that make the material more robust and therefore usable in harsher environments?
We can deposit it on chips, there is lots of copper (relatively speaking) in a chip so this could improve efficiency. Of course the semiconductor (silicon) is intentionally resistive, so waste+heat wouldn't go away entirely.
Note that when we invented the aeroplane, uses weren't immediately obvious.
People would have suggested things like cities in the sky, looking down on things, and traversing marshland easily.
The actual main use for planes has turned out to be fast long distance travel. But we don't actually theoretically need to be up in the air to travel fast or far - in fact, had we never invented the aeroplane, we'd probably have cars or trains by now that moved as fast as present day planes do.
The revolutionary effect of new inventions is often hard to see, particularly for basic science research like superconductors.
Can you? The proposed model implies this relies on non-periodic impurities to achieve superconductivity, and the displayed strength is consistent with superconductivity only appearing on some places spread inside the material. This seems qualitatively different from YBCO.
I don't know enough to be sure on the certainty of that model, but it seems well supported. So I'd be surprised if only improving the material quality was enough to make it strong.
You are probably right about the details, but as a general observation: industrial products tend to get better over time as people learn how to make them more properly. The first batches coming out of a lab are usually terrible compared to what's coming out of factories a few decades down the line.
They've just proven (if true of course) that it's possible at all. That is a massive, massive leap.
And once it's possible, it won't be long until it's optimized. We've seen this everywhere -- transistors were once huge and now nanometers; solar cells have improved in every where; batteries are cheaper and better than ever.
I was with you on the first part. If this proves room-temperature/ambient-pressure is possible at all, that is huge.
Not so sure about the "won't be long until it's optimized," though. There are a lot of examples where something seems perpetually 20 years away. I'd advise tempering the transistor-based optimism with just a skosh of fusion energy skepticism.
Compared to fusion it should be a lot simpler and if there is one material that exhbits these properties there might be more. I'm really hoping this isn't a scam and that there isn't some kind of critical error. Regardless of how much more work needs to be done to get this to commercially viable at scale if true I would imagine that massive investment will start chasing that goal.
Just thinking about the possible applications for storage makes me dizzy. Fingers crossed.
>There are a lot of examples where something seems perpetually 20 years away. I'd advise tempering the transistor-based optimism with just a skosh of fusion energy skepticism.
most of the common examples are in-the-works or exist in some form, they just don't satisfy the 'every-person' checkbox yet.
AI? sure. Flying cars? sure. Robots? sure.
Fusion is in the works, too. Tens of billions of dollars being thrown into the ring by private capital -- and recently -- which is a pretty good indicator of 'perceived realistic' historically.
Also, it's kind of apples/oranges. We had equivalent mechanisms before the transistor, transistors just lead to extreme miniaturization of logic gates that we now enjoy. Fusion energy production doesn't (really) have that equivalent.
similarly : room temperature atmospheric pressure superconductors are a new thing if proven possible.
My favorite example is the hydrogen fuel cell. It was invented before the lead acid battery back in the 1800s. PEM gave it a boost around the Apollo era, but that wasn't enough to make it widespread either. Lead-Acid went through its whole 100+ year character arc and hydrogen fuel cells still haven't found product market fit. Sometimes that's how it is.
There are plenty of commercial applications of hydrogen fuel cells though. The biggest issue has been pretty much a constant over the time since it has been invented: keeping the membranes free from impurities is hard.
But there are all kinds of transportation devices using hydrogen in production today.
Sure, but the point is that they hardly caused a revolution in energy storage. If fuel cells didn't exist, for the average person life would be exactly the same.
Revolutionary tech does change normal peoples lives, and sometimes very rapidly, but a lot of stuff that looks revolutionary just kind of never works out.
I'd say nuclear power is probably the prime example of this. It was supposed to bring us electricity too cheap to meter, but it's actually the most expensive form of generation that anyone bothers to build.
> It was supposed to bring us electricity too cheap to meter, but it's actually the most expensive form of generation that anyone bothers to build.
Hardly, coal is much more expensive if you price in the externalities. We just pretend they don't exist for coal, and we staple anything that moves to nuclear.
Coal kills 25 people per TWh generated, and the actuarial cost of a death is about $10M as used by the nuclear industry, not to mention the environmental costs. That means the all-in cost of coal is much much higher than the LCOE - about 16c/kWh according to the Government of Canada. [1] The 2019 US EIA LCOE for nuclear is about 7.7c/kWh. [2]
Nuclear is cheaper than coal and costs around the same as solar/wind + storage - less, depending on the desired level of equivalence between the two. It has high up-front capital costs and a long payback period so the cost depends primarily on cost of capital. Fuel costs are $0.015/kWh to $0.00015/kWh in uranium.
There are places that get lots of cheap, reliable no-carbon power from nuclear. For instance Ontario, at about $0.10CAD/kWh ($0.075USD/kWh), delivered. [3]
Can you give me an example of a nuclear power station that was built entirely without taxpayer subsidy by a private company, and manages to sell electricity to the grid cheaply and make a profit?
> Can you give me an example of a nuclear power station that was built entirely without taxpayer subsidy by a private company, and manages to sell electricity to the grid cheaply and make a profit?
Why is that a goal? Zero-carbon electricity is a goal, so that we don't all sink. Profit isn't. If ever there were a job for taxpayer dollars, IMO, this is it.
"Yes the planet got destroyed. But for a beautiful moment in time we created a lot of value for shareholders."
Not at all. I quoted the US EIA in that 7.7c/kWh figure on the pre-subsidy LCOE of plants coming online in 2023. It was listed in my [2].
"In 2019 the US EIA revised the levelized cost of electricity from new advanced nuclear power plants going online in 2023 to be $0.0775/kWh before government subsidies, using a regulated industry 4.3% cost of capital (WACC - pre-tax 6.6%) over a 30-year cost recovery period" [old 2, sourced from new 1]
The response to you was a separate opinion on the role of government in the energy sector. After all, we've put trillions of subsidies into fossil fuels the least we could do is put money into something that solves problems instead of creating new ones. I also said I don't care whether it's public or private funds that are used to construct it.
Really nothing at that scale is built without subsidies, but the 7.7c/kWh rate was before subsidies.
Did I miss something? I thought I answered your question with that figure and its origin, it sounds like exactly what you wanted to know. I don't know which precise power plants they included but it's probably in [1].
[edit] I guess it's weird that we're so stuck on this one specific technology. What's the un-subsidized cost of oil power when the price of oil is set by OPEC, externalities aren't factored in, and every time it goes up we unload the Strategic Oil Reserve? How do you price in drilling in ANWR?
Coal, I mean, it's all unpriced externalities - death, environmental toll.
Solar 90% of the panels come from China, how much does the PRC subsidize the plants and materials that go into making the panels for their own geopolitical goals? Rare earths for wind? They all come from China too. Lithium for storage?
My question is sort of more "can anyone name any utility scale power project of any type that was built by a private entity without government subsidies of any sort? Why would they do that if they didn't have to? What does that even mean? And really, does that even matter?"
The reason is pretty obvious and doesn't require any kind of conspiracy.
Nuclear can be done safely, we know this, because every single time there has been an accident it's because an operator did something wrong.
The problem is that nobody has yet designed a reactor that a sufficiently amoral operator could not make unsafe. Even if you have completely automatic and passive safety features, a bad operator could disable them if a false positive happens even once and costs them money.
For this reason nuclear has a LOT of regulation and red tape. It has far more than any other kind of energy, because even though the risk of accident is low the outcome of an accident is worse than any other kind of energy except hydro. Hydro has fewer things that can go wrong that are cheaper to check however, so regulations there tend to not be as expensive.
Molten salt reactors manage to be expensive for perfectly normal engineering reasons though. The salt is highly corrosive, meaning you need tons and tons of extremely expensive piping that can withstand extremely high temperatures and extremely corrosive environments.
There's a reason none of _those_ have been built either. No amount of red tape would make them unviably expensive if the end product was cheap enough to run, but it isn't.
Also I should mention, part of what makes them passively safe is there is a plug at the bottom that melts if the reactor overheats. This is easy to bypass, put something over the plug that won't melt.
> There's a reason none of _those_ have been built either.
Let me introduce you to the Molten-Salt Reactor Experiment[1].
What you probably meant is that none have been built commercially. That is true, but again as I mentioned, not because of their technical drawbacks but because of politics. In fact, the inventor of the light water reactor, Alvin Weinberg[2], was a strong proponent of the molten salt reactor over his own invention. So strong that he fired was from ORNL because he was claiming that light water reactors are inherently unsafe and that MSR is a better design.
Nixon ultimately sacked him because he (Nixon) chose to support LMFBR (Liquid Metal Fast Breeder Reactor) because it was being built in California, and in return he got political support that he needed. MSR ultimately lost due to pork-barrelling.
> This is easy to bypass, put something over the plug that won't melt.
I mean you're shifting goalposts here. The "operator" has a specific meaning - someone controlling the reactor from the control room. They don't have access to the freeze plug during normal reactor operation.
But even if they did do what you're suggesting, the pressures inside the MSR are so low (on the order of couple of bars) that the damage would be quite limited.
We had a working reactor in the 1960s, but we chose not to develop it commercially due to our inability to choose rationally. That's why we are where we are now.
It's part of a larger trend of eroding competence at civic infrastructure scale construction, but also specific to nuclear we've found repeatedly that construction and decommissioning costs and schedules were wildly optimistic.
Plutonium-239 (just an example) has a halflife of 24,000 years, ground water is a thing and it moves a lot. Modern concrete is both water permeable and has a tendency to degrade aggressively in wet environments over alarmingly short periods of time. Try again?
Fuel cells are just another transformer like the dynamo, or any kind of motor. They turn one kind of energy into another and in the context of hydrogen (which you could produce out of water using electricity as a means of storing energy) it serves to reverse the storage step. This is nice to have but just like nuclear power it's a variation on stuff that we already have, it is at best a quantitative change (and hopefully an improvement).
Room temperature / ambient pressure super conductivity is something we do not currently have. The difference between having that and not having that is a qualitative difference and hence it will enable a whole raft of applications for which we currently do not have a solution.
> By that logic a super conductor is just a variation of a conductor.
No it is not. The difference between 0.1 and 0.0 can't be expressed in orders of magnitude.
> Nuclear power is more distinct from burning coal than any superconductor is distinct from copper wire.
Nuclear power is an incredible invention. Unfortunately it has some problems that won't go away by wishing it to be so, and there are many similarities with coal (as well as some obviously differences).
But this thread isn't about coal vs nuclear.
Frankly, if you don't actually see the difference between the relative importance of superconductors vs copper wire and nuclear vs coal then I really don't think I have anything to say that will interest you. Suffice to say that nuclear didn't change the world all that much (except in a weapons sense) but superconductors at room temperature and ambient pressure have the potential to change the world in ways that would be hard to even imagine. Even if true I still don't think it would be in time to help us address some of the more urgent problems we are facing. Neither does nuclear. And come to think of it: if this tech is real (big if) then it will actually probably cause a revolution in nuclear as well because it would allow for nuclear power to be transmitted the world over without the non-proliferation headaches associated with shipping reactors to various countries. It wouldn't solve the waste problem (though there are some interesting reactor designs now) and it won't happen overnight but it would make a difference.
> superconductors ... have the potential to change the world in ways that would be hard to even imagine.
Such as? I do not see how superconductors help with the challenges of Climate Change, food insecurity or danger of nuclear war. What will be the change for the average Joe? Maybe a better electric car?
Energy storage and distribution alone can affect all three of your examples and they are very trivial ones. Then there is medicine, possibly a better shot at fusion and so on. Better electric cars are at the bottom of my wish list (because they're still cars). But yes, those too (much lighter but more powerful motors means you can do away with the drive train completely and it would also allow you to get rid of the brakes) assuming the superconductivity can be maintained in strong magnetic fields (not a given).
okay, could you be more spesific - what kind of improvement can we expect in storage? Is the improvement measurable - like will I be able to buy more kilowathours of storage per dollar?
You'll be able to buy more KWh of storage per dollar (but likely not initially) and it will be relatively dense compared to current - pun intended - options and very likely have a much higher number of cycles (because there is no chemical cycle, just electron movement). The 'if only we had a room temperature superconductor' list of inventions that got temporarily shelved is longer than my arm, the words 'game changer' were never more applicable. If it is replicated. If it can manufactured competitively. If it (or a variation) works at higher current densities.
Nuclear power and coal power are both heat engines turning heat into mechanical energy and subsequently electricity. They merely use a different heat source.
They share a lot of qualities because of that. They are relatively centralized and best run in a base-load rather than a load-following mode to reduce mechanical stress and increase longevity.
>Nuclear power and coal power are both heat engines turning heat into mechanical energy and subsequently electricity. They merely use a different heat source.
Not completely true. There are some experimental nuclear reactors that convert nuclear energy directly to electricity without the heat cycle, such as [Helion](https://en.wikipedia.org/wiki/Helion_Energy).
When presenting working experimental nuclear reactors Helion is not the company that I would use as my example. They are borderline scammy and given their lack of progress they seem to be stuck in the moving the goalposts phase for a long long time now. I wouldn't bet on them ever completing a working reactor that produces net power.
Maybe, but my point is that it does seem to be possible to generate electricity directly from nuclear reactions, without going through a thermal cycle (making heat, creating steam, using that to turn a turbine). I think there's some other experimental process that promises to do this with fission.
Fusion, specifically, is meant to be the one 'too cheap to meter'. The thought being it'd be ready soon, and grouping both kinds of nuclear together worked as better branding for getting govt. funding.
Well, the other 'biggest issue' is that hydrogen is only a terrible battery.
You need an energy source to make hydrogen (eg out of water, or you make it via fossil fuels etc). When you use up the hydrogen, you get some energy back out. A lot less energy, to be honest.
So it's equivalent to a battery. Not to an energy source.
The bikini swimsuit was named after the Bikini Atoll. A bit of a mixup from OP though: it wasn’t named after fusion bombs. The bikini swimsuit was announced a few days after the first public fission bomb test there (Crossroads Able) in 1946. The first fusion bomb test there (Castle Bravo) wasn’t until 1954.
The sun's core is actually very hot, it is the outer layers of the sun that are much cooler. We're trying to do this at roughly twice the temperature than the core of the sun, and I realize the difference is millions of degrees but on a relative scale this doesn't add much complexity, it would be almost as difficult if the plasma would be only half the temperature that they are shooting for.
And in a way that higher temp is a result of trying to do this at a smaller scale, if you want to be net-positive it gets easier as you get hotter as far as I understand it.
So what we are doing is in fact to re-create conditions roughly on par with what is happening in the core of the sun. And it turns out that doing that small, for extended periods, net positive and reliable (without the machine suffering damage from the process) is a very hard problem. Even so I'm very much impressed with these projects, the engineering and the physics are way over my head but I do hope that one day they'll get it working. But I'm not going to hold my breath.
Incidentally, the implications for energy storage if TFA turns out to be on the money are possibly more interesting than fusion in the short term.
> what we are doing is in fact to re-create conditions roughly on par with what is happening in the core of the sun
My understanding is we are not. (Not an expert!) The Sun's core runs around 15 MK [1]. A tokamak, 150 MK [2]. Orders of magnitude rarely come for free in physics.
We need those higher energies because we can't, like the Sun, swaddle with the mass of a hundred thousand worlds a low-temperature, low-frequency weak-force mediated proton-proton reaction [3]. The Sun relies on quantum tunneling to overcome the Coulomb barrier. We humans have to increase the reaction energy so it doesn't all bleed off before anything happens [4], which means using the strong force [5].
If you start to think of 'temperature' of individual particles as 'speed with which they move' that is a useful rough approximation of trying to figure out what it means that something has a particular temperature. Containing the plasma is hard not just because of the temperature it is at but simply because it tends to destroy anything that contains it and that doesn't really change all that much for 15 million degrees Celsius, 30, 100 or 150. What it does change is that at 150 million degrees Celsius you have some hope of extracting useful work from a very small quantity of plasma. If you don't get it up to those temperatures - again, as far as I understand it - then you will always be putting in more energy than you are gaining because of some fundamental physics limitations.
So the smaller you make your reactor the hotter you'll have to make it to make it net positive. This leads to the counter intuitive result that making a much larger reactor is actually quite possibly easier than making a really small one. The rate of heat loss is much smaller for a larger reactor and so it becomes easier to sustain the reaction and to extract useful energy from it.
It is very well possible that none of the reactors currently on the drawing board and under construction are going to be working well enough to give us a sustained reaction resulting in net yield. But we're getting closer and closer to that and there is some (small) chance that I will still see this in my lifetime.
The catch is that as long as you can't get a small reactor to work getting funding for a much larger one (which you actually may be able to get to work) is going to be extremely difficult. We like to see proof before we scale up. In this case it may well be that such small scale proof can't be done or can't be done in a way that it it will convince backers that a larger scale device will work.
Yes, true. Apropos antimatter, recently I read here on HN somewhere that lightning generates antimatter as well, and it made me wonder if earthquakes do too but I haven't been able to get a clear answer on that. Fascinating stuff.
Larger reactors may simplify the plasma physics, but it complicates the materials engineering significantly. A huge problem already is creating a structure that can bear the weight of the reaction vessels and the gigantic magnetic fields used for containing the plasma, and also continue to do so for a decent amount of time after being exposed to the constant neutron bombardment of D-T fusion.
I very much doubt currently known materials and structures could be used to construct a reactor 10 times the size of ITER.
This is a high value comment - it's got a hook that I sort of mostly get, but follows that up with jargon laden things I don't understand well, and your references gave me a half hour of rabbit-hole learning. I appreciate the casual knowledge you've passed along. Thanks!
It has 4 fairly common ingredients and only needs a couple of days to create. You can be sure that China will make a spreadsheet with all possible combinations of synthesis and farm them out to their Universities for rapid development... and then they start hunting for the 'ideal' version... flexible, fast to synthesize etc.
The Manhattan project and moon landings happened because the US spent a significant % of it's GDP on the project. We might have Fusion already if they repeated it...
LK-99 is just chemistry... not nearly as complicated.
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)
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
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
Many years ago, as an undergrad, I was telling a grad student friend how I'd been learning about the Selection algorithm- it lets you pick the Kth largest element from an unsorted list in linear time, which is pretty neat.
I said "It's O(n), but the constant is ridiculous in most implementations so it's usually better just to sort and then pick the kth element". The grad student friend said something that stuck with me: "Sure, but the algorithm proves it's possible to find the kth element in linear time. That was never guaranteed. Now we just need to find a better way to do it."
Random conversation that stuck with me, and they probably forgot it a moment later.
Branching off into a philosophical thought here, but I find this to be completely wrong. It was always guaranteed; logic, like physics and chemistry is not an environment that changes.
We have discovered a functioning technique which might be improved upon. What wasn’t guaranteed was that it would be found.
Biology is the root of most, perhaps all, uncertainty. After all, it is our biology that makes us imperfect observers, thinkers, and makers(but also enables us to do those things at all!).
I think this is important, because their is a significant difference in mindset between making something, and looking for something. Science is looking, technology is making. Things are always “seen” before they are “made”.
I remember the first superconductors (long predicted) being announced in the mid '80s. They stayed high on the nerdy headlines for quite a few years. Excitable write ups in New Scientist for us civilians. Nuclear fusion was still 50 years off but room temp superconductors were only a few years off (nope). I went to a posh school in Oxfordshire in the mid to late '80s and my physics class (form) had a field trip to Culham and also a double lesson/lecture done by a handful of Culham physicists back in school. I am very aware of what a privilege that was.
Now I'm 53 and been around the block a bit, I really appreciate how time is required for some things. A lot of time.
Superconductivity was first observed in solid mercury at a temperature of 4.19 Kelvin in 1911, not long after liquid helium was first produced in 1908.
The 1980's discoveries were of the first "high temperature" superconductors (where "high temperature" means "above the boiling point of liquid nitrogen").
Liquid nitrogen is much easier to deal with than liquid helium.
Those mid 80s high temperature superconductors are now mass produced for NMRs and fusion startups.
I don't think it's given that all superconductor breakthroughs will require 40 years to get to that point and there's good reason to believe they won't (startup penalty, industry bootstrapping, market finding, etc. have all been completed).
Those mid 80s high temperature superconductors are now mass produced for NMRs and fusion startups.
As alluded to those same pop science magazines promised a fusion future too. Here we are, magazines extinct, with fusion startups using LN2 superconductors. Also: no quantum computers, no space colonies, no flying cars (or even supersonic planes), and twitter/reddit/facebook are worse than Usenet.
> As alluded to those same pop science magazines promised a fusion future too.
I get it ...
But how many of them predicted their use in ~36,000 advanced medical imagery devices world-wide?
I'd love fusion power (and flying cars), too, but there's a whole lot of interesting technology between "check out my shiny new super-conductor" and "let's use it to contain plasma that's hotter-than-the-core-of-the-sun-kind-of-hot[0]" that we do benefit from[1], today, to not be too disappointed that we haven't quite reached the greatest potentials.
I don't know enough to speak intelligently on any of this -- who knows -- maybe fusion won't be a possibility until even higher-temperature super-conductors are created ... or maybe there's some other "not possible" in the way (until another discovery is made).
[0] And (if I understand things correctly) it's probably really unfortunate that they traditionally require extreme cooling, likely made more complex given the heat involved and almost certainly requiring far more power than would be required if said super-conductors worked at much higher temperatures.
[1] Myself, personally -- and I have a pretty cool 3D file of my brain backed up to my server as a result.
/// apologies: reading this over it sounded a little hostile; that wasn't intended -- I was merely offering a competing perspective, albeit poorly :)
> I don't think it's given that all superconductor breakthroughs will require 40 years to get to that point
Absolutely right. People generally understand that "collective human knowledge[0]" grows but they think of it as a linear system. The speed at which knowledge grows accelerates -- not at an even pace -- but I'd wager somewhere near exponentially in a lot of places.
And each discovery can change our understanding of other things/accelerate discovery in other areas.
Very true. I remember cheering since the mid 80's every time the temperature for superconductivity went up, sometimes with 20 degrees K in one go. And then it was quiet for a long long time with a plateau. More recently, two major jumps, the last one of > 50 degrees (2017, H2S), and now this...
I've forgotten how many times one of the most important thresholds in our times has been bumped up a bit. Now we seem to be offered heaven on a plate.
If superconductance can be reliably demonstrated at RTP (you wear a light cotton shirt, instead of 1cm thick fancy weaves involving an awful lot of rubber) then we are laughing all the way to ameliorating climate change.
Even if this result is confirmed then I think it will take at least 20 years to dig in to reversing climate change.
No, the argument is that if this is true and it can be commercialized cost effectively that there may be an energy storage solution just over the horizon that would allow for all kinds of things that are currently impossible, such as summer/winter energy storage and other very nice to haves. It is obviously much too early to say anything about this so think of it as hope rather than anything more solid but it isn't necessarily about cheaper energy, just an almost perfect companion to cheap renewables whose main issue is that it is hard to store their output for the time when you need it most.
It may also make the energy (and economic) costs of fusion make a lot more sense, since superconductors are used to contain the plasma in fusion reactors.
I believe the biggest envisioned possibility is superconducting power lines. Those would allow long-distance power transfer with minimal losses. In the most idealistic scenario, you could imagine a belt of solar power plants around the globe connected by superconducting power lines, providing solar power 24h a day.
Of course, there are huge hurdles to such a project even if we did have the superconducting lines, but there are more realistic similar applications that might actually work.
>In the most idealistic scenario, you could imagine a belt of solar power plants around the globe connected by superconducting power lines
There's no technical impairment for doing this with current tech, and it's not clear the new tech is cheaper.
Power lines are already very efficient, especially the long-distance ones. We would save a bit on converting from HVDC to AC but that's also very efficient.
The numbers I found on a quick search are 3% loss per 1000 km for HVDC lines. That's a pretty huge loss for the 20k+ km lines you'd need to transmit power from daytime to nighttime areas on the globe.
I thought these were mostly fixed conversion losses, but checking this again you're right, it's 3% per 1000km (not including the conversion loss at the stations).
There absolutely is. Once you think about this on a global scale HVDC doesn't quite cut it. You can extend the day/night cycle by a few hours each way, which is already very impressive but it isn't enough to cover 24 hours and it definitely isn't going to help you in winter when you want to transport energy from the sunny hemisphere to the darker one.
We can easily generate more than enough renewable energy, just not when and where we need it. Being able to transmit energy over vast distances would greatly improve the economics of our existing renewable energy generation solutions.
I'm not sure what the GP envisions but one thing you could use superconducting materials for that don't require a bunch of extra gear to operate is to store energy in loops of it. This may well allow for a relatively high storage density (but probably not nearly as high as chemical ways of storing that energy but with better efficiency, and for stationary applications density is less of a factor than for anything mobile) with near instant charge/discharge times. Kind of like a solid state version of a flywheel.
That in turn could power an energy revolution which has the potential to reduce carbon based fuel consumption dramatically.
That's SF right now, but there are pathways to very interesting futures unlocked by a material such as the one described in the paper, all of them subject to the usual caveats that it's a 'mere matter of engineering' and that it may prove to be far too costly in practice. And it wouldn't reverse climate change but it could help slow down the acceleration of climate change.
Room temperature super conductors don't quench. Or at least, not until they reach the temperature at which they no longer work as superconductors, which for this one is 127 degrees Celsius.
That does make for an interesting failure mode if anything should every cause a small spot on a longer conductor to reach that temperature...
No, at the breach it will just burn up until the arc dissipates. But it will be an impressive fireworks display. A superconductor is in the end just another conductor, it has a well defined current carrying capacity while superconducting and if it stops doing that then that current will suddenly see an increased resistance, how much current is moving through it at the time it failes determines how fast and how violent it burns out when it goes, but it won't be unlike another transmission line failure. Those are still very impressive:
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.
Reminds me of a story: I was in college physics in fall '89 and our professor was telling us how he and his son spent the summer in Alaska prospecting for whatever material was all the rage in superconductors at the time. He was explaining that once superconductors broke the liquid helium temperature, it was going to be a game changer. He said "If you buy it by the gallon, liquid helium is cheaper than beer."
To which a student replied "You buy beer by the gallon?"
I'd use it for making my own SQUIDs[1], as a start. There are a number of experiments I want to do, and things I want to understand[2][3], and not having to have cryogenics keeping the detectors cold would be helpful.
I'd also like to use this for antennas, transmission lines, and tuned cavities.[4] There are a lot of things you could do at VLF frequencies[5] that require long, long wires... with lots of resistance, unless you have a defense budget, the resistance eats into efficiency. Superconductors could help deal with that.
Just for comparison, an typical MRI magnet is 1.5 Tesla. An NMR spectrometer can go up to 28 Tesla (using new high-temperature superconductors). The LHC magnets are around 8 Tesla.
Those are the kinds of magnetic fields the classic superconductors and the newer high-temperature superconductors can achieve.
> the material as it is might have limited applications
Is LK-99 part of a larger (either known or emerging) class of materials? I'm not understanding what the lead and copper ions are doing to create internal stress, and why that leads to superconductivity.
Pb(2)-phosphate is a crystalline compound. They are creating a 2D film of it using vapor deposition, then doping it with copper ions. This is a standard process in semiconductor manufacturing. There are room temperature ambient pressure materials doped to create quantum wells in production right now. They are not super conductors, because the quantum wells are merely impurities that reduce the resistance of the material. I believe this paper is claiming a crystal so saturated with quantum wells that it conducts primarily through quantum wells with almost no resistance (and that all of the other physical properties of a superconductor arise from this).
Just like in previous super conductor findings once a material is made and understood that usually paves the way to new discoveries, sometimes those are (big) improvements on the status quo. I'd expect this finding - assuming it is true and verified - to result in massive funding towards the material science labs to try to improve on it. So I'd say this is example '1' of a new class of materials and if it holds up then probably we will find more members of that class once the mechanisms are understood.
For some reason, there’s a contingent of people that think that by poking holes and pooh-poohing things, it gives them clout. It happens far too often in tech and I hate it. Look how often the post has “can’t” or “couldn’t”.
Instead of giving reasons why something sucks, how about being supportive and talking about why it’s awesome and what possibilities this opens up?
I don't think OP is being overly negative in relation to the tone of the rest of the comments here. Nobody else up until this comment had mentioned anything about the actual important performance characteristics that the paper's authors' are claiming, and this does put it into perspective with the current state of the art. And OP does even end on an optimistic note anyway. No need to resort to personal attacks.
Edit: I appreciate you toning down the more combative part of your comment.
While I often agree that the tone on these kinds of posts on HN is often annoyingly and unproductively cynical, I think him just pointing out the current limitations of the result is not that much of a problem. It isn't like he's making the overused "perpetually 20 years away" joke about potentially revolutionary technologies.
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.
My understanding is that modern CMOS circuits dissipate around 1 pJ (10^-12) per bit, so even if we are limited by the Landauer's principle, it would still be a 9 orders of magnitude improvement. I would surely love a CPU that uses microwatts instead of hundreds of watts.
Yup, the current dominating factor is resistance, not the Landauer limit.
Biological systems supposedly operate at about one order of magnitude above the Landauer limit [0], i.e this is completely practical and has been happening before we even made computers... we probably wouldn't exist without being this efficient, imagine how much energy our cells would need to consume and emit as heat if it were similar to a CPU of today!
I apologize, I couldn't not resist to the occasion of being technically correct. I should also have stated that a superconductors based CPU would be incredibly cool figuratively and physically!
While a room temperature superconductor would potentially have some uses in building a CPU… it’s not as relevant as you might think due to the semiconductor being the operating physics at play to make the transistors and perform the electrical switching and everything stemming from that underlying electrical unit.
You could absolutely use superconductors for all the connecting wires, and with a little engineering it might also be good for conducting heat away from the chip die as part of the larger CPU package… it wouldn’t be a good interface material (pins for connecting to the motherboard) as you want oxidisation resistance and a level of ductility and malleability to help with making a very good electrical connection between the surfaces when they are mechanically pressed together. But overall it will have some uses, it’s just not an immediately applicable technology for the silicon chips themselves… lots of potential in circuit designs and I’m sure if someone invented a way to lay this material onto a PCB as easily as we can print copper traces on them today that inventor would get pretty rich… it’s just not likely to make much of a change to the silicon chip die itself due to the need for semiconductors to do the transistor switching …
Of course someone might have invented a superconducting transistor that I haven’t heard of and if that’s the case disregard most of what I’ve just written haha.
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 miniature circuits with…. But one issue I don’t think they mentioned will be grain sizes our transistors are getting very very small with current lithography technology. And it may be difficult to get equivalently small features (to use the industry term for the wires and bits we build silicon chip transistors out of) using superconducting materials where we have to control grain sizes and multi element mixtures, there will be lots of work on it so I’m sure it may change, but there will be a fundamental difference in how small we can make the conductor if it involves having multiple elements and crystal grains in specific structural arrangements, unlike a pure metallic wire which can be as thin as a few atoms (at this size your limits entirely depend on how tolerant you are of electrons accidentally tunnelling to other nearby conductors)
> 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.
I work in research, so I understand that it is very important to keep in mind the limits imposed by nature itself. Heck, I had more than one argument with idiot bosses who wanted to break the laws of physics or maths...
Say we use this (or any other) superconductor to build an AND gate. Assume one input is zero, so the information of the other input is lost.
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?
If that's the case, simply redesigning our logic gates to have as many outputs as they have inputs, with some of these outputs feeding indirectly back to the power source without being read, seems feasible.
It's a thermodynamic argument. Suppose you have a system of n bits each in an arbitrary state, so it has 2^n microstates. You set one bit to 0, regardless of what it was originally. It now has 2^(n-1) microstates. Finding entropy S for a given number of microstates N, S = k_b ln N, and so dS = k_b * (ln 2^(n-1) - ln 2^n) = k_b * ln 2 * (n - 1 - n) = -k_b ln 2, i.e. entropy has decreased by a constant amount. But by the second law of thermodynamics, entropy cannot decrease in a closed system, and the way it's dissipated is as heat. How much heat has been released? dE = T*dS, so dE >= k_b * ln 2 * T. Note the dependence on temperature: you can reduce how much heat is released by having it operate at a lower temperature. Even at room temperature, however, this is a billion times less than existing heat dissipation, so there's lots of room for improvement before we start hitting the Landauer limit.
This can be worked around by introducing ancilla bits to maintain the number of states in the system, but the instant you destroy the ancilla bits (e.g. by feeding them back to the power source), you dissipate energy. The exact mechanics of this would depend on the implementation of the device you're talking about, but you'd inevitably encounter it and be unable to overcome it.
> 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 possible outputs, one for each input. But we only want one output for the rest of our computation, so the other one dump into the environment somehow.
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.
I think that you could move those bits to destroy them somewhere else but what I got from pezezin post is that there are many order of improvement to achieve before that loss becomes significant enough to warrant the incredible complexity of shipping wasted bits to the heat sink.
This is the first time I'm hearing it phrased this way and I wonder why it hadn't occurred to me before. Thanks so much, in any case, you have just increased my understanding quite a bit. :) slapshead
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!).
Reversible logic is fun, but the memory requirements get intense. You need enough storage to retain every intermediate value used in a computation. If you have a 1GHz 64-bit processor and it does an hour-long computation, you need to store the entire 29TB history of its intermediates... and then spend an hour unwinding it!
But currently, the adiabatic chips has a bigger issue with getting to zero: their control circuitry is a bank of AWGs, each burning probably hundreds of watts at room temperature. They ideally don't produce heat in the cold zone, which is great for the cryogenic system, but if we have room temperature superconductors, that's suddenly moot.
How powerful is the magnetic field in typical brushless motor? Even if it can’t be used for an MRI machine, it could do wonders for efficient (and/or compact) robotics and electric vehicles.
I’m also very curious what kind of inductors you could make for switching power supplies using superconductors.
Do you need steel? What about a brushed(Assume some fancy future micrometer gallium filled gap that doesn't wear or something) motor that just has superconducting coils attracting each other?
You could probably do that but it wouldn't be a whole lot better than the existing traces: it's not usually the resistance that limits the size of circuit traces but the mechanical requirements, such as your ability to connect to them and to space them apart so you don't get crosstalk due to capacitive or inductive coupling.
If you could use it to make circuits, especially of a high level of integration then it might well be something much more interesting (Josephson tunneling is briefly mentioned in the article). That could theoretically give rise to very efficient switching gear and if it can be miniaturized enough to efficient CPUs and memory. This is because the typical transistor uses power mostly in the time between the transition between the 'on' state and the 'off' state, when it is acting as a resistor. If you could get rid of that resistance during the transition then you might be able to reduce the amount of power a given circuit uses, but there are still lower limits off losses that you won't be able to escape, so it will not make your CPU magically use zero energy.
Given the contents of the paper such applications are a very long way off and may in fact never happen. Let's first see (1) if it is true and (2) if it is true how well it stacks up against copper wire of the same diameter and commercially available super conductors in terms of cost and practical current carrying capability. If that's all good then this will really be a game changer.
Sometimes the resistance of the trace matters. I’m designing a motor controller that needs to carry 100 amps and the resistance of the copper means that large planes are needed to carry the current without overheating.
Beyond that I agree with everything you’re saying.
That's absolutely true, in power electronics there are applications where the current carrying capability of the traces really matters. Typically you'd either use a very wide trace or some other trick such as via'ing together multiple layers of traces or even to tin-plate the trace. In extreme cases I've seen traces reinforced with solid copper bars.
There is also extra thick copper clad board ('heavy copper PCBs').
One of the authors in a related paper[1] is Hyun-Tak Kim. He has many publications in peer-reviewed journals[2]. One even has > 1500 citations[3].
I can't tell if there is a catch anywhere, this seems pretty legitimate. Also, unlike some previous claims that required sophisticated setup to reproduce, this seems dead simple. I think we will hear from other researchers very soon.
1. Superconductor Pb10-xCux(PO4)6O showing levitation at room temperature and
atmospheric pressure and mechanism: https://arxiv.org/pdf/2307.12037.pdf
The actual picture of (poor) levitation in the paper you linked is pretty compelling. This isn’t a complex, noisy measurement showing something that’s related to superconductivity — this is a magnet and a supposed superconductor repelling each other.
As far as I know, that’s possible with permanent magnets (and it would be weird, but not impossible, if the group instead synthesized a novel ferromagnet and didn’t notice), electrets (seems pretty unlikely here), very extreme amounts of static charge (again, seems unlikely), and actual superconductivity (would be awesome).
Random bits of cooked oxides, ceramics, and such don’t float on a magnet.
Believe it or not, the levitation effect can be found in non-superconducting materials with a high diamagnetic constant such as pyrolytic carbon. Induced magnetic fields are created by "effective currents," which can occur in zero-resistance systems that are not called superconductors (because they can't conduct across a significant distance, only around a tiny loop) like molecular or atomic orbitals.
Copper and a magnet can certainly interact. Drop a magnet through a copper pipe and the eddy currents will induce a field that's opposed to the magnet causing a damping effect. Maybe something like this is going on where movement of the magnetic field is inducing an opposed magnetic field in the copper, and thus interacting.
Anyhow it will be interesting. if It can generate a field of 1.5-2 Tesla you could have more efficient solenoids and probably motors.
Yeah, that thing does really want to stay in a constant level on the magnetic field. That would dispel every other explanation on the GP, as it's not simply being repelled or attracted.
I found that video very compelling. If it was eddy current, the float standoff distance would have decayed. It sure looked to me like there was no decay at all, and wow! if true.
Eddy currents can be induced in non-superconducting materials that make it look like levitation, but the catch is that there has to be relative motion between the magnet and the object 'levitating' to generate the currents in the first place.
But in this sample video, the standoff distance doesn't appear to be slowly dropping at all, which would rule out eddy currents as a source of the behavior. If you continue watching the linked video to 13:27, he talks about how and why superconductors levitate.
I would say that this type of levitation where it sort of half levitates is quite common. I taught YBaCuO superconductor experiments for a few years. That Meisner effect would get full marks in my institution!
>As far as I know, that’s possible with permanent magnets (and it would be weird, but not impossible, if the group instead synthesized a novel ferromagnet and didn’t notice)
As far as I know a stable arrangement of permanent magnets levitating is impossible without a baring surface to keep them aligned. (i.e. free floating levitation is not possible without active control)
* ferromagnetic - attracted to one pole of a magnet but not the other (in a given orientation), this is what everybody thinks of when they think of "magnets"
* paramagnetic - attracted to both poles, i.e. stuff that sticks to magnets
* diamagnetic - repelled by both poles, except in superconductors, this effect is very weak compared to the forces experienced involving ferro-ferro or fero-paramagnetic materials.
There isn't another category, everything fits in to one of those buckets.
Saying
>Just so everyone is on the same page, static passive diamagnetic levitation is possible with materials like pyrolytic graphite.
is a bit deceptive, as what people know as "magnetic" materials are ferromagnetic.
That's not quite true. There is a Halbach array with a bunch of compensation coils that will nicely center as long as it is moving, no active control or bearing required.
stationary. Hence the 'as long as it is moving' bit above. Because the motion allows for the coils to generate enough of a current to drive the compensation. So you need a support system to bring the assembly up to a certain minimum speed above which it will stably levitate.
I wonder how long you could get one of those to spin in a vacuum.
Halbach arrays with compensating coils have been proposed for some interesting applications, such as low loss flywheels for electrical storage. I don't know if that ever got commercialized but I do recall that some prototypes were made by a US company. I can't find a reference to it though.
Its not a dirty secret, but just like the rules on chemicals under the organic certification, if you can show that there's no way to do what you want to do with lead-free, you can get an exemption. I suspect that "significantly lowers the cost of power generation" would outweigh "contains lead".
> if you can show that there's no way to do what you want to do with lead-free
The bar is even lower than that. For example, bullets are still made of lead, not because it's necessary, but because it's cheap, and despite the fact that it contaminates the meat of the hunted animal with lead.
Tangentially, the US Army has completely stopped using lead in bullets. Their 5.56 NATO ammo has copper where the lead used to be (i.e., inside a brass jacket) which reduces performance because copper is only 2/3 as dense as lead.
First, terms - brass is not used to "jacket" a bullet. Brass is used as the case material for the cartridge. Steel, and nickel plated steel are some times also used here. "Jacketing" (as in, Full Metal Jacket) refers to the material that wraps around the exterior of the projectile. As far as I'm aware, the material used here is almost always copper, or a copper alloy (cupronickel).
The US standard bullet is the M855. It's a lead core with a soft soft steel penetrator at the tip, that's jacketed with copper.
There's an advanced version of the M855, the M855A1, which is an entirely steel slug, jacketed with copper. This bullet has better terminal performance at longer ranges, and slightly better armour piercing capabilities.
The US army standard training round is the M193. It is a lead bullet jacketed with copper. Interestingly, it in many ways has better terminal performance than the M855 because this is the bullet the M16 and M4 rifles were designed around, and the M855 only exists because of NATO politics.
There are no bullets in the US inventory, to my knowledge, that use a copper core. Copper is simply far too expensive to be used at that scale, and, as you pointed out, reduces the weight of the projectile which has negative effects on terminal performance.
"Why are bullets jacketed in copper" you might be wondering here - when rifle cartridges were invented, they still used black powder, and all bullets were lead. When smokeless powder was invented, it became possible to have more explosive power per unit of volume. However, this had two negative effects - one, the lead projectile would either disintegrate, or became entirely inaccurate, at the speeds it was accelerated to. Second, the force of the bullet against the rifling of the barrel was rubbing away metal from the bullet, leaving lead deposits which fouled the gun and made it inaccurate. All steel bullets solved this problem, but increase the wear on the barrel. The solution was to coat (jacket) each bullet in a thin layer of copper, which was stiff enough to withstand the force of friction in air, while also softer than the steel barrel and reduced wear and tear on the rifles
M855 has a lead plug behind a steel penetrator. M855A1 has a copper plug behind a steel penetrator. So, I stand by my "copper where the lead used to be". I never said there wasn't a steel penetrator.
>For general issue, the U.S. Army adopted the M855A1 round in 2010 to replace the M855. The primary reason was pressure to use non-lead bullets. The lead slug is replaced by a copper alloy slug . . . The U.S. Marines adopted the Mk318 in early 2010 due to delays with the M855A1. This was a temporary measure until the M855A1 was available for them, which occurred in mid-2010"
As you probably know, most combat soldiers in the US Army and Marines carry a rifle (usually an M4 these days IIUC) that fires 5.56×45mm NATO, so it is probably the ammo type that the US military uses the most of.
This post is a master class in why you shouldn't get all your information from Wikipedia. Press releases are not reality.
Yes the M855A1 was developed and started operational testing in 2010. However, it wasn't available to anyone who wasn't forward deployed until...my memory says 2015. The M855 is still used on post because a) it's cheap, and ballistically similar to the M855A1 and b) the production lines at Lake City are still geared for them
The Marine corps didn't formally adopt the M855A1 until 2017/2018. Brass didn't like it because it broke the feed ramps on machine guns. There was a big procurement SNAFU about this.
I get that you're trying to be snide because you were so publicly wrong, but your tone here really just makes you sound like you're trying to sound smart about something you know nothing about. Something to consider. Frantic googling does not an expert make.
You're right about the copper core on the new model A1 - I thought it was steel entirely with thin jacket. I would argue that when, by weight, the majority of the bullet is steel, my original point still holds.
I worded my original assertion the way I did (lead replaced with copper) so that it would be true even if the majority of the bullet is steel.
>I get that you're trying to be snide because you were so publicly wrong, but your tone here really just makes you sound like you're trying to sound smart
Right back at you. I don't think I'm motivated by trying to sound smart, but rather by curiosity about the subject. Well, OK, half by wanting to sound smart (and win arguments) and half by curiosity.
In particular, I'm still curious about whether ammunition containing lead is still routinely used by the US military--if you still want to talk about it. I realize Wikipedia can be totally wrong. So far I haven't succeed in wringing information out of Google Search that would corroborate or support your assertion. When's the last time you (or someone you know to usually tell the truth) has observed M855 being used by the US military in significant quantities?
Answering without doxxing myself is harder than I thought. The last time I was on a US military range, which to be fair was right before the pandemic so things probably have changed - we drew green tip (M855) from the range master. My understanding was that a) the steel targets were getting beat up by A1 and there wasn't any money to replace them and b) we weren't a combat group so we didn't rate the good shit.
EDIT TO ADD:
I don't know if that qualifies as "quantities" and anecdotes are just that, but that's been my experience.
Thanks for taking the time to set me straight on that. I didn't realizes I was posting misinformation when I wrote, "the US Army has completely stopped using lead in bullets".
>The US army standard training round is the M193. It is a lead bullet jacketed with copper. Interestingly, it in many ways has better terminal performance than the M855 because this is the bullet the M16 and M4 rifles were designed around
As I understood the standard M4 with 1:7 barrel can't shoot M193 accurately
Copper bullets date back to the 80s, they're not a new development. Copper bullets have higher penetration despite having less mass, which makes them better against armored targets, and NATO still held on to lead for so long just because it's cheaper.
They date back further than that. In WW1, French troops were mostly shooting full copper/bronze shot. The reason was that it was cheaper and easier to mass-produce solid copper bullets than it was to increase the production of jacketed bullets by a similar amount, and with Germany excluded from naval trade, there was suddenly a lot more copper available on the market.
Yeah, I just mentioned in another comment that there already exist exemptions such as server/networking hardware:
"Lead in solders for servers, storage and storage array systems, network infrastructure equipment for switching, signalling, transmission, and network management for telecommunications"
Lead is used everywhere. Not in paint anymore but you can buy lead weights at hardware stores. Don't grind it up and put it in your muni water supply, but it's a household substance that is harmful if ingested, like many others.
Both lead solder and lead-free solder are commonplace. Lead is standard in aerospace and military applications, while lead-free is standard in most products sold in the EU.
It's more about producing toxic waste and contaminating the environment - no one's licking the solder joints in their electronics either, but you still have to use lead-free solder.
Compared to refining traditional conductors and recycling/disposing of used electronics?
> you still have to use lead-free solder
One, fumes. Two, people touch their solder and then grab a cookie.
We're premature. The results need to be proven. But the benefits of RTP superconductors is mindblowingly high enough that risks from lead contamination (far from a novel problem, I might add) can be safely ignored.
Soldering temperatures don't produce significant lead fumes. The fumes you see are flux fumes (which are also bad to inhale).
IMO, the most dangerous thing about lead solder is cleaning the iron. Both the common methods (damp sponge and brass wool) create many tiny little balls of solder that are hard to see and bounce about all over the place. Because of the high density of lead they're less affected by air resistance than you might expect, and they roll easily, so they can move surprising distances. They can easily end up caught in clothing, and from there fall into food. This will result in much higher lead ingestion than just touching solder then touching food.
I personally always use lead-free solder. If you have a good temperature controlled soldering iron it's nearly as easy to use as leaded solder.
Lead-free through-hole soldering is easy and practical. Unfortunately, for SMT prototyping (including reflow soldering), lead-free work is no longer that easy. Another problem, even in through-hole devices, is when you have large metal parts - a tough problem for RF/microwave circuits full of SMA and BNC connectors, backed by 1 or even 2 layers of solid ground planes, providing excellent a heatsink and a lot of cursing during work and rework. With lead-free solder, I found the iron needs to be cranked up to 420°C for a usable experience (but a larger iron tip may reduce that to a more reasonable level), and I don't know what temperature does it take to desolder them.
The last time I checked, low-temperature bismuth-tin alloy is only available as solder paste, unfortunately not available as flux-core solder wires (they're not really a good choice for connectors to begin with as the alloy is brittle, but I only need it to survive before the next prototype...)
It's trivial to experimentally demonstrate that solder fume contains almost no lead, the quantity is negligible. Claiming the contrary is the electronics equivalent of saying HTML is a programming language. Please don't do that again. The fume is indeed toxic, but it's due to the VOCs from the flux core, not the lead in the alloy.
A more solid (no pun intended) argument can be the hazards of debris. Furthermore, in my opinion, a newer and more serious problem of leaded solder today, in a workshop setting, is its use in solder paste. Solder paste and a reflow oven are required for prototyping any circuit boards with surface-mount components (SMT) - basically any modern circuit board today. Solder paste is a tube of toothpaste-like chemical mixture that contains tiny, micrometer-sized metal particles, mixed with sticky flux. If they're used without care, a solder paste spill is a sure way to contaminate the floor or work surface of your workspace. The sticky paste is also hard to wash away from skin.
Unfortunately, reflow soldering of surface-mount components can be really challenging, even more so when doing it by hand. Thus, classic lead-tin alloy is often used to reduce difficulties of assembly during workshop prototyping due to its technically superior properties. Switching to lead-free is only possible when you have a tightly-controlled and consistent work flow.
If you want lead-free, for small-scale prototyping and rework, a non-toxic bismuth-tin alloy is sometimes a good alternative to standard SAC305 lead-free solder thanks to its low melting temperature, which is one main reason that makes most lead-free alloys difficult to use (it even has considerable popularity in mass production of LED devices, as they are heat-sensitive). But its surface tension is slightly different, weakening the self-alignment effect of components during reflow soldering, increasing the chance of defective joints - a concern in prototyping. Its brittle nature also increases failure rates in the field, among other caveats.
> Solder paste and a reflow oven are required for prototyping any circuit boards with surface-mount components (SMT) - basically any modern circuit board today.
This is incorrect. You can easily do small scale work with almost all SMT components without solder paste. Solder paste is required for automated assembly processes. But almost anything done by hand can also be done with conventional solder.
Source: I worked as an electronics designer for a few years, and assembled prototypes and small production batches by hand with SMT parts (0603's, TTSOPS, etc) every day.
The one exception is BGA devices, because the solder pads are underneath the device. But doing those by hand requires precise alignment that is difficult enough that few people do it. Also, for smaller BGA devices with fewer pins, skilled operators can still solder them in place with a heat gun by covering the pads with solder and flux and just melting them into place.
I know two people (one of which is here on HN) who do fairly large BGAs by hand, I wonder if that skill is really that rare. I couldn't do it myself though, I did try but for some reason I can't make it work reliably enough to risk it on stuff that matters.
> This is incorrect. You can easily do small scale work with almost all SMT components without solder paste. Solder paste is required for automated assembly processes. But almost anything done by hand can also be done with conventional solder.
I disagree. I don't consider 0603 passives and TSSOP packages "modern" anymore. Of course these components can be hand soldered with ease (possibly at top quality with the aid of a microscope). Unfortunately, the industry is gradually abandoning TSSOP and QFP in favor of DFN, QFN, and LFCSP in recent years. For anything that does high-speed signaling or multiplexing above 1 Gbps (which is old by computer's standard) like USB 3.0, PCIe 1/2, QFN goes without the need for a mention (short of using BGA). But the thing is, even in simpler ICs like DC-DC controllers, you can see the same trend. Simple RFICs are another source of heavy users of these packages, reduced circuit parasitics is certainly a factor.
These packages are all leadless, and frequently with thermal pads at the bottom. An older term for leadless packages is BTC - Bottom Termination Components. [1] After a few successive and multiple failed QFN soldering attempts, I switched to ordering stencil, solder paste, and a hot plate. It worked perfectly on my first attempt, so I never looked back.
Unless you have top 10% soldering skills, which I don't (experienced smartphone repair technicians seems to have mastered the art of QFN), I found solder paste is required for maintaining your sanity with leadless packages. Furthermore, without reflow soldering, prototype assembly can be very time-consuming and takes hours, especially when you need 3 or more prototypes.
Occasionally, leadless packages also have optional difficulties turned on, completely eliminating the possibility of hand soldering, such as multiple bottom pads for different nets (to minimize parasitic inductance), or having two layers of contacts, one row on the exterior and on row on the interior.
> You can easily do small scale work with almost all SMT components without solder paste. [...] The one exception is BGA devices
And DFN, and QFN, and LFCSP, and...
Thanks to industrial and automotive users, some ICs still have QFP versions for these markets (due to their vibration resistance) that are friendly for hand operation, but you have to pay a premium.
Finally, even plain-old QFP chips have bottom thermal pad these days (in that case, you can manually apply a blob of solder on the PCB and reflow again with a hot air gun, but manually apply a drop of paste is easier to work with).
---
[1] But these days it would make people think it's some kind of a Bitcoin mining ASIC. BTW, the last time I've checked, these ASICs are indeed QFN, so one can say they're BTC BTC chips...
It's like fundamental best practice to always wash your hands thoroughly with soap if you handle leaded solder.
You might want to read more in the links I shared about the harmful effects of lead before "whatabouting" to other problems of electronics recycling/waste.
and yes, it's entirely possible this application would get an exemption from usual restrictions on lead. For example in the EU directive, one of the exemptions is:
> Lead in solders for servers, storage and storage array systems, network infrastructure equipment for switching, signalling, transmission, and network management for telecommunications
> fundamental best practice to always wash your hands thoroughly with soap if you handle leaded solder
But people don't, particularly students, and sometimes they also let their irons run too hot at which point fumes become an issue. Also, there is an easy alternative, so why not.
If the choice is lead superconductor or not, nobody is going to pause on a use case because there is lead. If they do, and if this is real, please let me know--I'd love to have them as competition.
> might want to read more in the links I shared about the harmful effects of lead before "whatabouting" to other problems of electronics recycling/waste
The point is, whether a RTP superconductor does or doesn't contain lead is irrelevant to its adoption. The advantages are too large. What current directives say are, similarly, irrelevant.
Oh, sure. You could have just said that then. You instead originally said something about "no one licks the insides of the computers", which isn't the reason lead in electronics/PCBs/etc. is restricted, and what I was pointing out.
Usually people who are making the argument you were making with the words you were using are signalling that lead is "lump of rock from center of nuclear reactor" dangerous. Honest to god, a lot of people believe this
Why is this being downvoted into oblivion? It's a completely valid, good-faith point explaining why lead has restrictions on its uses other than "someone might lick it"... It would be nice if people actually responded and vocalized their disagreement or described the flaws in my reasoning, rather than just suppressing my message.
As for how to avoid lead poisoning, coat the lead with a thin layer of some substance, perhaps a plastic or rubber that doesn’t affect its magnetic capabilities.
Or perhaps they can galvanize it with safer metal, leaving a really small part exposed.
I think people are talking about RoHS rather than practical danger. Since RoHS is incredibly strict about quantities, e.g. if you can mechanically seperate a piece of the widget, that's what gets measured.
Cobalt is way more toxic than lead and yet every consumer grade lithium ion battery contains it. The fact something is toxic is not that important. What is that we manage the end of life for the products it contains responsibly.
I mean, modulo edge cases, lead is a lot scarier than CO2; it's only because of the ridiculously obscene quantities of CO2 being produced that it's a more immanent threat. There's obviously not enough information yet to weigh the value/consequences of the amount of lead used here, but if your measure of whether something is a good idea for mitigating carbon emissions is just "it's not carbon emissions", you're going to find yourself kicking a can a bit down the road, or (much) worse.
Maybe they could pack it into epoxy encapsulated modules of standard size, so you could always reuse it in another motor or transformer or what have you, assuming you were willing to disassemble the scrapped gadget?
If you think carbon dioxide is scary, wait for your cup of Pepsi.
(Low toxicity of CO2 is actually one of the reasons it is not treated seriously enough).
> Superconductor Pb10-xCux(PO4)6O showing levitation at room temperature and atmospheric pressure
Is it late April Fools joke?
It can’t be true.
Edit: I am not surprised it levitates. I am astonished by how much it will reshape our world if it is real room-temp and ambient-pressure superconductor. Also is easy to produce. Just too good to be true.
Levitation is to be expected for any superconductor when it's in a superconducting state; that part is banal. The big question is whether it's actually a superconductor at RTP. Their results are strong enough that it's unlikely to be a mistake, though fraud is possible too (although it is so easily uncovered given the simplicity of preparing the material and the strength of the reported effects that fraud seems almost pointless since it'll be uncovered immediately).
The recipe in the paper is so simple that it's giving me Pons-Fleischmann vibes. It reads more like an entry from an alchemist's journal, reproducible with chemicals and equipment you could buy on eBay or Amazon.
I wonder if anyone has tried to contact one of the authors to confirm the paper is legitimate (i.e. someone isn't spoofing the author's names in order to create chaos).
Silicon is one of the most abundant elements on Earth and for thousands of years humans had no idea what would be possible with very controlled etching of it.
Mildly-topical Terry Pratchett amusement quote, since it involves a society that has overlooked the power of silicon plus the potential of superconductivity:
> Detritus blinked. There was a tinkle of falling ice. Odd things were happening in his skull. Thoughts that normally ambulated sluggishly around his brain were suddenly springing into vibrant, coruscating life. And there seemed to be more and more of them.
> 'My goodness,' he said, to no-one in particular.
> This was a sufficiently un-troll-like comment that even Cuddy, whose extremities were already going numb, stared at him.
> 'I do believe,' said Detritus, 'that I am genuinely cogitating. How very interesting!'
> 'What do you mean?'
> More ice cascaded off Detritus as he rubbed his head.
> 'Of course!' he said, holding up a giant finger. 'Superconductivity!'
> 'Wha'?'
> 'You see? Brain of impure silicon. Problem of heat dissipation. Daytime temperature too hot, processing speed slows down, weather gets hotter, brain stops completely, trolls turn to stone until nightfall, ie, colder-temperature,however,lowertemperatureenough,brain operatesfasterand—'
> [...] Detritus sat down again. Life was so simple, when you really thought about it. And he was really thinking. He was seventy-six per cent sure he was going to get at least seven degrees colder.
Assuming the lift is there or the magnets are strong enough, it would be plausible to have an electromagnetic hover skate park where you could pay by the hour, and possibly even future X-game like events where the boards and riders could move in any direction they can get acceleration in.
I want them to have enough current passing through them in a rod shape that it will run the current against the Earth's magnetic field to cause vertical movement.
Not so fast... These superconductors although revolutionary loose superconductivity in high magnetic fields (or with high currents).
If this proves true I'd see their use more in electronic circuits. Novel sensors etc rather than classic high power high field uses people dream about when the words "room temperature superconductivity" gets thrown about.
MRI will get much cheaper, but you still need a good upper critical field and a proper access control (Zone 2/3/4) protocol. So probably not in very small buildings.
From what I can tell this material can't provide higher than 0.3T. We've had permanent magnet MRI at 0.3T but the drawbacks vs superconducting magnets are weight and lack of active shielding.
With room temperature superconductivity doesn't it become possible to turn the magnet on and off far more easily? MRIs would be much safer if they were only energized during the actual imaging process.
They are already superconducting and using liquid helium to cool. They have failure modes of spilling gas out into the room (patient and operators have to evacuate.)
Superconductors will typically levitate if placed above a magnet, and vice versa. Magnets are weird--superconductors even more so. I assume that's what they were referring to?
Edit: Judging by Fig 4, which has a large object conspicuously labeled "magnet", that's probably what they're referring to.
This whole experiment is quite reminiscent of an experiment I did in high school. We synthesized a high temperature superconductor (IIRC it was YBCO) by grinding some powders together with a mortal and pestle and baking the result. And we stuck it in a little cup of LN2 and floated a magnet on it. It really works!
This group used somewhat nastier powders, they had to cook parts of it in a vacuum, and they floated the result on a magnet instead of vice versa. And it only floated a bit. But they did it without any cooling!
I would guess that it'll take a month or two to repro the procedure. The paper was uploaded in the last week, so we're still probably a few weeks out on peer review.
The method to produce this material as described in the related paper [1] is fairly simple and could be done at home with a $200 home metal melting furnace from amazon and the precursors (which also seem to be fairly standard easy to obtain metals).
If this is real, I'd expect some smart people from hackaday / youtube to reproduce this within weeks if not days.
If this is real, it'll change society quickly and permanently for the better. There's obvious wins in energy transportation and even generation, but actually having a room temperature superconductor is likely to result in an explosion of engineering use cases. It will be like the discovery of lithium ion which slowly transformed the use of energy throughout society, but faster.
Given the materials and methods involved it really isn’t that dangerous. With basic precautions I’d say go for it, worst case is honestly just blowing a few hundred bucks. If this pans out, there will definitely be some do it yourself tutorials on YouTube in the coming weeks.
I doubt this one chemistry will be all that useful on practice. But after people understand it, I expect them to recreate the effect with completely different components, not on just slightly different ones.
For years, and then after the explosion too. The last reactors were decommissioned around 2015 (it takes years, so the dates are bit washy).
Chernobyl wasn't the accident people seem to think. It wasn't inevitable, it was the result of numerous self-serving decisions exacerbated and even required in the very messed up Soviet system of management that enforced following the party instructions over all other possible complications.
Unfortunately they have a point, in that there is no ISO or DIN standard that covers a plant that has been rigged with explosives by invading barbarians.
The solution isn't to abandon nuclear power, but to make it very costly for aggressors to meddle with it. E.g., deploy UN forces to the plant at the first sign of trouble.
Seriously, people should stop panicking about lead that much. You know there is this fairly common hobby people have, it's called casting bullets. With lead. I've done it, I know many people that do it regularly and they're all fine.
Furthermore, shooting ranges are full of lead in the ground. The laws around here(Poland) require a cleanup by specialised companies every few years and a concrete slab to separate the lead/soil mix from the groundwater near the targets, but still there are tons of the stuff just sitting there for years and no one gets hurt. Fun fact. These specialised cleanup companies don't cost anything for big ranges. They're either free, or they pay the shooting club that owns the range money, because the lead they recover is worth a lot.
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.
Actually, firing ranges almost certainly are bad for your health and you should wear a particulate filter when going into one. https://ehjournal.biomedcentral.com/articles/10.1186/s12940-... for instance. I'd wager there is no small link between heavy firearm hobbyist and a proclivity for paranoia, conspiratorial thinking and other Q-Anon adjacent traits.
"No one gets hurt" - perhaps no one dies, but there are no safe levels of lead exposure.
Is the superconductivity present in the powder? Or does it require vapor deposition?
If the latter, it implies a cloth versus fibre topology, which forces an interesting rethink of many paradigms forced by the ductility of our present conductors.
> could only cause problems solvable by more superconducting railguns
If the projectile is ferromagnetic, or potentially even just diamagnetic, a defense system involving shaped ultra-high intensity magnetic fields becomes conceivable.
A sister paper [0] has a photo of the material exhibiting the Meisner effect and levitating over a magnet, and claims to have a video too.
Either they blatantly photoshopped the photo or they actually made a room temperature super conductor. I can’t see how the could have made a subtle mistake that resulted in magnetic levitation at room temp without making a superconductor.
Indeed, this will change pretty much everything if true. A true room temperature / ambient pressure superconductor will cause a revolution in so many fields that I find it hard to believe. But if... Let's wait for replication before throwing a party. This is on par with the discovery of the transistor and possibly bigger.
Superconductors have a current limit above which they are no longer superconductors. It is possible that a room temperature superconductor could be created that has a limit too low to be of any practical use.
It seems this is worth cautious excitement, but don't get too excited yet.
Oof, all right then. Perhaps there's room for improvement, but there would need to be a lot before this is useful/competitive even in lab settings.
For comparison, high temperature superconductors (in this context high temperature means tens of degrees kelvin) like the recently rather revolutionary ReBCO has critical current values measured in hundreds of thousands of amps per square centimeter. That would be a factor of a million.
It's a thin film according to the article linked, but there is no mention of how thin it is (it could be a monolayer) and there is no mention of how wide the film was so the 250 mA figure can not be used to determine whether or not there is 'room for improvement' or even a necessity for that (unless it was already normalized, for which I see no evidence). The 'Critical current' isn't mentioned at all in terms of the cross section of the conductor, just as a function of temperature and magnetic flux which they really should have provided to be able to make sense of the figure. ReBCO is 8 MA / cm^2 (that's million, not milli), the thin film layer they tested with could well be so thin that it is in the same ballpark or it could be a small fraction.
This is clearly a very early result and until they have more insight into how it works (assuming it really works...) we'll have to be patient before we get more meaningful figures on the actual current carrying capacity of thicker conductors made out of this stuff. They were happy enough to be able to prove superconductivity at room temperature and normal pressure, clearly they are still a ways away from being able to line up a comparison with ReBCO with respect to current density. But surely that will happen soon if this is real.
If it is a thin film it may have to be a thin film to get the effect in which case you still need a million of them bundled together to get comparable currents. It's not a certainty but a fact that dials back the excitement of this announcement from potentially world changing to interesting but quite limited applications.
>In 2008, Gozar et al. reported hightemperature interface superconductivity between metallic and insulating copper oxides(39). The
thinner the layer, the greater the stress-inducing effect, the greater the strain, which seems to be the higher the superconducting transition temperature. Therefore, we argue that the stress caused
by temperature and pressure brings a minute structural distortion and strain, which create an electronic state for superconductivity.
So the paper seems to confirm this, though the authors seem to be hopeful for general applications.
What we have here seems to be a clever trick to have ambient pressure superconductors by introducing crystal structure/microstructure stresses.
>But surely that will happen soon if this is real.
What I'm saying it that this is not so sure, may not be possible for a bulk material, may be insanely too expensive to be useful otherwise, and may be limited to very niche applications where milliamp superconductors might be useful (think sensors, microchips, and the like)
Sure is cool, but at the same time... cool your jets, eh?
Absolutely, but layers can be stacked (if they really are superconducting there won't be much of an issue to get rid of waste heat, there will be very little of that).
As for cooling my jets: I don't think we'll see any real application of this in the next 10 years at a minimum, this stuff is the first step on a very long road towards commercialization. From the first mention of the photo electric effect (~1890) to practical (1956), affordable (1990's) solar panels took roughly a century.
I hope that this superconductor, assuming it's real can be fast tracked given our much improved knowledge of materials and fabrication methods. But I'm realistic enough to realize how much work would still have to be done even if it is real. The road from the lab to the shelf is a long and expensive one and even in the best of scenarios I can't imagine anything on a timescale of less than a decade.
Let's wait to see what the maximum number of A/cm^2 is before determining if that is even necessary.
It's possible that they already normalized the figure, and if that's the case then 125 mA/cm^2 would be 'bad news' in the sense that even though the temperature and pressure are much better than other superconductors the critical current is much, much worse. But given the way the paper is formulated I'm not sure if that is a proper reading and it is very well possible that they are talking about a particular thin film sample (which would make it a small fraction of a square centimeter in cross section) and how much current they passed through that sample. In which case the situation would be much better already, especially if it turns out that the sample was extremely thin and/or narrow.
> I really need someone to bring me down a notch. This is too exciting!
It's on arXiv, which is a preprint journal, which means it has no peer-review; and is therefore generally less trustworthy (especially when the paper has no connection to a technical conference or is not being published elsewhere, and is in a non-computer science or mathematics field).
In addition to this, claims of room-temperature superconductors have been mired in controversy or otherwise proven false:
Considering that many fraudulent claims of room-temperature superconductivity have gotten into Nature and other top-tier publications, I would wait for multiple independent recreations of the results in the paper.
AFAIK doesn't pyrolytic carbon need a N-S field in order to levitate? That's the one key difference I can see - this looks like the traditional superconductor trick of just levitating in a simple field.
But it still looks dependent on their being a NS pole at a corner.
That said...from this video https://sciencecast.org/casts/suc384jly50n I'm very suspicious of the behavior you see in the last few seconds where it gets pushed over to the corner and seems to fall right to the magnet That would be consistent with their being a ring magnet underneath the top magnet their, and once suitably over into the corner it loses the diamagnetic property because there's no N-S pole. The "seam" on what should be a bulk magnet in both videos that are out seems like an obvious problem.
So yeah...I think put me down for this is diamagnetism with pyrolytic carbon (the image in the paper also notably hides what you see in the video - that there's a seam on the magnet where it looks like it's a stack of two).
The effect is weak, but seeing that it behaves the same by flipping the magnet means that it can't be a standard magnet like we're used to seeing. (If I understood some of the other comments correctly).
In the video, it's when they stop moving the magnet, it maintains its position, neither repelling nor attracting.
Several physicists have spoken up and said this, and a few other tells distinguishes it from any conventional materials, which is why they made the video to begin with I'm sure.
That said I'm just parroting back the things I've picked up from this discussion.
Unmoving copper also neither repels or attracts a magnet.
Eddy currents impede movement of non ferrous metals in a static magnetic field. This looks like slow motion falling or resistance to spinning when the metal is in a fixed field.
This is how auto belays work.
If you move the magnet, the metal will also move since you're inducing a current and the fields from the eddy currents will react against the moving magnet.
That said, I'm enough of a layman not to be able to connect this explanation to what I saw in the video.
Are you saying because it wasn't moving in "slow motion," we can rule out non-ferrous metals? Or are you saying the alternating movement/stillness of the magnet shows this?
As I've said, I'm fuzzy on the details, so I'm relying on the expertise of the physicists here.
I can tell it doesn't react to a magnet in ways that I'm familiar with (copper, iron, other magnets), but that's all the detail I can tell from the video.
It's also suspicious that there's not a control sample of copper in the video. Any scientist trying to be thorough would have controlled for this - shown that you don't get the same effect with just a copper sample as you do with a copper sample that's been coated.
Well after seeing the second video I'm pretty convinced it's superconductive or a good scam. The effect was probably just not strong enough in the first video.
I'm suspicious of the magnet. Take a real close look in the second video: the paper cuts the image so the seam of the magnet blends with the table. But in the video it looks much more obviously like there's two magnets stacked on top of each other.
Which is a weird thing to do when for superconductors you shouldn't need it, but for pyrolytic graphite levitation you would (to get an N-S pole).
They specifically act in a way to rule out fakes. For example they turn the magnet around to show that there are no small wires connecting the edges. They start and stop many times, they move in different directions. They knew the video would be watched with the default mind set that it is fake.
On reality, you would need a good computer with a large set of sound emitters just outside of the screen and a huge lot of tries. It would be a project for a small team and many months of work.
Or maybe a few transparent wires and less photoshop.
I do think the easiest way to fake a video like that would be to use a cool superconductor and change the atmosphere so nobody notices its temperature.
Complicated fakes wouldn't masquerade as scientific papers though. The FTL neutrino comes to mind, where it turned out to be a misconnected fiber optic cable - but everyone involved was genuine.
The bits and pieces of this certainly look like little are being genuine, so the new question is what non-obvious mistake could they be making?
It's my impression, and it seems to be the consensus here that it is very unlikely that this is a mistake. This is either very real or completely fabricated. You don't have a piece of ceramic keeping its distance to a magnet by some unexpected phenomenon or measurement error.
And given the easiness in reproducing the study, there doesn't seem to be any point in fabricating it.
The main worry is whether we're dealing with wholly rational actors. People convince themselves they're seeing an effect, and then seemingly completely erratic things to try and prove it on the conviction that with just a bit more effort they'll get it for real.
Like you'd question why someone would photoshop results[1] in a paper, because surely they'd have to realize they're fabricating data, but they go ahead and do it anyway.
The videos are convincing but are they of what they really purport to show? I agree - what would be the point of fabricating it. But weirder things have happened in the breadth of human experience.
This is very much the truth. The scariest founders during due diligence are the ones that are totally convincing, true believers and yet utterly wrong. They've even convinced themselves, but that failed to convince mother nature. It can be super hard to detect this.
I will say this, I haven't found the "it's not real" responses very compelling either. I've also found that people who actually work in the field seem less skeptical than knowledgeable people adjacent to the field. If it's not fraud, it's at least something new. Here are the reasons I've seen provided by adjacent folks:
Nonscientific objections:
* it was published in a low h-index journal (not a scientific objection)
* poor formatting, misspelled title (not a scientific objection)
* patented and has a company (not a scientific objection)
* seems too simple, it has to be more complex than that, how could we have missed that? (not a scientific objection, also rather ahistorical)
I consider all of these pretty irrelevant given that the authors are not no-names and the actual paper makes clear claims, does exactly what everyone says you should be able to do if you have a real superconductor (show a video of it floating!) and makes replication easy. If it's straight up fraud it will be easy to discover.
There were also many pseudoscientific objections raised by field-adjacent people that I found uncompelling, responses from people actually in the field in parentheses:
* The first video looks like normal copper, the second like other diamagnetic materials or is otherwise unconvincing (not evidence against it being superconducting, at least one materials science lab had several members look at it and thought it looked legit).
* They are trying to hide the magnet structure somehow (the video shows it in clear view).
* The wafer isn't fully levitating or the way it falls is suspicious (not really unexpected given that the superconductive part is supposed to be present in only a few percent of the material).
Scientific objections I find more compelling made by people more familiar with the field, but more bourne of natural skepticism than disqualifying, with there being a lot of subtlety:
* both effects shown can be achieved in known ways by non-superconducting materials (but at the same time? would at least be a major material science advance in that case as it would apparently require diamagnetism ~ 150x as strong as graphite. Author who mentioned this said it would be "materials science magic" and I'm not sure why you'd rather believe in this than superconductivity given that neither have ever been seen before and it's consistent with sueprconductivty. Unless it's straight up fraud).
* Mesner effect graph don't go exactly to zero / happen exactly where you'd expect, maybe reflects a measurement error? (apparently, given the small % of the material that's supposed to be superconducting and material distribution, this isn't really evidence either way. not like we have other room temperature superconductors to compare it to).
* no max temperature where superconductivity vanishes measured, so is it really superconducting? (standard measurement devices only go up to what they reported, scientists seem very mixed about whether it would be easy to DIY measurement at higher temperatures for such a small current)
* not a similar mechanism to known good past "high-temperature" superconductors, and proposed explanation doesn't really make sense given slight deviations in pressure compared to what is in this substance (other scientists seem to disagree and think there could be something there, but it would also not be the first time something novel was discovered and worked for reasons totally different than those the scientists initially imagined)
Overall I find the quality of the objections really weak which increases (to me) the chances that there is something novel here, even if it's not superconductivity. That or it's obvious fraud and we'll know in like three days.
The trouble with the shown videos is that with a limited perspective, they do look a lot like the sort of single-camera trick that a lot of "free energy" device videos use - e.g. [1]
Fortunately if we're dealing with a real effect, this will be easily replicated and proven. But with the fixed perspective of a video, you can create a large number of apparent effects that look real in the constraints of the video format.
The biggest point in favor is that there's full reproduction instructions. I am eagerly waiting someone to try and pull this together separately.
Where I get hung up is, it's an extraordinary, world-changing claim. The standard of proof is very high (and while I could get access to a kiln, I can't get access to high pressure vacuum vessel on short notice).
After reading some responses suggesting the authors don't understand how to measure superconductivity, I double checked the senior author's credentials. He is very much a legit scientist but seems to be a relative newcomer to superconducting. There is a long established history of respected and productive scientists entering fields they don't really know anything about and engaging in mild to moderate quackery. In this case, I am now fairly confident that the following is true:
* he and his team did discover a (probably) novel diamagnetic material.
* it may or may not have interesting properties
* however, it is not superconductive.
According to people who were able to more fully read the "real" paper, the key issue is that their measurements, if taken at face value (and not as due to, e.g., bad contacts with the material) suggest two contradictory things:
* the sample is extremely pure (due to the shape of the first graph).
* the sample has impurities causing it to not exhibit zero resistance, and not to exhibit "full" superconductive properties (i.e. having zero resistance under a magnetic field with increasing strength).
Additionally, since they were never able to measure Tc, they can't show the full Meissner effect as that requires heating up the sample to above its Tc first and then cooling it and flipping it, something you can't do with a diamagnet. By itself the fact that they didn't reach this temperature did not bother me, because I assumed that the senior authors were experts in superconductivity and had made sure that the material simultaneously exhibited other superconductive properties like zero resistance (or close enough when factoring in impurities). The fact that they were so focused on replication and the process was so simple made it unlikely to be fraud.
But, the fact that the first chart doesn't make sense unless the sample were completely pure, plus the lack of expertise they have with superconductors, indicates that it is much more likely measurement error on their parts, in which case it's not clear whether there's any evidence at all for superconductivity right now outside the diamagnetism. Given that there are many room temperature diamagnets known (albeit perhaps none as strong as this one?) and no room temperature superconductors known, this puts the odds that this isn't a superconductor at practically certain, IMO.
I mean sure, it would not be hard to fake this if it's a total fraud. It will also be discovered almost instantly so I don't find that case interesting. The more interesting question to me is, (1) are there glaring red flags indicating it's a fraud (no), and (2) if it's not a fraud, what are the odds that it's superconductivity? For me, seeing how weak the criticism is, I'm moderately higher on it actually being superconductivity than I was before, since alternative explanations also seem to require materials with novel properties.
Well normal copper does this in presence of a strong magnet. I don't think we are seeing superconductivity, just regular copper Meissner effect. Super conductive would frame lock the copper. right?
But it wouldn't lock the target in place when they stop, which is what this video demonstrates very well. The conductor would move towards the magnet and try to stick to it.
>The conductor would move towards the magnet and try to stick to it.
No, only ferromagnetic material would behave like that. Copper foil will also move in a moving magnetic field, and won't be attracted to a stationary magnet.
Is there an alternative explanation possible for the video? Couldn't it just be a magnetized piece of ferrite that is magnetized in a weird way causing it to lift up like that on a strong magnet?
Pyrolytic graphite looks exactly like this and behaves in exactly this way (without being superconducting) as long as one side is anchored. With a careful array of magnetic poles, graphite will levitate at room temperatures.
I'll get this out of the way first: I'm a couch scientist (even that is probably stretching it).
That said, from the video it mentions the superconductor was applied as a film over copper. But wouldn't plain copper also exhibit this effect due to eddy currents? I fail to see how the (supposedly) thin film is affecting the plate in this experiment. I'm probably missing something and I hope someone can enlighten me.
In a normal conducting material eddy currents dissipate relatively quickly. The shard of material in the magnet video appears to be floating quite stably for dozens of seconds, which implies that eddy currents are not being dissipated. I'm personally excited, I think it's the real deal but with some limits on maximum field strength and current
Ohh ... this could actually be relatively big.
From abstract: "The superconductivity of LK-99 originates from minute structural distortion by a slight volume shrinkage"
There was previously research done investigating how changes in atomic structural alignment affect superconductivity (such as by cooling). I think researchers were trying to maintain the spacing that superconductors had while cool even when it was heated up. This sounds line with that other research, though I can't find the article again, please correct me if you find otherwise.
Still likely to be rather fragile and temperamental to work with ... but this seems like it's possibly legit.
Yes! That was exactly what I was thinking of! I love one of the comments - "But might this physical stretching then also allow room temperature superconductors, if not why not?"
They were thinking of stretching at a macro scale (like bending a bar of stuff), rather than essentially "stretching" at the chemical scale which is what I understand they did here. Super cool!
It gets even better. fwlr, in a comment further down that thread, expands:
> I think the “tension axis” is more likely to be fruitful in a different way, where we find some structure e.g. a crystalline formation that happens to hold atoms apart with just the right amount of tension. But this is all very speculative - the “tension axis” is just a random thought I had while reading the article!
They hit the nail on the head pretty well, I’d say!
The graphs on page 3 are exactly what you would expect with a real superconductor. The current/voltage/temp relationship especially. In fact I don't see how you get graphs that look like that unless you either created a superconductor or are just blatantly making up the data. This could be enormous.
My first thought was “I really hope this is real and not someone having left the data collection software in simulation mode.” If this reproduces, it’s historic. If it doesn’t, it’s either cold fusion or faster-than-light neutrinos.
Lots of problems with the paper, they claim. It is not up to the standards of current SC research. One of them says Dias's work shows more merit than this.
All valid points but just below that comment someone asked if he/she was reading the new paper (apparently there's an older paper), he/she didn't respond/haven't responded yet.
His criticism of figure 1b doesn't seem reasonable to me, given that the are resistance measurements in 1a and 1c that show zero resistance coming and going in roughly the expected way as a function of temperature and magnetic field. Unlikely that the connections would break and reconnect in just the right way.
big if true. far from a chemistry expert here, but synthesis looks basically trivial (if you consider 10e-5 torr vacuum to be trivial), and the materials are readily available. hell, from the instructions alone i could probably make it at home.
i mean the search space is unfathomably large, so i suppose it’s possible that something like this exists, but the paper quality itself doesn’t.. spark joy? :)
i’ll maintain a healthy level of skepticism until some real materials scientists opine and/or someone else is able to reproduce.
I've made YBCO superconductors in my garage many times and the solid state synthesis method in the paper is very similar to that used by hobbyists. In fact, it seems to not require the usual careful slow annealing under flowing oxygen.
I wouldn't be at all surprised if even simpler methods are feasible.
For instance, there's a rapid synthesis method for YBCO that uses a small alumina boat, some glass wool, a residential 800w microwave oven, and slightly modified mixture of precursors to allow free oxygen to be liberated in the mixture during heating and trapped in the wool around the sample so you don't need to rig an oxygen concentrator up. IIRC it only takes about 15 minutes to prepare a sample.
This is extremely exciting! I've read hundreds of papers on superconductor manufacture and testing over the years and this has all the hallmarks of legitimacy, at least from my citizen-mad-scientist perspective.
I've looked briefly at the materials synthesis (first part of their Supplementary Materials section). I agree with you, the synthesis is trivial. The 10e-5 vacuum is easily reached with a turbopump backed by a mechanical pump, nothing exotic or expensive.
indeed, and i wonder if you could elide the vacuum entirely with a noble gas (presuming the vacuum is required to avoid reactions with atmospheric gases)
Its not hard to achieve at all. Electron beam welders at work have 10E-6/10E-7 in the E-gun chamber all day long held by a little turbo or diffusion pump. The chambers aren't made from anything exotic just stainless steel and/or aluminum with viton o-rings.
Its not hard to achieve at all. Electron beam welders at work have 1E-6/1E-7 in the E-gun chamber all day long held by a little turbo or diffusion pump. The chambers aren't made from anything exotic just stainless steel and/or aluminum with viton o-rings.
My little e-gun experiments are all done with a Alcatel Pascal 2008 and I can achieve ~3E-3 with just that pump. I'm building a bigger system with a VHS4 diffusion pump w/cold trap that should get me into -6 territory easily.
Neat. I had a Thermal Dynamics 12 KW plasmacutter and a rig to control it across three axis. Best tool I ever owned bar none. From thinking about something to having it in your hand in a couple of minutes in steel up to 1" thick. Amazing toy.
I figured out that by moving it faster than it can cut you can 'score' steel and if you use that creatively you can make fold-at-the-lines steel structures that you then weld up on the edges. You can make super complex stuff like that in no time at all and you usually don't need any jigs other than a few magnets to line things up prior to tack welding.
well.. my understanding is that the difficulty with those projects is converting fast moving neutrons into electricity without degrading the material.. :)
but a room-temperature superconductor would certainly lower the operating costs of all of the prototype fusion reactors that currently exist.
Exciting paper. I hope this won't be the same scenario as the other team that claimed a room-temperature superconductor in 2020 and was later proven to be a fraud.
The other team had a very complex to evaluate claim about the specific data indicating superconductivity, and the methodology required a lot of pressure and was quite difficult to replicate (and ultimately, of course, impossible, as the results were false).
The claims in this case are very simple to understand and very consistent with superconductivity, demonstrated on a macro scale at normal pressures and temperatures, there's video of the phenomena that doesn't make sense absent superconductivity, and most importantly: the method to produce the material is very simple, it is not going to be difficult at all for labs around the world to replicate this, and as other commenters have pointed out a lot of YouTubers are going to be able to replicate this.
So basically, this result could be fake, but it would need to be entirely faked results, faked video footage/photos, and it would be discovered very, very quickly because this is so easy to replicate. If it's true, people will have replicated this within a couple of weeks, which would be mostly sourcing materials. It will take longer than that for replications to publish (probably shorter for YouTubers), but this isn't going to be a situation where two years later we find out it's a fraud - we will know within a maximum of a couple of months that YouTubers can or can't replicate these results, and within a year whether a lab can or can't.
>If it's true, people will have replicated this within a couple of weeks, which would be mostly sourcing materials.
I wonder how much it would cost to try and replicate this, in materials, labor costs, and vacuum furnace time/costs. My naive guess is that that labs in general aren't just going to drop everything to try an replicate every instance of someone declaring they've discovered room temperature superconductivity. Seems more like a "there's a lull in paying work, so hey, why don't some of you junior technicians try this out" thing? Anyone have insight into this? I suppose a university lab might have more leeway here to try out spur of the moment experiments? Maybe this is a "I'm personally interested in this and I'll work in the evenings to test it out, instead of on company/university time"?
After skimming the paper, it reads like a legitimate paper even though I have zero expertise in the area. That it is in Word instead of LaTeX makes it feel a bit less legitimate to me and they could of course always have some error in there setup.
The most notable thing to me was that this was done in a thin film where structural defects are supposedly responsible for strain in the material which in turn enables the superconductivity. Probably because it is only a thin film, the material could only support about 250 mA at 25°C before losing superconductivity. So even if the paper is correct, it might turn out to be challenging to get to higher currents. Or maybe not and one could just roll up a wide thin film and have as much amps as one likes.
EDIT: I misread the thin film thing, they also produced a thin film but primarily they describe the material testes as follows without any dimensions I could immediatly spot.
After the reaction, a dark gray ingot was obtained reproducibly and then made into the shape of
thin cuboids for electrical measurements [...]
(note: using language that accepts the claims of the paper for simplicity -- I remain skeptical)
For what it's worth, superconductors have a shared budget[1] of (magnetic field, temperature, current). At 25°C, the material is near its critical temperature, so its current-carrying capacity is necessarily diminished. At a lower temperature, the film should be able to carry more current.
That said, 250mA is plenty of current if you're interested in making a superconducting CPU.
edit after reading the paper: they claim an extraordinarily high critical temperature of ~126°C. You can see the temperature dependence in Figure 1e; they're much further from the critical temperature than I expected, and at room temperature, a little cooling appears to go a long way. I'm eager to see an attempt to reproduce this result. That said, the material is essentially a 2d molecule -- we've been hyped on graphene for decades, and have yet to see it integrated into a scalable process.
If you read some real papers and some crackpot papers, you can learn to identify bad papers without having to have much knowledge on the topic. Bad papers will, for example, often lay out trivial things at length, i.e. have very low information density. Or they will say things that are incoherent even if you do not understand all the details. Or there will be no references to legitimate other literature. This paper is dense and coherent and does not contain obvious nonsense even to an non-expert. More I did not want to imply, just that it does not look like a a crackpot paper. For a more detailed judgment, for example whether the experiments they performed or the numbers they got are reasonable or something like that, I am indeed unqualified.
LaTeX is of course big in math and physics because its math typesetting is unparalleled. And generally it’s just much more convenient to write a lot of math in LaTeX than a wysiwyg editor once you’re proficient. Outside hard sciences it’s probably not common.
My advisor was a physicist, and a Fellow of too many societies (IEEE, IoP, APS, etc).
He did not know LaTeX. Most of his papers probably were in LaTeX, as his students knew it. But I remember multiple papers he "authored" in Word, because that's what the student preferred.
I was in a top 10 school (in physics and engineering), and I can assert that the fraction of physics faculty who did not know TeX/LaTeX was at least a quarter, and could be as high as 50%.
All the major physics journals would accept Word submissions.
As a physicist, it's not a red flag... It's a red klaxon blaring out an alarm.
I have only met a few physicists who don't write papers in latex. They are all 65+ and generally work with younger scientists/grad students who prepare the paper in latex for final drafts and submissions.
TeX was written in the 1970s for typesetting when there were no word processors by a computer programmer who couldn’t afford professional typesetting and couldn’t be bothered to learn assembly language so he wrote his own fictional one for his book — the same book he wrote TeX to publish.
This is already very tangential, but just for the benefit of anyone who may miss the humour and take the above comment seriously:
- re “couldn't afford professional typesetting”: Knuth was happy when Addison–Wesley approached him, specifically because he liked the high-quality typesetting of their books (like Thomas' Calculus) that he had used as a student. He was happy with the typesetting of the first editions of Vol 1 and 2, and only for the second edition, when the publishers moved from hot-metal typesetting to phototypesetting (that is, when the quality of the best achievable professional typesetting deteriorated), and he learned of the existence of digital typesetters, that he was motivated to come up with his own solution.
> There should be no hesitation about learning a new machine language; indeed, the author has found it not uncommon to be writing programs in a half dozen different machine languages during the same week! Everyone with more than a casual interest in computers will probably get to know several different machine languages…
When I was still in academia in two years ago, there was plenty of materials scientist, chemists and yes, experimental physicists I worked with who used Word, depending on the journal.
Sometimes you have to collaborate outside of physics!
What's more interesting is flexibility. Current ceramic liquid-nitrogen-cooled superconductors are not flexible at all; they are brittle. This can be fine for a transmission line, but makes things hard for various coils.
So you're saying it could be a great sensor, similar to a Josephson junction? :-)
Update: "yes", from the paper: "The Josephson-like phenomenon for the under-damped junction of superconductor-normal metal-superconductor(21, 22) or Inter-grain coupled superconductors(23) and the thermoelectric effect(24-26) of the inter- or intra-grain network were also observed."
Yeah, it seems like (to me, a naive layperson) to be similar to how a prince rupert's drop exerts strong forces thanks to the mechanism of its cooling/shape. The copper somehow forcing other structures to form in an atypical way which enables the superconductivity.
And even at 250mA, there'd be tons of different usecases for a superconductor.
I got this wrong, they also produced a thin film in addition to bulk material. And my worry was that one could maybe not easily scale this up in case the effect relied on it being a thin film in which case you can only make ever so wide before it becomes impractical or you have to layer or fold the thin film which might also be problematic. But as I said, I just read this wrong.
Word is one of the most common tools for writing papers. There was a study a while back that looked at the quality of Word or Latex papers. The study found that researchers using Word were more effective, and the working theory that explained it was that people who focused on the research did better research, and people focusing on the typesetting do better typesetting.
Ironically, the paper itself was republished to fix figure placement [1].
To your main point, no, theoretical physics paper are almost all written in latex. I can't recall word-written theory paper. Experimental papers are sometimes word, but pretty rarely. You can try randomly sample papers from cond-mat arxiv to verify it.
I've done professional typesetting and cataloging with QuarkXPress and InDesign both and it was extremely fast, that's for professional high quality publishing. .doc and .md is fine for information first publishing.
Latex is not simple and is in my opinion just a big nerd snipe, its the intrusive thought of layout software, for humanities sake we'd be better off with simpler tools like markdown + math notation and if latex had been never invented.
Every task? If I want to rename all of the .pdf files in the folder to .avi I would just do it in the command line
Or would you rather have me google a GUI that lets me "quickly rename" and download a few programs that have this capability? Or do a few hundred files by hand?
The GUI for that is called file manager, there are quite a few available and they can be far more sophisticated than an ad-hoc command pipeline. If you manage your files on a regular basis (manual sorting, metadata, mass renaming etc), you already have a serious file manager that allows you to do this.
Command line is... fine for doing this occasionally, but it's hardly "quick" or usable for this, I'm saying that as an advanced commandline user. You're just using the tool that you already have and know, and it happens to be the system shell. It doesn't have to be.
(another question is that classic file management at the scale where a sophisticated tool is needed is mostly automated nowadays, and yes there's scripting as well)
There are these things called programming/scripting languages, look it up. python for example.
And you end up with very short and simple - and most importantly - human readable programms instead of cryptic Unix two letter commands with bunch of arcane single letter flags and other legacy pdp11 nonsense from 1970ties
I think it would be nice if everyone can decide for themselves which software they prefer. Some people prefer Latex, others prefer Word or InDesign etc.
I would prefer not to have gatekeeping either way, both "It was written using Word, it must be fake" and "Latex should never have been invented."
I'm not saying latex should be banned or disallowed anywhere, no actual gatekeeping in that regard.
There are big geek communities that lead newbies astray by recommending it, it's a nerd snipe that wastes a lot of brain cycles better used elsewhere. It's only little b bad, not big B bad.
I am saying it's a poor tool, a waste of time and an evolutionary dead end, people are allowed to fetishize poor tools, efficiency, simplicity and legibility are very poor in latex world with a high learning curve for a task that is at best tertiary to the task of doing real research, it's a tool that promotes rabbit trails, bike shedding and procrastination.
And the small amount of research that has looked into this has apparently born this out in at least some small degree. It's not a hot take if it's got backing.
I can believe that this is true today. As recently as 15 or 20 years ago, Word was awful enough that seeing through significant technical documents was a terrible experience. Horror stories of large corrupted documents and mysterious formatting behaviors were very common.
Today, Word is much more capable as a scientist's tool.
Superconductors are basically perfectly conductive wire. Wires that transfer 100% of power over arbitrary distances and that don't heat up. Obviously there are limits, you can't put arbitrary power over a hair thin filament but as long as you're under that limit you get perfect efficiency.
MRI machines can be made a lot simpler as you no longer need to use liquid nitrogen to cool the superconductors. MRI machines could end up being small and cheap.
Perfectly efficient electromagnets make a lot of problems in fusion reactors simpler, I'm not sure that room temperature superconductors make fusion reactors instantly viable but it's a big step and would reduce the energy requirements for a fusion bottle by a lot.
Basically anything involving electromagnets becomes a lot more efficient. Motors can be made smaller, generators can be made much more efficient for the weight, maglev trains can require very little power to hover. It has effects on almost every industrial process as it fundamentally changes the weight and energy efficiency of anything involving electromagnets.
One neat things would be surgical robots that can work as an MRI while also levitating a small blade in a 3D space. Challenging for sure but when you can replace complicated liquid-nitrogen cooled coils with an array of simple passive coils a lot of options open up.
Superconductors can also be used for power storage, and at room temperature that becomes a lot more viable.
A note about MRI machines: they use liquid helium, not liquid nitrogen. LN2 isn't cold enough. Being able to eliminate liquid helium would be huge, as helium is scarse and quite expensive. Its roughly 10x the cost of LN2 and only going to get more expensive.
Previous improvements in high-temperature superconductors already made it possible to build a MRI machine using LN2 instead of LHe. I think all existing operational units still use LHe, but using LN2 has been demonstrated in lab conditions, and the next generation of machines will almost certainly use it instead of helium.
It still might be worth cooling this with LN2, in many applications, assuming critical current and critical field scale up as temperature decreases as they do with other superconductors.
It takes a long time to validate new stuff for medical devices. Even if this discovery completely pans out, there will be two or three generations of MRI machines based on LN2-cooled superconductors.
They use both liquid helium and liquid nitrogen. The nitrogen is used to cool the helium. On MRI scanners that have come to market in the last few years, helium volume has been reduced at least 100x and is now only a few liters (i.e. previously >1000L and requiring frequent top off to <1L and requiring refill only after emergency/full power loss).
Superconductors are a transferring energy technology, not a storing energy technology. Although they would likely augment the efficiency of storage technologies.
> What kind of energy density could we get using it for energy storage?
Actually, not a lot. The are some very compelling uses of them for storing energy, but they are much more relevant for distribution grid stability and control than for raw energy storage.
There are people here are pushing some really non-compelling use cases (like long distance power distribution), but there are plenty of transformative ones.
(But the thing is that this one on the paper is much less useful than it could be. There is still some work on understanding why and fixing it.)
Don't forget about computer chips that do not emit heat. So much wasted power at the datacenter scale simply to keep things cool. At a personal computer level things get way more efficient, too, resulting in cheaper, smaller, quieter computing devices.
Superconductors change every assumption about how we harness electricity and magnetism. Beyond reducing the cost of electricity transmission, they enable all sorts of fascinating applications:
- They enable low cost, continuous, passively-stable magnetic levitation. Superconductors could replace ball bearings in many applications.
- They enable permanent magnets that are far stronger than any we make from conventional magnetic materials. For example, motors tend to run at high speed and low torque, so as to minimize heat generated from current in the copper windings. Superconducting direct-drive motors could allow for ultra-high-torque actuators without any need for gearing, and with minimal heat generation or losses. So superconducting electromagnets could replace everything from electric motors to hydraulic pistons to simple springs.
- Superconductors allow for very sensitive antennas and magnetic field sensors, allowing for near-field detection of very small signals (such as from neurons firing in the brain). There is a lot of impressive technology that only exists inside research labs where a generous supply of cryogenic liquids are always on hand. Those could make their way into mass-market products.
Something that immediately comes to mind for me in Sweden, is that the country is fairly long in latitude, and most of our electricity production is from hydroelectric power in the northern half of the country, while most of the population is in the southern half of the country. Better energy transmission could help a lot.
It probably wouldn't greatly affect the heat generation in a PC, unless the transistors could themselves be replaced with some superconducting alternative. Harnessing the efficiency from that would probably require that the computer be designed as a reversible computer. It would be its own research avenue.
Unfortunately, as soon as you actually use the result of the computation in any kind of practical manner as an output, you break reversibility, though you could make the heat production happen away from the computation.
The idea of reversible computing is that if you only add heat in a few instructions, you can have a much more economical computer. And magnetronics is a good candidate for implementing this, so yeah, computers that use a lot less power are an application too.
I haven't seen any reversible low power superconducting gate that can credibly operate at a high temperature - not because of the superconductor itself, but because of thermal noise. Again, I haven't read through the literature in this field for a while (and it wasn't that extensive either), but from what I recall what you're proposing is roughly as difficult as making a gate for a quantum computer, and you have to keep your system way colder than your critical temperature from that due to thermal noise. If you have any links for high temperature physically reversible logic gates I'm all ears.
I don't think you actually need reversibility if you don't discard the energy but return it to the power supply?
In other words, "reversibility", but you can actually pool the useless results together, you don't need to separate them later. Or so I read somewhere...
I might be wrong since I've studied this a long time ago, but from what I remember, in order to do that classically, you need to copy the output bits somewhere else before uncomputing your system and recovering the ancilia.
That's technically fine, as long as you have an infinite supply of stably initialized bits onto which to copy your result. Initializing those bits is going to be non-reversible in some way.
Computation inherently generates heat, but if you could make chips that release negligible amounts of heat, you would unlock the third dimension which would help with reducing signal length and enable computers to be significantly faster.
That this as a solution applicable to _personal_ computing is a bonus. The real benefit is in datacenters which could be made smaller, more efficient, and cheaper while simultaneously adding capacity.
Other commenters have science fiction dust in their eyes, and speak of room temp superconductors in general. But this particular discovery is a brittle crystalline structure that cannot be extruded into wires, and does not have the high current capacity required for power transmission or rail-guns.
It's an important, exciting step but it's very far from world-changing at this stage. Or if it is in a limited way. The first transistors were clunky affairs, of limited usefulness, world changing for ship-to-shore communication in the military. But then people discovered how to make them with deposition instead of factories, and they got smaller and faster, and they really did change the world. We're in the "clunky transistor" period.
Exactly. But that clunky transistor was in fact world-changing. It just took a while for the changes to take place but the stage was set when that first device showed that it could be done at all.
Oops, the first practical radios were powered by semiconductor rectifiers, not transistors. The Pickard silicon point detector circa 1906 was used in WWI (btw owning/making a radio was illegal during the war!)
I believe MRIs use superconductivity, so I assume any application of superconductors that doesn't require heavy, large, energy-consuming cooling will benefit greatly.
Perhaps MRIs will become ubiquitous and cheap, something we all get every time we go to the doctor?
Superconduction also has some weird magnetic properties I believe, so there could be benefits regarding maglev transport.
And finally and most basically, the movement of electrical energy across potentially large distances with zero loss would be a great thing.
I have no real idea what I'm talking about but figure 1 has critical magnetic flux curve ranging up to 3000 Oe so... in MRI-speak maybe it tops out before 0.3T? IIRC permanent magnet MRI have already been built in the 0.3T range, but they're very heavy and outclassed by the higher-field scanners. Clinical MRI nowadays typically runs at 1.5-3T (with some clinical scanners at 5-7T).
Having said that there is a resurgence of interest in low-field MRI lately, primarily marketed for use in developing nations and for combination machines that integrate radiation therapy. From what I've heard from diagnostic radiologists, the low-field MRI scanners seem to be of limited diagnostic value on their own.
Anyway that's just my thought that the best/first applications here may not be about generating magnetic fields.
I assume we could make CPUs stupid fast if we didn't have to worry about heat as much, though I'm not sure how much is lost to resistance vs operating transistors.
And I think that's what we are seeing in the video. The eddy current effect isn't permanent like in superconductivity. They have to keep moving the magnet around.
well that one looks great. Maybe in the original video a superconductive effect was there, but not strong enough to frame lock. But you can see it in the newer video.
Expect the first iterations of that material to not actually hold currents well in a long (macroscopic) distance and create much weaker magnets than one would expect from a random superconductor.
But it's also a surprise for theoreticians, and I guess the mechanism is very prone to improvement.
2 years after the patent application and 4 months since publication and not involving any lab an author is not apart of to replicate a process that should take a week - a reason to wait for seems hard to justify.
Maybe it's some kind of game where they pre file things and then fill in the details but get a better date? I was concerned when I saw this as well though
I mean- not really? They have developed / synthesized the material, and they collaborated with another lab that had the skills and equipment to conduct and interpret specific experimental techniques and results.
Fairly common, especially in life sciences, and I suspect chemistry and materials science.
Added in edit: This doesn’t make the result any more or less credible; for that, the true test is independent replication of both the synthesis as well as the experimental measurements. But the fact that the two authors published two papers with different groups is orthogonal to whether the result is real / an experimental error / fraud. I so hope its true - but..lets wait for replication and validation by other qualified experts :)
I think they also make mention of the other paper in the one being discussed, pages 12,13:
"The Additional experimental results and discussions on LK-99 will be published immediately in the next paper, including an interesting controllable levitation phenomenon and the coexistence of magnetism and superconductivity, theoretical calculation, etc."
The one you linked is about retraction, not replication. Interestingly, they're both near 25%, which seems kinda contradictory. The retraction one has a deadline of Jan 1, 2024, but the replication one is Jan 1, 2025.
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.
That makes me even more sceptical. In recent years confirmed discovery of superconducting materials have gone from working at best up to ~100K below room temperature to at best a few 10s of K below. To jump to a material that claims to exhibit superconductivity as far as >100K above room temperature, at ambient pressure too, is an extraordinary claim and so needs to be presented with extraordinary evidence.
I mean, the paper has experimental results and it should be easily reproducible by pretty much any lab. Do you think they should be hopping on CNN to give a public demonstration with the announcement?
If a material with the properties described actually exists, this paper is exactly the kind of announcement and evidence we'd want for it.
No, I agree with you that a quiet “this is what we've found, this is what we think it means, please reproduce or tell us if you find something we've misinterpreted”, rather than a public fanfare, is how a potential scientific breakthrough should be done IMO.
I think I cross-pollinated this thread with another where someone was asking “if this is true why isn't it on the front pages”. The extraordinary evidence I'd want before it hits the front pages and TV talk shows is other scientific/engineering groups managing to reproduce the findings, or at least showing a significant improvement over previous discoveries (there could be a mistake that means the result isn't that big a thing while still leaving room for it to be a significant finding).
But this is exactly the quiet please reproduce? It's a preprint posted to arxiv, with a very easy to follow material synthesis process in the supplemental materials section?
In fairness, the paper isn't exactly humble about its claims. But I appreciate their candor, and if they believe they've found a RTP superconductor and sufficiently verified it is a RTP superconductor, a bit of arrogance isn't unwarranted.
Yep. But that doesn't stop me being sceptical of such a jump in success (from tens of K below room to tens+ above at ambient pressure) which is where this sub-that started.
As already stated ("I think I cross-pollinated this thread with..." in the post you replied to) I confused things by mixing replies to different posts in the same place.
It's not out of line with previous the previous jump: the difference between the originally known superconductors and 'high temperature' superconductors was similarly large. If it is a novel mechanism allowing for it then we would not expect that the threshold would necessarily wind up close to room temperature (TBH, I this makes me think it is less likely to be fraud: I think a fraud would temper expectations by claiming it barely works at room temperature). I do agree it needs backing up, though, it could still be an error or more savvy/brazen fraud.
The critical temperature (Tc) >= 400 K or about 127 C, so apparently this material requires relatively high heat to reach superconductivity.
This is unusual, superconductivity is a low temperature phenomenon. Recently though, other researches have claimed room temperature superconductivity at high pressures, but low temperatures.
Uh no, I'm pretty confident they are just saying that whatever the Tc is, it's at least 127°C. I don't think they're redefining Tc to mean that it superconducts above that temperature. That would be... interesting.
"You can't run across this bridge without falling? Here, I'll have an elephant bounce up and down on one end, that'll make it easier!"
Wasn't there some recent excitement about some hydrogen sulfide superconductor thing? But the pressure required was wild/not-useful-for-use or something like that?
Yes, H2S is superconducting at higher temperatures than anything else up to that point (but still well below zero), but it required very high pressure making it impractical for a lot of applications.
I share your doubt, but on the other hand I wonder why? Could you tell how a breaking message of this magnitude should be decorated to make all doubts go away?
> Could you tell how a breaking message of this magnitude should be decorated to make all doubts go away?
You'll never make all doubt go away on a new extraordinary discovery, mainly because most claims of an extraordinary discovery turn out to be mistakes (like the FTL neutrino thing a while ago that turned out to be a wiring fault that caused a minute timing error) or occasionally fabrications.
A quiet publication of “this is what we've found, this is what we think it means, please try reproduce or tell us what you think we've misinterpreted” is the way it should go. Unfortunately too subtle a release would be at risk of being ignored, and on the other side you get the mad public press and massive recriminations when it turns out a mistake was made and the finding is not reproducible (like the cold fusion thing I remember from the late 80s).
The cold fusion people were actively touting data that didn't align to known fusion reactions. Like there are a limited number of elements one can fuse, but for some reason their reaction (which is known) had the energy off by like 300-400 KeV. For example: a proton signal of 2.6 MeV instead of the known 3MeV signal.
Keep in mind that superconductors are not just useful for powerful electromagnets! They're also excellent for all sorts of other functions such as EM shielding, antennas, etc...
High temperature superconductors are not likely to be useful as powerful magnets, but they can be useful for almost everything else.
This is almost certainly a sham. I had hopes before watching the videos, but the only effects shown are normal paramagnetism (from the copper substrate) and diamagnetism (pyrolytic graphite).
I generally understand that superconductivity under normal human conditions is desirable, but could someone summarize what this material might be used for near-term, and what this might lead to?
If this is comparable to the development of the transistor, what are the analogous vacuum tubes that I am living with today?
If it works as advertised, it would make a fantastic toy. Various different types of levitating toys would now be possible that would have previously required liquid nitrogen on hand. A lot of CEOs are probably going to have very pretty and novel floating desk ornaments. Not really a great toy for children or general consumption due to the lead content, though.
For all of the big use cases people mostly talk about when referring to room temperature superconductivity, like very cheap and easy MRIs, lower losses in power grid transmission, more powerful motors, cheaper and easier nuclear fusion (potentially necessary for commercial viability), this material as-is won't be suitable because it can't deal with that much current. We would need to explore this new family of materials and try to find one that maintains the superconductivity but significantly increases critical current and critical Tesla.
That said, this material could be genuinely revolutionary for consumer electronics and computation. Increasing computational energy efficiency on the chip level is going to be really valuable, but it's also probably going to take a long time to make it into actual electronics. Although, it is encouraging that the process for making this is similar to processes that are already used widely in industry, even in semiconductors specifically.
Monopole magnets probably aren’t allowable in our current understanding of physics since the magnetic field is just a consequence of a relativistic E-field.
>"In 2008, Gozar et al. reported hightemperature interface superconductivity between metallic and insulating copper oxides(39). The thinner the layer, the greater the stress-inducing effect, the greater the strain, which seems to be
the higher the superconducting transition temperature. Therefore, we argue that the stress caused by temperature and pressure brings a minute structural distortion and strain, which create an electronic state for superconductivity."
Not necessarily. While obviously it would be nice to not have to cool superconductors, it's not much of a technical challenge. Much more relevant is the strength of the magnets - fusion reactors need very strong magnets which is why they use superconductors, but there is still a limit to how strong they can be made. Unfortunately the higher temperature a material becomes a superconductor, typically the less able it is to handle strong magnetic fields. The extent depends on the type of material it is and there can be other benefits like smaller size that could justify using weaker magnets, so it is still possible it could help, but it's unlikely to be a game changer.
Ah interesting, thank you! Maybe I can hope that the discovery leads to further novelty then :) Maybe the same effect can occur in lower temperature superconductors as well. I guess there's a sweet spot for ease of construction, field strength, and temperature.
If you look at the 2013 design of the ARC fusion reactor concept (a high field tokamak), most of the mass of the reactor is the steel structure needed to resist the JxB forces from the magnets. This will be needed even if the magnets are made of room temperature resublimated unobtainium.
Good news if true, but are there any comprehensive accounts of what actual benefits/applications ambient superconductors would have?
It seems to me the hype is along the lines of 'free electricity', 'levitating trains', 'magnetic space launches', 'climate change solved', etc, etc, but these seem either wrong or unrealistic to me.
Electricity transmission efficiency can improve a little, for some routes. Same for electric motors, but they're already 95%+ efficient in some cases.
Maybe it would be useful for energy storage, maybe not - depends on capabilities and especially cost.
Might be useful for levitating trains if suitable, but even then this would be a relatively minor part of any overall design.
I can see a lot of applications/possibilities in research, and in sensors, and maybe it enables some things that aren't currently possible, but what?.
It's undeniably neat and interesting, but it seems over-hyped; maybe someone can enlighten me? Is there a 'killer app'?
Ideally you build an international power grid. Solar in the Sahara powers Europe but then you loop it around the world and we have 24 hour power from Australia and the Atacama, tied into hydro, nuclear and wind.
Put it in your battery anode and you can charge your car in a few seconds.
Computers won't need cooling and can be way smaller. Quantum computing becomes more practical. AGI is more likely.
Huge implications for Fusion, which then means we can start pulling CO2 from the air since we'll have more power than we need...
This is an unreviewed preprint coming out of South Korea. If it’s reproducible it would be the biggest scientific discovery of the last hundred years. It will literally reshape the world.
However, the most likely thing is they made a mistake and the paper will be withdrawn.
From what they show, the critical field and critical current seem very low. 2500 Oe is like 0.25 Tesla. Even REBCO at 77K is >1T. And 2500 Oe is not even at critical temperature but much lower. From skimming through the article I couldn't find the sample size of the current measurement to get the critical current density, not just current which is meaningless (and around 300 mA).
This means you can't actually push big current through this thing (yet). You can't make a powerful magnet, and you can't make viable power lines, both applications that were the hallmark of "room temperature superconductor revolution".
Of course, maybe one or a few more tweak(s) of the material and boom, it will give high J_c and B_c. I really hope it does, it would be super cool!