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Comment by telltruth | Hacker News Reader

Could someone explain why is this world changing?

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.

Here's this big wikipedia page on applications of superconductivity: https://en.wikipedia.org/wiki/Technological_applications_of_...

Also on the less useful side, rail guns.

What kind of energy density could we get using it for energy storage?

Maybe it’s competitive with batteries if you don’t need any cooling?

Like 1-10 wh/kg from what I've seen. Probably better off building a ring around the planet so we can just always have solar panels lit up somewhere.

I wonder if that low number includes all the cooling equipment though?

But even if not it could be great for a capacitor alternative or stationary storage.

Superconductors are a transferring energy technology, not a storing energy technology. Although they would likely augment the efficiency of storage technologies.

Actually both https://en.m.wikipedia.org/wiki/Superconducting_magnetic_ene...

They can be used to store energy, though they're pretty terrible at it for all but specialized applications.

> 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.)

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.

Or maybe not anymore ...

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).

i bet companies that make elaborate cooling system for gaming pcs are getting nervous hah.

thanks for this. I didn't understand what this changed until I read your comment.

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.

That's just a very short list.

What if your PC did not need cooling, because it generated no heat? How much more potent could computers be?

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.

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.

Pentium 4 to 10 GHz, here we come!

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.

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.

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.

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.

> 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.

His many devices rely on coduction, how many are thermally limited by efficencies?

I read that as an overly conservative cry :D

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