Physicists have shown that an idealized form of magnetism is heatproof | Hacker News Reader

Physicists have shown that an idealized form of magnetism is heatproof

quantamagazine.org

93 pointsheadalgorithm14 comments

The main result is not about magnetism, it is that it is possible within quantum field theory to have phenomena that are stable whatever the temperature is. That is really interesting.

Interesting. It would be huge if this can help room temperature superconductivity. It seems like nobody knows what to do with it yet though.

It's a very idealized system, close to magic than to a real system. They are interesting but most of them are very far away from an application. They have a layer of spins with 2 directions with coupling (that is usual), and then a layer of spins with directions in a lot of dimensions (like 15 IIUC) that is not usual.

As a sibling comment notes, the first layer of spins is usually made of atoms, and arranged in a crystal, and when the temperature is high enough the crystal will melt and you will not have the nice layer of spin anymore. The second layer is too close to magic, but I guess they will need to be supported by atoms and they will melt too.

Also, I don't understand how this system is related to superconductivity as they say in the article. I see no Cooper pairs, and my understanding of high temperature superconductivity is too weak, but it's about something line flux pinning and it doesn't look related at all.

> nobody knows what to do with it yet though.

I've sent a lengthy email to Atomic Rockets strongly suggesting that cloaking devices are back on the menu. No reply yet and I know I've said this a few dozen times before but I really think we got 'em this time!

Isn't this why magnetism is used to contain plasma in stellerators?

No, this is an idealized substance, doesn’t exist irl.

Heat would definitely kill fusion reactor magnets.

That’s why they’re so hard to build, plasma of a million degrees has to sit only a meters away from superconducting magnets which have to stay cryogenically cooled to near absolute zero.

Well, that’s one reason they are hard to build. Neutron flux is also a big reason.

Magnetism is used because it's long enough range that nothing has to actually touch the million degree plasmas and be instantly vaporized. If the materials actually generating the magnetic fields reached anything like the plasma temperatures, they would cease to exist.

> Physicists have shown that an idealized form of magnetism is heatproof

Everything idealized is posdible on paper.

Heatproof might have a limit. Every material has a failure point, some temperature when all the particles decide to part ways. Those arrows mean little once elections start moving around as individuals.

Isn't this exactly what the article says is not true according to the research? The whole point is that given the ideal setup they describe, the prediction is that the structure would remain orderly regardless of temperature.

I believe they predicted something slightly different. That the magnetism would remain until structural failure. .

Simply put physics says if you put enough energy on an atom in a solid, it will eventually leave the solid on the solid/vacuum boundary from raw kinetic energy alone. Now, if you're trapped in an infinitely large solid, there would be no boundary and the magnetism could remain. For example the example of the early universe would be an example of one of these near infinite structures where magnetism remains. Large astronomical objects with lots of gravity may be able to reproduce these conditions somewhat like this.

With all that said, it should give us means of maintaining magnetism in an ordered manner in structures we'd consider hot as a human.

It seems a lot like their "structure" is a model, and not composed of atoms, or anything physical at all. It's still very interesting, but it's not something one could go out and build, even in theory.

The structure is a made-up quantum field theory.

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