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by memen 1047 days ago
Couldn't this be explained by magnetism alone? How does it show superconductivity?
4 comments

This man claims to have reproduced the same kind of effects with a simple ferromagnetic sample:

https://nitter.net/VanGennepD/status/1688052003216261120

The picture on figure 4 of this paper rules out ferromagnetism, assuming it's legit https://arxiv.org/pdf/2308.01516.pdf
People seem skeptical that it's actually been ruled out by that test. Regardless, that paper found diamagnetism on the level of pyrolytic graphite, which would be interesting in this material albeit not really evidence of superconductivity, but from what I've heard it is very easy to get anomalous reports of diamagnetism during zero field cooling if there is a high-temperature ferromagnetic transition, and you have to be extremely careful about your measurements and do lots of repeated tests to be sure. AFAIK, every other paper has either only seen very weak diamagnetism (expected given the compounds involved) or none at all.
except he didnt reverse the poles of the magnet like multiple replication videos so he didnt really reproduce the same effect
Do you mean flipping the magnet over? If you scroll down he did that.
It’s not proof of anything, but it’s suggestive. The only other known materials that show that degree of diamagnetism are superconductors. That magnet is tiny!
Magnetic levitation can't be done with normal magnets alone: https://en.wikipedia.org/wiki/Earnshaw%27s_theorem

TL;DR: Normal magnets have two poles, and will try to flip themselves around to achieve a lower energy state. You cannot levitate a normal magnet on another magnet without mechanical stabilization. Superconducting materials actively repel all magnetic field lines and can achieve levitation without external stabilization.

> “You cannot levitate a normal magnet on another magnet without mechanical stabilization”

The mechanical stabilisation is right there in plain sight where one side of the magnet is clearly resting on the other magnet (physically in contact). Anyone who’s played around with magnets that are heavy and too weak to flip themselves around will not be satisfied with this video. It could be explained by two South Poles opposing each other.

> Magnetic levitation can't be done with normal magnets alone

Technically it can be done with an array of magnets with opposing polarities.

Without more details from on this video's source and legitimacy, one could argue that an array of magnets is hiding under the 'single magnet' cover plate.

I am not saying this is a hoax, but as exciting as this seems we just have to wait it out for more replication publications to make that call.

If we doubt the legitimacy of basic claims like a fair setup of magnets, then there are much easier ways to create a fake, like just tie something on top of it.. but why would we doubt the legitimacy of reliable institutions?
Grand parent was saying it's "impossible". I say it is _technically_ possible.

To which I added:

"I am not saying this is a hoax, but as exciting as this seems we just have to wait it out for more replication publications to make that call"

It has been a little over 2 weeks since the first pre-print from Korea University.

The hashing out of a fabrication process with less impurities will be a long process. My point is not that everyone is pulling a con, my point is that we need to wait it out.

> Technically it can be done with an array of magnets with opposing polarities

How?

An example of Pyrolytic Carbon levitating on top of a 2x2 matrix of magnets. [0]

[0] https://en.wikipedia.org/wiki/Diamagnetism#/media/File:Diama...

No, it mathematically cannot be done with any combination of permanent magnets.
aside from non-superconducting diamagnetic materials, I think it can be done with non-static magnets, for example: https://en.wikipedia.org/wiki/Spin-stabilized_magnetic_levit...
Oh of course. Brainfarted and fused "static permanent magnets" into just "permanent magnets".
Why can't the weakly positive results be explained by an irregular formation of magnetic crystals that stabilizes the forces, in a way a single magnetic object cannot? As in, not a superconductor, just a novel configuration of magnetic particles?
Absolute layman here, but from what I've read it's supposed to show diamagnetism and the Meissner effect and flux pinning. Assuming no new weird physics, the only materials that exhibit those behaviours are superconductors.