Such tiny samples warm up to room temperature very quickly, on the order of a few seconds. In my experience, it's not possible to make such small pieces of YBCO superconductor levitate, they warm up too fast.
No frost on the sample either. The only way I can think of to fake this in camera is to make the "sample" out of a strong magnet, and make the "magnet" a hollow shell concealing a chilled piece of YBCO!
You would be surprised what can be achieved with bit of nylon string and an appropriate camera setup. If this is a most groundbreaking discovery, why waste all that screen resolution on the backdrop?
I don't think that's right. Diamagnetic levitation is one of the ways you can get around Earshaw's theorem.
Funny enough this is a quote taken directly from the wikipedia article that Andercot linked, in the "loopholes" section:
>Earnshaw's theorem has no exceptions for non-moving permanent ferromagnets. However, Earnshaw's theorem does not necessarily apply to moving ferromagnets,[4] certain electromagnetic systems, pseudo-levitation and diamagnetic materials. These can thus seem to be exceptions, though in fact they exploit the constraints of the theorem.
...
>Diamagnetic materials are excepted because they exhibit only repulsion against the magnetic field, whereas the theorem requires materials that have both repulsion and attraction. An example of this is the famous levitating frog (see Diamagnetism).
Sure enough. Which, well, makes sense, since superconductors are "perfect" diamagnets, so them being able to do it seems to necessitate that the greater class of diamagnets on the whole can too.
The only examples I can find of stable non-superconductor diamagnets involved 4+ magnet arrays, though, or multipole magnets, e.g. https://phys.org/news/2014-08-diamagnetic-levitation-pyrolit... and not dipole configurations like this video seems to show.
How can a diamagnet be stable on top of a single dipole? Earnshaw's criterion being invalid just means that there is at least one static arrangement of magnetic dipoles that lead to stability. However, if you have a point-like diamagnet resting on top of a single dipole it can't possibly be stable because there is no point at which it will have zero net force and stable higher-order derivatives. You need something like a bowl-shaped magnetic field arrangement for it to stay in a single point, or have the diamagnet itself be shaped something like a bowl over the field.
Yeah you bring up a good point... I don't think it can.
But you CAN do it with concentric rings of magnets. Such magnets seem common for this exact demonstration actually. It doesn't look like one of those in the video though.
I mean based on current understanding a previous video that showed levitation independent of the orientation was already sufficient to show it's not diamagnetic but superconducting. Assuming this is not a hoax actually the very first video together with the paper already shows everything. (Levitation, mentioning of zero resistivity regions)
Although generally the accepted method is that other labs reproduce it and that the paper passes peer review. Some videos aren't enough.
Hoax is quite a strong word where there's been quite a few replication attempts with various degrees of success. Like others have said, we're not sure what this is, but it almost certainly isn't a hoax.
As for this video, well, it's like all the other ones that came before it, we'll know more once we have more data/videos/replication attempts.
The source[0] seems to be the Douyin (TikTok) user 炼丹师阿翔[1], who also posted a different LK-99 demonstration video[2] a few days ago that shows similar results to previous demonstrations by other researchers.
Yes but what research institute are they affiliated with? For all I know this is an pseudonymous TikTok user who is good at faking videos. Why should I take this for anything but complete fiction?
Certainly not making any claims of the legitimacy, just providing the original sources. There doesn't seem to be any attribution besides the anonymous account.
The Chinese subtitles in the first demonstration claim "further efforts will be made to reduce impurities", then the subsequent video claims "technical details will be published once they are properly organized and documented".
In fact I see some serious lab quality glassware in the background. But posting without its provenance is a weird for sure.
IMO there’s an awful lot of amateur / informal attempts that are promising enough that, while not convincing, are inspiring of hope. But I do wonder how much is fake. But more than a few seem to be clearly not fake, such as the work Varda is posting.
