Two reports have increased my patience factor a lot on this

First, a theoretical study found that the phase that’s reported to be superconducting is likely to be metastable based on some density functional theory calculations. That implies that actually making it may be rather difficult, and raises the bar for reproductions to show exactly what they are finding is superconducting or not. https://arxiv.org/abs/2307.16892

The second study was a comparison of the properties of superconducting Pb thin films with some of the data people have been reporting on LK-99 repro attempts. The authors hypothesize that people are getting micron to several nanometer sized particles of the superconducting phase embedded in an amporphous non-superconducting phase, and that this explains the mixed results. https://arxiv.org/abs/2308.01723

So, more careful analysis is needed and I’m still optimistic. I want to see much better x-ray and microscopic characterization along with the resistance data and so on, especially because the property measurements can be tricky. (My background is materials science but not superconductivity or condensed matter physics if that matters)

Ahh, fingers crossed then! I'm really hoping this is real, I just hope I'm not disappointed in the end.

My takeaway is that nobody, not even the original authors, knows a good, easily replicable way to make LK-99.

A clear no would be multiple sources synthesizing a material that is clearly the same as LK-99 (e.g. by showing most or all of the behavior shown in the videos or described in one of the papers), and then showing experimentally that it isn't actually a superconductor but that some other effect is at play.

Which is why one simple way to clear up a lot of the ambiguity would be to make the "working" sample available for a few other trusted 3rd parties to run some quick tests on.

That isn't simple. The sample needs to be shipped. You have to ensure it doesn't get damaged in shipment. If some lab has a an unknown evil intent they can destory the sample and claim it was shipping damage.

They say they are willing to let other labs examine their sample. If nothing has happened in two months i'll get worried, but for now I don't expect any lab to have seen it

Obviously they wouldn't just slap it in a box and send it through FedEx. The authors would personally deliver it.

The authors might damage it in transit, either accidentally or for nefarious purpose. No one knows enough to confidently say "this method of handling won't affect future measurements" because no one knows for certain what is going on here.

Ah, you're right, I hadn't realized they probably didn't manage to make it well enough.

It could just be hard to make this material.

The only thing we need is solid evidence that it's superconducting. If anyone has a stone that's superconducting at room temperature, then we know it's out there, it's possible to make it. It doesn't matter so much how it was made. If it exists, that's a great step in itself, isn't it?

Yes, but keep in mind that showing superconductivity on very small samples is hard. You never actually measure 0 resistance - you measure a resistance at the limit of your equipment sensitivity.

The smaller the sample, the smaller the resistance is even if it's not superconducting, and all sorts of other effects come into play - i.e. your wires and leads have a resistance you need to account for, parasitic inductance and capacitance climbs etc.

I'm sure I'm misunderstanding something, but couldn't one measure the extraordinarily large magnetic field that should appear when applying a voltage to (even a tiny sample of) such a material?

A magnetic field is the result of moving an electric charge (in this case electrons). Applying the voltage will move the electrons. The only thing the material being a superconductor changes is that the electrons will lose less energy to resistance while traversing the sample.

No, superconducting states break down in the presence of sufficiently strong magnetic fields.

Hard to say. The samples that didn't achieve diamagnetism don't tell us much except that creating LK-99 is tricky, which is not a big deal.

If someone can show both diamagnetism and prove that it is not a superconductor then that would be pretty discouraging.

Hm, but diamagnetism in itself doesn't mean that it's a superconductor, no? There are a few diamagnetic materials that aren't superconductors, AFAIK.

However, we have never seen a material with such strong diamagnetism that is not a superconductor

Really? That's encouraging, thanks.

Yes LK-99 if not a superconductor would be the strongest diamagnetic material by orders of magnitude.

And even if it turns out it isn't a superconductor, that's pretty cool in its own right, no? At least this layman would think so.

And it would go a way in explaining why so many take the claims seriously and try to replicate it, if we know there's something exciting going on either way.

True, but what I meant was that the labs that couldn't replicate even diamagnetism clearly haven't created the same material, as the original LK-99 was shown to be diamagnetic.

If someone can show that it is diamagnetic and not superconducting then that could be evidence that they recreated the same material, but that it doesn't show superconductivity.

That makes sense, thanks. So if the replication is not diamagnetic, it means that it's not LK-99, rather than that LK-99 is not diamagnetic itself, thanks.