Stating with confidence that anything has been conclusively shown about it is a sign you’re arguing from a position not based on evidence.
There simply is not enough evidence to say anything yet. Claiming there is means you either don’t understand it or are willfully misrepresenting it. Either way: no.
The evidence that has come out so far against LK99 in the past few days is pretty strong (particularly the paper out of Peking), not conclusive but it would take some very strong results in the other direction to suggest we are seeing anything like superconductivity.
I have worked in the field of characterizing high temperature superconductivity, there appears to be a lot of motivated reasoning going on around this topic. I would love for this to pan out and while I was initially skeptical I thought there could be a chance. I think the evidence of the past two days has been pretty strong for the negative case and I have adjusted my likelihoods significantly downwards in response.
I agree that recent results have been negative. The reason why they were negative when other previous ones were more positive is, however, undetermined.
With a process that seems to be highly variable, and that the original paper had a only 1 in 10 chance of any success PLUS one that seems to be highly change to produce similar results (but unconfirmed if the same) I’m not too surprised at the high variability of the tests so far.
Frankly, I think it’ll be several years before we get anything close to more conclusive results in either direction. The replication results so far have been… enthusiastic but not exactly stringently controlled.
But the wide variety of samples indicates that there isn't convergence yet on what the intended process is. Until that happens any conclusions are just data points - nothing more, nothing less.
The fact that they were able to replicate the original effect (what people thought was flux pinning) that made everyone think it is superconductivity and then conclusively show that it is not superconductivity is pretty strong evidence.
That's exactly what I thought at first. And then I realised that the 'ferromagnetism+diamagnetism' article does not actually provide a mundane explanation of the "half levitation": They estimated that their sample had very strong diamagnetism -- at least the 2nd strongest of any known (non-SC) substance, assuming their sample was pure (but we can assumeit isn't, considering that they just had one tiny flake levitate), so quite possibly the strongest. And superconductivity is a possible cause of diamagnetism.
It still hugely weakens the levitation effect as evidence for SC, but "conclusively show that it is not superconductivity" is not quite true.
There is no meissner effect, so it is not superconductive. I worked in this field, the paper as described is pretty damning. I think your reasoning is motivated.
As everyone seems to keep forgetting the original scientists said that less than 10% of their replication attempts was successful.
We don't have 10 replications total let alone 10 based on their exact process which is unknown to everyone except them at this point.
So not sure on what basis you can claim replication has thoroughly failed.