The paper shows a clear phase transition to diamagnetism as the material is cooled. That would be seen in superconductors and not in regular diamagnetic materials. I'm not aware of any that have that kind of phase transition. Though since we're in weird territory here, it's important to note some weird non-superconductor behavior that's beyond regular diamagnetism might be going on as an alternative explanation. But it is weird.
ETA: also, in the presence of a magnetic field, that transition temperature decreases. That's pretty huge. Unless this paper is fraudulent, I take this as the biggest positive evidence so far that something besides simple diamagnetism is going on. And, cards on table, with the assumption that the paper is not fraudulent, this pushes my odds above 50% for the first time.
Magnetic transitions as a function of temperature are not unheard of, and it makes sense for them to depend on external field (they are magnetic after all). Lanthanum cobaltite for example has transition from diamagnet to paramagnet, likely due to change of spin state (see, e.g., [1]). I'm not saying that's what's happening, but transition (if it is there, hastily written papers tend to have subtle inaccuracies) doesn't rule out non-SC diamagnetism
Can one know how many people are in that market? When prediction markets where mentioned early during the LK-99 story, I looked a bit around out of interest, which platforms exist, which topics they cover, how many people participate in that markets. Where I could find the number of predictors, it seemed pretty underwhelming - one, ten, fifty, a hundred, I think the highest I ever saw was a bit over a thousand, but even then less than a hundred or so where using real money, the majority was using play money. Did I miss the place where everyone is? Is this to expected because the are so many topics you can bet on? Are the resulting prices still meaningful even with a small number of predictors only?
I wanted to bet 10$ or so, but the two links above both seem to be some sort of cryptocurrency thing. I dunno, isn’t there a way to gamble on the future that isn’t so… shifty?
How did I imply that there are many real money prediction markets, that was exactly my question, did I miss the ones where everyone is or are prediction markets just not that popular and that is why even the big ones do not have a large number of predictors.
There is just one real working prediction market: Polymarket. However, it is currently illegal to use in the US, because of old laws. This can be circumvented with cryptocurrency, but most Americans still won't use such a hack. Which strongly limits the popularity of Polymarket, as US Americans happen to be the people who are most interested in prediction markets.
There are also the prediction ... platforms Metaculus and Manifold, which are legal in the US, since they only use made-up internet points instead of real money. I'm not sure whether this even hurts their accuracy compared to Polymarket though.
If enough people cared, you could probably make the same argument that got sports betting into a place of legality and get at least some subset of prediction markets legalized.
The sportsbook argument was that sports betting involves more than random chance - knowledge of the game, the players, etc. effectively turn it into a matter of skill.
I doubt there are enough interested parties to bother for prediction markets, though.
They got about 50 degrees C, but note that the bulk sample and the more pure tiny sample are different.
It definitely contributes to the general feel that however this works, it's an inefficient synthesis that's problematically generating the material we want.
It certainly makes me wonder if something like molecular-beam epitaxy would be able to directly grow a more pure sample (but I imagine that's expensive and time-consuming to setup, plus not really what we're hoping for if we want to use lots of it).
326K (+127 deg F) and 340K (+152 deg F) for their less and more pure samples respectively. And, yes, if it's a superconductor as we understand them, that's the temperature at which it would have zero resistance as well.
It's obviously a hyperbole. But if we once were to use these SCs to transport energy from solar farms in Sahara, it might have to operate in that temperature range.
Five meters down in the desert you're under 25 degrees year round. It's the average that matters for soil temps, not the peaks. You can approximate this by taking the average air temperature and defining the surface as the top five meters. Below the 10 meter mark the day/night cycle influence is pretty much negligible (but that would be more costly).
LK99 isn't necessarily a stand-in for helium cooled superconductors - if all SC were equivalent to any other, YBCO and similar would have been enough to make MRIs significantly cheaper - LN2 is easy and cheap to produce.
First it shows a temperature graph vs moment, as they heat it it loses the diamagnetism around the temperature LK99 is said to be superconducting.
Second only a superconductor will have net-zero field, which means "stable" levitation. In the video they approach the sample with the magnet and flip it while the piece is mostly "in place". A regular diamagnet generates a external field that "follows" the field applied so it would likely move sideways, that is why to "levitate in place" a diamagnet people normally use a Halbach array.
EDIT: A Halback array is made alternating the poles N-S of the magnet, so that forces of repulsion created by the diamagnet cancel. This is why you will see people using multiple magnets when levitating pyrolytic graphite.
They have quantitative magnetization-versus-temperature data taken using a PPMS (an automated physical property measurement system). It shows strong evidence of some kind of diamagnetic transition at ~ 320K. It seems very likely now that this material has some kind of interesting magnetic property, whether or not it's due to superconductivity.
Back then, many asked if this was superconduction or merely diamagnetism. Does the new paper shine any light on this question?