Resolves YES if LK-99 is shown, in scientific publications of sufficient quality to produce a consensus among physicists, to be more diamangetic than any known non-superconducting material at room temperature and pressure.
The most diamagnetic material currently known is pyrolytic graphite, with a magnetic susceptibility χ ≈ −4.5×10^−4 in one plane.
This market will resolve YES either:
If LK-99 is superconducting at room temperature and pressure, in which case it would be extremely diamangetic indeed, or
If LK-99 is not superconducting at room temperature and pressure, but has a negative and larger (i.e. more negative) magnetic susceptibility than that of pyrolytic graphite.
Resolves NO at the end of 2024 if no such evidence is forthcoming. I reserve the right to extend the market close date if at the end of 2024, there is new evidence under active consideration.
Update: I'll follow @QuantumObserver's criteria for whether impurities/alternative formulations count as LK-99 for the purposes of this market:
Materials Impurities:
This question is specifically about LK-99. In the absence of overwhelming expert consensus (see below about resolution caveats), adding materials not in the original synthesis or characterization (replacing Cu with Au, Ag, etc) will not count toward a YES resolution.
Removing impurities (like CuS) is OK.
Increasing impurities that were also present in LK-99 original XRD is OK, up to a point. I think I would be more accepting of this is it’s convincingly shown that the impurities are important to the superconductivity of LK-99.
Synthesis of LK-99 by other means is totally fine, as long as the material characterization satisfies the criteria above.
Related questions
I'll follow @QuantumObserver's criteria for impurities/alternative formulations:
Materials Impurities:
This question is specifically about LK-99. In the absence of overwhelming expert consensus (see below about resolution caveats), adding materials not in the original synthesis or characterization (replacing Cu with Au, Ag, etc) will not count toward a YES resolution.
Removing impurities (like CuS) is OK.
Increasing impurities that were also present in LK-99 original XRD is OK, up to a point. I think I would be more accepting of this is it’s convincingly shown that the impurities are important to the superconductivity of LK-99.
Synthesis of LK-99 by other means is totally fine, as long as the material characterization satisfies the criteria above.
So extra oxygen and modifying the synthesis process is fine since the material contains oxygen already and even if it didn't it would plausibly be present as a contaminant if they had crappy vacuum.
This preprint appears to be first measurement of the diamagnetic susceptibility of LK-99 (or whatever the replication attempt synthesised - you can never be sure, and they emphasise this!):
The subtracted diamagnetic susceptibility (∼ −2 × 10−6 emu/g) is larger than that of Bismuth (∼ −1.6 × 10−6 emu/g) and water (∼ −10−7 emu/g) but smaller than that of Pyrolytic carbon (∼ −4 × 10−6 emu/g), indicating that this part is not from the superconductivity.
It's a highly uncertain measurement by the looks of things, so wouldn't be surprised if further measurements refine it to be different. As it is, being the second-most diamagnetic material known would be surprising, especially since according to the replication attempt, this isn't what gives rise to the partial levitation of large samples - they say that's due to ferromagnetism.
Note that I don't understand the units of susceptibility here, which I thought was dimensionless. I'm trusting the the authors here comparing it to bismuth and graphite, but I'll look up what these units mean before resolving this market (which I will not do yet - one preprint does not come close to being enough to establish consensus).
@chrisjbillington I'm confused here too. I think emu/g is the mass-based susceptibility in slightly weird units (dimensional analysis goes to inverse density). That makes sense in context, it's easier to measure the sample mass than sample volume. But the numbers for graphite and bismuth look more like the traditional numbers for volume susceptibility (dimensionless).
I'm inclined to trust the authors, this is not my field of expertise. I just pretend I know how to do dimensional analysis occasionally...
@EvanDaniel Yeah I noticed the same thing about the other numbers, made me initially assume these units must have been equivalent to the dimensionless ones.
Since lead is like ~20× heavier than carbon, units stuff involving density could make a pretty huge difference comparing to graphite.
Guess we'll find out!
I wrote a related Metaculus question:
https://www.metaculus.com/questions/18243/highly-diamagnetic-room-temperature-material/