Hacker Newsnew | past | comments | ask | show | jobs | submitlogin

The Fig 3a)b) graphs are not showing superconductivity. That just looks like the resistance dips below the ~1e-5 mark and goes goes deep into the noise. That just looks like a normal conductor that has a positive temperature coefficient.

edit: to add speculation, I think they made something that's not quite LK-99, and it's behaving like a normal conductor with no superconductance.



An excitation of 1mA and R = 1e-5 means the voltage is 10 nV (1e-8). Also the chart has a logarithmic y-axis.


I know, I'm just saying their test condition has a really high noise floor and once you dive into the noise floor there is no meaningful result.


That would be my interpretation too. Usually you get a stronger transition to 0 at the critical temperature but I can't see this (although it could be hidden under the noise)


The noise is probably just an artefact from measurement.


that's almost literally the definition of noise.

I'm saying the results are useless because the noise floor is obscuring any interesting behavior (if any).

Some people are saying "well, the Tc is 160K, so this result is invalid"--the way I see it, the Tc is not 160K because the test setup is so noisy so you're not really seeing any superconductivity at any temperature (not because it doesn't exist, but because their test setup is shitty)


I also agree, looks like they just reached the instrument noise floor. This result should be taken with a grain of salt.


What would be the acceptable noise floor here?


that's the wrong way to look at this.

what i see in this noisy measurement is nothing interesting. that always means:

a) the noise is obscuring something interesting

b) there is nothing interesting

for a), if it's practical and/or likely that there is something interesting in the noise, I'd try to find a way to lower the noise (or SNR).

you would assert b) if you have some strong convictions that there's nothing interesting down there.

Since the assertion that LK-99 is superconducting at room temp, there's already enough data to say that this is either A) whatever they measured is not LK-99 B) whatever they measured is LK-99, but doesn't superconduct at room temp.

Their ridiculous interpretation pointing at the SNR=1 point saying that's the critical temperature is actually hilarious.




Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: