In this preprint, the authors synthesize samples based on the claimed room temperature superconductor LK-99, and observe half-levitation similar to that seen in other recent videos, which has been ascribed to the Meissner Effect (a signature of superconductivity).

However, they performed a careful magnetization measurement and found that the sample is ferromagnetic. They also did a resistance measurement on a larger sample, and found that the majority of the material is a semiconductor. This points to a simpler explanation for the half-levitation phenomenon: it is a consequence of ferromagnetism (+ mechanical effects due to friction and sample shape), rather than the Meissner Effect.

Unless someone can demonstrate full levitation or better resistivity data for LK-99, this is arguably fatal for the claims of room temperature superconductivity.

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[–] expatriado 49 points 1 year ago (1 children)

i decided not to get excited until replicated experiments by third parties were done, it was too good to be true

[–] gibmiser 16 points 1 year ago (2 children)

I know better and still got excited.

I know we need to fix our problems as a society, but damn that technology hopium really gets me going.

In unrelated news, did you see the fusion news! We did it! Net positive energy! Fusion will be in our toasters in a few short years!

[–] 6mementomori 11 points 1 year ago (1 children)

i hate to break it to you, but net positive isn't exact here. the "energy in" used to calculate it is the energy of the actual photons, but to actually fire those lasers, you need 100 times the energy, so it's a net 1%

[–] [email protected] 4 points 1 year ago

The fusion definition of "net positive" has always been heavily inflated so that investors and governments will actually put money into these dreams

[–] cyd 8 points 1 year ago (3 children)

In unrelated news, did you see the fusion news! We did it! Net positive energy! Fusion will be in our toasters in a few short years!

Now they simply have to figure out how to get that super-powerful laser, which can fire only once a day, to firing once every milisecond ;-)

[–] [email protected] 7 points 1 year ago

Easy! Run it on fusion!

[–] [email protected] 4 points 1 year ago (1 children)

Do you have more information on said laser? I work on lasers that I would consider quite powerful and they fire at 6 kHz, soon to be 8 on the next model. I'd like to compare the specs

[–] cyd 3 points 1 year ago (1 children)

The National Ignition Facility has an explainer here. Typically, these facilities operate at petawatt peak powers by using lots and lots of pulse amplifiers. From what I heard, after every shot, the staff have to comb through the facility making sure things are still working, replacing blown out components, etc...

[–] [email protected] 3 points 1 year ago

Oh wow a few Joules, that's orders of magnitude bigger than ours

[–] jpeps 1 points 1 year ago

You may know more than me on this, but I believe multiple fires per day are possible now. Besides, tokamak reactors show more promise.