[sbierwagen]

It really is authentically zero. No resistance at all.

The thing that prevent infinities showing up, or letting us pour gigawatts of power into a single superconducting magnet until it turns into a black hole is that superconductors have a "critical current" over which it falls out of the superconducting state. (At which point it enters the normal, resistive state, suddenly becomes very hot, and boils off all your very expensive liquid helium, a "magnet quench" https://en.wikipedia.org/wiki/Superconducting_magnet#Magnet_... )

LK-99's published critical current is actually quite low, maybe because of sample purity issues. Hopefully it can be improved, otherwise we might be in the comical situation where room temperature superconductors exist and can be used but the cables end up being too thick and can't compete economically with copper.

[tetha]

> LK-99's published critical current is actually quite low, maybe because of sample purity issues. Hopefully it can be improved, otherwise we might be in the comical situation where room temperature superconductors exist and can be used but the cables end up being too thick and can't compete economically with copper.

This would btw be similar to a proof of P = NP, including the caveat that the best-case runtime of an NP-hard problem is a polynomial of degree 40000. It'd be polynomial runtime, but very much in the "ouch" and "infeasible" territory.