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Cake day: July 3rd, 2023

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  • Mind you, the DFT calculation from the Griffin paper is not a proof of LK 99 being a superconductor in any way. What it showed is the (potential) formation of flat bands near the Fermi surface. Band dispersion is associated with the kinetic energy of the electrons, so materials with flat band (and therefore electrons with suppressed kinetic energy) at the Fermi surface are more susceptible to interaction effect (and strong interaction causes all sorts of nonintuitive quantum effects). I’m not a DFT expert in any sense, but from what I’ve heard, it is quite easy to “tune” your model to produce narrow (the limit of which being flat) bands from substitutions (e.g. the Cu substitution in this case) and such, which don’t necessarily lead to superconductivity.

    So I’ll take the DFT papers (there are quite a few now) as saying, “hey you want some flat band? Here’s some. We’ve done our part. Now some other theorist, do your magic and conjure up some superconductivity”. It’s a cog in the full picture, if there is a full picture


  • The point is there are established conventions among the practitioners on how these are pronounced, and not getting them right says something about the youtuber who may otherwise appear as an expert.

    You might be right on how the name ‘Schrieffer’ should be pronounced in its original tongue, but I’ve heard multiple former students and colleagues of Bob Schrieffer pronounce it otherwise to conclude that theirs is probably how Schrieffer himself intended his name to be pronounced.

    Yeah, can’t wait to hear economists’ take, or The Economist’s…




  • It is waiting for reproducibility is what it is. It won’t matter much if it got published today in some no name journal – a journal is going to gamble just as this youtuber did, for the slim chance of this being true (not saying it isn’t)

    Also, a quantum well is just particle in a box. Nothing fancy about it. Guy mentioned tunneling a lot but tunneling happens in metal, semiconductor, and insulator. Doesn’t really mean anything. In fact if you need to tunnel, that means there’s a chance to back scatter, so it won’t be superconducting.