LW - LK-99 in retrospect by bhauth

The Nonlinear Library: LessWrong

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Welcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: LK-99 in retrospect, published by bhauth on July 7, 2024 on LessWrong. About a year ago, there was a lot of public interest in a supposed room-temperature superconductor called LK-99. What I publicly said at the time was, basically: 1. We should remember the possibility that apparent levitation is from ferromagnetism or paramagnetism. Iron filings can stand up on a magnet, and pyrolytic graphite can float over a strong magnet. 2. If we consider some known high-temperature superconductors: YBCO has flat sheets of copper oxide, and superconductivity happens along those planes. The copper in that has high positive charge density, comparable to aluminum atoms in alumina, which gives strong bonding to the oxygen. H3S (paper) has unusually strong bonds between the sulfur and hydrogen, which only form because the atoms are pressed into each other with enough pressure to substantially compress liquid water. Superconductivity comes from flow of Cooper pairs, and the electron-phonon interaction must be stronger than random thermal movement. LK-99 doesn't seem to have any reason to have exceptionally strong such interactions. (Yes, I'm simplifying, you have to consider phonon bandgaps, but the point is at least directionally correct.) 1. The focus on "room-temperature" superconductivity is a bit silly. Even with systems using liquid nitrogen cooling, the superconducting wires are much more expensive than the cooling. What's really needed for superconductors to be practical is cheaper superconducting wires, not higher-temperature ones. At the time, I found the unusual amount of public interest a bit bemusing. There have been various claims of near-room-temp superconductivity, but none of them attracted as much public attention as LK-99. A few months earlier, Ranga Dias published a paper claiming room-temperature superconductivity; he's now up to 5 retractions. What was different about LK-99? That was supposedly superconducting at ambient pressure, which makes it more practical, but also means less specialized equipment is needed to replicate it - or claim to replicate it. LK-99 had a video that appealed to people. There were also a few social conditions that I think were important: 1. It had been a while since that last major excitement about fake science news. After some big story that turns out to be wrong, people are more skeptical of science stories in every field for a while, and then things gradually go back to a baseline. (That's how things were after eg the "arsenic in DNA" story, which didn't make sense either: arsenate esters aren't stable enough for DNA.) I understand the heuristic that people applied but the way it's applied here doesn't really make sense. 2. Misleading short videos + social media is a combination that hadn't really been applied to bad science stories before. 3. I think the atmosphere at the time had a lot of demand for ammunition in a wider techno-optimist vs techno-pessimist conflict. ("Room-temperature superconductors and Boom Technology making practical supersonic aircraft! We're so back!") I think those overall conditions caused the LK-99 story to be self-amplifying, because: Several twitter accounts made fake videos showing "replication" of LK-99 superconductivity, because it was just good social media strategy. I think iris_IGB is still up a lot of followers overall. Don't hate the player, hate the game, I guess. Some theorists jumped on the story by finding "theoretical justifications" because it seemed like a net career positive, statistically speaking. In many cases, whether the social status of a scientific theory is amplified or diminished over time seems to depend more on the social environment than on whether it's true. For example, the amyloid theory of Alzheimer's is still going, and real money is being paid for drugs based on it that...