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Some background: there were two Chinese teams publicly pursuing LK-99-derived room temperature superconductor, which I arbitrarily named "north China team" and
by sanxiyn 3y ago
Some background: there were two Chinese teams publicly pursuing LK-99-derived room temperature superconductor, which I arbitrarily named "north China team" and "south China team". North China team was headed by Hongyang Wang (who lives in Beijing) and south China team was headed by Yao Yao (who lives in Guangzhou). They used different synthesis and different analysis, i.e. north China team used hydrothermal synthesis and used SQUID measurement, while south China team used solid state synthesis and used EPR measurement.
This is a joint paper of both teams. They reproduced results of each other (this is unclear in the paper, but stated in their behind-the-scene posts) and measured a clear sign of superconductivity. It is "near room temperature", because they are sure about 250 K (hence "near"), but not sure about 300 K. As for "possible", the behind-the-scene post makes it clear it is false modesty.
If you are interested, you definitely want to read behind-the-scene posts. Read them here: https://www.zhihu.com/question/637763289 https://www.zhihu.com/question/637763289 (they are in Chinese). Hongyang Wang is 真可爱呆 and Yao Yao is 洗芝溪.
- bloopernova 3y agoHow does 250 K compare to current[1] superconductors? [1] pun definitely intended.
- belter 3y ago250K is -23,15°C This post because, laziness is a science...
- deleted 3y ago[deleted]
- sanxiyn 3y ago250 K at ambient pressure is still revolutionary, as it can be reached by dry ice. The highest critical temperature at ambient pressure had been something like 150 K: still above boiling point of liquid nitrogen, and won Nobel Prize in Physics in 1987.
- VikingCoder 3y agoI grew up in Minnesota, and I have to laugh that 250 K is -9.67 F, and yeah, we had a lot of days like that. It's amazing to think that future childhood toys could be superconducting outside on those cold Minnesota days.
- rsaxvc 3y agoAsk your hometown to build an antigravity skating rink with magnet shoes.
- MobileVet 3y ago“Those boards don’t work on water!”
- 14 3y agoI laugh but also sad I’m betting a lot of the younger HN crowd doesn’t get the reference.
- sixothree 3y agoMovies of the 80s and 90s feel a lot more modern compared to the “old movies” we had living in the 80s. Black and white movies with cardboard acting sure felt quaint for the tv generation. Today though I’m constantly surprised by the number of young people who recognize things from 80s movies and especially music. I’d say that number is higher compared to our generation.
- Sanzig 3y agoThe 80s and 90s produced a lot of movies that became pop culture classics (Back to the Future among them). Millenials and Gen Z grew up in an era with much easier access to older media than previous generations. First was the video store - while Gen X had this too, it really took off in the 90s. I remember when I was a kid in the late 90s and early 2000s, it was $5 to rent a new release or 3 for $5 for old releases. This meant that we were basically encouraged by our parents to watch older stuff, and of course the fact that they lived through the 80s themselves meant they tended to recommend movies to us from that era. Of course, after the video store came VOD services like Netflix. Old movies are a great way to pad out a VOD catalogue, so that increased the access to 80s/90s movies even more. It also doesn't hurt that, as you've pointed out, many of these films still hold up pretty well today.
- VikingCoder 3y agoJokes like that are going to get a lot of resistance. Oh well, time to amp it up. Best chart I could find. Looks like there's another at 250 K from 2019. But what I don't have here is the Temperature / Pressure / Timeline, though...? What is the Pressure in the article? Is it STP? https://en.wikipedia.org/wiki/Superconductivity#/media/File:Timeline_of_Superconductivity_from_1900_to_2015.svg https://en.wikipedia.org/wiki/Superconductivity#/media/File:...
- Hugsun 3y agoWhat in the post is false modesty? What is the pressures required for the effect? Are there other requirements that limit it's practical usage.
- nemo44x 3y agoSo, we're back?
- hn_throwaway_99 3y ago> As for "possible", the behind-the-scene post makes it clear it is false modesty. It's not false modesty to withhold a conclusion that is unwarranted without more evidence. The last time this happened there was also "possible Meissner effect" that turned out to be diamagnetism. There are no downsides to being conservative until more evidence is acquired.
- sigmoid10 3y ago>There are no downsides to being conservative until more evidence is acquired. That's true, but one upside here is that this is not from the guy at Rochester who already got burned twice for publishing false superconductor discoveries. This is at least a report that can't be dismissed immediately.
- hn_throwaway_99 3y agoI don't know who you're referring to "from Rochester", but the excitement from last summer around LK-99 came from two South Korean researchers. Which, mind you, all turned out to be faulty interpretation of their data. To be clear, I don't mean to cast unnecessary shade on these current results, I'm just saying the sane and prudent thing to do, especially given LK-99's recent history, is to hold off on any champagne popping, and that appropriate restraint shouldn't be characterized as "false modesty".
- godelski 3y ago> Which, mind you, all turned out to be faulty interpretation of their data. Which we should be critical of, but understandable, since that's one of the main reasons to publish (and why I think it is weird we say arxiv papers aren't peer reviewed. That was probably one of the most peer reviewed works in the last decade) and since we're all human. Science is full of mistakes, and is unsurprising when a lot of it is literally trying to do things that humans have never done before (much more to science than this too). What I thought was really cool about LK-99 is that it isn't too often that people get a first hand look at what goes on inside the science communities. An abnormal amount of attention and openness, but illustrative. Just not sure this is the takeaway people got. But I saw science working in action, and it was really cool.
- gwern 3y agoThis is LK-99 derived? Now I'm even less interested. Because if you believe this one, you need to believe that despite LK-99 being bogus, that somehow, trying to make a new LK-99 variant was lucky enough to find the one compound out of countless attempts that winds up working - as opposed to coming out of a completely different, still viable, line of research. Stranger things have happened in the history of science & technology... but not that many.
- fouc 3y agodid you catch the part about sulfur? i.e. LK-99 w/ sulfur contamination was originally blamed for the magnetism. This new variant is explicitly sulfur-based.
- sanxiyn 3y agoYes this is LK-99 derived. (See the paper's reference 4 and 5.) Eh, of course it is unlikely LK-99 is bogus and this one is not, but then the correct conclusion to draw is that LK-99 is not bogus?
- gus_massa 3y agoPerhaps LK-99 is bogus, and they were triying to reproduce the result, they failed succesfully and they got another similar compound that is not bogus.
- gfodor 3y agoThat’s possible but far less likely than the alternative explanation that either this is bunk too or LK-99 contained signal that people dismissed due to a hole in our methodology.
- mort96 3y agoWait how are all the flaws in the paper and all the failed reproductions of LK-99 and all the signs that LK-99 is just diamagnetism compatible with LK-99 being a proper superconductor?
- dash2 3y agoTranslated with Safari, those posts are awesome: "The first law of superconductivity: stay away from theoretical physicists." What should I say, the rules are all used to be broken? I haven't been drunk for many years. Last Friday, I always stayed there to test and kept sending me photos and live broadcast the real-time measurement results. Every time I sent one, I couldn't help drinking a drink. I was directly broken. I was carried back by the students. It's embarrassing~~
- lucasban 3y agoWhat impressed me was that Safari translated the text in the screenshots as well, I wasn’t expecting that.
- wolfi1 3y ago"possible" was also used in the Bednorz/Müller paper, "possible" is therefore an established term