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Superconductor news: What’s claimed, and how strong the evidence seems to be

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Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#91

Post by groestl »

scarmig wrote: post #3

One odd thing that I've not seen any discussion on: the reported heat capacity of LK-99 decreases above 250K, which is pretty atypical. Has there been any commentary on that?

> Has there been any commentary on that?

German, but nevertheless: http://blog.fefe.de/?ts=9a3f8740

"I work in the field [...] we don't believe a word of this. [...] The data set in Fig. 4(b) is also a treat. It is VERY unusual when the heat capacity decreases again at high temperatures. This can happen at low temperatures, but not at high temperatures. [...] My personal assumption is that the authors measured an insulator, so no current flow and therefore no voltage occurred (4-point measurement). This would look like a superconductor. But if you then turn up the current (i.e. the applied voltage), breakdowns may occur and a current begins to flow. That would explain the sharp increase."

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#92

Post by carabiner »

Researcher on reddit thinks it's probably spurious measurement artifacts, not superconductivity:

> I would say they are not faking it, but instead they just don’t understand what they are looking at. Based on what measurements they are doing, as well as how they are doing them, they do not have a good understanding of the standard processes to characterise a superconductor. Also, based on their analysis/discussion, they do not have scientific knowledge of the background theory. In review of these two papers, it’s terrible science, not something malicious (as has been seen before in RT superconductivity work…). Even if these claims turn out to be true, it's still terrible science, and that's my main criticism. Either way, these types of claims are not uncommon, see for example this paper from a few years ago which went nowhere. https://doi.org/10.48550/arXiv.1807.08572

https://www.reddit.com/r/worldnews/comments/159g2k4/comment/...

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#93

Post by MikeBVaughn »

thepasswordis wrote: post #67
archepyx wrote: post #47

Another comment from a well informed source on the topic: https://nitter.net/condensed_the/status/1684255515944034304 Also, on the sentences in the manuscripts trying to explain the effect: I think that is wild guess at best. The measurement results done in the manuscripts probably can be taken at at face value (at least until there is a reproduction). Whether they really indicate superconductivity or something else…

It's probably better to link to the original, not this mirror: https://twitter.com/condensed_the/status/1684255515944034304

The replies don't load for me in this one.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#94

Post by dexwiz »

jpmattia wrote: post #58
mmastrac wrote: post #12

This is an extremely useful summarization of the original paper. > The authors believe that the modified/strained structure of their material creates a large number of “quantum wells” between particular lead atoms and the adjacent oxygens of the phosphate groups bound to them, in effect making a two-dimensional “electron gas”. They propose that electron tunneling between these quantum wells, which are between 3.7 and…

> They propose that electron tunneling between these quantum wells, which are between 3.7 and 6.5 Ångstroms apart, is the superconducting mechanism. That is a very strange explanation. As someone who has done a decent amount of solid-state physics work, I would expect the explanation to involve a mechanism for pairing of electrons. Mere tunneling between quantum wells has been a staple since the "metamaterials" of th…

Are you referring to a Cooper pair?

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#95

Post by IX-103 »

perihelions wrote: post #61
curiousObject wrote: post #36

While we’re waiting for experimenters to reproduce this, it’s worth comparing this amazing announcement to the Cold Fusion affair of 1989[1] It’s notable that the first publications about attempts to reproduce the Cold Fusion experiment all reported positive results. It’s probably because experimenters who got negative results decided they might have done something wrong so they kept trying, and delayed, and they did…

Another example of this was Millikan's determination of the fundamental electric charge (of one electron). The first, famous experiment had a major error; and subsequently everyone who independently replicated the experiment, for two decades, came up with the same error, in the same direction. The people whose experiments got the correct value probably self-selected themselves out of publishing it. https://en.wikiped…

It is interesting to note that while the error was in the same direction, the magnitude of the error decreased in subsequent studies. No one expects to get exactly the same result, so there was room for variation towards the true result.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#96

Post by nharada »

floxy wrote: post #4

Lots of people are saying there should be a quick turnaround time here for trying the replication. I wonder how much it would cost to try and replicate this, in materials, labor costs, and vacuum furnace time/costs. My naive thought is that that labs in general aren't just going to drop everything to try an replicate every instance of someone declaring they've discovered room temperature superconductivity. Seems more…

Under a week of work to publish potentially the highest impact paper of your PhD (especially if you're first)? I'm guessing most students would take that chance.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#97

Post by willis936 »

NotYourLawyer wrote: post #51
swader999 wrote: post #27

Earlier quoted context omitted.

Nuclear fusion much easier, quantum computing, lossless electricity transmission, insane batteries. Dirt cheap MRIs, Basically welcome to the Jetsons. Much easier to mitigate climate change to the point where we can just deal with it.

This would only solve one of the more minor problems with fusion. And what would it do for batteries?

The challenge of fusion is a collection minor problems that add up to machines that are unviable for our current level of industrial output. Eliminating one of the three key plant systems (cryo, vacuum, and heating) is not a molehill, especially when it is the second highest user of power (after heating).

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#98

Post by prasadjoglekar »

mthomasmw wrote: post #88
local_issues wrote: post #78

Earlier quoted context omitted.

Ding ding ding! We still don't know how bikes work, we have a pretty good but incomplete model for lift on airplanes, and no one has the faintest why Tylenol works. We should figure that out! But we can definitely keep using all the applications until then. (Except for Tylenol, we keep learning how bad that stuff is) EDIT: It won't let me post more, so here's the answers to responses. For sure! https://www.cbc.ca/new…

Do you have a link handy for "we don't know how bikes work" ?

[flagged]

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#99

Post by willis936 »

hatsunearu wrote: post #39
orblivion wrote: post #18

So what kinds of cool stuff could be built with a room temperature superconductor? Better levitating trains?

The last line of the paper says this discovery will lead to a new age of humanity, and they aren't joking.

Lead is used in many places. You should avoid checking what battery is in your ICE vehicle.

What matters is how lead is handled. With hope, mankind will never lead a generation the way burning millions of gallons of leaded fuel did. Certainly no use of a lead superconductor could hope to accomplish that level of damage.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#100

Post by scarmig »

groestl wrote: post #91
scarmig wrote: post #3

One odd thing that I've not seen any discussion on: the reported heat capacity of LK-99 decreases above 250K, which is pretty atypical. Has there been any commentary on that?

> Has there been any commentary on that? German, but nevertheless: http://blog.fefe.de/?ts=9a3f8740 "I work in the field [...] we don't believe a word of this. [...] The data set in Fig. 4(b) is also a treat. It is VERY unusual when the heat capacity decreases again at high temperatures. This can happen at low temperatures, but not at high temperatures. [...] My personal assumption is that the authors measured an ins…

Nice find.
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