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Superconductivity fight

Posted: Thu Mar 17, 2022 9:00 am
by shpalman
Preprint server removes ‘inflammatory’ papers in superconductor controversy

This is about that business of high-pressure room-temperature superconductors (i.e. "we got them to work at room temperature we only need a huge pressure to do it") as opposed to normal-'pressure low-temperature superconductors (i.e. "we got them to work at normal pressure we only need a low temperature to do it"). The low temperature is probably easier but yeah, room-temperature superconductors, if you believe the results, which there are obviously some who don't.

Re: Superconductivity fight

Posted: Thu Mar 17, 2022 4:17 pm
by Grumble
shpalman wrote:
Thu Mar 17, 2022 9:00 am
Preprint server removes ‘inflammatory’ papers in superconductor controversy

This is about that business of high-pressure room-temperature superconductors (i.e. "we got them to work at room temperature we only need a huge pressure to do it") as opposed to normal-'pressure low-temperature superconductors (i.e. "we got them to work at normal pressure we only need a low temperature to do it"). The low temperature is probably easier but yeah, room-temperature superconductors, if you believe the results, which there are obviously some who don't.
The temperature of superconductivity was a hot topic back in the 90’s when I was learning about it. Terrible straight-line extrapolation from essentially 2 groups of data points to show how it was all but inevitable that we would get room temperature superconductivity sometime soon. Motivated reasoning in abundance.

Re: Superconductivity fight

Posted: Thu Mar 17, 2022 4:21 pm
by shpalman
Grumble wrote:
Thu Mar 17, 2022 4:17 pm
shpalman wrote:
Thu Mar 17, 2022 9:00 am
Preprint server removes ‘inflammatory’ papers in superconductor controversy

This is about that business of high-pressure room-temperature superconductors (i.e. "we got them to work at room temperature we only need a huge pressure to do it") as opposed to normal-'pressure low-temperature superconductors (i.e. "we got them to work at normal pressure we only need a low temperature to do it"). The low temperature is probably easier but yeah, room-temperature superconductors, if you believe the results, which there are obviously some who don't.
The temperature of superconductivity was a hot topic back in the 90’s when I was learning about it. Terrible straight-line extrapolation from essentially 2 groups of data points to show how it was all but inevitable that we would get room temperature superconductivity sometime soon. Motivated reasoning in abundance.
Our lecturer had just written a textbook on superconductivity in which he wrote that he'd left the chapter on high-Tc until last in the hope that someone would have figured out how it worked by the time he got around to it. That was also back in the 90's.

Re: Superconductivity fight

Posted: Thu Mar 17, 2022 4:57 pm
by dyqik
shpalman wrote:
Thu Mar 17, 2022 4:21 pm
Grumble wrote:
Thu Mar 17, 2022 4:17 pm
shpalman wrote:
Thu Mar 17, 2022 9:00 am
Preprint server removes ‘inflammatory’ papers in superconductor controversy

This is about that business of high-pressure room-temperature superconductors (i.e. "we got them to work at room temperature we only need a huge pressure to do it") as opposed to normal-'pressure low-temperature superconductors (i.e. "we got them to work at normal pressure we only need a low temperature to do it"). The low temperature is probably easier but yeah, room-temperature superconductors, if you believe the results, which there are obviously some who don't.
The temperature of superconductivity was a hot topic back in the 90’s when I was learning about it. Terrible straight-line extrapolation from essentially 2 groups of data points to show how it was all but inevitable that we would get room temperature superconductivity sometime soon. Motivated reasoning in abundance.
Our lecturer had just written a textbook on superconductivity in which he wrote that he'd left the chapter on high-Tc until last in the hope that someone would have figured out how it worked by the time he got around to it. That was also back in the 90's.
Really high temperature superconductivity would be fantastic for fusion power... ;)

Re: Superconductivity fight

Posted: Thu Mar 09, 2023 9:31 pm
by shpalman

Re: Superconductivity fight

Posted: Thu Mar 09, 2023 10:57 pm
by Grumble
I mean calling 10kbar “near ambient” is a very relative term. This kind of thing should be replicable so I shall reserve judgement. I hope it’s true.

Re: Superconductivity fight

Posted: Thu Mar 09, 2023 11:42 pm
by dyqik
Given that their previous paper at even higher pressures was retracted due to major issues, I'm not paying much attention to this.

Re: Superconductivity fight

Posted: Sat Mar 11, 2023 11:31 am
by shpalman
More on those major issues from a freelance science writer based in New York who had no communication about this story with his father the Managing Editor of Phys. Rev. Lett..

I'm paying attention to this to see how it turns out to be faked/wrong this time... It's a much more accessible pressure but they can always claim that the other groups haven't made the material properly when they fail to replicate, while never letting anyone else have their "working" samples for spurious IP reasons.

It's a different kind of "pressure" but we regularly make samples with about 1 GPa of biaxial elastic stress in them.

Re: Superconductivity fight

Posted: Sat Mar 11, 2023 1:47 pm
by dyqik
There's already an arxiv paper from one Chinese team showing that they failed to replicate it.

Re: Superconductivity fight

Posted: Sat Mar 11, 2023 1:58 pm
by Grumble
Side note from this, I wonder if there’s a region of Jupiter where temperatures and pressures are in the right region to have superconducting hydrogen, and if so would we be able to detect it?

Re: Superconductivity fight

Posted: Sat Mar 11, 2023 1:59 pm
by shpalman
dyqik wrote:
Sat Mar 11, 2023 1:47 pm
There's already an arxiv paper from one Chinese team showing that they failed to replicate it.
This? Superconductivity above 70 K experimentally discovered in lutetium polyhydride

Re: Superconductivity fight

Posted: Sat Mar 11, 2023 2:04 pm
by dyqik
shpalman wrote:
Sat Mar 11, 2023 1:59 pm
dyqik wrote:
Sat Mar 11, 2023 1:47 pm
There's already an arxiv paper from one Chinese team showing that they failed to replicate it.
This? Superconductivity above 70 K experimentally discovered in lutetium polyhydride
Yeah, I think so. In that they couldn't get above 71K or below 161 GPa

Re: Superconductivity fight

Posted: Mon Mar 13, 2023 11:23 pm
by jimbob
I'm now imagining using this to carry the electricity from my cold fusion rig

Re: Superconductivity fight

Posted: Tue Apr 04, 2023 8:17 am
by shpalman

Re: Superconductivity fight

Posted: Tue Apr 04, 2023 11:32 am
by dyqik
I've never really trusted Nature. It only takes the most surprising and potentially significant results in any particular field, and passes them through an non field-expert editorial team, who have to find good reviewers for that paper. That makes the likelihood of any particular paper being shown to be wrong much higher than a boring paper in a boring field specific journal, whether that's due to malfeasance, researcher or reviewer incompetence or just bad luck.

Re: Superconductivity fight

Posted: Fri Apr 21, 2023 4:51 am
by shpalman

Re: Superconductivity fight

Posted: Wed May 10, 2023 12:47 pm
by shpalman

Re: Superconductivity fight

Posted: Wed Jul 26, 2023 6:12 am
by shpalman
The First Room-Temperature Ambient-Pressure Superconductor

Of course nobody actually believes it.

Re: Superconductivity fight

Posted: Wed Jul 26, 2023 10:23 am
by Brightonian
shpalman wrote:
Wed Jul 26, 2023 6:12 am
The First Room-Temperature Ambient-Pressure Superconductor

Of course nobody actually believes it.
room-temperature superconductor (Tc≥400 K, 127∘C)
I think even my father would find a room temperature of > 127° a tad high. (Obviously, there's a specialist meaning of room temperature in fizziks.)

Re: Superconductivity fight

Posted: Wed Jul 26, 2023 10:26 am
by dyqik
Brightonian wrote:
Wed Jul 26, 2023 10:23 am
shpalman wrote:
Wed Jul 26, 2023 6:12 am
The First Room-Temperature Ambient-Pressure Superconductor

Of course nobody actually believes it.
room-temperature superconductor (Tc≥400 K, 127∘C)
I think even my father would find a room temperature of > 127° a tad high. (Obviously, there's a specialist meaning of room temperature in fizziks.)
The paper claims to show superconductivity at temperatures below 400K, including ambient. Tc is the upper temperature limit for superconducting effects.

Re: Superconductivity fight

Posted: Wed Jul 26, 2023 10:29 am
by dyqik
The paper does include most, if not all, of the direct measurements of superconducting effects that I would expect to see in a proper discovery of a new superconducting material.

The claimed material is also the right kind of structure that might possibly show higher temperature superconductivity.

But obviously, any claim like this needs replication, either in measurements on additional samples produced by the group, or made independently.

Re: Superconductivity fight

Posted: Wed Jul 26, 2023 10:38 am
by Brightonian
dyqik wrote:
Wed Jul 26, 2023 10:26 am
Brightonian wrote:
Wed Jul 26, 2023 10:23 am
shpalman wrote:
Wed Jul 26, 2023 6:12 am
The First Room-Temperature Ambient-Pressure Superconductor

Of course nobody actually believes it.
room-temperature superconductor (Tc≥400 K, 127∘C)
I think even my father would find a room temperature of > 127° a tad high. (Obviously, there's a specialist meaning of room temperature in fizziks.)
The paper claims to show superconductivity at temperatures below 400K, including ambient. Tc is the upper temperature limit for superconducting effects.
I see, thanks.

Re: Superconductivity fight

Posted: Wed Jul 26, 2023 10:51 am
by dyqik
dyqik wrote:
Wed Jul 26, 2023 10:29 am
The paper does include most, if not all, of the direct measurements of superconducting effects that I would expect to see in a proper discovery of a new superconducting material.

The claimed material is also the right kind of structure that might possibly show higher temperature superconductivity.

But obviously, any claim like this needs replication, either in measurements on additional samples produced by the group, or made independently.
But as an ambient environment superconductor, replicating measurements should be easy. That makes it difficult to imagine getting away with a grift on this, while high pressure measurements are harder to replicate.

ETA: which means it's either very interesting or a very stupid grift.

Re: Superconductivity fight

Posted: Wed Jul 26, 2023 11:06 am
by shpalman
Brightonian wrote:
Wed Jul 26, 2023 10:23 am
shpalman wrote:
Wed Jul 26, 2023 6:12 am
The First Room-Temperature Ambient-Pressure Superconductor

Of course nobody actually believes it.
room-temperature superconductor (Tc≥400 K, 127°C)
I think even my father would find a room temperature of > 127° a tad high. (Obviously, there's a specialist meaning of room temperature in fizziks.)
What I think they mean is that they went up to 400 K and still hadn't seen the transition out of "superconductivity" which does strongly suggest to me that they're never in superconductivity in the first place.

Re: Superconductivity fight

Posted: Wed Jul 26, 2023 11:12 am
by shpalman
LK-99 is a gray-black color, as shown in Figure 3(b). It is the superconductor with the same color as typical superconductors.
Oh well if it's the same colour it must be a superconductor.