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Observation of zero resistance above 100 K in Pb₁₀₋ₓCuₓ(PO₄)₆O

arxiv.org

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Re: Observation of zero resistance above 100 K in Pb₁₀₋ₓCuₓ(PO₄)₆O

#281

Post by segfaultbuserr »

amelius wrote: post #206
segfaultbuserr wrote: post #21

Earlier quoted context omitted.

The resistance curve stopped at 1e-5 Ω because it has nearly reached the resolution limit of their instrument. Using 4-wire Kelvin sensing, the measurement current was 1 mA, the voltage read-out across the material was around 1 to 10 nanovolts - this is around the scale that some of the world's best general-purpose voltmeters can measure down to. The authors assumed that the negligible voltage drop, combined with the…

Curious, why didn't they use a larger current for the measurement?

Who knows... Too afraid to damage their only sample?

Re: Observation of zero resistance above 100 K in Pb₁₀₋ₓCuₓ(PO₄)₆O

#282

Post by dougmwne »

ur-whale wrote: post #231

And now for a slightly different take on the much-discussed room temp. superconductors: on the off chance that this LK-99 stuff is actually going to be a thing, how should that influence my investment portfolio over the course of the next five years? Should I buy lead mining stock ?(joke, obviously, but you get the point).

It would bias our energy markets towards electric and away from fossil fuels. But due to climate change, there’s already a lot of pressure to go in this direction.

Re: Observation of zero resistance above 100 K in Pb₁₀₋ₓCuₓ(PO₄)₆O

#283

Post by jpambrun »

daemontus wrote: post #274
jpambrun wrote: post #262

Earlier quoted context omitted.

A contaminated sample that materially change the composition but still yield a superconductor would be a novel finding. An error in manipulation leading to an external communication on something this high profile is sure to affect your career. It's like a biologist claiming to have found evidence extraterrestrial life and having to retract. I think I would consider hara-kiri..

But the thing is... except for the original authors, none of these papers so far really claim to have a room-temperature superconductor, right? They claim "simulated band structure with low Fermi level", or "unusual levels of diamagnetism", or "almost zero resistance up to -100°C (but lack of phase transition)", etc. Yes, retracting these is still shameful, but it's not a "we found extraterrestrial life" claim. It's…

This is not my area of expertise, but as a former scientist (at least at the PhD and postdoc level) I would not stake my credibility on something without being 1000% sure on a normal day, let alone when the topic is extraterrestrial life or room temperature superconductors.

Also, it's not true at all the retraction have no consequences. It is an indelible mark of shame.

Re: Observation of zero resistance above 100 K in Pb₁₀₋ₓCuₓ(PO₄)₆O

#285

Post by cthalupa »

daemontus wrote: post #274
jpambrun wrote: post #262

Earlier quoted context omitted.

A contaminated sample that materially change the composition but still yield a superconductor would be a novel finding. An error in manipulation leading to an external communication on something this high profile is sure to affect your career. It's like a biologist claiming to have found evidence extraterrestrial life and having to retract. I think I would consider hara-kiri..

But the thing is... except for the original authors, none of these papers so far really claim to have a room-temperature superconductor, right? They claim "simulated band structure with low Fermi level", or "unusual levels of diamagnetism", or "almost zero resistance up to -100°C (but lack of phase transition)", etc. Yes, retracting these is still shameful, but it's not a "we found extraterrestrial life" claim. It's…

I wouldn't bet on LK99 being a RTAPS but "Replicating a bunch of weird shit that we don't really understand that at least somewhat align with the possibility" really isn't a damning position to be in when the starting point is "The team says they only get a working sample about 10% of the time and everyone else is working off of pretty meh instructions on how to replicate"

Re: Observation of zero resistance above 100 K in Pb₁₀₋ₓCuₓ(PO₄)₆O

#286

Post by dmarchand90 »

mycologos wrote: post #267
psychphysic wrote: post #198

Earlier quoted context omitted.

Anyone can edit Wikipedia.

Yes, in particular, anyone can add citations that you can check if you're skeptical. In this case, the citation is an article from science.org [1], which includes the following quote: > “They come off as real amateurs,” says Michael Norman, a theorist at Argonne National Laboratory. “They don't know much about superconductivity and the way they’ve presented some of the data is fishy.” On the other hand, he says, rese…

What makes me excited is there is very good theoretical work, using 'standard techniques ' that shows it either is a superconductor or will have very good properties in designing one.

Cold fusion, the EM drive, time traveling neutrinos, and all the other false excitement never had a theoretical backing. So 'guarded optimism' seems warranted

Re: Observation of zero resistance above 100 K in Pb₁₀₋ₓCuₓ(PO₄)₆O

#287

Post by fallingknife »

jacquesm wrote: post #279
matkoniecz wrote: post #268

Earlier quoted context omitted.

> Being perma-skeptic is as bad as being a perma-fanboy Not really? Perma-skeptic will be far more accurate than perma-fanboy. Depends on context but for example believing every get-rich-quick scheme will get you robbed by scammers, while perma-skeptic will miss very occasional actual opportunity. Obviously catching and exploiting great opportunities would be even better, but of these two perma-skeptic is better.

> Perma-skeptic will be far more accurate than perma-fanboy. That's not accuracy, that's statistics. Once you bias for the expected outcome the perma skeptic will be just as often wrong or right as the perma optimist. They have no information about the thing they are talking about, they only have information about that expected outcome based on previous observations. If they had information about the thing itself the…

Perma optimist has more fun, though

Re: Observation of zero resistance above 100 K in Pb₁₀₋ₓCuₓ(PO₄)₆O

#288

Post by eric_cc »

whimsicalism wrote: post #161
jseip wrote: post #157

Earlier quoted context omitted.

"It's not that extraordinary." How is that possibly true? LK-99 is already amongst the highest-temperature superconductors ever found (with that claim substantiated by at least two independent research teams as of this moment).

I don't know if you work in this field, but you are putting way too much faith in what has been reported so far People are way, way overconfident. Most people in the field would not be willing to put it at >50% odds at this point.

> Most people in the field would not be willing to put it at >50% odds at this point.

Do you have a source for this claim? It sounds like you just made it up.

Re: Observation of zero resistance above 100 K in Pb₁₀₋ₓCuₓ(PO₄)₆O

#289

Post by bluGill »

marcosdumay wrote: post #96
tomohelix wrote: post #89

Earlier quoted context omitted.

Personally, I think we are past the point of this being nothing. There have been multiple confirmations of at least something unexplained going on. Maybe all of them are wrong but honestly, that is more of an extraordinary claim than saying this is something interesting, just not a full on room temp superconductor.

It's not that extraordinary. When people rush to replicate an experiment, everybody with a positive result has something to publish very quickly, and everybody with a negative result need a lot more time to be certain of it. The kinds of results we are seeing are very hard to get by chance or due to bad experimental setup. But as a rule, we can't really differentiate a real thing from random noise in as little time a…

But that people have a positive result at all to publish is extraordinary. If this isn't a super conductor at this point that is probably even bigger than a superconductor - it means there is other physics we are not aware of to investigate.

At this point I've changed to this is probably true, but I don't know how big it is. (if it is true but impossible to produce at industrial scale it is not revolutionary)

Re: Observation of zero resistance above 100 K in Pb₁₀₋ₓCuₓ(PO₄)₆O

#290

Post by jacquesm »

fallingknife wrote: post #287
jacquesm wrote: post #279

Earlier quoted context omitted.

> Perma-skeptic will be far more accurate than perma-fanboy. That's not accuracy, that's statistics. Once you bias for the expected outcome the perma skeptic will be just as often wrong or right as the perma optimist. They have no information about the thing they are talking about, they only have information about that expected outcome based on previous observations. If they had information about the thing itself the…

Perma optimist has more fun, though

That's a fact.
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