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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

#101

Post by Qem »

ianai wrote: post #53
throwawaylinux wrote: post #44

Earlier quoted context omitted.

Is this kind of thing typical for experiments working to confirm such significant results, or is there a mad rush to publish? Do you really get a lot of prestige from confirming somebody else's result? I would have thought the risk to reputation from sloppy work would far outweigh it (see: the cold fusion shenanigans).

Probably a lab that confirms any piece of it will get a significant share of attention and acclaim. I heard the research group got scooped by a former researcher. Former researcher outed them before they were ready for all the relevant questions. Not a particularly good thing to do for a career to out colleagues like that.

> I heard the research group got scooped by a former researcher. Former researcher outed them before they were ready for all the relevant questions. Not a particularly good thing to do for a career to out colleagues like that.

Either this or they tried to deny proper authorship to the guy, that antecipated the publishing in self-defense. It's early to point who was the party at fault, without proper investigation.

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

#102

Post by DistractionRect »

keyle wrote: post #26

> In conclusion, we successfully synthesized the compound Pb10-xCux(PO4)6O, and observed the zero resistance above 100 K. However, the Meissner effect has not been observed yet in our samples, which suggests that the superconducting volume is relatively low. In conclusion, ... nothing?

It's likely that impurities in the bulk of the sample are why we aren't seeing the Meissner effect. Seeing super conductivity though is extremely promising.

We've seen a sample be super conductors at 110k ambient pressure, diamagnetism, and (unconfirmed) flux pinning. So it's likely there's something here, but right now the main hurdle is synthesis. It's difficult to make and there's no clear path to consistency, purity or scale.

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

#103

Post by LightMachine »

yongjik wrote: post #68
Waterluvian wrote: post #45

I don’t understand the physics, but it feels like a truly zero resistance conductor would violate some law of thermodynamics or something. Is a superconductor truly zero impedence or just very very very low? Because I’m seeing a lot of these graphs with something like: “0.00001ohm” as the y-axis floor.

Not an answer, but if you think superconductor is weird, look up superfluid, now that's going to make your head spin.

why there are no good videos of superfluids in action in the whole internet?

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

#104

Post by Arnavion »

8n4vidtmkvmk wrote: post #100
Arnavion wrote: post #88

Earlier quoted context omitted.

The submitter also fixed the incorrect use of the degree symbol before K, lol.

"degrees Kelvin" is wrong? Why's that?

Technically the units of temperature are "degrees Celsius", "degrees Fahrenheit", "Kelvin", etc. ie "degrees" is part of the name of the units "degrees Celsius" and "degrees Fahrenheit". "Kelvin" is the name of the unit by itself, so "degrees" is not supposed to be used before Kelvin.

In practice everyone's so used to saying "degrees" for temperatures that they end up saying it with Kelvin too.

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

#105

Post by throwawaylinux »

soerxpso wrote: post #83
throwawaylinux wrote: post #64

Earlier quoted context omitted.

> Probably a lab that confirms any piece of it will get a significant share of attention and acclaim. Why is that though? They're taking a discovery that somebody else came up with, and (mostly) follow a recipe they're given. I mean if they were synthesizing a theorized substance or significantly improving its production, or measuring an effect that was previously undetectable by known instruments and experiments the…

It demonstrates efficiency and ability to do something complicated and challenging under time pressure. Maybe it shouldn't be considered a big academic achievement, but it's definitely an impressive practical achievement. I don't think that being wrong looks bad. There are a lot of understandable ways to be wrong, and it's not like any of these labs are being dishonest about their level of confidence (you can't reall…

It's having these suspected dirty probes that they haven't investigated yet which is in particular what I'm talking about though. Since they made no particular experimental or theoretical breakthrough here, I just would have thought they would want to be meticulous about confirming an unexpected result. As you say, the point is to show their experimental capabilities.

> I don't think that being wrong looks bad. There are a lot of understandable ways to be wrong, and it's not like any of these labs are being dishonest about their level of confidence (you can't really be "wrong" if you're not overcommitted to a stance).

I'm not in the field, but I would have thought it would look pretty bad if they were wrong and their experiment had obvious sloppy practices. https://en.wikipedia.org/wiki/Cold_fusion apparently that sunk a few reputations.

I completely understand a private rush to replicate for the purpose of building on it and making new discoveries, but just to put rush out a confirm paper? I suspect it's less about demonstrating actual efficiency and ability and more about the paper mill.

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

#106

Post by evancox100 »

bandrami wrote: post #70
evancox100 wrote: post #63

Earlier quoted context omitted.

Not a superconductor expert, but resistance exponentially decreasing with temperature is not a normal phenomenon in most cases!

Most semiconductors have a thermal regime where that happens, it's just a relatively small regime, I thought?

I should probably be fired for my prior answer because things like pn-junction diodes can definitely have an exponential-like dependence on temperature.

In my head I was thinking of pure elements, like bulk metals. But there definitely could be more interesting things going on in the sample, like diode formation (internally or at the contacts) or weird doping profiles. That may be part of why it's hard to measure the properties!

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

#107

Post by fragmede »

LightMachine wrote: post #103
yongjik wrote: post #68

Earlier quoted context omitted.

Not an answer, but if you think superconductor is weird, look up superfluid, now that's going to make your head spin.

why there are no good videos of superfluids in action in the whole internet?

I thought https://youtu.be/2Z6UJbwxBZI was pretty good, even if it's low res from being a bit dated.

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

#108

Post by agnosticmantis »

ianai wrote: post #53
throwawaylinux wrote: post #44

Earlier quoted context omitted.

Is this kind of thing typical for experiments working to confirm such significant results, or is there a mad rush to publish? Do you really get a lot of prestige from confirming somebody else's result? I would have thought the risk to reputation from sloppy work would far outweigh it (see: the cold fusion shenanigans).

Probably a lab that confirms any piece of it will get a significant share of attention and acclaim. I heard the research group got scooped by a former researcher. Former researcher outed them before they were ready for all the relevant questions. Not a particularly good thing to do for a career to out colleagues like that.

In this particular case I’d be less cynical as even laypersons are anxious to know what’s the result. So it’s natural that scientists that have the lab equipment are rushing to replicate or falsify the results.

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

#109

Post by rsfern »

8n4vidtmkvmk wrote: post #100
Arnavion wrote: post #88

Earlier quoted context omitted.

The submitter also fixed the incorrect use of the degree symbol before K, lol.

"degrees Kelvin" is wrong? Why's that?

The SI unit is just “kelvin” because it’s an absolute scale. Usually “degrees” is only used with Celsius and Fahrenheit scales because they are relative. Not sure about Rankine…

https://www.nist.gov/si-redefinition/kelvin-introduction

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

#110

Post by gandik »

This is so reminiscent of what happened after Fleischmann & Pons. Labs attempting to replicate saw this property, or that property, but never the whole, unequivocal picture.

Here we have a room temperature superconductor that isn't a superconductor at room temperature. A sample that has no measured Meissner Effect at any temperature. And the authors admit that some (many?) of the samples tested out as semiconductors.

Also, they don't happen to mention how they measured resistance. 1mA current, yes, but what equipment? And what setup? Micro-measurement of resistance is hard. We really need to know more about that.

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