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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

#271

Post by [deleted] »

nonethewiser wrote: post #264
blueprint wrote: post #128

Earlier quoted context omitted.

> The worst case scenario is that there is actually nothing interesting with LK-99, and everything we've seen that suggests otherwise is experimenter bias heaped on top of experimental error. well while we're one-upping each other I'm pretty sure the worst case scenario is some lk99 synthesizer actually creates a black hole which gobbles up the planet.

What if thats where all black holes come from and thats why we haven’t found any aliens? Just a misfortune reality that “accidental blackhole” is lower on the tech tree than fast space travel.

[deleted]

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

#272

Post by mmusson »

ThrowawayTestr wrote: post #35
brucethemoose2 wrote: post #33

Earlier quoted context omitted.

Some literature suggests its a "one dimensiononal" superconductor only kinda works in tiny monocrystaline grains. ...But maybe thats even more interesting for, say, microelectronics? Especially if the resistance orthogonal to the superconductivity is high, if such a thing is even possible?

Zero loss diodes seem pretty useful.

How would that work? A diode requires a p-n junction created by doping the substrate. It has low resistance in one direction but ideally infinite resistance in the other direction.

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

#273

Post by Larrikin »

ekianjo wrote: post #248
drexlspivey wrote: post #242

Earlier quoted context omitted.

This doesnt pass the smell test. Why would multiple independent labs fake their videos? What’s the conspiracy here? There is no upside, we will know in a couple of weeks if it’s real or not.

> Why would multiple independent labs fake their videos Why would different newspapers spread hoaxes? Yet it happens...

Which hoax specifically was completely fabricated by the newspapers and spread by multiple newspapers? State run media obviously doesn't count.

Poor source checking and then issuing a retraction is not the same as a conspiracy among the papers to make something up completely.

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

#274

Post by daemontus »

jpambrun wrote: post #262
daemontus wrote: post #259

I see a lot of "This must be real, why would labs publish this if they don't think it's real, they have nothing to gain." sentiment on HN lately. Or "Researcher's career would be ruined if they falsely claim to replicate." , and so on. I also want to believe! But I should add a bit of skepticism to the hype :) - "this could ruin their career": Depends. If they posted completely fake numbers or intentionally fake vide…

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 a "we received weird signals from a nebula that we don't understand so far" claim.

And yes, a lot of supporting but inconclusive evidence is still supporting evidence. My point is not that (most) scientists would risk lying about replicating a superconductor, but rather that uncertain or inconclusive results with a solid chunk of plausible deniability in a rapidly evolving environment go a long way towards being "in the room where it happened".

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

#275

Post by ClumsyPilot »

Analemma_ wrote: post #125
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.

I understand why a lot of people think this, but I don't think we can say that with confidence yet. Cold fusion "replicated successfully" multiple times in the 80s too.

Thats because Cold Fusion does work, its just useless. It loses energy.

You need Muons, a negatively charged particle that is 200 times heavier than an electron. They replace electron in the atom. Two Muon-replaced atoms of hydrogen can fuse at room temperature.

The problem is that muons a very expensive to produce and decay quickly. So you spend more energy producing muons than you get from fusion.

https://en.m.wikipedia.org/wiki/Muon-catalyzed_fusion

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

#277

Post by throwaway849755 »

kurthr wrote: post #36
lifthrasiir wrote: post #8

I'm very much conservative about this paper because while the graph in Fig. 3a says $T_c^{zero}$ being 110 K, the "zero" resistance is actually only 1e-5 Ω (!) and even if the sample is possibly superconducting its critical temperature would be much lower than 110 K anyway. I'm aware of the difficulty in obtaining larger samples, but the label in that graph is really misleading regardless.

Well, it's at a 1mA test current (I'm assuming a 4 point probe to mitigate contact resistance) so 10u Ohm would give a 10nV DC signal. That's a pretty small voltage signal and comparable to a fairly standard chopper stabilized instrumentation amp rms noise at room temp near DC. I'm not sure whether higher currents are all that reasonable. Cooling the precision amp is an option to reduce the noise figure, but at that…

A comment above says they are using https://www.qdusa.com/products/ppms.html with the DC 4-wire option.

All my instincts would prefer they were using the AC 4-wire option, given any reason to question results, and/or issues with contact effects, etc.

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

#278

Post by 23B1 »

jcranmer wrote: post #74
tomohelix wrote: post #30

Summary of events so far: The claim: Room temp (~300K) superconductor exists and we got it! The replication attempts: The production method is so poorly documented only a fraction of the samples being made shows any interesting properties. And among those interesting ones, results varies. Very few, if any, attempt actually completely shows the entire spectrum of properties and behaviors of a true superconductor at ro…

> Worst case scenario, we got another class of high temp (warmer than liquid nitrogen but cold enough that applications are limited) superconductor but nothing revolutionary since at this point, it is pretty conclusive that there is something interesting with LK-99. I don't think that's the worst case scenario. The worst case scenario is that there is actually nothing interesting with LK-99, and everything we've seen…

We skeptics have just grown tired of arguing (with everyone, on everything, all of the time)

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

#279

Post by jacquesm »

matkoniecz wrote: post #268
throwawaymaths wrote: post #80

Earlier quoted context omitted.

You're right that this is the worst case scenario, but each interesting replication or semi-replication, even sloppy replication, or theoretical model erodes at that. Being perma-skeptic is as bad as being a perma-fanboy Anyways your memory is really short. Don't you remember how when it first came out (not even a week ago) everyone was hollering that it was fake? Inb4 "extraordinary claims...": there is no fundament…

> 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 they wouldn't be wrong for those things that turn out to be true (but then, I guess they wouldn't be perma skeptics to begin with). So, a perma skeptic misses all of the real stuff and a perma optimist misses all of the bad stuff. Neither shows intelligence.

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

#280

Post by stephencanon »

jcranmer wrote: post #74
tomohelix wrote: post #30

Summary of events so far: The claim: Room temp (~300K) superconductor exists and we got it! The replication attempts: The production method is so poorly documented only a fraction of the samples being made shows any interesting properties. And among those interesting ones, results varies. Very few, if any, attempt actually completely shows the entire spectrum of properties and behaviors of a true superconductor at ro…

> Worst case scenario, we got another class of high temp (warmer than liquid nitrogen but cold enough that applications are limited) superconductor but nothing revolutionary since at this point, it is pretty conclusive that there is something interesting with LK-99. I don't think that's the worst case scenario. The worst case scenario is that there is actually nothing interesting with LK-99, and everything we've seen…

Why would skeptics waste their time commenting on LK-99 threads? There are much better things to do.
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