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

arxiv.org

81–90 of 389 posts

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

#81

Earlier quoted context omitted.

Why do MRIs need zero resistance vs incredibly low resistance?

Because the resistance is the limiting factor in how strong a magnetic field can be made in a given volume using the conducting material. Copper across an area of 1 cm ^2 does about 300A, compare with https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8047038/ for what some superconductors can do.

Link says 90 MA per cm^2, or 30,000X more than copper.

Gulp!

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

#82
post #5

Is this one also written in Word so it automatically loses LaTeX-credibility, as was commented under the first paper? (:

I would have said latex gatekeepers are the worst, but now I know eMacs geeks so no. Or was it vim? Can never tell!

‘eMacs’? It’s LaTeX that has the self-conscious capitalization!

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

#83
post #53

Earlier quoted context omitted.

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.

> 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 really be "wrong" if you're not overcommitted to a stance).

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

#85

Earlier quoted context omitted.

MRI machines work using superconducting magnets as does the LHC. So you better believe it buddy.

Why do MRIs need zero resistance vs incredibly low resistance?

I think it's a fair question. I guess the answer is "because we have superconductors, and no material with 'very small resistance' instead".

Also note that while there is zero resistance you still have parasitic currents and general interaction with the rest of the environment. So no perpetual motion for us today!

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

#86

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…

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?

I think you are referring to the pioneer work done by Prof. Chair Tong-seek (or Dongsik Choi as another spelling) here? https://twitter.com/sanxiyn/status/1684437744406392833

Any Korean can give some brief summary over the book that tweets mentioned?

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

#87
post #53

Earlier quoted context omitted.

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.

> 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 is hard work, but relatively easy work proportional to the possible rewards, and has very few downsides:

1. An early preprint provides instant press coverage for the researchers, their lab and the entire university. Such opportunities are rare: I worked in academia full-time for decades, and never had an opportunity to do some fixed amount of well-understood work that guarantees an appearance in the national press. Such an appearance is very useful in inter-departmental politics, not to mention when dealing with government organizations staffed by non-researchers. E.g. if "biggest newspaper in country X" reported about your research, that by itself ensures that you won't have to apply for "shitty academic visitor visa to the UK", but can credibly apply for a "global talent, go straight to indefinite leave to remain" one instead. And if the effect turns out to be real, and you managed to reproduce the effect while lots of others tried and failed, that's going to look really good on the grant application where you have to explain why your lab is the best place to spend money earmarked for superconductor research. This is unlike other replication papers, which are not usually the "gets reported on national media kind, or even "many others tried and failed" kind, but usually the "nobody else cared" type.

2. The article will definitely garner some citations. Even if LK-99 does not pan out, there will be many many survey articles written about what's unfolding right now, and they will all definitely cite the earliest replications. Moreover, it doesn't matter if your first preprint has shit writing: you'll still be cited if the final version gets accepted 4 months from now, after many rewrites. This is unlike most random "reproduction" papers, which are unlikely to get published, much less cited. So reproducing LK-99 is in fact a good way to increase h-index.

3. As long as you don't do anything fraudulent, there's very little career risk involved with being fast-and-loose in a preprint. If LK-99 pans out you're definitely in the clear. If it doesn't, well, as every second comment here mentions, materials science is difficult, honest mistakes are easy to make, even reproducing results is incredibly finicky and hard. It's not like your lab was the only one making anomalous observations. Chances are nobody's going to care if you were involved in a false positive replication. In fact, probably nobody's going to read and scrutinize your whole publication list when hiring or promoting you, but they'll definitely care about your citation metrics. This is unlike most other reproduction papers, where you wouldn't get many citations even if you managed to publish, because nobody cared.

All in all, dropping everything else and working on this right now is a good strategy, even for investigators in prestigious labs that would otherwise not bother with reproduction papers.

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

#88
post #38

Off-topic, but I admire the effort to translate the formula to Unicode characters in the title. It's not just a simple copy-paste from the article.

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

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

#89

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…

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.

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

#90

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…

Most papers are so bad its nearly impossible to replicate the synthesis.
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