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Andrew McCalip demonstrates synthesis of LK99

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Re: Andrew McCalip demonstrates synthesis of LK99

#321

Post by marcosdumay »

ThePhysicist wrote: post #243
floxy wrote: post #224

Earlier quoted context omitted.

There have been some people saying that LK-99 might only be superconducting in one dimension. Does anyone know how that (or even just 2-D/planar superconductivity) would effect the levitation of samples? For the 1-D case, maybe there would be issues in creating loops in the bulk material for persistent currents to flow in? It might be hard to make a Josephson junction unless you knew the orientation of the supercondu…

The superconducting wave function can have different symmetry, e.g. most/all low-temperature superconductors have s-wave symmetry (meaning the wave function amplitude is the same in all directions), whereas high-temperature superconductors have d-wave symmetry, which means the wave function amplitude has lobes and drops to zero along the diagonal axes. There are no p-wave superconductors to my knowledge (which I gues…

> which I guess is meant when they talk about a 1D superconductor, i.e. the wave function has p-symmetry, but not even sure if that's what they mean

I think they mean it only appears on islands that are much longer than they are wide or high. I.E. I understand it as a geometric limitation on the form of the crystals they can make.

The theoretical stuff that got here implies it has d-wave symmetry, and so does the original paper.

Re: Andrew McCalip demonstrates synthesis of LK99

#322

Post by marcosdumay »

anonylizard wrote: post #112
DoingIsLearning wrote: post #60

Earlier quoted context omitted.

The first pre-print came out on 22 July (if I am not mistaken). Not enough time has passed pure and simple. If I was an academic working on this, I would be following the Sagan Standard and triple checking my results before claiming anything. I think we are all suffering from 24 hour news cycles. The work in China and now Varda is very exciting but they are warp speed developments.

This is simply what post-peer-review looks like. Instead of a few anonymous peer reviews, you get the entire planet to replicate. Moment you get something meaningful, publish it on arxiv. Quantity, not quality is king. Anomalies are drowned out by large samples. Questionable methods get mass debated in public. Scientists are dependent on public funding, why squander the biggest moment in pop science for literal decad…

> Quantity, not quality is king. Anomalies are drowned out by large samples.

Yeah, that's not how it works.

At practice, anomalies are hyped into everybody's attention, and large samples are drowned out by lack of novelty. You don't need questionable methods to get bad results, you just need quantity.

All the things that are happening are great, and this may be an astonishing discovery. But don't put more certainty on it than it's warranted.

Re: Andrew McCalip demonstrates synthesis of LK99

#324

Post by lyapunova »

sashank_1509 wrote: post #40

This makes me extremely bullish about Varda Space, they have engineers of high quality and expertise that they could do a decent replication very quickly (if they got access to raw materials earlier, they might have been first to do so, comparable with the Chinese Groups) while working on their off time (from what I’ve seen of their twitter) and not a single big academic lab has managed to complete any sort of replic…

The word "bullish" and fundamental science should stay as far away from each other as possible.

Re: Andrew McCalip demonstrates synthesis of LK99

#325

Post by nyospe »

MetaWhirledPeas wrote: post #286
dotnet00 wrote: post #277

Earlier quoted context omitted.

Maybe I'm misunderstanding, where did withholding information come into this?

> Maybe I'm misunderstanding, where did withholding information come into this? When I mentioned gatekeeping I was specifically referring to how there's this formula that was kept secret since 1999. At some point the potential significance surely became apparent, and one of the only speculations I can come up with to justify that would be gatekeeping; keeping the information out of the hands of the filthy commoners f…

In 1999, I was still a student in solid state physics, not far past my bachelor's degree, and happened to notice the publication of something that, to this day, I suspect might be (note, load bearing "might") a critical breakthrough for desalination. Nothing came of it. Nobody has published any follow-up for it. Nobody has done any research that would contradict it either. It's just sitting out there, unnoticed, decades later.

Was it withheld from the public? Eh... yes? Kind of? Because it was only ever published in a journal - probably Materials Letters, but this was a long time ago - that you would only have access to if you were a graduate (or ambitious undergraduate) student with plenty of time to read in a university library, or a specialist in the very narrow field that journal was for, somebody with a membership included subscription...

This isn't gatekeeping, this is, to be blunt, profit motivated hoarding by a handful of publishers in the academic journals business. And this is the thing that arXiv.org and other pre-print venues are actually having an impact on. I, for one, am strongly in favor of academic information being widely available. I'm not as much in favor of people who have not demonstrated their competencies in something that requires a great deal of both knowledge and skill feeling entitled to being given a platform for their (usually laughably clueless) proposals. If you've done enough work to have a tested hypothesis, that's different.

Re: Andrew McCalip demonstrates synthesis of LK99

#326

Post by brakedam »

kijin wrote: post #297
username332211 wrote: post #260

Earlier quoted context omitted.

Any time the material exhibits a properties inconsistent with superconductors, the to-go explanation is that it's supposedly extremely difficult to manufacture. Not to mention, the original instructions include stuff like "The sealed tube containing the mixed powder was heated in a furnace at 925°C for 5-20 hours." which sounds a tad bit imprecise. Don't you think in those conditions it's at least a little bit reason…

One would think so, if the rest of the world weren't already cooking up similarly half-levitating samples in their kitchens and garages.

This is very ambiguous. So, everyone can make samples in their kitchens, but unfortunately, the researchers don’t have enough samples to provide, right? Researchers have their own primary responsibility to prove it, not the public. And this was not a debatable issue before the LK-99 bomb.

Re: Andrew McCalip demonstrates synthesis of LK99

#327

Post by peteradio »

_jal wrote: post #242
kjkjadksj wrote: post #228

Earlier quoted context omitted.

To be fair, no one in the us has a grant to replicate something that came out this week. Its also the academic summer. A good amount of PIs are probably nowhere near their labs on vacation currently.

> To be fair, no one in the us has a grant to replicate something that came out this week And yet researchers in other countries managed to find the money this week. That would seem to point to a real relative weakness that's worth thinking about. Whether it is the result of gatekeeping, bureaucracy, academic squabbling, or something else, a cranky (and hilarious) Russian did better, faster work in her kitchen. Even…

Seems kind of stupid to do chemistry in your kitchen. What exactly is the rush here to come out with results right now?!

Re: Andrew McCalip demonstrates synthesis of LK99

#328

Post by marcosdumay »

jcranmer wrote: post #290
notfish wrote: post #265

Earlier quoted context omitted.

I’m not sure I understand your point. Are you trying to say that people shouldn’t be paying attention to this? I would personally be horrified if I found out that the paper on the synthesis of a room temperature superconductor went through the normal peer review process instead of letting the world know they discovered something huge.

My point is why should this unreviewed claim of ambient condition superconductor be exalted as the holy grail and all of the other unreviewed claims of ambient condition superconductor languish in obscurity when they come out? It's definitely not for the strength of evidence!

It's pretty much due to the strength of evidence.

There is no conclusive proof that this is a superconductor on the replications, but the evidence has been on a different level from nearly everything else you'll find on Arxiv since the beginning.

Re: Andrew McCalip demonstrates synthesis of LK99

#329

Post by jcranmer »

marcosdumay wrote: post #328
jcranmer wrote: post #290

Earlier quoted context omitted.

My point is why should this unreviewed claim of ambient condition superconductor be exalted as the holy grail and all of the other unreviewed claims of ambient condition superconductor languish in obscurity when they come out? It's definitely not for the strength of evidence!

It's pretty much due to the strength of evidence. There is no conclusive proof that this is a superconductor on the replications, but the evidence has been on a different level from nearly everything else you'll find on Arxiv since the beginning.

AIUI, things that float in a magnetic field at ~room temperature are moderately common claims, and this is really the only evidence that LK-99 might be a room-temperature superconductor. The published ancillary evidence in the original paper actually raises red flags that isn't a superconductor--the "0 resistivity" domain in their temperature-dependent resistivity plot is (when you realize the units they're using) actually slightly less resistive than regular copper wire, which suggests that the sharp drop in resistivity may be nothing more than a pedestrian phase change in the material.

Re: Andrew McCalip demonstrates synthesis of LK99

#330

Post by kijin »

brakedam wrote: post #310
zarzavat wrote: post #276

Earlier quoted context omitted.

They’ve said they will provide samples after peer review. Which seems fair doesn’t it? How can they complete their paper and peer review without the samples? And if the samples get damaged they will be regret ever handing them over. If you were in the same situation you’d make the same decision. I and everybody else would love them to hand over the samples for external testing, but it’s their samples so they can do w…

But I heard that in the interview, Dr. Kim said they have various samples that have different magnetization properties. It doesn’t make sense that they have only a few samples, ironically. I’m sorry, but this makes me think that they are trying to move the public some other way.

Judging from the Korean-language interviews making the rounds today, there seems to be some sort of political tension between the researchers and the so-called verification committee. There's disagreement about whether anyone actually demanded samples, or whether it was just a polite request...

I have a hunch that this might have something to do with the late professor Chair (Choi?) who came up with the idea back in the 90s, and whose last wish his disciples claim to be following. Chair was a sort of outcast in the superconductor research scene, and the methodology his disciples have been using are also, um, unorthodox at best. Someone might stand to lose a lot of credibility if the verdict goes one way or another. We know there's been tension even inside the team, as one of the three men named in the first paper was dropped from the second paper. At this stage, I'd be more concerned about these internal tensions and personal grudges than any attempt to manipulate the public at large.

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