Replication of room-temperature superconductor fails to show superconductivity | Hacker News Reader

Replication of room-temperature superconductor fails to show superconductivity

phys.org

89 pointsairstrike30 comments

>The Chinese team is not rejecting the results obtained by the team at UoR—instead, they suggest it is possible that the nitrogen dopant present in their material was of insufficient quantity to produce the desired effect. They also note that in their sample, the dopant was unevenly distributed. They suggest further testing is needed to verify the results obtained by the group at UoR.

Replication can be hard. Failure to replicate shouldn't lead to immediate rejection.

If something can’t be reproduced it definitely should be rejected.

Yes, but one team failing to reproduce it doesn't mean it can't be reproduced. Once there's two or three teams unable to reproduce it we can be confident to say "the described method doesn't work".

That usually means the initial team did not describe the experiment sufficiently accurately.

(Unless it is fraud.)

Or didn't control it well enough, and the important details are something completely different. Or that they made a mistake.

I see a juggler handling five balls. I succeed at three balls. I fail at four balls. Have I proven that it's impossible to juggle five balls at once?

I see a juggler handling an unspecified quantity of balls. They will not tell anyone how many balls are being handled. How do I know what they accomplished? How would I replicate it without knowing?

You've proven that the juggler's instructions alone are insufficient to juggle five balls. In this case, the juggler presumably has muscle memory you don't, which is equivalent to running an experiment on equipment that behaves differently. Or perhaps the juggler didn't convey the special trick you need for four or more balls.

Maybe the juggler was juggling 5 balls, but they made a mistake with serendipitous consequences and then told everyone they juggled 5 balls, when they really don’t know how they were juggling 5 balls. In fact one of them might have been a different sized ball or maybe it was a cube.

Worse still, they won’t let you check their original balls to see if they actually are capable of being juggled.

Lol ball juggling /s

In this case I mostly agree, but more generally there are so many more wrong ways to do something difficult that you could have 100 failed replications and 2 reproductions and it would just mean 2 people did it right.

'Cannot' being the operative word.

'Did not' does not necessarily mean 'cannot'.

exactly.

If we want to go down the pedant route, the original group did not share their samples, therefore a true 'cannot reproduce' claim will remain out reach until they do so.

Replication can be hard. Failure to replicate shouldn't lead to immediate rejection.

My understanding, though, is that this researcher has a very problematic track record. It may not be appropriate to give him the benefit of the doubt here.

Maybe we should just ignore all findings until another team has independently reproduced the result.

Even if what the original team concludes is true, a repro failure could indicate that it's under-documented. And if it's under-documented, then has science really moved forward?

Or we could come back to reality and listen to the actual professionals about why the reproduction might not have worked, because of known issues in the reproduction.

The only conclusion I can come to is that the comments here are exceptionally low value.

At the same time extraordinary claims require extraordinary proof. The refusal to allow anyone to use their samples, or to apparently provide sufficient information to allow someone else to create the material they claim to be a room temperature superconductor, leans to it reasonably being an incorrect claim. Others point to past behavior as indicating this is fraudulent, but I'm just going to assume it's accidental error.

The title of the paper is: "Evidence of near-ambient superconductivity in a N-doped lutetium hydride". The Nature editors (and perhaps the authors themselves) covered their backs. They previously had to retract a related paper (from the same group) with much bolder claims.

Both sides are putting their credibility on the line. And this is good Science.

The retracted paper contained obviously faked data. This is not "good science" by any means.

Semi-related: I find the seemingly simple (or basic?) issue of cooling to be really interesting. Mainly because so much energy, effort, and cost is spent on cooling, and our tech and manufacturing industries depend so much on it, yet I don't see anyone trying to "disrupt" it. I very well could not be plugged in enough to know if anyone is or isn't though.

That being said it seems like one could offer cooling solutions that would cost them very little after initial setup, like providing infrastructure in places that are "naturally" very cool. This would probably be either deep in the oceans (I believe Microsoft piloted deep-submerged servers) or high up in the atmosphere, or even space itself.

Just a thought exercise I suppose...

If you are trying to cool something to <10K, I don't think it matters all that much what temperature you start at. Unless you start at space, which is already that cold (in shadow) but sending and operating stuff in space is hardly a cheap alternative.

Yeah that's was what I suspected. Outside of space-based infrastructure or at massive crush-depths in the ocean the "naturally" cool places wouldn't really make a dent in the required temperatures.

I don't wonder then if, when the cost of build goes down and speed of transmission goes up, space based infra for these things will be a big industry.

If anything it’s a lot harder to cool things in space because you are limited to radiating it.

The ISS has massive radiators almost as large as the station itself at 1800 square ft of radiator panels.

That makes sense. I don't know why I just assumed the vacuum of space would provide a perfect and passive cooling environment, but of course that's not the case.

There are a lot of examples in movies and the zeitgeist, even where other harder Sci fi Is obeyed, so it's hardly surprising if you'd never stopped to think about it. Welcome to the 10,000.

Qua intuition: Think vacuum flask aka thermos flask. (though these also try to reduce radiative cooling with a mirror-finish)

Convective cooling is a very efficient form of cooling, but obviously doesn't exist in a vacuum. Typically people resort to radiative cooling in space. This requires larger radiators.

I fail to see how you could "disrupt" something like cooling solutions in the way I believe your post implies.

First, the ability to remove large volumes of heat from a DC (or analogous plant) is largely dependent on the local geography/environment. In modest cases, that may come down to average ambient temperatures and the cost of electricity. In more extreme cases, access to a massive heat sink such as a body of water may be necessary.

Second, the technology used to evacuate heat is very mature. The modern world depends on HVAC and has for a very long time. While there are incremental advances such as new refrigerants and compressor technology, there is always a cost to performance tradeoff.

Note that the theoretical limit on cooling performance (CoP) of a Carnot engine is ~7.8. Check out this report by the IEA (page 43) https://iea.blob.core.windows.net/assets/0bb45525-277f-4c9c-...

Disrupting the 2nd law of thermodynamics has proven hard, yes. I for one wouldn’t bet against it.

Cooling in space is actually very difficult. While unlit space can be thought of as "cold" (ie you're in thermal equilibrium with a very cold resevoir) vacuum is an incredible insulator so once you get any heat coming in (including the onslaught of heat from the local giant nuclear fireball) it's very difficult to dissipate.

More generally, ambient temperature is irrelevant, what matters is heat transfer rates. If you just stick something someplace cool, it'll heat up. You need something like a flowing river to carry the heat away. This is one reason that things like power plants tend to be built on rivers. For things like computing, total heat production is much less of an issue and can easily be conveyed away from the building by airflow. The difficulty is cooling within the building, as tightly packed server racks are not very conducive to airflow, so you need active cooling.

Surprising coming from the fraud that published/retracted previous paper.

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