Saturday, June 24, 2023

A busy and contentious week in condensed matter physics

There were a couple of interesting and controversial things afoot this week in the condensed matter world.

  • There was a new preprint from the group of Prof. Hemley at the University of Illinois Chicago featuring electronic transport measurements in samples of the putative room temperature superconductor made from Lu-N-H, samples synthesized by the group of Ranga Dias.  This was mentioned as a potential confirmation of the room temperature superconductivity result by the New York Times.  Plotting the full raw data that goes with the new preprint, however, certainly gives many people (including me) pause.  The raw resistance vs temperature sweep traces have unphysically narrow (in temperature) drops to and rises from zero, as shown.  Obviously I don't know with complete certainty, but this looks exactly like what would be seen if one of the contacts was bad.  Time will tell, but the raw data surely look like a flaky contact rather than some weird re-entrant and thermally hysteretic superconductivity.
  • Meanwhile, Physical Review did something quite unusual, as they explain in this editorial that ran in Phys Rev B.  They allowed the Microsoft Quantum group to publish their latest report about looking for Majorana fermions in superconductor/semiconductor hybrid structures, without giving readers all of the necessary parameters and information necessary for reproducing the work.  The rationale is that the community is better served by getting this result into the peer-reviewed literature now even if all of the details aren't going to be made available publicly until the end of 2024.  I don't get why the researchers didn't just wait to publish, if they are so worried about those details being available.  There has been enough controversy about data availability in the Majorana arena that I don't understand why anyone would invite more discussion about transparency on this. Meanwhile, another group reports related phenomenology, though they argue that due to disorder they are not seeing Majoranas in their devices.  A review about the experimental hunt for Majoranas in condensed matter systems also came out this week in Science. 
I'm at a workshop this week, so posting and commenting may be a bit thin.


Anonymous said...

Sergey Frolov has spoken about this paper in depth way back when it was apparently submitted to PRX. See this video

As always, the proof is in the pudding. If Microsoft really saw something, then we should soon see the fruits of that because this paper is already getting pretty old. I'd wager we won't see anything like that, but that's my opinion.

Sad to see condensed matter going on a non-reproducibility streak like this. But, it is the science of dirt, so we should roll up our sleeves and get ready to deal with the dirty-...

Anonymous said...

In other news, John B. Goodenough sadly passed away on June 25.

Stefan Bringuier said...

@Douglas Natelson,

I agree with your sentiment about the unusual publishing decision made by PRB. In my opinion, this is exactly why preprint servers exist: to allow for the swift dissemination of potentially impactful research prior to the full peer review process.

It seems bad for science for PRB to knowingly permit a "half-baked" paper, in the sense that the results are most likely not reproducible due to missing details, to go through the peer review process.

The Microsoft Quantum group conducts solid research, and I don't intend to dismiss or undermine that. However, in my view, a peer-reviewed journal's main role is to ensure scientific accuracy and reproducibility.

One could argue that preprints might not be reproducible as well, but at the preprint stage, that's not the criteria for community acceptance. Preprints serve as an avenue to communicate new ideas, hypotheses, and ongoing research. They are meant to be part of a scholarly dialogue, not the final, vetted historical product of science.

I'm curious to see if this happens more often.

Anonymous said...

While I concur with the general sentiment, I note that the APS ethics guidelines here

present this (starred highlight mine):

Research results (e.g., data, findings, software) should be openly and promptly available, as soon as there has been an opportunity to establish intellectual property rights. Following publication, requirements for open access to the published data set by legislation or funding agencies must be followed. All research products should be retained for a reasonable period and be available promptly and completely to responsible scientists. **Exceptions may be appropriate in certain circumstances in order to preserve privacy, trade secrets, or national security.**

And that the authors claim that there is enough detail in the paper for it to be reproduced (one has to take that for what it's worth).

Regarding the high-Tc paper, they were measured on samples from the Rochester group, moreover Hemley is hardly independent confirmation as he had helped with the structure studies in the original paper of Dias.

Anyway, as we see more often these days, the saga continues.

Anonymous said...

From Vincent Mourik (

"Here's the full background of my involvement with the recent Microsoft Quantum paper. APS pulled off an arcane unofficial off the record peer review already one year ago when it was presented at PRX. And then published it anyway at PRB..."

Anonymous said...

Hirsch has a new pre-print out, well worth a look. He develops a toy percolation model that can reproduce the strange resistivity behaviour seen by Dias et al.

Anonymous said...

@Anon 4:09AM
That preprint was published recently, in Journal of Superconductivity and Novel Magnetism; see

He also had a comment on Dasenbrock-Gammon et al. published in the same journal; see

Finally, here's a recent experimental preprint arguing that there is a metal-to-poor-conductor transition in the system:

Ross H. McKenzie said...

I found the commentary of Vincent Mourik enlightening and disturbing.

I do have concerns about the unusual practice used by PRX and the precedent of publishing with incomplete details. However, my bigger concern is that it is not clear that this paper should have been published in any rigorous scientific journal. I fear that in order to "compete" with the luxury journals Phys Rev has descended to their low scientific and ethical standards.