Black Holes, Quantum Systems, Superconductors and Planck’s Constant Are Related | Hacker News Reader

Black Holes, Quantum Systems, Superconductors and Planck’s Constant Are Related

nextbigfuture.com

63 pointsneom16 comments

The only connection to black holes that I could find is, that they use mathematics first developed for string theory [1], so it's bit tenuous to say superconductors are related to black holes. Once you read a few of these articles you start seeing the same tropes. I yearn for articles with less hype, and more honesty.

The main result of the paper seems to be Fig. 3B and Fig. 4B. The black line represents the limit set by the uncertainty principle, and they argue that all these superconductors lie right at the limit, which they call Planckian dissipation. However, I have a sense that a lot of cherry-picking data is going on. They claim this is a universal behaviour, but the paper doesn't even mention whether it applies to the most well-known and highest temperature superconductors like YBCO and HBCCO. I suspect because it doesn't. Another omission is NCCO, for which they have data for in Fig. 4A (from which Fig. 4B is calculated), but then they don't plot it in Fig. 4B. I am guessing because it again didn't match claim. I wonder how thorough the review process was, if at all.

[1] https://en.wikipedia.org/wiki/AdS/CFT_correspondence#Condens...

There is a symmetry between how quickly black holes can absorb matter/energy and scramble information and how quickly electrons in these materials can dissipate energy: Both do it as quickly as possible, with "as quickly as possible" being somehow related to h-bar.

Is it a red herring or a pointer to some deeper, heretofore unexpected relationship? That's the cool part, no one yet knows.

From my understanding, they're claiming that the linear resistance-temperature curve with a slope of h-bar is evidence that the electrons are in something akin to a maximally entangled state.

Via the AdS-CFT correspondence, such a maximally entangled state is mapped to a black hole in AdS space in +1 dimensions.

With regards to cherrypicking, I don't think they're suggesting all HTSC demonstrate this behavior, but rather that the same principle is responsible for this phenomena in all materials in which it occurs.

I have certainly missed some details as I've never actually learned quantum field theory, so I'd appreciate someone more qualified correcting me.

The blog post links to this much longer Atlantic article: https://www.theatlantic.com/science/archive/2018/11/planckia... -- the link probably should be changed to that instead.

And the Atlantic article is just a repackaging of the original Quanta magazine article: https://www.quantamagazine.org/universal-quantum-phenomenon-...

A little hidden on the article, but source-

https://www.nature.com/articles/s41567-018-0334-2

It's not surprising that Planck's constant is important here, but this seems to have much more to do with crystallographic vacancy "holes" than anything even tenuously related to black holes or cosmology. I'm no physicist though.

> In cuprates, a perfect T-linear resistivity as T → 0 has been observed (once superconductivity is suppressed by a magnetic field) in two closely related electron-doped materials

This is pretty cool nonetheless.

Copying my reply to a different post:

From my understanding, they're claiming that the linear resistance-temperature curve with a slope of h-bar is evidence that the electrons are in something akin to a maximally entangled state.

Via the AdS-CFT correspondence, such a maximally entangled state is mapped to a black hole in AdS space in +1 dimensions.

Ah, thanks!

edit: do you think Legros et al. agree with that interpretation, or is the Quanta magazine -> Atlantic -> nextbigfuture article just using the Legros paper as an excuse to bring up the "holographic duality" views of Hartnoll and Sachdev?

> this seems to have much more to do with crystallographic vacancy "holes" than anything even tenuously related to black holes or cosmology.

Yep. Typical over-hyping in the article (the actual scientific paper itself seems fine).

"There appears to be holographic duality that mathematically connects systems of scrambled quantum particles, like those in strange metals, to imaginary black holes in one higher dimension."

Sounds like taken straight of a Sci-Fi movie.

anyone with a physics degree able to weigh in? could this be used to narrow the search for high temperature superconducting materials?

Or, does it constrain how high a temperature superconductivity can exist at?

Perhaps unification of QM and general relativity?

It did get me thinking about the 'cool horizons' paper again - https://arxiv.org/abs/1306.0533

Schwartzchild Proton

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