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Comment by jansenv | Hacker News Reader

>Amazingly, the observed deviation from the Lifshitz-Kosevich formula was presaged in 2010 by Sean Hartnoll and Diego Hofman, both then at Harvard University, in a paper that recast strongly correlated materials as higher-dimensional black holes, those infinitely steep curves in space-time predicted by Albert Einstein.

This is boggling to me. Higher dimensional black holes!?

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I think it is bad journalism, intended to boggle not enlighten.

The paper mentioned is http://arxiv.org/pdf/0912.0008, and does not itself make mention of black holes.

Presumably the "higher-dimensional" aspect is coming from Hartnoll and Hofman's "large number of degrees of freedom" analysis.

I don't know anything about this area to guess whether there is really a black hole analogy.

But I am confident it isn't a useful analogy to make anything more clear!

That paper does not directly mention black holes, but holographic correspondence (which is even in the title!) does seem to have strong connection to black holes and higher dimensions, which is further spelled out in the references. As far as I can tell (which admittedly isn't much), the black hole connection goes deeper than just an analogy. Overall, I don't feel like Quantas short reference there is bad journalism, the subject matter being truly quite mind-boggling.

Here is another article from the same reporter about this holographic stuff:

https://www.quantamagazine.org/20130701-signs-of-a-stranger-...

In the same paragraph where "Higher Dimensional Black Holes" is mentioned, the journalist hedges the outlandish suggestion with "But no theory yet captures the whole story. “I do not think that there is any remotely credible hypothesis proposed at this moment in time,” Zaanen said."

So... "Yea.. uh huh... interesting concept, not a chance" to paraphrase.

In what is known as the "AdS/CFT correspondence" or "holography", it is conjectured/believed (based on many reasonable physical arguments) that a condensed matter system will have an equivalent description in terms of a gravitational system in one higher dimension.

In those models, the temperature of the system in the lab typically corresponds to the Hawking temperature of the black hole in the higher dimensional gravitational system. (That is where my knowledge of the subject stops.)

For thos who seek technical details, Hartnoll has a short summary (2009) of the formalism on which the 2010 result is based: https://arxiv.org/abs/0909.3553

@dzdt: A little too hasty to judge don't you think? (ref comment quoted below)

> I think it is bad journalism, intended to boggle not enlighten [...] I don't know anything about this area to guess whether there is really a black hole analogy [...] But I am confident it isn't a useful analogy to make anything more clear!

I think this is a reference to higher dimensional gravity, it's not coming from General Relativity but more of an attempt generalize or reconcile 4-dimensional GR gravity with more modern higher dimensional theories (usually string theory or one of it's offshoots).

To put it more "exactly" they might be referencing the topology of black holes vis-à-vis gauss–bonnet gravity or something similar which would produce non-spherical black holes.

Tho this is stretching my understanding of physics to it's limits, Quanta Mag is usually an excellent source as far scientific reporting goes, it usually holds a pretty solid footing which makes it accessible to popsci lovers and people in the know alike.

I've seen some oddities in Quanta articles before, I usually attribute them to using a very high end subject matter too liberally, but it could also be some misunderstanding by the reporter.

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