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The Universal Pattern Popping Up in Math, Physics and Biology (2013)

144 points| kerim-ca | 1 month ago |quantamagazine.org

54 comments

order

readingnews|1 month ago

Not sure why you have to read 3/4 of the article to get to a _link_ to a pdf which _only_ has the _abstract_ of the actual paper:

N. Benjamin Murphy and Kenneth M. Golden* (golden@math.utah.edu), University of Utah, Department of Mathematics, 155 S 1400 E, Rm. 233, Salt Lake City, UT 84112-0090. Random Matrices, Spectral Measures, and Composite Media.

blurbleblurble|1 month ago

Well I'm not sure why I have to dig my way past this comment to find the substantive discussion.

Quanta is not doing hypey PR research press releases, these are substantive articles about the ongoing work of researchers.

troelsSteegin|1 month ago

heres's a corresponding video: https://www4.math.duke.edu/media/index.html?v=3d280c1b658455...

"We consider composite media with a broad range of scales, whose effective properties are important in materials science, biophysics, and climate modeling. Examples include random resistor networks, polycrystalline media, porous bone, the brine microstructure of sea ice, ocean eddies, melt ponds on the surface of Arctic sea ice, and the polar ice packs themselves. The analytic continuation method provides Stieltjes integral representations for the bulk transport coefficients of such systems, involving spectral measures of self-adjoint random operators which depend only on the composite geometry. On finite bond lattices or discretizations of continuum systems, these random operators are represented by random matrices and the spectral measures are given explicitly in terms of their eigenvalues and eigenvectors. In this lecture we will discuss various implications and applications of these integral representations. We will also discuss computations of the spectral measures of the operators, as well as statistical measures of their eigenvalues. For example, the effective behavior of composite materials often exhibits large changes associated with transitions in the connectedness or percolation properties of a particular phase. We demonstrate that an onset of connectedness gives rise to striking transitional behavior in the short and long range correlations in the eigenvalues of the associated random matrix. This, in turn, gives rise to transitional behavior in the spectral measures, leading to observed critical behavior in the effective transport properties of the media."

magicalhippo|1 month ago

From the abstract:

In this lecture we will discuss computations of the spectral measures of this operator which yield effective transport properties, as well as statistical measures of its eigenvalues.

So a lecture and not a paper, sadly.

0134340|1 month ago

>The data seem haphazardly distributed, and yet neighboring lines repel one another, lending a degree of regularity to their spacing

Wow, that kind of reminds me of the process of evolution in that it seems so random and chaotic at the most microscopic scales but at the macroscopic, you have what seems some semblance of order. The related graph also sprung to mind just how very like organisms repel (less tolerance to inbreeding) but at the same time species breed with like species and only sometimes stray from that directive. What is the pattern that underlies how organisms determine production or conflict with other organisms and can we find universality in it?

I guess it's called "universality" for a reason. I suppose if we look hard enough, we'll see it in more things. I read the article and I'm hoping some brilliant minds out there can dissect musical tastes in the same way. I'd love to see if it could relate to what we find harmonious in music and what we find desynchronous via different phase, frequency and amplitude properties.

bob1029|1 month ago

> I guess it's called "universality" for a reason.

> I'm hoping some brilliant minds out there can dissect musical tastes

There has to be some reason there are "Top 10" listings for video games, music, art, tv, movies, anime, vacation destinations, toys, interior designs, historical buildings in NYC, et. al.

Certainly there is a great deal of variance in the order and membership of these lists, but you do find a lot in common. Without some underlying pattern or bias, I don't think we'd see this in so many places so consistently.

I am fairly convinced there is something to do with biological efficiency around information theory that drives our aesthetic preferences.

blurbleblurble|1 month ago

Today I was thinking about how observing the macroscopic is not a neutral process, it involves processing more and more information the further you zoom out. Perhaps there's something about these "zooming out" kinds of processes that resembles the law of large numbers but more broadly?

cjohnson318|1 month ago

This spacing reminds me of Turing patterns, or activator/inhibitor systems, but I'm gobsmacked that this occurs in random matrices.

FjordWarden|1 month ago

Maybe also heap fragmentation

redleader55|1 month ago

This is interesting, do you have a link to any research about this?

kerim-ca|1 month ago

didn't realize this post got traction, it seems like it was HN pooled, I came across this article and related topics after trying to search what would be rigorous and closest to the phenomenon of the unreasonable effectiveness of mathematics by wigner, renormalization groups were the closest that I came across, the reason why the post title doesn't match the story title is likely due to the story being switched to a more detailed article I considered posting, the title is from a quanta video covering universality, linked below

- https://www.quantamagazine.org/the-universal-pattern-popping...

- https://www.quantamagazine.org/tag/universality/

- https://en.wikipedia.org/wiki/Universality_class

- https://en.wikipedia.org/wiki/Renormalization_group

-https://en.wikipedia.org/wiki/The_Unreasonable_Effectiveness...

wduquette|1 month ago

The article has a graphic contrasting a "Random" distribution vs. a "Universal" distribution vs. a "Periodic" distribution. I'm guessing the "Random" distribution is actually a Poisson distribution, as that arises naturally in several cases.

But the big question is, does this "Universal" distribution match up to any well known probability distribution? Or could it be described by a relatively simple probability distribution function?

CrazyStat|1 month ago

I think you mean a Poisson process rather than a Poisson distribution. The Poisson distribution is a discrete distribution on the non-negative integers. The Poisson process’s defining characteristic is that the number of points in any interval follows the Poisson distribution.

There have been a large variety of point processes explored in the literature, including some with repulsion properties that give this type of “universality” property. Perhaps unsurprisingly one way to do this is create your point process by taking the eigenvalues of a random matrix, which falls within the class of determinantal point processes [1]. Gibbs point processes are another important class.

[1] https://en.wikipedia.org/wiki/Determinantal_point_process

JKCalhoun|1 month ago

Just a layman: the graphic suggested to me that you might take the lines and their deviation from a periodic distribution. The random distribution is clearly further from periodic, the universal one closer. I wondered if there was some threshold that determined random vs. universal.

dist-epoch|1 month ago

There is the well known problem that "random" shuffling of songs doesn't sound "random" to people and is disliked.

I wonder if the semi-random "universality" pattern they talk about in this article aligns more closely with what people want from song shuffling.

pegasus|1 month ago

It's not that a random shuffling of songs doesn't sound random enough, it's that certain reasonable requirements besides randomness don't hold. For example, you'd not want hear the same track twice in a row, even though this is bound to happen in a strictly random shuffling.

blurbleblurble|1 month ago

Thank you for reading and understanding the article

stronglikedan|1 month ago

Song shuffling has been broken for ages now. It used to work correctly, like shuffling and dealing a deck of cards, only reshuffling and redealing when the entire deck has been dealt (or the user initiates a reshuffle).. Now it's just randomly jumping around a playlist, sometimes playing the same song more than once before all the songs are played once. I have a feeling that money is involved somehow, as with everything else that's been enshittified.

Lichtso|1 month ago

Another point in case: Life only exists in liquids, not in solids (too much structure) and not in gases (too much chaos).

In fact one could argue that this is a definition of an interesting system: It has to strike a balance between being completely ordered (which is boring) and being completely random (which is also boring).

Joel_Mckay|1 month ago

The Physics models tend to shake out of some fairly logical math assumptions, and can trivially be shown how they are related.

"How Physicists Approximate (Almost) Anything" (Physics Explained)

https://www.youtube.com/watch?v=SGUMC19IISY

If you are citing some crank with another theory of everything, than that dude had better prove it solves the thousands of problems traditional approaches already predict with 5 sigma precision. =3

kitd|1 month ago

> The pattern was first discovered in nature in the 1950s in the energy spectrum of the uranium nucleus, a behemoth with hundreds of moving parts that quivers and stretches in infinitely many ways, producing an endless sequence of energy levels. In 1972, the number theorist Hugh Montgomery observed it in the zeros of the Riemann zeta function(opens a new tab), a mathematical object closely related to the distribution of prime numbers. In 2000, Krbálek and Šeba reported it in the Cuernavaca bus system(opens a new tab). And in recent years it has shown up in spectral measurements of composite materials, such as sea ice and human bones, and in signal dynamics of the Erdös–Rényi model(opens a new tab), a simplified version of the Internet named for Paul Erdös and Alfréd Rényi.

Are they also cranks? Seems it at least warrants investigation.

topaz0|1 month ago

This isn't crank stuff, and operates on different kinds of problems/scales than "grand unified theory" type cranks. This is about emergent statistical order in complex interacting systems of sufficient size, not about the behaviors of the individual particles or whatever.

seanhunter|1 month ago

I'm going to go out on a limb and say you posted this accidentally on the wrong thread somehow, but this isn't (at all) a theory of everything, nor is it some crank producing anything.

Eg https://arxiv.org/abs/0906.0510

See the authors- in terms of contemporary mathematics they are pretty much as far from a crank as it's possible to be. Universality seems to be some sort of intrinsic characteristic of the distribution of eigenvalues of certain types of random matrices which crop up all over the place. That seems interesting and the work is serious academic work (as you can see from the paper I linked) and absolutely doesn't deserve the sort of shallow dismissal you have applied.

nkrisc|1 month ago

What does “5 sigma precision equals 3” mean?