Fractons, the ‘weirdest’ matter, could yield quantum clues | Hacker News Reader

Fractons, the ‘weirdest’ matter, could yield quantum clues

quantamagazine.org

85 pointsjnord28 comments

> The odd but customary way certain physicists understand this movement is that the electron moves because space is filled with electron-positron pairs momentarily popping into and out of existence. One such pair appears so that the positron (the electron’s oppositely charged antiparticle) is on top of the original electron, and they annihilate. This leaves behind the electron from the pair, displaced from the original electron. As there’s no way of distinguishing between the two electrons, all we perceive is a single electron moving.

I've never heard this idea before. I haven't finished the article yet but this is fascinating to me.

That sounds more like a computer simulation: you don't directly "move" an object, you copy it first and then delete the original.

"God" is the Matrix Server Admin?

So every powerline in operation is a high-intensity gamma ray emitter? This explanation seems to be missing something.

Virtual pairs virtually annihilate I suppose.

So there's an entire virtual world that needs to exist, but only virtually, to support the real world? That looks like the modern Ptolematic system to me.

Yeah, I think this is the basis for Hawking Radiation as well.

They’re mathematical conveniences; they don’t really exist. There are formalisms such as quantum lattice models in which they aren’t needed.

This isn't really saying anything. What does exist then?

A dozen (17?) complex-valued (some scalar, some vector) fields, where the square of the absolute value of a field gives the chance of seeing a particle in a given state.

I think. I’m still learning, and from MOOCs and YouTube not a university course.

The phase space describing those fields, where the measure of each term of the universal wavefunction is equivalent to the amplitude of one point in this space.

Your description suffices for pure states, IIRC. It’s been a while since I did physics.

I think the gamma gets absorbed when the next pair appears. https://en.m.wikipedia.org/wiki/File:Bhabha_S_channel.svg

Check out this video describing the “one electron universe”

https://youtu.be/9dqtW9MslFk

Funny this showing up here -- fractons are one of the first things I came across in pursuing my strange belief that fundamental particles are manifestations of defects in some "space-time crystal". But where Seiberg says “Quantum field theory is a very delicate structure, so we would like to change the rules as little as possible,” -- I have the exact opposite view: we'll probably need to tear down the vast majority of mathematical structures that are the foundation of QFT and QM, and build from scratch on a discrete combinatorial foundation. Luckily doing that is turning out to be a lot of fun and involve some interesting new mathematical ideas. But more often old mathematical ideas, like curvature, holonomy, and gauge symmetry, but resurrected in new forms.

Intriguing. A more discrete combinatorial approach could imply a corresponding proximity to programming language theories and type theories. This may be a bit far-fetch, but is there any chance introduction of parser/intrepreter-like constructs can be of useful significance?

> A more discrete combinatorial approach could imply a corresponding proximity to programming language theories and type theories.

I'm just curious, what theories are you talking about?

This this is the approach that Stephen Wolfram's physics project is exploring. In their model, everything is made of space, and space is a hypergraph.

https://www.wolframphysics.org/

...and I just read your bio - ha!

It isn't really. Wolfram's approach is relatively unique in that he bases it entirely on graphs alone, and no other structure.

There are several hints in more "standard" physics that a possible TOE could be based a model where you can think of the "stuff" of the universe more like a crystal with defects.

A 'crystal with defects' sounds like a graph to me, but I'm only a dilettante.

Interesting. Then what is a "node" in a graph? What is made of? Could it be a graph?

I'm having a hard time parsing whether this kind of particle has ever been experimentally observed or if it's just theoretical.

I'm also confused how it's incompatible with quantum field theory, but it was discovered in a simulation of some sort. If the simulation was compatible with QFT, then the particle should be too, right? If the simulation was not compatible with QFT then why do we think this is a possible particle?

I have a little heuristic I use for pretty much every particle/quantum physics phenomena I come across, I assume “theoretical” until such time I’m presented with evidence. These fields are so dominated by theoreticians that experiments are considered by some in the field to be a “different discipline” and something they need not worry about.

I had the impression particles are all just theoretical.

Like, they're just some extreme field values.

The article touches on your first comment:

> Fractons are quasiparticles — particle-like entities that emerge out of complicated interactions between many elementary particles inside a material.

Quasiparticles are common models in physics. Sound waves in solid matter are sometimes modeled as phonons, for example. Do they exist? Sure. But they're not what you probably think when you hear the word "particle".

Sure, but being a quasiparticle doesn't mean it's been observed. It could still be entirely theoretical.

> colleagues are developing novel quantum field theories that try to encompass the weirdness of fractons by allowing some discrete behavior on top of a bedrock of continuous space-time.

Try using AI and genetic algorithms to "breed" a model or equation that best matches observed behaviors.

Why is this being downvoted? Genetic programming successfully recovered Kepler’s Laws

>"It means fractons’ microscopic structure influences their behavior over long distances."

PDS: Sounds to me like yet another Bell's Theorem, "Spooky action at a distance", possible FTL candidate...

[...]

>"Using a computer algorithm, he turned up a new theoretical phase that came to be called the Haah code."

(add'l info on Haah Code: https://arxiv.org/abs/1812.02101)

[...]

>"Certain crystals with immovable defects have been shown to be mathematically similar to fractons."

https://en.wikipedia.org/wiki/Fracton_(subdimensional_partic...

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