
Quasiparticles and the Miracle of Emergence - simulate
http://www.ribbonfarm.com/2015/10/29/quasiparticles-and-the-miracle-of-emergence/
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lambdapie
When high level behavior that can be described by simple equations emerges
from low level laws, we call it physics. When it doesn't, we call it
chemistry, biology, geology, etc. (EDIT: how could I forget econoimics :-))

 _There is only one thing which is more unreasonable than the unreasonable
effectiveness of mathematics in physics, and this is the unreasonable
ineffectiveness of mathematics in biology._

— Israel Gelfand

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selimthegrim
See also "Can a biologist fix a radio?"

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powertower
You can consider a "lack of an electron" as the same thing as an "Electron
hole quasiparticle".

The problem is this only holds 100% true in the abstract thought and specific
mathematical frameworks (and their formulas) you are working in.

While you can do the math, and get the right results, it does not
_necessarily_ make it real outside of the human brain.

The majority of quasiparticles are just another way of looking at things. Some
are totally human creations, others are combined effects, and some emergent
phenomena.

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gradys
> While you can do the math, and get the right results, it does not
> necessarily make it real outside of the human brain.

Following this same logic, nothing is necessarily real outside of the human
brain.

No experiment you can do, including simply observing human-scale events with
your eyes, necessarily tells you anything about the "real" world. Everything
that has ever been done in science amounts to doing the math and getting the
right results.

This is a rift in the philosophy of science: is science telling us real things
about the real world, or is it just producing models that happen to fit data
generated from experiments?

I take the latter position, but rather than concluding from this that I should
no longer use the term "the real world", I find it more useful to simply
redefine "the real world" to be the set of models that are consistent with
data generated from experiments. This means that if multiple models that
explain the same phenomenon are all consistent with the data, all of the
models are equally "real".

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baq
one interesting related question is "is math real?" does math exist without
human brain? i mean there's a reason why mathematicians prefer the word
'discover' instead of 'invent', but can something that theoretically could
exist without a universe to belong in be real? there's a lot of interesting
reading at
[https://en.wikipedia.org/wiki/Philosophy_of_mathematics](https://en.wikipedia.org/wiki/Philosophy_of_mathematics)
if you've got time to spare.

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pierrec
Emergent structures have the property of being possible to generalize about
and simulate to some extent by simpler means than the modeling of their most
fundamental components. When this is not the case, it means the large scale
result of the fundamental components is chaotic.

But if such a chaos were to characterize any given scale of any universe,
intelligent life at that scale would be impossible. When the author asks, "How
can the same sorts of simple equations keep appearing at every scale of nature
that we look for them?", my (perhaps simplistic) answer is that if chaos were
to entirely characterize a given scale, that scale would be too remote from
ours to be observable. Chaos would be the barrier to observation.

So, I would venture that emergence as we observe it in the universe is not
that surprising or miraculous, but inevitable. Though I may be wrong and/or
not the first to provide this "explanation".

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Retra
"Emergence" is such a useless word. Everything is emergent. Temperature is the
emergent consequence of small-scale particle motions. Orbits are the emergent
consequence of particles moving in potential wells. Intelligence is the
emergent consequence of neuron chemistry. Traffic is the emergent consequence
of driver's goals.

It's especially irritating because people like to say things like this:

 _" Emergent structures have the property of being possible to generalize
about and simulate to some extent by simpler means than the modeling of their
most fundamental components. When this is not the case, it means the large
scale result of the fundamental components is chaotic."_

Our brains require abstractions to function because our brains are _subsets_
of reality. You simply cannot pack all of existence into your brain to
conceive the whole thing at once. So _everything_ \-- every perceivable
phenomenon or relation that exists in any possible experience -- is going to
be _modeled_. This means that there does not exist anything that "when broken
into its components" is made of fewer abstract components than the whole.
That's contradictory nonsense.

Which means you can't assume that "when it happens," you'll get a chaotic
universe (or whatever you meant by that.) It's got nothing to do with scale,
since choosing to call one thing 'fundamental' and another an 'emergent whole'
is no less of an abstraction that swapping them around. You could just as
easily say the motion of particles is an emergent property of the temperature
of the whole, and you'd be no less wrong about it. It's a dualistic relation.

Which makes "emergence" a pointless concept. There is no "absolute simple" for
you to take as a fundamental abstraction from which other things emerge. And
I'm pretty sure the concept has never actually been used to solve a single
problem. Not even hypothetically.

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oofabz
I wonder if all the things we think of as particles, like electrons and
protons, are actually quasiparticles on top of more fundamental mechanics.

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mathgenius
This is Laughlin's thesis in his book [1]. The idea is that the mathematics of
renormalization as used by the particle physicists, is the same mathematics
used to describe quasiparticles. It seems physicists in general have not had
much to say in response to this idea.

[1]
[http://www.physicscentral.com/explore/writers/laughlin.cfm](http://www.physicscentral.com/explore/writers/laughlin.cfm)

~~~
tfgg
> It seems physicists in general have not had much to say in response to this
> idea

Huh? My impression is that the notion that the current laws of physics are an
effective field theory of some more fundamental theory is pretty widespread
and mainstream.

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mathgenius
Sure, maybe I am not channelling Laughlin very well. Perhaps it was his
general pessimism that any deeper theory could be derived from the emergent
phenomenon. It was a while since I read that book.

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srunni
Also see:
[https://en.wikipedia.org/wiki/The_Unreasonable_Effectiveness...](https://en.wikipedia.org/wiki/The_Unreasonable_Effectiveness_of_Mathematics_in_the_Natural_Sciences)
(full article:
[https://www.dartmouth.edu/~matc/MathDrama/reading/Wigner.htm...](https://www.dartmouth.edu/~matc/MathDrama/reading/Wigner.html))

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irisyao
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