
Researchers blur the line between classical and quantum physics - evo_9
http://phys.org/news/2016-07-blur-line-classical-quantum-physics.html
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antognini
Here is a link to the arXiv page for the paper:

[http://arxiv.org/abs/1601.00600](http://arxiv.org/abs/1601.00600)

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mywittyname
I never got past first-year physics in college, so hopefully you guys can help
me understand these findings a bit more.

So, quantum entanglement is essentially the idea that the quantum state of a
group particles cannot factored out individually. Chaos theory is the idea
that complex systems are deterministic, but that even minute changes in the
initial parameters of the system, or the forces applied to the system can
cause dramatically different outcomes.

The issue with binding these models is that quantum mechanics operates on
probabilities, which are fundamentally incompatible with the idea of
determinism. It's impossible to call a quantum system deterministic when, for
example, measuring the spin of a particle has a 50% chance of a different
outcome each measurement, regardless of the initial state.

Is this understanding somewhat correct?

If so, the implication of this research is that quantum entanglement somehow
produces a deterministic environment from a large collection of probabilities?
Almost like a reverse monte carlo simulator?

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jessriedel
> Chaos theory is the idea that complex systems are deterministic, but that
> even minute changes in the initial parameters of the system, or the forces
> applied to the system can cause dramatically different outcomes.

You can have chaotic deterministic dynamics, and this can help explain why
formally deterministic systems are indeterministic in practice. But you can
just as well have chaotic dynamics in a formally indeterministic system. Chaos
is about (a) sensitive dependence on initial conditions and (b) bounded phase
space (or some sort of other restriction that implies the "folding" phenomena
when combined with (a)). In particular, there is a whole field of quantum
chaos, and there's nothing contradictory about it.

> If so, the implication of this research is that quantum entanglement somehow
> produces a deterministic environment from a large collection of
> probabilities?

Nope.

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kordless
If I may make a correlation to initial conditions and randomness:
[https://bl.ocks.org/mbostock/19168c663618b7f07158](https://bl.ocks.org/mbostock/19168c663618b7f07158)

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gsmethells
So, entanglement could be said to be chaotic. Sounds more plausible than most
attempts to bind these models together more succinctly.

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Aelinsaar
Interesting, another link between classical thermodynamic processes, and
quantum processes involved in non-locality. Speculation as to the nature of
the arrow of time being a result of decoherence, and now a link between the
behavior of entangled ensembles and chaotic systems thermalizing.

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tremon
Could someone try to explain why "there's no idea of chaos in a quantum
system"? To me that sounds weird -- I thought the entire premise behind
quantum probabilities was our inability to get more definite answers from the
subatomic world?

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antonb2011
For chaos to manifest itself you need at least two things. First, the
equations of the dynamical system have to be nonlinear. Second, the
dimensionality of the systems has to be greater than 3. In quantum mechanics,
all the equations are linear, so there is no place for chaos in a strict
mathematical sense.

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kapv89
I was really into physics in college. After taking a course on chaos theory
and one on advanced quantum mechanics, I started getting a very strong feeling
that whole quantum mechanics is kinda BS(like its just a mathematical model,
not a representation of reality, ala GTR). And that chaotic systems is where
the key to understanding the quantum world is.

So I took some time out to step back and see what my life would look like if I
pursued physics, given the current state of affairs. Didn't like it at all.

Dropped out, learnt programming, started a company this year, finishing up the
product for first 10 customers, and have a very strong feeling that we are
onto something big!

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ZeroFries
Everything you could possibly use to describe reality is a model. What else
could it possibly be?

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kapv89
A model you can talk about without mathematics. Which doesn't need mathematics
to form an intuition about.

STR and GTR are perfect examples of models which you can help even a layman
develop an intuitive understanding of by just talking to them, without
mathematics.

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nilkn
You can certainly explain even something as sophisticated as quantum field
theory to laymen if you take the right approach. Feynman did just this in his
lectures on QED, now available in book form. He didn't use any math, even
though he talked about his own solution to the entirely mathematical problem
of renormalization in QED.

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monk_e_boy
ELI5 - please :)

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jokoon
Physicists are working, it's difficult, they might need help.

