
The Platonic solids and fundamental tests of quantum mechanics - mathgenius
https://quantum-journal.org/papers/q-2020-07-09-293/
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mellosouls
Whole article rendered beyond the summary (this link is from the page in the
OP):

[https://www.arxiv-vanity.com/papers/2001.00188/](https://www.arxiv-
vanity.com/papers/2001.00188/)

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messe
Thank you for introducing me to arxiv-vanity. I've always hated reading PDFs
of papers on my phone.

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andybak
> I've always hated reading PDFs of papers on my phone.

I've always hated reading PDFs of papers on a desktop PC as well. It's a
horrible format for reading on-screen generally. No automatic text-flow or fit
screen by default, fonts are usually too small, too much margin white space
etc etc

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messe
I agree to that as well. When I'm at my PC/laptop, I usually have my iPad at
my side, which with the pencil, is ideal for pdf reading and annotation, so I
have less complaints there. If I'm travelling or in bed, the phone is often
easier.

But yeah, we really need to move on from formats designed for print. HTML/CSS
needs more typesetting options and native math support though for that to be
feasible, unfortunately. There's no math typesetting conventions for
responsive design yet.

> No automatic text-flow or fit screen by default

Aside: While it's a hack, and only useful if you've a supported e-reader, I've
found Koreader does decent reflowings of LaTeX-rendered pdfs these days.

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haecceity
Bell's inequality was used to prove incompatibility between local and hidden
variable theories. What's the point of fancier Bell's inequalities?

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mellosouls
From the abstract, among other things:

 _[We] find a Bell inequality that is more robust to noise than the celebrated
Clauser-Horne-Shimony-Holt Bell inequality. Finally, we elaborate on the
tension between mathematical beauty, which was our initial motivation, and
experimental friendliness, which is necessary in all empirical sciences_

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whatshisface
I don't get it, is there something special about Platonic solids in this
context, or can you construct Bell inequalities that are maximally violated
along any set of vertices? Randomly gluing two things together isn't
"beautiful mathematics," beautiful mathematics is when you _discover_ a
connection.

~~~
kmill
I don't know the physics well enough, but having skimmed the paper it looks
like it has something to do with crystallographic point groups[1]. The point
sets are invariant under some of these groups, and that symmetry can help you
do some calculations. They also seem to make some use of dualities of the
solids, which correspond to polyhedra with the same point group. It might have
been more interesting to consider _all_ of the point groups, but, again, I
don't understand the physics to know why they did what they did.

[1]
[https://en.wikipedia.org/wiki/Crystallographic_point_group](https://en.wikipedia.org/wiki/Crystallographic_point_group)

