
Weyl points, first predicted in 1929, observed for the first time - _pius
http://newsoffice.mit.edu/2015/Weyl-points-detected-0716
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privong
For those interested (and with subscriptions or institutional access), here
are the abstracts for the two papers, the first from the MIT group and the
second from the Princeton group:

[http://www.sciencemag.org/content/early/2015/07/15/science.a...](http://www.sciencemag.org/content/early/2015/07/15/science.aaa9273.abstract?sid=31d8c875-11ca-4da8-aeeb-32719f4e4395)

[http://www.sciencemag.org/content/early/2015/07/15/science.a...](http://www.sciencemag.org/content/early/2015/07/15/science.aaa9297.abstract?sid=31d8c875-11ca-4da8-aeeb-32719f4e4395)

The MIT group's paper appears to be on arXiv:
[http://arxiv.org/abs/1502.03438](http://arxiv.org/abs/1502.03438) (albeit
with a somewhat different abstract; perhaps a pre-acceptance version).
Unfortunately the Princeton group's paper doesn't appear to be posted on
arXiv.org as of right now.

~~~
selimthegrim
The Princeton group's has a different title, and was posted March 9 (I
downloaded it about a month later so pulled it off my hard drive when I saw
this comment)

[http://arxiv.org/abs/1503.02630v1](http://arxiv.org/abs/1503.02630v1)

~~~
privong
Thanks! I had only done quick searches on the titles.

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ta92929
I'm confused. It sounds like they though neutrinos were Weyl points, and
neutrinos are real particles. But it also sounds like this experiment created
quasiparticles. So are Weyl points still a proposed real particle? Or was it
only ever theorized to be some kind of emergent phenomenon? Or did they really
create a new type of real particle?

~~~
selimthegrim
You mean Weyl _fermions_. Weyl fermions obey the Weyl equation, and Majorana
fermions the Majorana equation. Majorana fermions are their own anti-
particles, while Weyl fermions are not. They are cousins of the Dirac equation
(think about how a Dirac point and a Weyl point are related). There is still
some debate about whether neutrinos are Weyl or Majorana fermions.

~~~
didgeoridoo
"I have no doubt that in reality the future will be vastly more surprising
than anything I can imagine. Now my own suspicion is that the Universe is not
only queerer than we suppose, but queerer than we can suppose." \- JBS Haldane

~~~
danieltillett
This is almost certainly true when you consider almost nobody understands what
as humanity we actually know right now about the universe.

The chance that the smartest person in the world is just smart enough to
understand exactly how the universe works is very unlikely considering
understanding of the universe has never been under evolutional selection. We
are going to have to wait for the Singularity to tell us how it really works
:)

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technofiend
>That issue of scalability in optical systems is “quite fundamental,” Lu says;
this new approach offers a way to circumvent it. “We have other applications
in mind,” he says, to take advantage of the device’s “optical selectivity in a
3-D bulk object.” For example, a block of material could allow only one
precise angle and color of light to pass through, while all others would be
blocked.

Putting my science fiction hat on, if that meant you could build a light-
absorbing material you could potentially have (for instance) camouflage that
reflected on a certain wavelength only known to your friendly forces. Or
hidden assets that require a filter to see - hidden keypads, hidden
instructions, that kind of thing.

~~~
Dylan16807
It's already easy enough to make things that only reflect at specific angles.
Filtering by exact wavelength doesn't add a lot; it leaves your message
visible in sunlight and incandescent light, at the very least.

Plus camouflage isn't very useful in the first place if you have wide-spectrum
cameras.

I don't understand what you mean about 'requiring a filter' to see something.

Sorry, I know you're trying to come up with fun ideas, but I think you're
going in the wrong direction.

~~~
mgsouth
Message could be written on a background of a slightly different frequency.
Multispectral light would't differentiate. Similar to a color-blindness test.

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contingencies
No way! I read about chaos theory butterflies. But now you're saying butterfly
wings contain _whales_? Gnarly, man.

On a more serious note, it's good to see Zhejiang University from China in
there. Their library also provides the only scanned copies online of some
important ancient Chinese historical sources. Except for the big name
unversities in China (Tsinghua, Fudan, etc.), this is a university to watch.

~~~
ximeng
Link for the scanned copies?

~~~
contingencies
[https://archive.org/stream/06061161.cn#page/n0/mode/1up](https://archive.org/stream/06061161.cn#page/n0/mode/1up)

~~~
ximeng
Thanks

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edwinjm
For a moment, I confused Weyl points with Ley lines and was shocked by
disbelief.

Ley lines:
[https://en.wikipedia.org/wiki/Ley_line](https://en.wikipedia.org/wiki/Ley_line)

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mey
I'm curious about the impact this has on lasing.

