
100-year-old physics problem has been solved - c517402
https://m.phys.org/news/2017-06-year-old-physics-problem.html
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daveguy
Apparently the same scientist published the description of these materials 10
years ago in Nature:

[https://www.researchgate.net/profile/Kosmas_Tsakmakidis2/pub...](https://www.researchgate.net/profile/Kosmas_Tsakmakidis2/publication/5843358_Nature_Trapped_Rainbow_Storage_of_Light_in_Metamaterials/links/541054f70cf2df04e75d2438/Nature-
Trapped-Rainbow-Storage-of-Light-in-Metamaterials.pdf)

~~~
jpmattia
I haven't studied both the original link and your link in detail, but at a
quick look: They are different things.

Metamaterials usually are periodic combinations that exhibit interesting
properties. So-called "photonic bandgap materials" are an example. The paper
you linked shows that strange things can happen to the group velocities in
these types of materials.

The phys.org link (based on a Science paper [1]) is about a cavity utilizing
non-reciprocal materials. Normally systems involving Maxwell's equations are
reciprocal; you can switch the input and output and expect the same behavior.
For a basic example, if you look through a tube and see me at the other end,
then I will be able to see you as well.

In a non-reciprocal system, this property breaks down. Microwave circulators
are a good example: A device with three ports A, B, and C can have

energy coming from A going to B,

energy coming from B going to C,

energy coming from C going to A.

This device is handy if you don't want reflected E&M power from your antenna
coming back into your generating circuit. It was well known to guys working on
radar, for example.

The real miracle in this paper is that no one put it together sooner: Non-
reciprocal devices have been around forever, and resonators more so, but that
the combination might be useful has not occurred to anyone? Quite amazing.
They probably blew all kinds of time researching through old literature to
make sure this hasn't already been mentioned by the radar guys in the 40s.

[1]
[http://science.sciencemag.org/content/356/6344/1260](http://science.sciencemag.org/content/356/6344/1260)

~~~
ttctciyf
> That was the very centre of his genius - he invented things that anyone
> could have thought of, and men who can invent things that anyone could have
> thought of are very rare men.

\- Terry Pratchett[1]

1: [https://libquotes.com/terry-
pratchett/quote/lbd3a3k](https://libquotes.com/terry-pratchett/quote/lbd3a3k)

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bmcooley
Ho. Lee. Shit. I'm in the satellite telecoms domain - this is incredible and
will have far reaching consequences after a decade. Unfortunate that R&D and
hardware lead times are so long in this industry.

~~~
kilroy123
Could you explain it like I'm 5? How will this have huge far reaching
consequences?

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pmoriarty
_" For more than 100 hundred years, these systems were held back by a
limitation that was considered to be fundamental ... But that limitation is
now a thing of the past."_

We should bear breakthroughs like this in mind every time someone appeals to
fundamental limitations of physics (or any other field).

So many times I hear people object that something can't be done because of
some fundamental limit. But research like this proves that limits that are
considered fundamental sometimes aren't, and we can't know ahead of time which
of these limits really are fundamental and which only appear so.

~~~
heimdall
> these systems were held back by a limitation that was considered to be
> fundamental

This is the key distinction: -proven- fundamental is very different from
-considered- fundamental.

Overturning Heisenberg's Uncertainty Principle would shatter physics as we
know it.

Overturning a misconception is far more mundane.

~~~
marcosdumay
How do you ever prove something in an empirical science?

~~~
vanderZwan
There are various levels of how rigorous evidence is. Apparently, the law in
question was made based on assumptions about the materials involved, and as
someone else pointed out there was a ten year gap between the mathematical
explanation and actual implementation, so I guess these materials are quite
complex.

Also, this does not invalidate the previous law necessarily; we still use
Newton's laws because its assumptions hold under most circumstances.

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jpfed
Doesn't the time-bandwidth reciprocity fall out of the same math as the
Heisenberg Uncertainty Principle? Does this work have implications for HUP
"workarounds"?

~~~
noobermin
If you read the paper, the answer is yes, but you can work around it by
basically breaking the symmetry between the "output" of a system and the
"input"[0]. For the output and input, they will satisfy basic fourier
uncertainty relations, but independently of each other.

[0] I've scanned the paper a couple of times and it's still a little murky for
me. I have other things to do, unfortunately. For a clue, see figure 2.

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shepardrtc
> "Other potential applications include ... broadband light harvesting and
> energy storage, and broadband optical camouflaging ("invisibility
> cloaking")."

Obviously these sorts of announcements often have hype in them - and that's
fine - but could someone really invent a cloaking device with this
advancement?

~~~
SamUK96
Don't worry, it's a click-bait term for being invisible to low-frequency
wavelengths, so not visible light.

The US military has been working on _microwave_ -invisible materials for a
while and they've gotten very close. But microwaves have wavelengths on the
order of a few cm (10^-2), meanwhile visible light is on ther order of 100's
on nm (10^-7).

As the wavelength gets shorter it gets much harder to make "negative-
refractive-index" materials - the material that enables to bend light around
an object.

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Tossrock
Very interesting - reminds me of superconductors. Some quantity which normally
cannot be escaped (ie, everything has some amount of resistance, or the Q
factor is a finite number) that under certain special conditions can actually
hit its singularity. Special conditions which necessitate exotic new theory.

Also, call me cynical but it seems like the natural application is pulsed
laser weapons. Now instead of spending infinity dollars on a portable megawatt
laser that can gimbal to attack a target, you have a kilowatt laser that
charges a waveguide until it has equivalent energy to the megawatt laser and
then discharges it as necessary.

~~~
irq
This type of laser already exists, they're called solid state lasers. [1].

(Note that these lasers are distinct from semiconductor lasers, which are more
colloquially called "diode lasers".)

EDIT: Q-switched laser may be closer to this. [2]

1: [https://en.wikipedia.org/wiki/Solid-
state_laser](https://en.wikipedia.org/wiki/Solid-state_laser)

2:
[https://en.wikipedia.org/wiki/Q-switching](https://en.wikipedia.org/wiki/Q-switching)

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woliveirajr
> "The reported breakthrough is completely fundamental —we're giving
> researchers a new tool. And the number of applications is limited only by
> one's imagination," sums up Tsakmakidis.

I like the idea of having a new tool available, but don't know why everything
has to be sooo revolutionary and unlimited.

~~~
PhasmaFelis
Yeah. You can tell the article writer isn't a scientist when they say "the
number of potential applications is close to infinite".

~~~
vanderZwan
> And the number of applications is limited only by one's imagination," sums
> up Tsakmakidis.

That's the scientist behind the publication

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Rainymood
non-mobile link: [https://phys.org/news/2017-06-year-old-physics-
problem.html](https://phys.org/news/2017-06-year-old-physics-problem.html)

