Slashdot Mirror
A Quasi-Quasicrystal
An anonymous reader sends along a link to a mindbending article in Science News on quasicrystals — odd materials with a structure partway between order and disorder. Now researchers have found something even odder: a material that's partway between a quasicrystal and a regular crystal. The order in the new structure is provided by the Fibonacci sequence. It was constructed with plastic beads and laser beams, so no new materials science inventions are on the horizon. "'We are absolutely sure that this structure should have properties that are not usual,' Mikhael says, because materials with odd structures almost always do. Now they just have to figure out what those properties are."
"'We are absolutely sure that this structure should have properties that are not usual,' Mikhael says, because materials with odd structures almost always do."
Sounds like something out of a Monty Python sketch.
Seriously, though, I'd rather hear about what interesting/new discoveries come out of this strange material than just hear about the possibility of its existence.
Catch telemarketers
Hey, it has worked before...
Remember the comic from XKCD about the spork cross breeds? This could apply to Quasy-Quasycrystals too. They could breed hybrids in proportions corresponding to every binary fraction in the whole spectrum between Crystal and Quasy-Crystal. Fear the powerful forces!
we used to just split hairs.
Now we split crystals. And get quasicrystals. Which were supposed to be unusual.
And now we have quasi-quasicrystals. And then they're "not usual."
And next we can get something somewhere between a quasicrystal and a quasiquasicrystal.
I'd rather hear about what interesting/new discoveries come out of this strange material than just hear about the possibility of its existence.
In 10 years' time you'll be hearing about the quasiquasiquasiquasiquasiquasiquasiquasiquasicrystal, but we still won't know what the heck to do with them.
"We are absolutely sure that this structure should have properties that are not usual," Mikhael says, because materials with odd structures almost always do. Now they just have to figure out what those properties are.
Property #1: the ability to endow a grad student with his PhD and a sizable chunk of grant money.
I could be a random resistance element that could be used as a random number seed. Or it could be the mythical room temperature non-conductor.
Now they just have to figure out what those properties are.
1) Does it taste like chicken?
150 Opening BINARY mode data connection for slashdot.sig (129323052 bytes).
Which one is it? The summary needs to make up its mind. Either it is something that occurs naturally (and TFA seems to suggest otherwise) in which case it would be "found" or it is something cooked up in a lab which would make it "constructed".
I have isolated a compound in my lab. I call it the Politiquasicrystal. I have determined that it can bend the truth with no expenditure of energy.
Why is there no mention of Penrose tiling in TFA?
Set your phasers on "funky"!
Much like LSD, it was found while trying to cook up something else in a lab. Who knows, someday we might identify naturally-occuring examples of this quasi-quasi crystalline structure... for now it's just a lab phenomenon.
Zlorfik!
Almost but not entirely unlike crystal?
Well, for those that didn't RTFA, I did for
you... and no... they didn't go to a piece
goods shop and buy a sack of necklace beads.
FTA:
To simplify matters, the team set out to create a quasicrystal from micron-sized plastic beads called colloidal particles.
For those unfamiliar with colloidals, it is
from the Greek work kolla, meaning glue as the
first colloids were just that. Particulate size
is such that surface area is greater than volume
thus the particulates tend not to settle from
gravity.
They're pretty useful in everyday life. Some
common items would be some aerosol sprays,
shotcrete for your pool out back and the yummy
emulsion, mayonnaise!
These in TFA however are just micron sized beads
of plastic.
-AI
For me, it is far better to grasp the Universe as it really is than to persist in delusion
We'd like to study these crystals, but we require more vespene gas!
Quasiquasicrystal doesn't roll of the tongue...
Quasi is roughly the same as almost, right?
What is the latin equivalent of "Barely"?
Diamonds are the hardest material known the man!
What the hell? What's next, psychedelic furs? Why not resurrect Marley, Hendrix, and Morrison and some Woodstockes and give them algea and foil and an audience in Stonehenge? Wait Wait, Don't tell me. the whirled will come stoned and UNhinged and unable to compute the motions to drink an conjugate swerves...
Previously: "Linux... Toward the Sunrise..." Now: "Linux... Toward the-- No, now, part of Every Sunrise"
In the 90s, I was a PhD student in theorethical physics. One of the paper I read showed a crystal with a structure based on the fibonacci sequence. Such structures were also realised in superlattices at LinkÃping University, Sweden, in a cooperation between the theoretical physics group and the thin film group. You could contact Dr. Rolf Riklund for the details, his PhD student did the study.
They had this ages ago, Kryptonite.
I realize someone is going to mod me flamebait or troll, but I just wanted to say the images remind me of the cellular automata simulations from Wolfram's "A New Kind of Science" in that they are semi-ordered but non-predictable. Neat stuff regardless.
Tic-Tac-Toe, Global Thermonuclear War, and relationships all have the same winning move.
Perfection is always just out of reach.
Stuff that matters, to people who don't think.
PhysOrg and Science Daily will fill your need for hard news. :)
"The fight for freedom has only just begun." - Geert Wilders
Hard news? As opposed to this soft news? Or as we call it in the trade B--lsh-t.
So I should just come to slashdot for rumours and gossip? What is this, a knitting circle of nerds?
"That was non- non-non non-heinous!"
Shouldn't this be from the fractal-quasiness dept instead of fractional-quasiness? :-)
Thats almost but not entirely unlike a meme.
What is this, a knitting circle of nerds?
No, that's what you end up with when someone confuses Perl and purl.
This comment is for entertainment purposes only. Any similarity to real insight or information is purely coincidental.
A quasi-quasicrystal, also known as "crystal"...
now is this an evil... quasi-quasi crystal?
http://forums.xkcd.com/viewtopic.php?f=7&t=22012
Quasiness is quantized, and two quasicrystals must differ in some parameter by n times a constant.
Quasi-mechanics.
Hasan
The researchers specifically said that they were expecting properties that were not usual.
Ahh - My eye!
The doctor said I'm not supposed to get Slashdot in it!
As mentioned in the article, a quasicrystalline arrangement basically contains symmetry elements which cannot fill space ('non-crystallographic'). In fact the only rotational symmetries that can fill space are 2-, 3-, 4- and 6-fold rotations. Again, to use the article's example, you can't tile a wall with pentagons-- the simplest shape with fivefold rotational symmetry.
...,exp((2*pi*i*4)/5)).
The idea of a "quasi-quasi-crystal" which approximates the forbidden symmetries of a quasicrystal quite well (e.g. almost-perfect-but-not-actual fivefold rotational symmetry) while filling space has been around for a while in the solid state chem/physics fields, and have been mathematically described since at least the 1950s (prolly earlier?). In fact there are intermetallic phases that form both quasicrystalline approximants and actual quasicrystals. So far the only quasicrystalline phase to be solved has icosahedral symmetry. It is beyond the scope of this post to discuss this further, but a google scholar (or scifinder, for thos that have it!) should turn up a lot of information.
Interestingly enough, forbidden symmetries in 2 or 3 dimensions can actually be crystallographic in some higher dimensional geometry; quasicrystals and their approximants can be described as projections from some space (usually 6- or 8-D real number space) to 3 dimensions.
To extend the article's tiling example, you can in fact tile a 2d surface with pentagons-- provided that the surface is wrapped around a 3d sphere! This is the dodecahedron, a platonic solid. The same concept applies to more dimensions; for example, you can fill space with 3d tetrahedra in 4 dimensions-- this is termed the 600-cell, a 4d platonic solid.
Without going into too much detail, a common projection involves the golden ratio "tau" (or "phi", depending on whether you're a crystallographer or a mathematician), while approximants involve numbers in the Fibonnacci sequence. The limit of the quotient of successive Fibonacci numbers is in fact the golden ratio tau=(1+sqrt(5))/2=1.618... Using tau as a parameter in the projection gives the quasicrystal, while using ratios of higher pairs of consecutive Fibonacci numbers gives larger/more complex approximants. (pithy search term: "cut-and-project quasicrystal")
Just for fun, you can make a 2d quasicrystal that looks pretty similar to the article's pictures by taking the dot product of all 5-dimensional vectors with integral components (e.g. (1 0 -2 0 7) etc.) with the vector containing the fifth roots of unity (0, exp((2*pi*i*1)/5),
IMHO the experiment to 'figure out the properties of quasicrystals' seems kinda BS because those properties arise from quantum/electronic interactions between atoms, not from interactions between particles and some completely external system. But this is pure speculation on my part. And the results are pretty fucking sweet. Especially considered that that they are actual images, not some mathematical construction.
In conclusion, this post could have been a book. GS, scifinder, wikipedia, your local math library have a wealth of info about this topic.
I am quite disappointed here, that nobody seems to know about the connection between "Quasicrystals", Chemistry and Mathematics. The posted article though is one of the worse I ever read about the topic. Most of the research was done in the 90s and they always tried to sell this mostly very theoretical research as "developing new materials with new properties", hence the "teflon-like behavior" mentioned in the article, but AFAIK nothing really "cool" for the everyday user was developed so far. But none the less a still very interesting field of research all hold together by the Fibonacci sequence resp. the Golden Ratio. ... but looks like those pages never changed since 1995.
There used to be some nice introductions into quasicrystals in the net
http://www.lassp.cornell.edu/lifshitz/quasicrystals.html
PS: the growths rate of rabbids follows the fibonacci sequence
1 1 2 3 5 8 13 21