writes with word that Dan Shechtman
of Israel's Technion has won the Nobel prize in chemistry
for his discovery of quasicrystals
, and provides a short description of why quasicrystals are exciting:
"Quasicrystals fill space completely, but do not repeat, even though they show self-similar patterns, the way pi has order, but doesn't repeat. That is, they tessellate in an ordered way, but do not have repeating cells. In art, Girih tiles showed the essential property of being able to cover an infinite space, without repeating. In mathematics, Hao Wang came up with a set of tiles that any Turing Machine could be represented by, and conjectured that they would eventually always repeat. He turned out to be wrong, and over the next decades, tiles that did not repeat, but showed order, were discovered, most famously, though not first, by Penrose. Physically, when x-rays diffract, that is are scattered, from a crystal, they form a discrete lattice. Quasicrystals also have an ordered diffraction pattern, and it tiles the way ordered non-repeating tiles do. Quasicrystal patterns were known before Shechtman labelled them. So why care? Because crystals have only certain symmetries, and that determines their physical properties. Quasicrystals can have different symmetries, and do not bind regularly, and so different physical properties – which means new kinds of materials. Some examples: highly ductile steel, and, in something that is a bit of a by-word among people who study them, cooking utensils."