Tuesday, October 05, 2010

Nobel prize for a (kind of) lattice

The Nobel Prize in physics 2010 has been awarded to Andre Geim and Konstantin Novoselov of the University of Manchester "for groundbreaking experiments regarding the two-dimensional material graphene".

Graphene is a novel form of carbon, in which the carbon atoms are bound into a hexagonal lattice covering a single flat two-dimensional layer. Graphite consists of lots of pieces of graphene jumbled together into a three-dimensional whole, so graphene is actually quite common, but Geim and Novoselov were the first to systematically isolate it and elucidate its unusual properties.

Graphene has a number of unique properties, not the least of which is that it has gapless excitations which are described by a Dirac equation -- massless electrons, so to speak. It is this particular feature of the graphene lattice which has inspired the study of graphene-like structures in higher dimensions as a means of obtaining minimally doubled fermions, i.e. lattice fermions that have the minimal number (=2) of doublers prescribed by the Nielsen-Ninomiya theorem. So even if the technological promise of graphene (described e.g. at the Nobel site) were not to be realised, it has at least given theoretical particle physicists something to think about.