Revealing the topology of quasicrystals with a diffraction experiment
  Topological properties of crystals and quasicrystals is a subject of recent and growing interest. This Letter reports an experiment where, for certain quasicrystals, these properties can be directly retrieved from diffraction. We directly observe, using an interferometric approach, all the topological invariants of finite-length Fibonacci chains in their diffraction pattern. We also demonstrate quantitatively the stability of these topological invariants with respect to structural disorder. 
A. Dareau, E. Levy, M. Bosch Aguilera, R. Bouganne, E. Akkermans, F.   Gerbier, J. Beugnon
cond-mat.mes-hall cond-mat.mtrl-sci physics.optics quant-ph