More on``Atomic motions in the crystalline Al$_{50}$Cu$_{35}$Ni$_{15}$   alloy''
  We refute recent claims that ultrafast atomic jumps as observed in quasicrystals (QC) could be called phasons in many crystalline alloys by pointing out that there is a genuine conceptual difference between the hopping dynamics in an imperfect crystal containing a substantial number of vacancies, and the hopping dynamics due to phason motion in QC. 
Gerrit Coddens (Laboratoire des Solides Irradies)