Exactly Stable Collective Oscillations in Conformal Field Theory
  Any conformal field theory (CFT) on a sphere supports completely undamped collective oscillations. We discuss the implications of this fact for studies of thermalization using AdS/CFT. Analogous oscillations occur in Galilean CFT, and they could be observed in experiments on ultracold fermions. 
Ben Freivogel, John McGreevy and S. Josephine Suh
hep-th