Highly nonlocal optical nonlinearities in atoms trapped near a waveguide
  Nonlinear optical phenomena are typically local. Here we predict the possibility of highly nonlocal optical nonlinearities for light propagating in atomic media trapped near a nano-waveguide, where long-range interactions between the atoms can be tailored. When the atoms are in an electromagnetically-induced transparency configuration, the atomic interactions are translated to long-range interactions between photons and thus to highly nonlocal optical nonlinearities. We derive and analyze the governing nonlinear propagation equation, finding a roton-like excitation spectrum for light and the emergence of order in its output intensity. These predictions open the door to studies of unexplored wave dynamics and many-body physics with highly-nonlocal interactions of optical fields in one dimension. 
Ephraim Shahmoon, Pjotrs Grisins, Hans Peter Stimming, Igor Mazets and   Gershon Kurizki
quant-ph physics.atom-ph physics.optics