Dipolar Bose-Einstein condensate of Stationary-Light Dark-state   Polaritons
  We put forward and discuss in detail a scheme to achieve Bose-Einstein condensation of stationary-light dark-state polaritons with dipolar interaction. To this end we have introduced a diamond-like coupling scheme in a vapor of Rydberg atoms under the frozen gas approximation. To determine the system's dynamics we employ normal modes and identify the dark-state polariton corresponding to one of the modes. We show that in contrast to atomic dipolar ultra-cold vapors dark-state polariton Bose-Einstein condensates proposed here can be stable for a negative dipolar interaction constant. 
Frank E. Zimmer, Gor Nikoghosyan and Martin B. Plenio
quant-ph cond-mat.quant-gas