Effects of strong correlations for 2D Bose-Einstein condensed dipolar   excitons
  By doing quantum Monte Carlo ab initio simulations we show that dipolar excitons, which are now under experimental study, actually are strongly correlated systems. Strong correlations manifest in significant deviations of excitation spectra from the Bogoliubov one, large Bose condensate depletion, short-range order in the pair correlation function, and peak(s) in the structure factor. 
Yu. E. Lozovik, I. L. Kurbakov, G. E. Astrakharchik, J. Boronat, M.   Willander