Microscopic Theory of Scattering of Weak Electromagnetic Radiation by a   Dense Ensemble of Ultracold Atoms
  Based on the developed quantum microscopic theory, the interaction of weak electromagnetic radiation with dense ultracold atomic clouds is described in detail. The differential and total cooperative scattering cross sections are calculated for monochromatic radiation as particular examples of application of the general theory. The angular, spectral, and polarization properties of scattered light are determined. The dependence of these quantities on the sample size and concentration of atoms is studied and the influence of collective effects is analyzed. 
I.M. Sokolov, D.V. Kupriyanov, and M.D. Havey
quant-ph physics.atom-ph