Can the exciton--polariton regime be defined by its quantum properties?
  Using a simple fully quantum model in an effective exciton scheme that takes into account the system--environment interaction, we study the different regimes arising in a microcavity--quantum dot system. Our numerical calculations of the emission linewidth, emission energy, integrated intensity and second- and third-order correlation functions are in good qualitative agreement with reported experimental results. We show that the transition from the polariton-laser to the photon-laser regime can be defined through the critical points of both the negativity and the linear entropy of the steady state. 
D. G. Su\'arez-Forero, G. Cipagauta, H. Vinck-Posada, K. M.   Fonseca-Romero, B. A. Rodr\'iguez
cond-mat.mes-hall