Polariton entanglement in the self-stimulated regime

We investigate the influence of environmental noise on polariton entangled pairs in the self-stimulated regime. By adopting a recent separability criterion, we show that self-stimulation may suppress the detrimental influence of noise on entanglement, but once effective, a noise-equipped classical model of parametric emission provides the same results of quantum theory with respect to the separability criterion. More generally we show that, in the macroscopic limit, it is not possible to observe violations of local realism with measurements of finite order n-particle correlations only. These results provide a prototypical case of the emergence of macroscopic local realism in the presence of strong entanglement even in the absence of decoherence.