We show that the combined effect of photon emission and Coulomb interactions may drive an exciton-polariton system towards a dynamical coherent state, even without phonon thermalization or any other relaxation mechanism. Exact diagonalization results for a finite system (a multilevel quantum dot interacting with the lowest energy photon mode of a microcavity) are presented in support to this statement.
@article{arxiv.cond-mat/0610795,
title = {Photon emission as a source of coherent behaviour of polaritons},
author = {Herbert Vinck-Posada and Boris A. Rodriguez and P. S. S. Guimaraes and Alejandro Cabo and Augusto Gonzalez},
journal= {arXiv preprint arXiv:cond-mat/0610795},
year = {2013}
}