In this paper we describe and thoroughly discuss three reported experiments in quantum optics (QO) involving interferometers and non-linear crystals. We show that by using a graphical method and an over-simplified model of the parametric down-conversion process, we arrive to explain all the important results reported in the respective papers. Indistinguishability is discussed in the case of separable/non-separable (i.e. entangled) quantum systems and our interpretation is sometimes at variance with the one given by the authors reporting the experiments.
@article{arxiv.1410.6649,
title = {The quantum optical description of three experiments involving non-linear optics using a graphical method},
author = {Stefan Ataman},
journal= {arXiv preprint arXiv:1410.6649},
year = {2015}
}