The multiphoton states generated by high-gain spontaneous parametric down-conversion (SPDC) in presence of large losses are investigated theoretically and experimentally. The explicit form for the two-photon output state has been found to exhibit a Werner structure very resilient to losses for any value of the gain parameter, g. The theoretical results are found in agreement with the experimental data. The last ones are obtained by quantum tomography of the state generated by a high-gain SPDC.
@article{arxiv.quant-ph/0510153,
title = {Non separable Werner states in spontaneous parametric down-conversion},
author = {Marco Caminati and Francesco De Martini and Riccardo Perris and Fabio Sciarrino and Veronica Secondi},
journal= {arXiv preprint arXiv:quant-ph/0510153},
year = {2009}
}