We present a method of generation of the Greenberger-Horne-Zeilinger state
involving type II and type I parametric downconversion, and triggering
photodetectors. The state generated by the proposed experimental set-up can be
reconstructed through multi-mode quantum homodyne tomography. The feasibility
of the measurement is studied on the basis of Monte-Carlo simulations.Comment: Paper submitted to the proceedings of the III Adriatico Research
Conference on Quantum Interferometry, ICTP, March 1-5,1999. 5 pages, 3 eps
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