Bourennane, Mohamed; Eibl, Manfred; Gaertner, Sascha; Kiesel, Nikolai; Kurtsiefer, Christian; Żukowski, Marek; Weinfurter, Harald Multiphoton entanglement and interferometry. (English) Zbl 1020.81003 Fortschr. Phys. 51, No. 4-5, 273-279 (2003). Summary: Multiphoton entanglement is the basis of many quantum communication schemes, quantum cryptographic protocols, and fundamental tests of quantum theory. Spontaneous parametric down-conversion is the most effective source for polarization entangled photon pairs. Here we show, that a class of entangled 4-photon states can be directly created by parametric down-conversion. These states exhibit perfect quantum correlations and a high robustness of entanglement against photon loss. Therefore these states are well suited for new types of quantum communication. Cited in 1 Document MSC: 81P68 Quantum computation 81V80 Quantum optics 81-05 Experimental work for problems pertaining to quantum theory 94A05 Communication theory 94A60 Cryptography Keywords:quantum communication; quantum cryptographic protocols; parametric down-conversion; polarization entangled photon pairs PDFBibTeX XMLCite \textit{M. Bourennane} et al., Fortschr. Phys. 51, No. 4--5, 273--279 (2003; Zbl 1020.81003) Full Text: DOI arXiv