Polarization-entangledWstate using parametric down-conversion
Takashi Yamamoto, Kiyoshi Tamaki, Masato Koashi, Nobuyuki Imoto · Physical Review A · 2002
An experimental scheme for preparing a polarization entangled W states from four photons emitted by parametric down-conversion is proposed. We consider two different configurations and a method of improving the yield by using single-photon sources. In the proposed scheme, one uses only linear optical elements and photon detectors, so that this scheme is feasible by current technologies.