We propose a protocol for the controlled generation of four-photon polarization-entangled decoherence-free states with a certain success probability. The proposed setup involves simple linear optical elements, two single-photon polarzaition entangled states, a pair of two-photon polarization entangled states, and conventional photon detectors that only distinguish the vacuum and nonvacuum Fock number states. This makes the protocol more realizable in experiments.
© 2008 Optical Society of America
Original Manuscript: May 30, 2008
Revised Manuscript: September 7, 2008
Manuscript Accepted: October 27, 2008
Published: December 19, 2008
Yan Xia, Jie Song, He-Shan Song, and Shou Zhang, "Controlled generation of four-photon polarization-entangled decoherence-free states with conventional photon detectors," J. Opt. Soc. Am. B 26, 129-132 (2009)