A Four-Photon Entangled State for Linear Optical Quantum Information Processing

摘要

We propose a simple experimental scheme for preparing a four-photon polarization entangled state which plays important roles for quantum information processing. By using the four-photon entangled state, we also present a scheme of a controlled-NOT gate through teleportation, in which both path and polarization freedoms of photons are utilized. These schemes are constructed with four photons from parametric down-conversion, linear optical devices, and conventional photon detectors, all of which are available in current technology.