Generation of four-photon polarization entangled state based on Einstein-Podolsky-Rosen entanglers

摘要

We show how to prepare four-photon polarization entangled states based on some Einstein- Podolsky-Rosen (EPR) entanglers. An EPR entangler consists of two single photons, linear optics elements, quantum non-demolition measurement using a weak cross-Kerr nonlinearity, and classical feed forward. This entangler which acts as the most primary part in the construction of our scheme allows us to make two separable polarization qubits entangled near deterministically. Therefore, the efficiency of the present device completely depends on that of EPR entanglers, and the preparation scheme is feasible in the current experimental technology.