Effective scheme for preparation of a spin-qubit Greenberger-Horne-Zeilinger state and W state in a quantum-dot-microcavity system

We propose a scheme for the preparation of a spin-qubit Greenberger-Horne-Zeilinger (GHZ) state and W state by using quantum dots (QDs) in double-sided optical microcavities with the help of polarized photons. The spin-selective photon reflection from the cavity provides us a perfect way to achieve the scheme by adding some simple linear optical elements and conventional photon detectors. A numerical simulation demonstrates that a perfect scheme of the GHZ state and W state generation can be achieved in one step, and high fidelities can be realized when the side leakage and cavity loss are low, which is feasible in the weak coupling regime. Therefore, our scheme might contribute to quantum communication, quantum teleportation, and some other fields in quantum information processing. (C) 2015 Optical Society of America