We present a N-particle Greenberger–Horne–Zeilinger (GHZ) analyzer in the context of cavity QED. All of the N-particle GHZ states can be discriminated with probability 1 in one step. We also present an application of our scheme in multiparticle entanglement swapping.
Using just polarizing beam splitters and half-wave plates, we present a practical experimental scheme, by which one can conveniently identify two of the three-particle Greenberger-Horne-Zeilinger (GHZ) states. The scheme can easily be generalized to the N-particle case. The GHZ-state analyzer is essential for multiparticle generalizations of quantum dense coding, quantum teleportation, and entanglement swapping.
We introduce a class of multi-particle Greenberger-Horne-Zeilinger (GHZ) states, and study entanglement swapping between two qubit systems for Bell states and for the class of GHZ states, respectively. We generalize the bi-system entanglement swapping of Bell states and multi-particle GHZ states to any number of qubit systems. We further study the entanglement swapping schemes between any number of Bell states and between any number of the introduced GHZ states in a detailed way, and propose the schemes that can generate two identical GHZ states. We illustrate the applications of such schemes in quantum information processing by proposing quantum protocols for quantum key distribution, quantum secret sharing and quantum private comparison.
We propose a deterministic scheme to realize N-atom Greenberger–Horne–Zeilinger (GHZ) state analyzer based on the cavity input–output process. In the scheme, we construct a two-qubit parity analyzer and a GHZ-state phase analyzer and show that all the N-atom GHZ states can be completely identified in a nondestructive way by combining these two kinds of analyzers. The fidelities of our analyzers are also calculated, which show that our scheme has a high performance in theory. The scheme opens promising perspectives for achieving efficient large-scale quantum communication and quantum information processing networks.
We present an efficient scheme for the complete analysis of hyperentangled Greenberger–Horne–Zeilinger (GHZ) state in polarization and time-bin degrees of freedom with two steps. Firstly, the polarization GHZ state is distinguished completely and nondestructively, resorting to the controlled phase flip (CPF) gate constructed by the cavity-assisted interaction. Subsequently, the time-bin GHZ state is analyzed by using the preserved polarization entanglement. With the help of CPF gate and self-assisted mechanism, our scheme can be directly generalized to the complete N-photon hyperentangled GHZ state analysis, and it may have potential applications in the hyperentanglement-based quantum communication.