Preparation of N-Qubit GHZ State with a Hybrid Quantum System Based on Nitrogen-Vacancy Centers

We propose a novel scheme for generating N-qubit GHZ entangled state with a hybrid quantum system, which consists of N nitrogen-vacancy centers, N transmission line resonators, a current-biased Josephson junction superconducting qubit, and three kinds of interaction Hamiltonians. The proposal requires no adjustment of the qubit level spacings during the entire operation. Moreover, it is shown that the operation time is independent of the number of qubits. The present proposal is quite useful, and is a promising step to realize the large-sized quantum networks for quantum information processing and quantum computation.