Eliminating Next-Nearest-Neighbor Interactions in the Preparation of Cluster State

By analyzing recent schemes for preparing the chain cluster state,we find that the existence of long-range couplings between qubits will induce a quick decay of the fidelity of the cluster state.We propose some schemes for eliminating the effect of the next-nearest-neighbor interactions in the XY and Ising models by dynamical decoupling method.In our approach,the undesired next-nearest-neighbor interactions are effectively suppressed and the fidelity of the generated cluster state is greatly improved by the pulse operations.