Preparation of a steady entangled state of two nitrogen-vacancy centers by simultaneously utilizing two dissipative factors

Abstract

A dissipation-based scheme is proposed to prepare the steady entangled state of two spatially separated nitrogen-vacancy (NV) centers fixed on the exterior surface of two microtoroidal resonators coupled by a whispering-gallery-mode (WGM) field. The effective operator method is used to get an effective master equation which simplifies the systematic dynamics into ground-state subspace. Based on the effective dynamics, the parameter condition to use the NV center's spontaneous emission and that to use the resonator's photon loss as resources to prepare entanglement are achieved. Interestingly, we find that these two conditions are almost the same. To some extent, these two dissipative factors are no longer detrimental, but can be used simultaneously as powerful resources to prepare the steady entangled state, which forms a sharp contrast with most of the currently schemes utilizing one dissipative factor. On the other hand, the different forms of the steady entangled state are achievable via modulating systematic parameters. The scheme is independent of initial states and does not require precise time control. Numerical results show that high fidelity and purity can be obtained and the scheme is robust against small parameter deviations.