Dissipative generation of NV-pair entanglement via antisymmetric optical drives

Abstract

We propose and analyze an NV-center implementation of a directed cavity-decay scheme for preparing the ground-state entanglement of two nitrogen-vacancy (NV) centers coupled to a single-mode optical cavity. By combining antisymmetric optical driving with a relative phase difference φ2−φ1=π, microwave-induced population reshuffling within a triplet subspace, and cavity-assisted dissipation, the system is driven toward a singlet-dominated steady state in the ground-state manifold. Starting from the full Lindblad master equation, we construct a reduced four-state effective description that provides a transparent picture of the dominant pumping and leakage processes responsible for the entanglement-preparation mechanism. Based on this reduced model, we obtain analytical expressions for the steady-state fidelity and the effective population-subspace dissipative gap. Within the ideal weak-driving model, the preparation fidelity is mainly limited by the cavity cooperativity C, and in the strong-microwave regime the steady-state infidelity scales as 1−F∼1/C. In contrast, the convergence speed is governed by the effective population-subspace gap, revealing the distinct physical roles of cavity-assisted pumping and microwave-induced reshuffling. Direct numerical simulations of the full Lindblad dynamics show quantitative agreement with the reduced description in the weak-driving regime. Deviations become visible at Ω/γ=0.3 and quantitatively significant by Ω/γ≃0.5, where higher-excitation corrections can no longer be neglected. Along the specific control path ΩMW=Ω/3, the full dynamics confirm a path-dependent speed–fidelity trade-off: increasing the optical drive accelerates the preparation but lowers the steady-state fidelity. Our results provide a useful route toward preparing entanglement between NV spins in hybrid quantum systems.