Entanglement dynamics for three nitrogen-vacancy centers coupled to a whispering-gallery-mode microcavity.

The solid-state qubits based on diamond nitrogen-vacancy centers (NVC) are promising for future quantum information processing. We investigate the dynamics of entanglement among three NVCs coupled to a microtoroidal cavity supporting two counter-propagating whispering-gallery-modes (WGMs) in the presence of Rayleigh scattering. Our results indicate that the maximal entanglement among all the NVCs could be achieved through adjusting several key parameters, such as the scattering-induced coupling between the WGMs, the distance between the NVCs, and the NVC-WGM coupling strengths, as well as the frequency detuning between the NVC and cavity. We show that entanglement of the NVCs displays a series of damped oscillations under various experimental situations, which reflects the intricate interplay and competition between the Rayleigh scattering and the NVC-WGM coupling. The quantum dynamics of the system is obtained via solutions to the corresponding microscopic master equation, which agrees well with the numerical simulation results using the phenomenological master equation. The feasibility of our proposal is supported by the application of currently available experimental techniques.