Generation of distributed steady entangled state between two solid-state spins

Abstract

The generation of distributed entangled states among solid-state spins is key to the development of large-scale quantum networks and quantum computation. We propose a dissipative scheme for generating stable entanglement between the electron-spin states of two separated nitrogen-vacancy centers, each coupled to a microtoroidal resonator and separated in space. An optical fiber-taper waveguide links the two microtoroidal resonators. Numerical simulations show that spontaneous emission from the NV centers and the collective decay of delocalized field modes can act as effective resources to generate stationary singlet-like states without the need for initialization and precise control of the evolution of the system over time. Results indicate that the proposed scheme can reach high-fidelity and purity of states, and is resilient against small parameter fluctuations. We also discuss how the pure spin dephasing that arises from longitudinal magnetic-near-field noise affects the fidelity of the target state.