The nuclear spin in the vicinity of a nitrogen-vacancy (NV) center possesses long coherence time and convenient manipulation assisted by the strong hyperfine interaction with the NV center. It is suggested for the subsequent quantum information storage and processing after appropriate initialization. However, current experimental schemes are either sensitive to the inclination and magnitude of the magnetic field or require thousands of repetitions to achieve successful realization. Here, we propose a method to polarize a 13C nuclear spin in the vicinity of an NV center via a dark state. We demonstrate theoretically and numerically that it is robust to polarize various nuclear spins with different hyperfine couplings and noise strengths.

Reference: Yang-Yang Wang, Jing Qiu, Ying-Qi Chu, Mei Zhang, Jianming Cai, Qing Ai, Fu-Guo Deng, Dark state polarizing a nuclear spin in the vicinity of a nitrogen-vacancy center, Phys. Rev. A 97, 042313 (2018).

Link: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.97.042313