The sensitivity of a practical quantum magnetometer is challenged by both inhomogeneous coupling between sensors and environment and errors in quantum control. Based on the physical criteria of modern quantum sensing, we present a robust and effective composite-pulse for high fidelity operation against inhomogeneous broadening of sensor and control errors via optimized modulation of control field. Such a technique is verified on nitrogen-vacancy (NV) center in diamond to keep almost perfect operation up to a detuning as larger as 110%. The sensitivity of the magnetometer with NV center ensemble is experimentally improved by a factor of 4, comparing to dynamical decoupling with normal rectangular pulse. Our work marks an important step towards high trustworthy ultra-sensitive quantum sensing with imperfect quantum control in realistic systems. The used principle however, is universal and not restricted to NV center ensemble magnetometer.
@article{arxiv.1811.00191,
title = {Room-temperature Composite-pulses for Robust Diamond Magnetometry},
author = {Jing-Yan Xu and Yang Dong and Shao-Chun Zhang and Yu Zheng and Xiang-Dong Chen and Wei Zhu and Guan-Zhong Wang and Guang-Can Guo and Fang-Wen Sun},
journal= {arXiv preprint arXiv:1811.00191},
year = {2018}
}