Dynamical decoupling (DD) is normally ineffective when applied to DC measurement. In its straightforward implementation, DD nulls out DC signal as well while suppressing noise. This work proposes a phase relay method (PRM) that is capable of continuously interrogating the DC signal over many DD cycles. We illustrate its efficacy when applied to measurement of a weak DC magnetic field with an atomic spinor Bose-Einstein condensate. Sensitivities approaching standard quantum limit (SQL) or Heisenberg limit (HL) are potentially realizable for a coherent spin state (CSS) or a squeezed spin state (SSS) of 10,000 atoms respectively, while ambient laboratory level noise is suppressed by DD. Our work offers a practical approach to mitigate the limitations of DD to DC measurement and will like find other applications for resorting coherence in quantum sensing and quantum information processing research.
@article{arxiv.2212.04829,
title = {Enhanced measurement precision with continuous interrogation during dynamical decoupling},
author = {Jun Zhang and Peng Du and Lei Jing and Peng Xu and Li You and Wenxian Zhang},
journal= {arXiv preprint arXiv:2212.04829},
year = {2023}
}