Chinese Physics B
Enhanced measurement precision with continuous interrogation during dynamical decoupling
Jun 军 Zhang 张, Peng 鹏 Du 杜, Lei 雷 Jing 敬, Peng 鹏 Xu 徐, Li 力 You 尤, Wenxian 文献 Zhang 张
Abstract
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 that is capable of continuously interrogating the DC signal over many DD cycles. We illustrate its efficacy when applied to the measurement of a weak DC magnetic field with an atomic spinor Bose–Einstein condensate. Sensitivities approaching standard quantum limit or Heisenberg limit are potentially realizable for a coherent spin state or a squeezed spin state of 10000 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 would find other applications for resorting coherence in quantum sensing and quantum information processing research.