论文标题
Ancilla辅助频率估计与Greenberger-Horne-Zeilinger状态相协变量的噪声
Ancilla-assisted frequency estimation under phase covariant noises with Greenberger-Horne-Zeilinger states
论文作者
论文摘要
已经证明，在频率估计中，在存在不相关的马尔可夫人dephasing的情况下，使用Greenberger-Horne-Zhilinger状态可实现的最佳灵敏度与频率估计中不相关的探针相同[S. F. Huelga等人，物理学。莱特牧师。 79，3865（1997）]。在这里，我们通过检查通过使用Ancilla辅助策略来实现的最佳频率灵敏度来扩展此问题，该策略最近提出了用于鲁棒的相位估计。我们介绍了在马尔可夫协变相噪声的情况下，列出了由量子渔民信息界的最终频率敏感性，以及可以饱和理论灵敏度界限的最佳测量值。我们还证明了Ancilla辅助策略在保存具有特定物理基础噪音的频率敏感性方面的有效性。
It has been demonstrated that the optimal sensitivity achievable with Greenberger-Horne-Zeilinger states is the same as that with uncorrelated probes in the frequency estimation in the presence of uncorrelated Markovian dephasing [S. F. Huelga, et al., Phys. Rev. Lett. 79, 3865 (1997)]. Here, we extend this issue by examining the optimal frequency sensitivities achievable by the use of ancilla-assisted strategy, which has been proposed recently for robust phase estimation. We present the ultimate frequency sensitivities bounded by the quantum Fisher information for a general case in the presence of Markovian covariant phase noises, and the optimal measurement observables that can saturate the theoretical sensitivity bounds. We also demonstrate the effectiveness of the ancilla-assisted strategy for preserving frequency sensitivities suffering from specific physically ground noises.
