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arXiv · 2006.11498

Ancilla-assisted frequency estimation under phase covariant noises with Greenberger-Horne-Zeilinger states

Rui-Jie Cai·Wei Zhong·Lan Zhou·Yu-Bo Sheng
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Abstract

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.

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Rui-Jie Cai, Wei Zhong, Lan Zhou, Yu-Bo Sheng. 2020-06-20. Ancilla-assisted frequency estimation under phase covariant noises with Greenberger-Horne-Zeilinger states. https://doi.org/10.1007/s11128-020-02867-3

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