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arXiv · 2506.07684

Phase estimation via delocalized photon subtraction operation inside the SU(1,1) interferometer

Zhihao Li·Qingqian Kang·Teng Zhao·Cunjin Liu·Liyun Hu·Chengzhi Deng
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Abstract

We propose a theoretical scheme to improve the precision of phase measurement using intensity detection by implementing delocalized photon subtraction operation (D-PSO) inside the SU(1,1) interferometer, with the coherent state and the vacuum state as the input states. We compare the phase sensitivity and the quantum Fisher information between D-PSO and localized photon subtraction operation (L-PSO) under both ideal and photon-loss cases. It has been found that the D-PSO can improve the measurement accuracy of the SU(1,1) interferometer and enhance its robustness against internal photon loss. And it can cover and even exceed the advantages of the L-PSO on two modes, respectively. In addition, by comparing the standard quantum limit, the Heisenberg limit and quantum Cram\'er-Rao bound, we find that the phase sensitivity of the D-PSO can get closer to the quantum Cram\'er-Rao bound and has the ability to resist internal loss.

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Zhihao Li, Qingqian Kang, Teng Zhao, Cunjin Liu, Liyun Hu, Chengzhi Deng. 2025-06-09. Phase estimation via delocalized photon subtraction operation inside the SU(1,1) interferometer. https://arxiv.org/abs/2506.07684

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