Two‐Parameter Estimation Via Photon Subtraction Operation Within a Feedback‐Assisted Interferometer

In this paper, the effect of multi‐photon subtraction operations in a feedback‐assisted interferometer can enhance measurement precision for single‐parameter and two‐parameter estimation is analyzed under both ideal and photon‐loss conditions. The effects of the feedback strength , the optical parametric amplifier's gain , the coherent state amplitude , and the order of multi‐photon subtraction on system performance are examined. It is demonstrated that an optimal feedback strength exists in both conditions. Selecting a suitable can significantly boost the system's robustness to photon loss, and markedly improve measurement precision. And the photon subtraction operations within a feedback‐assisted interferometer can further enhance measurement precision effectively. Additionally, it is found that increasing intramode correlations while decreasing intermode correlations can improve estimation accuracy. This work investigates a new method through the synergistic integration of feedback topology and non‐Gaussian operations into a multiparameter estimation system, along with their systematic study under both ideal and loss conditions. The findings may contribute to improving quantum‐enhanced measurements and hold promise for high‐precision quantum sensing research.