Two-parameter estimation via photon subtraction operation within a feedback-assisted interferometer

TL;DR

This paper explores how multi-photon subtraction in a feedback-assisted interferometer can improve quantum measurement precision, robustness to photon loss, and estimation accuracy by optimizing feedback strength and correlations.

Contribution

It introduces a novel method combining feedback control and non-Gaussian operations for enhanced multiparameter quantum estimation under realistic loss conditions.

Findings

Optimal feedback strength enhances robustness and precision.

Photon subtraction improves measurement accuracy.

Adjusting correlations boosts estimation performance.

Abstract

In this paper, we analyze how multi-photon subtraction operations in a feedback-assisted interferometer can enhance measurement precision for single-parameter and two-parameter estimation under both ideal and photon-loss conditions. We examine the effects of the feedback strength R, the optical parametric amplifier's gain g, the coherent state amplitude {\alpha}, and the order of multi-photon subtraction on system performance. We demonstrate that an optimal feedback strength R_{opt} exists in both conditions. Selecting a suitable R 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, we find 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.