Robust phase estimation of Gaussian states in the presence of outlier quantum states

TL;DR

This paper introduces a robust quantum phase estimation method for Gaussian states that effectively handles outlier quantum states using M-estimators within a statistical framework, improving reliability in noisy quantum measurements.

Contribution

It develops a quantum-specific robust statistical framework and applies M-estimators to enhance phase estimation accuracy amid outlier quantum states.

Findings

The proposed method outperforms classical approaches in robustness.

It provides a systematic and easy-to-implement solution.

The approach effectively suppresses measurement errors caused by outliers.

Abstract

In this paper, we investigate the problem of estimating the phase of a coherent state in the presence of unavoidable noisy quantum states. These unwarranted quantum states are represented by outlier quantum states in this study. We first present a statistical framework of robust statistics in a quantum system to handle outlier quantum states. We then apply the method of M-estimators to suppress untrusted measurement outcomes due to outlier quantum states. Our proposal has the advantage over the classical methods in being systematic, easy to implement, and robust against occurrence of noisy states.