Parametric amplification of continuous variable entangled state for loss-tolerant multi-phase estimation

TL;DR

This paper demonstrates that parametric amplification of entangled continuous variable states enhances multi-phase estimation sensitivity, making quantum metrology more robust against loss and detection inefficiencies in practical scenarios.

Contribution

It introduces a method of using optical parametric amplification on entangled states to improve loss tolerance in multi-phase quantum estimation.

Findings

Multi-phase estimation sensitivity is robust against loss and detection inefficiency.

Optical parametric amplification enhances entanglement for better measurement precision.

The approach applies to two-mode EPR and four-mode cluster states.

Abstract

Quantum parameter estimation exploits quantum states to achieve estimation sensitivity beyond classical limit. In continuous variable (CV) regime, squeezed state has been exploited to implement deterministic phase estimation. It is however, often restricted by fragility of quantum states. The quantum phase estimation sensitivity of squeezed state is significantly affected by loss or detection inefficiency, which restrict its applications. This issue can be solved by using a method of parametric amplification of squeezed state \cite{OPA}. In this work, we implement multi-phase estimation with optical parametric amplification of entanglement generated from squeezed states. We find multi-phase estimation sensitivity is robust against loss or detection inefficiency, where we use two-mode Einstein-Podolsky-Rosen entangled state and four-mode cluster state for analysis. Our work provides a method for realizing large-scale quantum metrology in real-world applications against loss or detection inefficiency.