Quantum parameter estimation with imperfect reference frames

TL;DR

This paper explores how imperfect reference frames introduce noise in quantum metrology, affecting measurement precision and quantum communication, and provides a framework to analyze these effects.

Contribution

It introduces a comprehensive framework to study the impact of imperfect reference frames on quantum parameter estimation and quantum communication protocols.

Findings

Imperfect reference frames cause noise that degrades measurement precision.

The framework quantifies how misalignment affects quantum estimation accuracy.

Results offer insights into designing robust quantum communication schemes.

Abstract

Quantum metrology studies quantum strategies which enable us to outperform their classical counterparts. In this framework, the existence of perfect classical reference frames is usually assumed. However, such ideal reference frames might not always be available. The reference frames required in metrology strategies can either degrade or become misaligned during the estimation process. We investigate how the imperfectness of reference frames leads to noise which in general affects the ultimate precision limits in measurement of physical parameters. Moreover, since quantum parameter estimation can be phrased as a quantum communication protocol between two parties, our results provide deeper insight into quantum communication protocols with misaligned reference frames. Our framework allows for the study of general noise on the efficiency of such schemes.