Quantum metrology and coherence

TL;DR

This paper explores the connection between quantum coherence and measurement precision, developing theoretical tools and optimizing resolution by treating coherence as a finite resource in quantum metrology.

Contribution

It introduces a quantum Wiener-Kintchine theorem and a method to compute Fisher information, integrating probe and measurement effects in quantum metrology.

Findings

Developed a quantum Wiener-Kintchine theorem for quantum rulers

Computed Fisher information considering probe and measurement contributions

Optimized measurement resolution based on coherence as a finite resource

Abstract

We address the relation between quantum metrological resolution and coherence. We examine this dependence in two manners: we develop a quantum Wiener-Kintchine theorem for a suitable model of quantum ruler, and we compute the Fisher information. The two methods have the virtue of including both the contributions of probe and measurement on an equal footing. We illustrate this approach with several examples of linear and nonlinear metrology. Finally, we optimize resolution regarding coherence as a finite resource.