Universal Method to Estimate Quantum Coherence

TL;DR

This paper introduces a universal, practical method to estimate quantum coherence by bounding various coherence quantifiers through measurable quantities like disturbance and measurement uncertainty.

Contribution

The authors propose a broadly applicable, efficient approach to estimate quantum coherence bounds, addressing the challenge of practical measurement in quantum information processing.

Findings

Provides measurable bounds for most coherence quantifiers

Utilizes disturbance effect and measurement uncertainty for estimation

Facilitates practical detection and application of quantum coherence

Abstract

Coherence is a defining property of quantum theory that accounts for quantum advantage in many quantum information tasks. Although many coherence quantifiers have been introduced in various contexts, the lack of efficient methods to estimate them restricts their applications. In this paper, we tackle this problem by proposing one universal method to provide measurable bounds for most current coherence quantifiers. Our method is motivated by the observation that the distance between the state of interest and its diagonal parts in reference basis, which lies at the heart of the coherence quantifications, can be readily estimated by disturbance effect and uncertainty of the reference measurement. Thus, our method of bounding coherence provides a feasible and broadly applicable avenue for detecting coherence, facilitating its further practical applications.