Characterizing quantum ensemble using geometric measure of quantum coherence

TL;DR

This paper introduces a new measure for characterizing quantum ensembles based on geometric quantum coherence, providing a quantifier of their quantumness useful for quantum information processing.

Contribution

The paper generalizes coherence measures from states to ensembles and proposes a fidelity-based quantumness quantifier that satisfies key axioms.

Findings

Quantumness measure satisfies axioms of a bonafide quantumness measure

Computed quantumness for well-known ensembles

Provides a new tool for quantum ensemble characterization

Abstract

The characterization of the quantum ensemble is a fundamental issue in quantum information theory and foundations. The ensemble is also useful for various quantum information processing. To characterize the quantum ensemble, in this article, we generalize the coherence measure of a state to the quantum ensemble. Exploiting the fidelity and affinity between the ensemble, we propose a quantumness quantifier for the quantum ensemble. It is shown that the proposed quantifier satisfies the necessary axioms of a bonafide measure of quantumness. Finally, we compute the quantumness of a few well-known ensembles.