Quantum coherence measure based on affinity

Abstract

Quantification of quantum coherence is a fundamental and key issue in the field of resource theory and quantum information processing. Exploiting an affinity-based metric, in this article, we define a faithful measure of quantum coherence. It is shown that the affinity-based coherence is bounded by that based on fidelity and trace distance. The measure of quantumness in terms of the difference between bipartite coherence and corresponding product state coherence is also identified. Finally, we interpret the operational meaning of the affinity-based coherence as a lower bound of interferometric power of the quantum state.