English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We study the average quantum coherence over the pure state decompositions ofa mixed quantum state. An upper bound of the average quantum coherence isprovided and sufficient conditions for the saturation of the upper bound areshown. These sufficient conditions always hold for two and three dimensionalsystems. This provides a tool to estimate the average coherence experimentallyby measuring only the diagonal elements, which remarkably requires lessmeasurements compared with state tomography. We then describe the pure statedecompositions of qubit state in Bloch sphere geometrically. For any givenqubit state, the optimal pure state decomposition achieving the maximal averagequantum coherence as well as three other pure state decompositions are shown inthe Bloch sphere. The order relations among their average quantum coherence areinvariant for any coherence measure. The results presented in this paper areuniversal and suitable for all coherence measures.

The Average Quantum Coherence of Pure State Decomposition