Abstract:
By regarding quantum states as communication channels and using observable
correlations quantitatively expressed by mutual information, we introduce
a hierarchy of entanglement measures that includes the entanglement of
formation as a particular instance. We compare the maximal and minimal
measures and indicate the conceptual advantages of the minimal measure over
the entanglement of formation. We reveal a curious feature of
the entanglement of formation by showing that it can exceed the quantum mutual
information, which is usually regarded as a theoretical measure of total
correlations. This places the entanglement of formation in a broader
scenario, highlights its peculiarity in relation to pure-state ensembles, and
introduces a competing definition with intrinsic informational significance.
Keywords:entanglement, mutual information, observable correlations, entanglement of formation.
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