Conditional quantum entropy: Difference between revisions

Revision as of 11:34, 6 June 2005

Revision as of 11:36, 6 June 2005

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By analogy with the classical conditional entropy, one defines the conditional quantum entropy as <math>S(\rho|\sigma) \equiv S(\rho,\sigma) - S(\sigma)</math>.

An operational definition of the quantum relative entropy (as a measure of the quantum communication cost or surplus when performing quantum state merging) was given by Michal Horodecki, Jonathan Oppenheim, and Andreas Winter in a recenttheir paper "Quantum Information can be negative" in [http://arxiv.org/abs/quant-ph/0505062].

==Properties==