Abstract
The property of superadditivity of the quantum relative entropy states that, in a bipartite system HAB=HA⊗HB , for every density operator ΡAB , one has D(ΡAB||σA⊗σB)=D(ΡA||σA)+D(ΡB||σB) . In this paper, we provide an extension of this inequality for arbitrary density operators σAB . More specifically, we prove that a(σAB)D(ΡAB||σAB)=D(ΡA||σA)+D(ΡB||σB) holds for all bipartite states ΡAB and σAB , where a(σAB)=1+2?σ-1/2A⊗σ-1/2BσABσ-1/2A⊗σ-1/2B-1AB?∞.
Original language | English |
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Journal | IEEE Transactions on Information Theory |
Volume | 64 |
Issue number | 7 |
Pages (from-to) | 4758-4765 |
ISSN | 0018-9448 |
DOIs | |
Publication status | Published - Jul 2018 |