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?∞.

Superadditivity of Quantum Relative Entropy for General States

Lucia A.;
2018-01-01

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?∞.
2018
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11311/1282555
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