Interpreting quantum discord through quantum state merging

Abstract

We present an operational interpretation of quantum discord based on the quantum state merging protocol. Quantum discord is the markup in the cost of quantum communication in the process of quantum state merging, if one discards relevant prior information. Our interpretation has an intuitive explanation based on the strong subadditivity of von Neumann entropy. We use our result to provide operational interpretations of other quantities like the local purity and quantum deficit. Finally, we discuss in brief some instances where our interpretation is valid in the single copy scenario.

5 pages, no figures. See http://arxiv.org/abs/1008.3205 for similar results. Typos fixed, references and acknowledgements updated. End note added

References in corpus (6)

• Quantum discord and the power of one qubit
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• Operational interpretations of quantum discord
• On the role of entanglement and correlations in mixed-state quantum computation
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• The thermodynamic meaning of negative entropy
• Operational interpretations of quantum discord
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• Linking Quantum Discord to Entanglement in a Measurement
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• Experimentally Witnessing the Quantumness of Correlations
• Quantumness of noisy quantum walks: a comparison between measurement-induced disturbance and quantum discord