Every entangled state provides an advantage in classical communication

Journal article (2019)

Authors

S.M.G. Bäuml Barcelona Institute of Science and Technology (BIST), QuTech Advanced Research Centre, NTT Corporation, QID/Elkouss Group - QuTech Advanced Research Centre
A Winter Catalan Institution for Research and Advanced Studies (ICREA), Universitat Autònoma de Barcelona
D. Yang China Jiliang University, University of Bergen and Bjerknes Centre for Climate Research
Research Group
QID/Elkouss Group (QuTech Advanced Research Centre) (TU Delft)
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Published Date

2019

Language

English

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Faculty

QuTech Advanced Research Centre

Department

Quantum Internet Division

Research Group

QID/Elkouss Group

Abstract

We investigate the use of noisy entanglement as a resource in classical communication via a quantum channel. In particular, we are interested in the question whether for any entangled state, including bound entangled states, there exists a quantum channel, the classical capacity of which can be increased by providing the state as an additional resource. We partially answer this question by showing, for any entangled state, the existence of a quantum memory channel, the feedback-assisted classical capacity with product encodings of which can be increased by using the state as a resource. Using a different (memoryless) channel construction, we also provide a sufficient entropic condition for an advantage in classical communication (without feedback and for general encodings) and thus provide an example of a state that is not distillable by means of one-way local operations and classical communication but can provide an advantage in the classical capacity of a number of quantum channels. As separable states cannot provide an advantage in classical communication, our condition also provides an entropic entanglement witness.