Discord vs Distortion: Classical vs Quantum

ORAL

Abstract

Quantum discord is a popular quantum-resource measure but a nonzero value does not necessarily imply quantumness; nonzero classical discord arises if local measurements disturb the stochastic information state [V. Gheorghiu, M. C. de Oliveira and B. C. Sanders, Phys. Rev. Lett. 115, 030403 (2015)]. The classical interpretation of discord breaks down if and only if entanglement of formation for the informational state is nonzero, thereby creating a tight link between entanglement and genuine quantum discord. Here we present mathematical relations, and specifically monotonicity between discord and channel-distortion measures such as mean-squared distortion and Kullback-Leibler divergence. Whereas the previous result showed discord can be nonzero for stochastic information, our new results demonstrate a tight link between classical discord and other information-theoretic measures of noisy channels.

*Australian Research Council via the Centre of Excellence in Engineered Quantum Systems (EQuS) project number CE110001013; National Science Foundation of China Grant 11675164; CAS PIFI program (Grant No. 2016PT003; Natural Sciences and Engineering Research Council; Alberta Innovates.

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Presenters

  • Barry C Sanders

    • National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China

Authors

  • Barry C Sanders

    • National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China

  • Wei-Wei Zhang

    • Physics, University of Sydney

  • Yuval R Sanders

    • Physics and Astronomy, Macquarie University

  • Nigum Arshed

    • National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China