Article | Published:

Quantum discord as resource for remote state preparation

Nature Physics volume 8, pages 666670 (2012) | Download Citation

Abstract

The existence of better-than-classical quantum information processing (QIP) models which consume very little or no entanglement suggests that separable or weakly entangled states could be extremely useful tools for information processing as they are much easier to prepare and control even in dissipative environments. It has been proposed that a resource of advantage is the generation of quantum discord, a measure of non-classical correlations that includes entanglement as a subset. Here we show that quantum discord is the necessary resource for quantum remote state preparation. We explicitly show that the geometric measure of quantum discord is related to the fidelity of this task, which provides its operational meaning. Our results are experimentally demonstrated using photonic quantum systems. Moreover, we demonstrate that separable states with non-zero quantum discord can outperform entangled states. Therefore, the role of quantum discord might provide fundamental insights for resource-efficient QIP.

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Acknowledgements

We acknowledge support from the European Commission, Q-ESSENCE (No 248095), ERC Advanced Senior Grant (QIT4QAD), and the ERA-Net CHIST-ERA project QUASAR, the John Templeton Foundation, Austrian Science Fund (FWF): (SFB-FOCUS) and (Y585-N20) and the doctoral programme CoQuS, and the Air Force Office of Scientific Research, Air Force Material Command, United States Air Force, under grant number FA8655-11-1-3004. The work is supported by the National Research Foundation and Ministry of Education in Singapore.

Author information

Author notes

    • Borivoje Dakić
    • , Yannick Ole Lipp
    • , Xiaosong Ma
    •  & Martin Ringbauer

    These authors contributed equally to this work

Affiliations

  1. Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria

    • Borivoje Dakić
    • , Yannick Ole Lipp
    • , Martin Ringbauer
    • , Časlav Brukner
    •  & Philip Walther
  2. Vienna Center for Quantum Science and Technology, Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria

    • Xiaosong Ma
    • , Stefanie Barz
    •  & Anton Zeilinger
  3. Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Boltzmanngasse 3, A-1090 Vienna, Austria

    • Xiaosong Ma
    • , Sebastian Kropatschek
    • , Anton Zeilinger
    • , Časlav Brukner
    •  & Philip Walther
  4. Centre for Quantum Technologies, National University of Singapore, Block S15, 3 Science Drive 2, 117543, Singapore

    • Tomasz Paterek
    •  & Vlatko Vedral
  5. Department of Atomic and Laser Physics, University of Oxford, Oxford OX1 3PU, UK

    • Vlatko Vedral

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Contributions

Y.O.L., X.M. and M.R. designed and carried out the experiment, analysed data and wrote the manuscript. B.D., T.P. and V.V. provided the theoretical analysis, analysed data and wrote the manuscript. S.B. designed the experiment, discussed the results and edited the manuscript. S.K. programmed the software. A.Z. supervised the project and edited the manuscript. C.B. supervised the project, provided theoretical analysis and wrote the manuscript. P.W. supervised the project, designed the experiment and wrote the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Borivoje Dakić or Philip Walther.

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DOI

https://doi.org/10.1038/nphys2377

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