Role of nonclassical correlations in quantum parameter estimation assisted by a local measurement scheme in thermal equilibrium

ORAL

Abstract

We discuss the role of nonclassical correlations in enhancing estimation sensitivity of parameters characterizing the quantum system in thermal equilibrium, in terms of greedy local measurement scheme, where subsystems are measured sequentially with the local optimal measurements. We introduce a practical discord, called discord for local metrology, to measure the nonclassical correlations induced by local optimal measurement, and we explicitly derive its relation to loss in quantum Fisher information in the high-temperature limit. We also demonstrate that discord for local metrology becomes diagonal discord when the estimated parameter is linearly coupled to the Hamiltonian. Practically, this result in the high-temperature limit could provide a measurement or control strategy to utilize nonclassical correlations to achieve a precise sensing or imaging in room-temperature NMR system or living cells.

*This work was supported in part by the U.S. Army Research Office through Grants No. W911NF-11-1-0400 and W911NF-15-1-0548 and by the NSF PHY0551153. AS acknowledges Thomas G. Stockham Jr. Fellowship. QZ acknowledges the U.S. Department of Energy through Grant No. PH-COMPHEP-KA24 and the Claude E. Shannon Research Assistantship.

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Presenters

  • Akira Sone

    • Nuclear Science and Engineering, Massachusetts Institute of Technology

Authors

  • Akira Sone

    • Nuclear Science and Engineering, Massachusetts Institute of Technology

  • Quntao Zhuang

    • Physics, University of California, Berkeley
    • Department of Physics, University of California, Berkeley, California 94720, USA
    • University of California, Berkeley

  • Changhao Li

    • Nuclear Science and Engineering, Massachusetts Institute of Technology
    • Research Laboratory of Electronics and Department of Nuclear Science and Engineering, Massachusetts Institute of Technology

  • Yi-Xiang Liu

    • Nuclear Science and Engineering, Massachusetts Institute of Technology
    • Massachusetts Institute of Technology

  • Paola Cappellaro

    • Nuclear Science and Engineering, Massachusetts Institute of Technology
    • Massachusetts Institute of Technology
    • Research Laboratory of Electronics, Massachusetts Institute of Technology
    • Research Laboratory of Electronics and Department of Nuclear Science and Engineering, Massachusetts Institute of Technology
    • Department of Nuclear Science and Engineering, MIT