Measurement-based quantum correlation in mixed-state quantum metrology
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Entanglement is crucial for realizing quantum advantages in metrology. However, entanglement has been outcast by discord in order to capture the worst-case sensitivity in quantum metrology to estimate an unknown parameter. In contrast to traditional measures—namely entanglement and discord—there exist noncommutativity-based quantum correlation measures induced by local von Neumann measurements. Such correlations are more comprehensive than entanglement and discord in quantum information processing. In this paper, we investigate the metrological resourcefulness of measurement-based quantum correlations (MbQCs). We provide a lower bound on the minimum precision of the estimation in terms of the MbQC. We show that the MbQC is more resourceful in quantum metrology than entanglement and super quantum discord. For any non-product state, the MbQC gives a metrological insight into the sensitivity of a mixed state toward perturbation caused by a local von Neumann measurement.
KeywordsQuantum measurement Quantum correlations Quantum metrology
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2016R1A2B2014462) and by the Basic Science Research Program through the NRF funded by the Ministry of Education (No. 2018R1D1A1B07050584), and ICT R&D program of MSIP/IITP [R0190-15-2030, reliable cryptosystem standards and core technology development for secure quantum key distribution network].
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