Quantum correlation based on weak measurements

Wang, Yangyang; Hou, Jinchuan; Qi, Xiaofei

doi:10.1142/s0219749917500411

Cited by 6 publications

(3 citation statements)

References 26 publications

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“…where the postselection on the subsystem C is given by the orthornormal basis of subsystem C. Let us mention that completely different approaches to characterize general quantum correlation based on weak measurement but without postselection, and thus independent of the concept of weak value, were reported in Refs. [47,48].…”

Section: General Nonclassical Correlation From Local Weak Value Measu...mentioning

confidence: 99%

Operational characterization of general quantum correlation via complex weak value measurement

Budiyono¹,

Dipojono²

2022

Preprint

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The last two decades have witnessed significant progress on the understanding the quantum correlation more general than entanglement, wherein even a separable state may yield correlation that cannot be emulated by any classical object. Such a general nonclassical correlation is not only intriguing from the fundamental point of view, but it has also been recognized as a resource in a variety of quantum information processing tasks and quantum technology. Here, we propose a characterization of the general quantum correlation in bipartite system in terms of direct laboratory operations using weak measurement with postselection. We define a quantity based on the imaginary part of weak values obtained via weak measurement of a local basis followed by a postselection of another local basis, and an optimization procedure over all possible choices of the two bases. We show that it satisfies certain desirable requirements for a quantifier of general quantum correlations. It may be statistically interpreted as the minimum genuine quantum share of uncertainty. It is a faithful witness of entanglement for general pure states, giving an observable lower bound to a scaled square root of the linear entropy of entanglement. We then suggest an information theoretic interpretation of the general quantum correlation in a multipartite state as the minimum mean absolute error in an optimal estimation of any local measurement basis, based on the outcomes of local projective measurement on the state, in the worst case scenario.

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Section: General Nonclassical Correlation From Local Weak Value Measu...mentioning

confidence: 99%

Operational characterization of general quantum correlation via complex weak value measurement

Budiyono¹,

Dipojono²

2022

Preprint

View full text Add to dashboard Cite

show abstract

“…Consider the economical phase-covariant QC quantum cloning, which is developed to use in the Quantum Key Distribution BB84 Protocol [4]. Here, we propose an alternative method to realize a high fidelity asymmetric QC machine using weak measurement, which has been widely employed in quantum information processing [40][41][42][43][44]. Compared with the previous scheme [18,22], the difference of the fidelity between two copies is reduced while the sum of the fidelity between two copies is enhanced.…”

Section: Introductionmentioning

confidence: 99%

Weak measurement induced asymmetric quantum cloning

Fang¹,

Chen²,

Chen³

et al. 2020

Laser Phys. Lett.

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Asymmetric quantum cloning (QC) is important for eavesdropping due to non-cloning quantum theorem. In this paper we propose a method to produce an asymmetric QC using weak measurement. Compared with previous proposals (1999 Phys. Rev. A 60 2764, 2004 Phy.s Rev. A 69 062316), the fidelity of one copy can be improved, while the other one reduces more smoothly. Also, the average fidelity of two copies can be raised.

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“…WMs can give rise to anomalous (imaginary and/or unbounded) values, whose real part is regarded as a conditional average of the observable in the zero-disturbance limit [9], while the imaginary one is related to the disturbance of the measuring pointer during the measurement [10]. Beyond having inspired a significant analysis of the meaning of quantum measurement [11][12][13][14][15][16][17][18], they have been used both to address foundational problems [19], like macrorealism [20,21] and contextuality [22][23][24], and as a novel, impressive tool for quantum metrology and related quantum technologies, allowing high-precision measurements (at least in presence of specific noises [25,26]), as the tiny spin Hall effect [6] or small beam deflections [27][28][29][30], and characterization of quantum states [31,32]. Furthermore, the absence of wave function collapse in WMs allows performing sequential measurements of even non-commuting observables on the same particle [33][34][35][36], a task forbidden within the strong measurement framework in quantum mechanics.…”

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confidence: 99%

Investigating the Effects of the Interaction Intensity in a Weak Measurement

Piacentini

Avella

Gramegna

et al. 2018

Sci Rep

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Measurements are crucial in quantum mechanics, for fundamental research as well as for applicative fields like quantum metrology, quantum-enhanced measurements and other quantum technologies. In the recent years, weak-interaction-based protocols like Weak Measurements and Protective Measurements have been experimentally realized, showing peculiar features leading to surprising advantages in several different applications. In this work we analyze the validity range for such measurement protocols, that is, how the interaction strength affects the weak value extraction, by measuring different polarization weak values on heralded single photons. We show that, even in the weak interaction regime, the coupling intensity limits the range of weak values achievable, setting a threshold on the signal amplification effect exploited in many weak measurement based experiments.

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Quantum correlation based on weak measurements

Cited by 6 publications

References 26 publications

Operational characterization of general quantum correlation via complex weak value measurement

Operational characterization of general quantum correlation via complex weak value measurement

Weak measurement induced asymmetric quantum cloning

Investigating the Effects of the Interaction Intensity in a Weak Measurement

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