Quantum-communication protocol employing weak measurements

Botero, Alonso; Reznik, Benni

doi:10.1103/physreva.61.050301

Cited by 20 publications

(19 citation statements)

References 16 publications

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“…Nevertheless, by repeating the measurements (i.e. performing a large number of independent measurements on identically prepared systems), A w can be determined to any desired accuracy [8].…”

mentioning

confidence: 99%

Revisiting Hardy's paradox: counterfactual statements, real measurements, entanglement and weak values

Aharonov¹,

Botero²,

Popescu³

et al. 2002

Physics Letters A

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350

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Classical-realistic analysis of entangled systems have lead to retrodiction paradoxes, which ordinarily have been dismissed on the grounds of counter-factuality. Instead, we claim that such paradoxes point to a deeper logical structure inherent to quantum mechanics, which is naturally described in the language of weak values, and which is accessible experimentally via weak measurements. Using as an illustration, a gedanken-experiment due to Hardy [1], we show that there is in fact an exact numerical coincidence between a) a pair of classically contradictory assertions about the locations of an electron and a positron, and b) the results of weak measurements of their location. The internal consistency of these results is due to the novel way by which quantum mechanics "resolves" the paradox: first, by allowing for two distinguishable manifestations of how the electron and positron can be at the same location: either as single particles or as a pair; and secondly, by allowing these properties to take either sign. In particular, we discuss the experimental meaning of a negative number of electron-positron pairs.

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mentioning

confidence: 99%

Revisiting Hardy's paradox: counterfactual statements, real measurements, entanglement and weak values

Aharonov¹,

Botero²,

Popescu³

et al. 2002

Physics Letters A

Self Cite

286

350

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show abstract

“…Gell-Mann and Hartle [23]); in superluminal tunneling (Chiao [22] and Steinberg [34]); in quantum information (e.g. the quantum random walk [8] or cryptography [16,15]), etc.…”

Section: Introductionmentioning

confidence: 99%

Pre- and post-selection, weak values and contextuality

Tollaksen¹

2007

J. Phys. A: Math. Theor.

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By analyzing the concept of contextuality (Bell-Kochen-Specker) in terms of pre-and-post-selection (PPS), it is possible to assign definite values to observables in a new and surprising way. Physical reasons are presented for restrictions on these assignments. When measurements are performed which do not disturb the pre-and post-selection (i.e. weak measurements), then novel experimental aspects of contextuality can be demonstrated including a proof that every PPS-paradox with definite predictions implies contextuality. Certain results of these measurements (eccentric weak values with e.g. negative values outside the spectrum), however, cannot be explained by a "classicallike" hidden variable theory.

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“…The usefulness of this description has been demonstrated, both theoretically and experimentally, in a number of applications in which novel aspects of quantum processes have been uncovered when analyzed in terms of * Electronic address: abotero@uniandes.edu.co weak values. These include photon polarization interference [7,8,9,10,11], barrier tunnelling times [12,13,14], photon arrival times [15,16], anomalous pulse propagation [17,18,19], correlations in cavity QED experiments [20], complementarity in "which-way" experiments [21,22], non-classical aspects of light [23,24], communication protocols [25] and retrodiction "paradoxes" of quantum entanglement [26,27,28].…”

Section: Introductionmentioning

confidence: 99%

Quantum averages of weak values

2005

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We re-examine the status of the weak value of a quantum mechanical observable as an objective physical concept, addressing its physical interpretation and general domain of applicability. We show that the weak value can be regarded as a definite mechanical effect on a measuring probe specifically designed to minimize the back-reaction on the measured system. We then present a new framework for general measurement conditions (where the back-reaction on the system may not be negligible) in which the measurement outcomes can still be interpreted as quantum averages of weak values. We show that in the classical limit, there is a direct correspondence between quantum averages of weak values and posterior expectation values of classical dynamical properties according to the classical inference framework.

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Quantum-communication protocol employing weak measurements

Cited by 20 publications

References 16 publications

Revisiting Hardy's paradox: counterfactual statements, real measurements, entanglement and weak values

Revisiting Hardy's paradox: counterfactual statements, real measurements, entanglement and weak values

Pre- and post-selection, weak values and contextuality

Quantum averages of weak values

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