Measurement of Quantum Weak Values of Photon Polarization

Griffith University, Southport, Queensland, Australia
Physical Review Letters (Impact Factor: 7.51). 07/2005; 94(22):220405. DOI: 10.1103/PhysRevLett.94.220405
Source: PubMed


We experimentally determine weak values for a single photon's polarization, obtained via a weak measurement that employs a two-photon entangling operation, and postselection. The weak values cannot be explained by a semiclassical wave theory, due to the two-photon entanglement. We observe the variation in the size of the weak value with measurement strength, obtaining an average measurement of the S1 Stokes parameter more than an order of magnitude outside of the operator's spectrum for the smallest measurement strengths.

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    • "Recently, the experiments have been proposed [19] [20] [21] [22] and demonstrated [23] [24] [25] which can be explained with quantum mechanical perspective. In [23], an entangling circuit has been shown to enable one single photon to make weak measurement of the polarization of the other. Further, weak values of the observables using entangled photons in parametric down-conversion have been explored in [19]. "
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    ABSTRACT: We show how two circular polarization components of a linearly polarized pulse, propagating through a coherently driven dilute atomic vapor, can be well resolved in time domain by weak measurement. Slower group velocity of one of the components due to electromagnetically induced transparency leads to a differential group delay between the two components. For low number density, this delay may not be large enough to temporally resolve the two components. We show how this can be enhanced in terms of mean time of arrival of the output pulse through a post-selected polarizer. We demonstrate the idea with all the analytical and numerical results, with a specific example of alkali atoms.
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    • "This kind of measurement approach may be useful in quantum optics and quantum communication, where the precision is as important as the precision of quantum state preparation. The technique of weak measurement have proven very useful tool for investigating fundamental questions in quantum mechanics and technological applications [4] [5] [6] [7]. "
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    ABSTRACT: Among many applications quantum weak measurements have been shown to be important in exploring fundamental physics issues, such as the experimental violation of the Heisenberg uncertainty relation and the Hardy paradox, and have also technological implications in quantum optics, quantum metrology and quantum communications, where the precision of the measurement is as important as the precision of quantum state preparation. The theory of weak measurement can be formulated using the pre-and post-selected quantum systems, as well as using the weak measurement operator formalism. In this work, we study the quantum discord (QD) of quasi-Werner mixed states based on bipartite entangled coherent states using the weak measurements operator, instead of the projective measurement operators. We then compare the quantum discord for both kinds of measurement operators, in terms of the entanglement quality, the latter being measured using the concept of concurrence. It's found greater quantum correlations using the weak measurement operators.
    8th Iberoamerican Optics Meeting and 11th Latin American Meeting on Optics, Lasers, and Applications, Porto, Portugal; 11/2013
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    • "Recently, two notable investigations [10] and [11] employing different methodologies have experimentally realized slit traversal determination with verified accompanying interference. The methodology of one investigation has its origins in an analysis by Aharonov et al. [12] showing that a " weak " measurement of a system can provide some degree of information about the system without significantly altering its subsequent interactions thereby providing an effective investigative tool [13] [14] [15] [16]. "
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    Journal of Modern Physics 07/2013; 4(07). DOI:10.4236/jmp.2013.47123
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