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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    • "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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    • "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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