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arXiv · 1604.04596

Particle Path Through a Nested Mach-Zehnder Interferometer

Robert B. Griffiths
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Abstract

Possible paths of a photon passing through a nested Mach-Zehnder interferometer on its way to a detector are analyzed using the consistent histories formulation of quantum mechanics, and confirmed using a set of weak measurements (but not weak values). The results disagree with an analysis by Vaidman [ Phys.\ Rev.\ A 87 (2013) 052104 ], and agree with a conclusion reached by Li et al.\ [ Phys.\ Rev.\ A 88 (2013) 046102 ]. However, the analysis casts serious doubt on the claim of Salih et al.\ (whose authorship includes Li et al.) [ Phys.\ Rev.\ Lett.\ 110 (2013) 170502 ] to have constructed a protocol for counterfactual communication: a channel which can transmit information even though it contains a negligible number of photons.

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Robert B. Griffiths. 2016-04-15. Particle Path Through a Nested Mach-Zehnder Interferometer. https://doi.org/10.1103/physreva.94.032115

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