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arXiv · 1904.01036

Post-Selection and Counterfactual Communication

David R. M. Arvidsson-Shukur·Crispin H. W. Barnes
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Abstract

A recent quantum protocol for counterfactual communication [Y. Aharonov and L. Vaidman, Phys. Rev. A 99, 010103(R), 2019] relies on post-selection to eliminate the weak trace in the transmission channel. We show that the post-selection in this protocol also eliminates the flow of Fisher information from transmitter to receiver. However, we also show that a classical communication protocol with post-selection can be counterfactual. Hence, we argue that post-selection should not be allowed in genuine counterfactual communication. In the quantum counterfactual communication protocol, the probability of discarding an event by post-selection tends to zero with an increasing number of ideal optical components. But the counterfactual violation strength tends to infinity at a faster rate. Consequently, the quantum protocol is not counterfactual proper.

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David R. M. Arvidsson-Shukur, Crispin H. W. Barnes. 2019-04-01. Post-Selection and Counterfactual Communication. https://doi.org/10.1103/physreva.99.060102

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