Evaluation of counterfactuality in counterfactual communication protocols

D. R. M. Arvidsson-Shukur, Axel Gottfries, C. H. W. Barnes

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

We provide an in-depth investigation of parameter estimation in nested Mach-Zehnder interferometers (NMZIs) using two information measures: the Fisher information and the Shannon mutual information. Protocols for counterfactual communication have, so far, been based on two different definitions of counterfactuality. In particular, some schemes have been based on NMZI devices, and have recently been subject to criticism. We provide a methodology for evaluating the counterfactuality of these protocols, based on an information-theoretical framework. More specifically, we make the assumption that any realistic quantum channel in MZI structures will have some weak uncontrolled interaction. We then use the Fisher information of this interaction to measure counterfactual violations. The measure is used to evaluate the suggested counterfactual communication protocol of H. Salih et al. [Phys. Rev. Lett. 110, 170502 (2013)]. The protocol of D. R. M. Arvidsson-Shukur and C. H. W. Barnes [Phys. Rev. A 94, 062303 (2016)], based on a different definition, is evaluated with a probability measure. Our results show that the definition of Arvidsson-Shukur and Barnes is satisfied by their scheme, while that of Salih et al. is only satisfied by perfect quantum channels. For realistic devices the latter protocol does not achieve its objective.
Original languageEnglish
Article number062316
Pages (from-to)1-15
Number of pages15
JournalPhysical Review A
Issue number6
Publication statusPublished - 18 Dec 2017

Keywords / Materials (for Non-textual outputs)

  • quantum communication
  • quantum protocols


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