Causal order as a resource for quantum communication

Ding Jia (贾丁) and Fabio Costa
Phys. Rev. A 100, 052319 – Published 14 November 2019

Abstract

In theories of communication, it is usually presumed that the involved parties perform actions in a fixed causal order. However, practical and fundamental reasons can induce uncertainties in the causal order. Here we show that a maximal uncertainty in the causal order forbids asymptotic quantum communication, while still enabling the noisy transfer of classical information. Therefore causal order, like shared entanglement, is an additional resource for communication. The result is formulated within an asymptotic setting for processes with no fixed causal order, which sets a basis for a quantum information theory in general quantum causal structures.

  • Figure
  • Received 25 January 2019

DOI:https://doi.org/10.1103/PhysRevA.100.052319

©2019 American Physical Society

Physics Subject Headings (PhySH)

General PhysicsQuantum Information, Science & Technology

Authors & Affiliations

Ding Jia (贾丁)1,2,* and Fabio Costa3

  • 1Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
  • 2Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5, Canada
  • 3Centre for Engineered Quantum Systems, School of Mathematics and Physics, University of Queensland, QLD 4072 Australia

  • *ding.jia@uwaterloo.ca

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Issue

Vol. 100, Iss. 5 — November 2019

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