Operational interpretation of coherence in quantum key distribution

Jiajun Ma, You Zhou, Xiao Yuan, and Xiongfeng Ma
Phys. Rev. A 99, 062325 – Published 20 June 2019

Abstract

Quantum coherence was recently formalized as a physical resource to measure the strength of superposition. Based on the resource theory, we present a systematic framework that connects a coherence measure to the security of quantum key distribution. By considering a generic entanglement-based key distribution protocol under the collective attack scenario, we show that the key rate can be quantified by the coherence of the shared bipartite states. This framework allows us to derive the key rate of the BB84 and six-state protocols. By utilizing fine-grained parameters, we also derive the improved key rates of both protocols within the coherence-based framework. Furthermore, we apply it to a practical issue, detection efficiency mismatch, and obtain an improved result. In conclusion, this framework demonstrates the interplay among coherence, entanglement, and quantum key distribution at a fundamental level.

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  • Received 9 March 2019

DOI:https://doi.org/10.1103/PhysRevA.99.062325

©2019 American Physical Society

Physics Subject Headings (PhySH)

Quantum Information, Science & Technology

Authors & Affiliations

Jiajun Ma1, You Zhou1, Xiao Yuan2, and Xiongfeng Ma1,*

  • 1Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
  • 2Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom

  • *xma@tsinghua.edu.cn

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Issue

Vol. 99, Iss. 6 — June 2019

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