Sending-or-not-sending twin-field quantum key distribution with discrete-phase-randomized weak coherent states

In many security proofs of quantum key distribution, the random phases of coherent states are assumed to be continuously modulated. However, in practice, we can only take discrete phase randomization to coherent-state sources. In this paper, we study the sending-or-not-sending (SNS) protocol with di...

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Main Authors: Cong Jiang, Zong-Wen Yu, Xiao-Long Hu, Xiang-Bin Wang
Format: Article
Language:English
Published: American Physical Society 2020-12-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/PhysRevResearch.2.043304
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author Cong Jiang
Zong-Wen Yu
Xiao-Long Hu
Xiang-Bin Wang
author_facet Cong Jiang
Zong-Wen Yu
Xiao-Long Hu
Xiang-Bin Wang
author_sort Cong Jiang
collection DOAJ
description In many security proofs of quantum key distribution, the random phases of coherent states are assumed to be continuously modulated. However, in practice, we can only take discrete phase randomization to coherent-state sources. In this paper, we study the sending-or-not-sending (SNS) protocol with discrete-phase-randomized coherent states. We present the security proof of the SNS protocol with discrete phase modulation. We then present analytic formulas for key rate calculation. With the decoy-state method and the properties of trace distance, we get the analytical formula of the upper bound of the phase-flip error rate. We also get the lower bound of the yield of untagged bits, which can be calculated by either analytical formula or linear programming. Our numerical simulation results show that with only six phase values, the key rates of the SNS protocol can exceed the linear bound and, with 12 phase values, the key rates are very close to the results of the SNS protocol with continuously modulated phase randomization.
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spelling doaj.art-ca847fc3dad24fff81087769b5acf5f32024-04-12T17:04:31ZengAmerican Physical SocietyPhysical Review Research2643-15642020-12-012404330410.1103/PhysRevResearch.2.043304Sending-or-not-sending twin-field quantum key distribution with discrete-phase-randomized weak coherent statesCong JiangZong-Wen YuXiao-Long HuXiang-Bin WangIn many security proofs of quantum key distribution, the random phases of coherent states are assumed to be continuously modulated. However, in practice, we can only take discrete phase randomization to coherent-state sources. In this paper, we study the sending-or-not-sending (SNS) protocol with discrete-phase-randomized coherent states. We present the security proof of the SNS protocol with discrete phase modulation. We then present analytic formulas for key rate calculation. With the decoy-state method and the properties of trace distance, we get the analytical formula of the upper bound of the phase-flip error rate. We also get the lower bound of the yield of untagged bits, which can be calculated by either analytical formula or linear programming. Our numerical simulation results show that with only six phase values, the key rates of the SNS protocol can exceed the linear bound and, with 12 phase values, the key rates are very close to the results of the SNS protocol with continuously modulated phase randomization.http://doi.org/10.1103/PhysRevResearch.2.043304
spellingShingle Cong Jiang
Zong-Wen Yu
Xiao-Long Hu
Xiang-Bin Wang
Sending-or-not-sending twin-field quantum key distribution with discrete-phase-randomized weak coherent states
Physical Review Research
title Sending-or-not-sending twin-field quantum key distribution with discrete-phase-randomized weak coherent states
title_full Sending-or-not-sending twin-field quantum key distribution with discrete-phase-randomized weak coherent states
title_fullStr Sending-or-not-sending twin-field quantum key distribution with discrete-phase-randomized weak coherent states
title_full_unstemmed Sending-or-not-sending twin-field quantum key distribution with discrete-phase-randomized weak coherent states
title_short Sending-or-not-sending twin-field quantum key distribution with discrete-phase-randomized weak coherent states
title_sort sending or not sending twin field quantum key distribution with discrete phase randomized weak coherent states
url http://doi.org/10.1103/PhysRevResearch.2.043304
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