Entropy bounds for device-independent quantum key distribution with local Bell test

Fuente: arXiv
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Autores principales: Tan, Ernest Y. -Z., Wolf, Ramona
Formato: Preprint
Publicado: 2024
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author Tan, Ernest Y. -Z.
Wolf, Ramona
author_facet Tan, Ernest Y. -Z.
Wolf, Ramona
contents One of the main challenges in device-independent quantum key distribution (DIQKD) is achieving the required Bell violation over long distances, as the channel losses result in low overall detection efficiencies. Recent works have explored the concept of certifying nonlocal correlations over extended distances through the use of a local Bell test. Here, an additional quantum device is placed in close proximity to one party, using short-distance correlations to verify nonlocal behavior at long distances. However, existing works have either not resolved the question of DIQKD security against active attackers in this setup, or used methods that do not yield tight bounds on the keyrates. In this work, we introduce a general formulation of the keyrate computation task in this setup that can be combined with recently developed methods for analyzing standard DIQKD. Using this method, we show that if the short-distance devices exhibit sufficiently high detection efficiencies, positive keyrates can be achieved in the long-distance branch with lower detection efficiencies as compared to standard DIQKD setups. This highlights the potential for improved performance of DIQKD over extended distances in scenarios where short-distance correlations are leveraged to validate quantum correlations.
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id arxiv_https___arxiv_org_abs_2404_00792
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Entropy bounds for device-independent quantum key distribution with local Bell test
Tan, Ernest Y. -Z.
Wolf, Ramona
Quantum Physics
One of the main challenges in device-independent quantum key distribution (DIQKD) is achieving the required Bell violation over long distances, as the channel losses result in low overall detection efficiencies. Recent works have explored the concept of certifying nonlocal correlations over extended distances through the use of a local Bell test. Here, an additional quantum device is placed in close proximity to one party, using short-distance correlations to verify nonlocal behavior at long distances. However, existing works have either not resolved the question of DIQKD security against active attackers in this setup, or used methods that do not yield tight bounds on the keyrates. In this work, we introduce a general formulation of the keyrate computation task in this setup that can be combined with recently developed methods for analyzing standard DIQKD. Using this method, we show that if the short-distance devices exhibit sufficiently high detection efficiencies, positive keyrates can be achieved in the long-distance branch with lower detection efficiencies as compared to standard DIQKD setups. This highlights the potential for improved performance of DIQKD over extended distances in scenarios where short-distance correlations are leveraged to validate quantum correlations.
title Entropy bounds for device-independent quantum key distribution with local Bell test
topic Quantum Physics
url https://arxiv.org/abs/2404.00792