Entanglement-based quantum key distribution with non-Gaussian continuous variables

Fuente: arXiv
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Main Authors: Jeng, Hao, Lam, Ping Koy, Assad, Syed M.
Format: Preprint
Published: 2025
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author Jeng, Hao
Lam, Ping Koy
Assad, Syed M.
author_facet Jeng, Hao
Lam, Ping Koy
Assad, Syed M.
contents Addition of single photons to two-mode-squeezed-vacuum states has the effect of distilling quantum entanglement, and, when deployed in quantum key distribution, should lead also to an increase in the secret key rate. However, the extraction of secret keys from non-Gaussian entangled states is a complex issue and is at present not fully understood. In this paper we describe a technique for adding photons to entangled states, and demonstrate how it leads to an increase in secret key rates and the maximal distance for which keys can be distributed assuming asymptotic conditions. The quantum correlations thus produced were found to be of a highly non-Gaussian character, such that the Gaussian extremity principle returns a negative keyrate and effectively kills the protocol; we have therefore developed methods of analysis that do not require prior assumptions about the state. Although it could have been that the addition of single photons would make the system more fragile, this turned out not to be the case. Rather, the addition of a single photon was found to protect the protocol against both passive and active decoherence.
format Preprint
id arxiv_https___arxiv_org_abs_2507_18000
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Entanglement-based quantum key distribution with non-Gaussian continuous variables
Jeng, Hao
Lam, Ping Koy
Assad, Syed M.
Quantum Physics
Addition of single photons to two-mode-squeezed-vacuum states has the effect of distilling quantum entanglement, and, when deployed in quantum key distribution, should lead also to an increase in the secret key rate. However, the extraction of secret keys from non-Gaussian entangled states is a complex issue and is at present not fully understood. In this paper we describe a technique for adding photons to entangled states, and demonstrate how it leads to an increase in secret key rates and the maximal distance for which keys can be distributed assuming asymptotic conditions. The quantum correlations thus produced were found to be of a highly non-Gaussian character, such that the Gaussian extremity principle returns a negative keyrate and effectively kills the protocol; we have therefore developed methods of analysis that do not require prior assumptions about the state. Although it could have been that the addition of single photons would make the system more fragile, this turned out not to be the case. Rather, the addition of a single photon was found to protect the protocol against both passive and active decoherence.
title Entanglement-based quantum key distribution with non-Gaussian continuous variables
topic Quantum Physics
url https://arxiv.org/abs/2507.18000