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arXiv · 2609.35488

Temporal trade-offs in high-dimensional entanglement: a comprehensive noise model for optimal time-bin QKD protocols

Alexandra E. Bergmayr-Mann·Gláucia Murta·Marcus Huber
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Abstract

High-dimensional time-bin entanglement is known for having high potential for quantum key distribution (QKD) applications, being easily implementable, robust and may offer better keyrates than simple qubit protocols. The temporal encoding, combined with limited clock resolution, however, implies a trade-off: Is it better to send more low-dimensionally encoded photons or few high-dimensional ones? Answering this question presents a hard challenge as it depends on the entire context of the protocol, including the production rates, losses, dark counts, timing jitters and many more. We answer this question for single Franson based interferometers and asymptotic key rate and shared entanglement as main figures of merit. We present a flexible noise model incorporating all relevant parameters and find that there are indeed regions where high-dimensional encoding still outperforms any qubit based version when the pair arrival rate is limited, for instance through loss or limited pump power.

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Alexandra E. Bergmayr-Mann, Gláucia Murta, Marcus Huber. 2026-09-28. Temporal trade-offs in high-dimensional entanglement: a comprehensive noise model for optimal time-bin QKD protocols. https://arxiv.org/abs/2609.35488

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