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arXiv · 2406.08544

A practical framework for analyzing high-dimensional QKD setups

Florian Kanitschar·Marcus Huber
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Abstract

High-dimensional (HD) entanglement promises both enhanced key rates and overcoming obstacles faced by modern-day quantum communication. However, modern convex optimization-based security arguments are limited by computational constraints; thus, accessible dimensions are far exceeded by progress in HD photonics, bringing forth a need for efficient methods to compute key rates for large encoding dimensions. In response to this problem, we present a flexible analytic framework facilitated by the dual of a semi-definite program and diagonalizing operators inspired by entanglement-witness theory, enabling the efficient computation of key rates in high-dimensional systems. To facilitate the latter, we show how matrix completion techniques can be incorporated to effectively yield improved, computable bounds on the key rate in paradigmatic high-dimensional systems of time- or frequency-bin entangled photons and beyond.

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Florian Kanitschar, Marcus Huber. 2025-07-03. A practical framework for analyzing high-dimensional QKD setups. https://doi.org/10.1103/physrevlett.135.01080

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