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arXiv · 2307.03203

'Frequency-modulated' pulsed Bell setup avoids post-selection

Mónica Agüero·Alejandro Hnilo·Marcelo Kovalsky·Myriam Nonaka
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Abstract

Excepting event-ready setups, Bell experiments require post-selection of data to define coincidences. From the fundamental point of view, post-selection is a true 'logical loophole'. From the practical point of view, it implies a numerically heavy and time consuming task. In Quantum Key Distribution (QKD), it opens vulnerability in case of a hostile adversary. The core of the problem is to synchronize independent clocks during long observation runs. A pulsed source gets rid of clocks' drift, but there is still the problem of identifying the same pulse in each remote station. We use a frequency modulated pulsed source to achieve it. This immediately defines the condition of valid coincidences in a manner that is unaffected by the drift between the clocks. It allows finding the set of entangled pairs avoiding post-selection and in a way that is found to be optimal. It is also robust against a hostile adversary in the case of QKD.

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Mónica Agüero, Alejandro Hnilo, Marcelo Kovalsky, Myriam Nonaka. 2023-07-05. 'Frequency-modulated' pulsed Bell setup avoids post-selection. https://arxiv.org/abs/2307.03203

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