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arXiv · 2403.14785

Joint-measurability and quantum communication with untrusted devices

Michele Masini·Marie Ioannou·Nicolas Brunner·Stefano Pironio·Pavel Sekatski
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Abstract

Photon loss represents a major challenge for the implementation of quantum communication protocols with untrusted devices, e.g. in the device-independent (DI) or semi-DI approaches. Determining critical loss thresholds is usually done in case-by-case studies. In the present work, we develop a general framework for characterizing the admissible levels of loss and noise in a wide range of scenarios and protocols with untrusted measurement devices. In particular, we present general bounds that apply to prepare-and-measure protocols for the semi-DI approach, as well as to Bell tests for DI protocols. A key step in our work is to establish a general connection between quantum protocols with untrusted measurement devices and the fundamental notions of channel extendibility and joint-measurability, which capture essential aspects of the communication and measurement of quantum information. In particular, this leads us to introduce the notion of partial joint-measurability, which naturally arises within quantum cryptography.

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Michele Masini, Marie Ioannou, Nicolas Brunner, Stefano Pironio, Pavel Sekatski. 2024-03-21. Joint-measurability and quantum communication with untrusted devices. https://doi.org/10.22331/q-2024-12-23-1574

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