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arXiv · 2202.12301

Channel capacity of relativistic quantum communication with rapid interaction

Erickson Tjoa·Kensuke Gallock-Yoshimura
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Abstract

In this work we study nonperturbatively the transmission of classical and quantum information in globally hyperbolic spacetimes, where the communication channel is between two qubit detectors interacting with a quantized massless scalar field via delta-coupling interaction. This interaction approximates very rapid detector-field interaction, effectively occurring at a single instant in time for each detector. We show that when both detectors interact via delta-coupling, one can arrange and tune the detectors so that the channel capacity is (at least) as good as the quantum channel constructed nonperturbatively using \textit{gapless detectors} by Landulfo [PRD 93, 104019]. Furthermore, we prove that this channel capacity is in fact optimal, i.e., both nonperturbative methods give essentially the same channel capacity, thus there is a sense in which the two methods can be regarded as equivalent as far as relativistic quantum communication is concerned.

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Erickson Tjoa, Kensuke Gallock-Yoshimura. 2022-02-24. Channel capacity of relativistic quantum communication with rapid interaction. https://doi.org/10.1103/physrevd.105.085011

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