Experimental Quantum Communication Enhancement by Superposing Trajectories

TL;DR

This paper experimentally and numerically investigates how superposing quantum trajectories through noisy channels can enhance quantum communication, highlighting the advantages of quantum-controlled operations in series within quantum interferometry.

Contribution

It compares different superposition strategies of trajectories in noisy channels, demonstrating the superiority of quantum-controlled series configurations for communication enhancement.

Findings

Quantum-controlled series channels provide the largest communication advantages.

Superposing trajectories can improve information transmission in noisy environments.

Experimental results support the theoretical benefits of quantum trajectory superposition.

Abstract

In quantum communication networks, wires represent well-defined trajectories along which quantum systems are transmitted. In spite of this, trajectories can be used as a quantum control to govern the order of different noisy communication channels, and such a control has been shown to enable the transmission of information even when quantum communication protocols through well-defined trajectories fail. This result has motivated further investigations on the role of the superposition of trajectories in enhancing communication, which revealed that the use of quantum control of parallel communication channels, or of channels in series with quantum-controlled operations, can also lead to communication advantages. Building upon these findings, here we experimentally and numerically compare different ways in which two trajectories through a pair of noisy channels can be superposed. We observe that, within the framework of quantum interferometry, the use of channels in series with quantum-controlled operations generally yields the largest advantages. Our results contribute to clarify the nature of these advantages in experimental quantum-optical scenarios, and showcase the benefit of an extension of the quantum communication paradigm in which both the information exchanged and the trajectory of the information carriers are quantum.