Experimental quantum communication enhancement by superposing trajectories

Giulia Rubino, Lee A. Rozema, Daniel Ebler, Hlér Kristjánsson, Sina Salek, Philippe Allard Guérin, Alastair A. Abbott, Cyril Branciard, Časlav Brukner, Giulio Chiribella, Philip Walther

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.

Quantum Optics, Quantum Nanophysics and Quantum Information, Research Network Quantum Aspects of Space Time
External organisation(s)
Southern University of Science and Technology, University of Oxford, University of Hong Kong, Fujitsu Laboratories of Europe Limited, Österreichische Akademie der Wissenschaften (ÖAW), Université de Genève, Institut NÉEL (CNRS), Perimeter Institute for Theoretical Physics
Physical Review Research
No. of pages
Publication date
Peer reviewed
Austrian Fields of Science 2012
103025 Quantum mechanics, 103026 Quantum optics
ASJC Scopus subject areas
Physics and Astronomy(all)
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