Experimental quantum communication

Harald Weinfurter, Anton Zeilinger

Feihu Xu, Juan Miguel Arrazola, Kejin Wei +6 more

Quantum communication holds the promise of creating disruptive technologies that will play an essential role in future communication networks. For example, the study of quantum communication complexity has shown that quantum communication allows exponential reductions in the information that must be transmitted to solve distributed computational tasks. Recently, protocols that realize this advantage using optical implementations have been proposed. Here we report a proof-of-concept experimental demonstration of a quantum fingerprinting system that is capable of transmitting less information than the best-known classical protocol. Our implementation is based on a modified version of a commercial quantum key distribution system using off-the-shelf optical components over telecom wavelengths, and is practical for messages as large as 100 Mbits, even in the presence of experimental imperfections. Our results provide a first step in the development of experimental quantum communication complexity.

Qiang Zhang

Quantum communication can provide information theoretical security communication based on the basic principle of quantum mechanics. Here, I would like to present the recent experimental progress in our group towards global quantum communication, including measurement device independent QKD over in the lab and metropolitan network, quantum teleprotation and entanglement swapping over metropolitan network, trust node based quantum main trunk line and free space quantum communication.

Michel Le Bellac

Giulia Rubino, Lee A. Rozema, Daniel Ebler +8 more

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.