Description:

Quantum networks will allow remote users to exchange information by sharing quantum states over large distances. This will greatly improve the security of communication systems using quantum communication protocols, will enhance the computational power of quantum computers by aggregating distributed quantum processors and will increase the sensitivity of measurements with quantum sensing applications. However due to the fragile nature of the quantum states several detrimental errors occur in a real implementation reducing, thus, the performance of such quantum technologies. Quantum error correction is  then used to correct those errors restoring the fidelity of the initial states. A physical quantum state is now encoded in a higher dimensional space using additional resources and sent over a channel connecting two nodes. Once received, the state is decoded and the information is retrieved. Nodes with a small number of physical resources and channels with low capacities might, however, compromise an efficient transmission of the information, reducing the communication rates. One can think of aggregating several paths connecting the nodes over which distributing those resources. Aggregated quantum networks will then release some constraints on the nodes increasing the overall network’s efficiency. A routing mechanism aiming to efficiently distribute those initial resources is then a fundamental issue that must be addressed to optimize the transmission of information. In my talk I will address this issue by introducing a routing protocol that assigns lossy channels of different length connecting two nodes in a quantum aggregation scenario. I will show the impact of the decoherence time on the fidelity of the transmitted encoded states. Then I will illustrate the steps required to optimize the assignment of the channels under specific regimes of operation. Finally I will discuss the main requirements that such a network must satisfy under a practical scenario.

Nicolo Lo Piparo, Assistant Professor, Okinawa Institute of Science and Technology Graduate University, Japan

Host: Istvan Kovacs