Multipartite communications over quantum networks

Abstract :
The field of quantum networks is currently a major area of investigation in quantum technologies. One of the simplest acts of quantum communication, the distribution of a single bipartite entangled state, has been highly studied as it is a simple problem to characterize, simulate and implement. It is also useful for a prominent quantum network application: the secured distribution of a cryptographic key. However, the use of quantum networks goes far beyond. We need to study the simultaneous distribution of multipartite states over quantum networks. In this manuscript, we report on several works of progress in the domain. We first study the recycling of previously distributed resources in the asymptotic regime by the use of entanglement combing and quantum state merging. Then, we characterize the distribution of quantum states using the tensor network formalism. We also characterize a broad class of classical distribution protocols by the same formalism and use this similarity to compare the distribution of classical correlations over classical networks to a the distribution of quantum state over quantum networks. We also build protocols to distribute specific classes of states over quantum networks such as graph states and GHZ states by using the graph state formalism and a bit of graph theory. Finally, we implement the previous protocols in a more realistic setting and participate in the elaboration of multipartite features for a quantum network simulator: QuISP. We also aimed to popularize the notions of quantum information to a broad audience. We report on the creation of a video game based on quantum optics, adding to the existing popularization ludography.