Quantum Information & Computation

Connecting quantum devices to harness their full power is the next step to establish useful applications of quantum technologies. This can happen over short and medium distances, e.g. to connect quantum computers or quantum sensors, or over long distances, with the ultimate goal to develop a quantum internet spanning the whole planet. Such a quantum internet does not only promise secure communication, but also makes quantum applications broadly accessible.

We develop protocols and methods to realize such networks, where establishing, distributing and utilizing multipartite entangled states is of central importance. To this aim, we design and investigate protocols for entanglement purification, entanglement certification and state distribution for different entangled resource states. We tackle these questions not only from a fundamental perspective, but also take practical problems and limitations – decoherence, noise and imperfections – into account, and study their influence and means to mitigate them. Our approach is focused on so-called entanglement-based quantum networks, where pre-established entanglement serves as a resource to perform network tasks and fulfill network requests. We are also interested in the design of such networks from a conceptual perspective, where we propose stack models and protocols beyond the physical layer. Furthermore, we pursue an approach to make quantum networks genuine quantum, by allowing for a quantum control plane with the possibility to perform tasks in coherent superposition – which may offer new and unexplored possibilities.