The Role of the Satellite in Quantum Information Networks

Quantum Information Networks (QIN) attract increasing interest, as they will enable interconnection of multiple quantum devices in a distributed organization thus enhancing intrinsic computing, sensing, and security capabilities. The core mechanism of a QIN is quantum state swapping, based on teleportation, which consumes quantum entanglement, and which can be seen in this context as a new kind of network resource. The satellite is expected to play a central role for supporting global connectivity in such novel networks in which ground fiber links have stringent restrictions in length due to the absorption losses in optical fibers. There is indeed fundamental limits in the maximal fiber links distance which may not be exceeded for any unitary links. In this paper we clarify our motivations to develop such networks with satellites, and we discuss their associated use cases based on entanglement distribution, and we present the future potential users. We also assess quantitatively the ranges for which the satellite becomes mandatory in quantum information networks.