Satellite-Based Photonic Quantum Networks Are Small-World

Recent milestone experiments establishing satellite-to-ground quantum communication are paving the way for the development of the quantum Internet, a network interconnected by quantum channels. Here, we employ network theory to study the properties of the photonic networks that can be generated by satellite-based quantum communication and compare them with those of their optical-fiber counterpart. We predict that satellites can generate small-world networks, implying that physically distant nodes are actually near from a network perspective. We also analyze the connectivity properties of the network and show, in particular, that they are robust against random failures. This positions satellite-based quantum communication as the most promising technology to distribute entanglement across large distances in quantum networks of growing size and complexity.