  Quantum repeaters are essential ingredients for quantum networks that link
distant quantum modules such as quantum computers and sensors. Motivated by
distributed quantum computing and communication, quantum repeaters that relay
discrete-variable quantum information have been extensively studied; while
continuous-variable (CV) quantum information underpins a variety of quantum
sensing and communication application, a quantum-repeater architecture for
genuine CV quantum information remains largely unexplored. This paper reports a
CV quantum-repeater architecture based on CV quantum teleportation assisted by
the Gottesman-Kitaev-Preskill (GKP) code to significantly suppress the physical
noise. The designed CV quantum-repeater architecture is shown to significantly
improve the performance of CV quantum key distribution, entanglement-assisted
communication, and target detection based on quantum illumination, as three
representative use cases for quantum communication and sensing.
