Open-Air Quantum Microwave Communications: Generation, Propagation and Detection

Quantum communications has emerged as an important paradigm for achieving secure fast communications. Significant technological breakthroughs have been achieved in this area over the years using quantum optics. In contrast, quantum microwaves are recently beginning to receive increased attention, due in part to the potential for an easier integration with current microwave communications infrastructure. This paper explores the generation, propagation and detection of quantum microwaves as processes required for open-air communication. It presents a brief description of the theory and provides a summary of recent progress in these operations. The paper ends by highlighting challenges regarding the practical realization of this technology.