Challenges in Open-air Microwave Quantum Communication and Sensing

TL;DR

This paper discusses the significant challenges faced in developing microwave-based quantum communication and sensing technologies, highlighting the need for a strategic roadmap to enable real-world applications.

Contribution

It provides a comprehensive analysis of current obstacles in microwave quantum technologies and proposes a roadmap for future development and practical implementation.

Findings

Microwave quantum communication faces unique technological challenges.

Quantum sensing with microwaves is less developed than optical counterparts.

A strategic roadmap is proposed for advancing microwave quantum technologies.

Abstract

Quantum communication is a holy grail to achieve secure communication among a set of partners, since it is provably unbreakable by physical laws. Quantum sensing employs quantum entanglement as an extra resource to determine parameters by either using less resources or attaining a precision unachievable in classical protocols. A paradigmatic example is the quantum radar, which allows one to detect an object without being detected oneself, by making use of the additional asset provided by quantum entanglement to reduce the intensity of the signal. In the optical regime, impressive technological advances have been reached in the last years, such as the first quantum communication between ground and satellites, as well as the first proof-of-principle experiments in quantum sensing. The development of microwave quantum technologies turned out, nonetheless, to be more challenging. Here, we will discuss the challenges regarding the use of microwaves for quantum communication and sensing. Based on this analysis, we propose a roadmap to achieve real-life applications in these fields.