Exploring The Quantum Frontier: Applications, Challenges, and Future Directions In Quantum Communication Technologies

Quantum Communication becomes a new field of communication technologies with highly diverse applications, and much complexity, and is a promising area deserving further exploration. This paper aims to provide a complete expository of quantum communication, describing the principles that govern it, which is quite different from classical communication. However, the paper also reflects on how the industrialization of quantum communication was achieved and examples of funded projects that were developed. Quantum communication is then considered in the context of $6 G$ networks, IoT, government, and defense to show the typical use of quantum communication in future information processing and secure communication domains. The paper aims to integrate the most recent developments, difficulties, and future outlook of the subject, hence serving as a thorough manual for researchers and practitioners operating in a complicated landscape of quantum communication technologies.