  The potential synergy between quantum communications and future wireless
communication systems is explored. By proposing a quantum-native or
quantum-by-design philosophy, the survey examines technologies such as
quantum-domain (QD) multi-input multi-output (MIMO), QD non-orthogonal multiple
access (NOMA), quantum secure direct communication (QSDC), QD resource
allocation, QD routing, and QD artificial intelligence (AI). The recent
research advances in these areas are summarized. Given the behavior of photonic
and particle-like Terahertz (THz) systems, a comprehensive system-oriented
perspective is adopted to assess the feasibility of using quantum
communications in future systems. This survey also reviews quantum optimization
algorithms and quantum neural networks to explore the potential integration of
quantum communication and quantum computing in future systems. Additionally,
the current status of quantum sensing, quantum radar, and quantum timing is
briefly reviewed in support of future applications. The associated research
gaps and future directions are identified, including extending the entanglement
coherence time, developing THz quantum communications devices, addressing
challenges in channel estimation and tracking, and establishing the theoretical
bounds and performance trade-offs of quantum communication, computing, and
sensing. This survey offers a unique perspective on the potential for quantum
communications to revolutionize future systems and pave the way for even more
advanced technologies.
