This book highlights practical quantum key distribution systems and research on the
implementations of next-generation quantum communication as well as photonic quantum device
technologies. It discusses how the advances in quantum computing and quantum physics have
allowed the building launching and deploying of space exploration systems that are capable of
more and more as they become smaller and lighter. It also presents theoretical and experimental
research on the potential and limitations of secure communication and computation with quantum
devices and explores how security can be preserved in the presence of a quantum computer and
how to achieve long-distance quantum communication. The development of a real quantum computer
is still in the early stages but a number of research groups have investigated the theoretical
possibilities of such computers.
