Progress and applications of quantum communications

In quantum communication, information or signals are transmitted and processed quantum mechanically, with the advantages of high security and high capacity. The main objective of quantum secure communication is to protect the security of information. Quantum secure communication, or quantum cryptography, includes quantum key distribution, quantum secure direct communication, quantum secret sharing, and so on. With quantum entanglement, quantum teleportation can use prior distributed entangled pairs to transmit an unknown quantum state without transmitting the particle itself. Quantum dense coding can transmit the information encoded in two particles by just transmitting one particle. In classical communication, these tasks would be impossible. In this paper we briefly describe the current status of research in quantum communication.