The York Research Database

We present a scheme for secure deterministic quantum communication without using entanglement, in a plug-and-play fashion. The protocol is completely deterministic, both in the encoding procedure and in the control one, thus doubling the communication rate with respect to other setups; moreover, the deterministic nature of transmission, apart from rendering unnecessary bases revelation on the public channel, allows the realization of protocols like 'direct communication' and 'quantum dialogue.' The encoding exploits the phase degree of freedom of a photon, thus paving the way for an optical fiber implementation, feasible with present-day technology.