title: Secure deterministic communication without entanglement.
abstract: We propose a protocol for deterministic communication that does not make use of entanglement. It exploits nonorthogonal states in a two-way quantum channel to attain unconditional security and high efficiency of the transmission. We explicitly show the scheme is secure against a class of individual attacks regardless of the noise on the channel. Its experimental realization is feasible with current technology.
authors.affiliation: Dipartimento di Fisica, Università di Roma La Sapienza, I-00185 Roma, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Lucamarini
authors.forename: Stefano
authors.initials: S
authors.lastname: Mancini