Deterministic Secure Quantum Communication with Cluster State and Bell-Basis Measurements

We present a novel protocol for deterministic secure quantum communication by using the four-qubit cluster state as quantum channel. It is shown that two legitimate users can directly transmit the secret messages based on Bell-basic measurements and classical communication. The present protocol makes use of the ideas of block transmission and decoy particle checking technique. It has a high capacity as each cluster state can carry two bits of information, and has a high intrinsic efficiency because almost all the instances except the decoy checking particles (its number is negligible) are useful. Furthermore, this protocol is feasible with present-day technique.