In this paper, a novel deterministic secure quantum communication scheme with four-qubit W states is proposed. By utilizing four kinds of unitary operations, the two legitimate users can directly transmit the secret messages based on the Bell measurements and some additional classical information. Analysis shows that our scheme has a high capacity as each W state can carry two bits of secret information, and has a high efficiency as the intrinsic efficiency approaches the maximal value 100% and the total efficiency is 33.3%. Moreover, this scheme is unconditionally secure and feasible with present-day technique.
['Wenjie Liu', 'Hanwu Chen', 'Tinghuai Ma', 'Wei Tian']
An Efficient Deterministic Secure Quantum Communication Scheme with W State