Feasibility Study On Anti - Intuitionistic Quantum Communication Scheme

With the wide application of communication technology in the society, the security of the communication has become the most important consideration in the information transmission. As the safety of the secret key distribution is the heart of communication, in 1984, Bennett and Brassard proposed the famous protocol for quantum key distribution (QKD), known as BB84 based on the non-clone theorem in the quantum systems. In the BB84 protocol, the security of protocol is guaranteed using single photon sent by Alice. For a high loss or not a perfect single photon state, Hwang proposed a decoy-pulse method to guarantee the security under the photon-number-splitting attack for the BB84. Another celebrated QKD protocol is E91 [6], which is based on the quantum entanglement. At same time, using the electromagnetic field amplitudes of "non-classical" light beams (squeezed or entangled light) to QKD also draw much attention.Recently, Salih et.al. proposed a protocol to realize direct counterfactual communication based on the previous work, which shown how to make an interaction free measurement(IMF). Here, direct means that no need for a prior quantum key distribution, and counterfactual means that no need for a particle transmitted in the public channel between Alice and Bob.In the protocol, they assumed an ideal condition that there is no dissipation and phase fluctuation in the devices (BSs, mirrors and field paths), and infinite number of BSs. However, in a real experiment, the finite number of BSs (usually less BSs is better), the dissipation (including the BSs themselves) and the phase fluctuation of the paths could not be avoided.Therefore, in the first part of our work, we consider the effect of the dissipation and the phase fluctuation on the direct communication, and analyze how the reliability of the direct communication can be preserved. Our calculation shows that the dissipation and phase fluctuation will dramatically decrease the reliability and the efficiency of communication, even to corrupt the communication. To counteract the negative effect of dissipation, we propose the balanced dissipation method, which substantially improves the reliability of protocol with an expense of decreasing communication efficiency.The counterfactual property in the protocol (no need for a particle transmitted in the public channel between Alice and Bob) has promised that there is no information leaks in the communication. However, Vaidman L. does not share the same opinion. Based on the weak measurement, he proposed the two state vector formalism (TSVF), which can provide the particle’s path information. The conclusion of TSVF shows that there is a trace left by the particle transmitted between Alice and Bob. Thus the counterfactual property does not exist in the direct communication, and IMF is also incorrect.The second part of our work will determine the argument on the counterfactual property in the direct communication. An experiment, which uses quantum non-demolition (QND) measurements to reveal the photon’s trace, is proposed. Our conclusion supports the Salih that there is no particle transmitted in the public channel between Alice and Bob. Our conclusion not only removes doubts or settles the argument on the counterfactual communication, while it also alerts us to the fact that we should pay attention to the weakness and limitations of the weak measurement and TSVF when we use them.We hope that our work can provide a theoritical foundation and experiment guide to the direct coumterfactual communication.