Research On Controlled Teleportation And Quantum Secure Dialogue By Quantum Entanglement

As the communication between people become more and more convenient, the demands on information exchange has been growing steadily, people pay more attention to the information security, quantum information is the product under this particular circumstance. Quantum information is a new interdiscipline which combined of quantum theory and information theory in nineteen-eighties, so far it has a development history of nearly three decades. It is a theory based on quantum entanglement, mainly including quantum private communication, quantum teleportation and quantum dense coding. As the core of quantum information, the realization of quantum entanglement is particularly important, and cavity quantum electrodynamics is recognized as one of the most promising schemes.In this paper, our research involved in the preparation of quantum entanglement,quantum teleportation and quantum private communication. The article is divided into four chapters, here is the content overview and innovation points:In chapter one: we introduce the background of the birth of quantum information.emphasis on the quantum communication which is the main research of quantum information, display the theoretical and experimental research achievements of domestic and overseas in the past 30 years, and show this paper’s main tasks and significance of research.In chapter two: we put forward cavity QED scheme which currently has a perfect theory and develop most for the preparation of quantum entanglement. Take preparation of EPR entangled states as an example, a scheme of prepare four-atom W states, GHZ class states and five-atom Brown states is proposed. The key to the success of those schemes depends on the sequence of atoms injected and the interaction time between atoms and the cavity. Of which, the scheme of highly detuned cavity QED with the assistance of a strong classical driving field to prepare five-atom Brown state is the easiest to achieve in experimentally.In chapter three: a scheme of controlled quantum teleporting entangled two-qubit state based on four particle GHZ state is innovatively proposed. On account of the controlled party’s intervene, the security of the above scheme is guaranteed.Considering the bidirectional of the real communication, we further propose controlled two-way teleportation via six-qubit maximally entangled state. Both legalsides and the controller sharing six-qubit maximally entangled state in this scheme.Since six-qubit maximally entangled state has more sustainable entanglement than GHZ class states and W states, therefore our scheme has largely improved whether in practical or in safety. Because of the maximally entangled state used in both schemes,the success rate are both 100 percent in principle.In chapter four: we propose controlled secure quantum dialogue based on Bell state and five-qubit Brown state respectively. Owing to the added entangled particles and the process of eavesdropping detection, the efficiency and security of later improved than former, and the later scheme up to the absolute safety which deserve to be called an indeed private communication.