The Entanglement Dynamics Of Two Moving Atoms Interacting With Optical Fields

Quantum information science, as an emerging interdisciplinary field of subjects in computer science, information science and quantum physics, has been established since the 1980s.1980s. Quantum information technology is based on quantum featuress such as quantum entanglement, quantum coherence, quantum non-locality, quantum non-cloning and so on, which are not available for present traditional information techniques. In the past two decades, quantum information technology has attracted domestic and overseas physicists'interests. It has been developing swiftly with plentiful and substantial achievements obtained.In the quantum world, quantum entanglement is the most profound, the most intriguing, the most incredible and wonderful phenomenon, which is totally different from the classical physics. It is also an important resource for quantum information processing and quantum computing. So far, there are lots of extensive researches focused on the essence, evolution, quantification, and applications of quantum entanglement. On the one hand, these researches are helpful to understand the basic problems of quantum mechanics. On the other hand, it will help us to find out the role of the quantum entanglement in quantum information processing. In this thesis, the entanglement of two moving atoms interacting with a single-mode field is investigated by using quantum theory and numerical methods, as well as the entanglement of two moving atoms interacting with a dual-mode field. A series of valuable conclusions are obtained.Chapter I:As an introduction, in this chapter, we introduce the basic principles of quantum information science used in this work:quantum entanglement, as well as its nature and quantification coherent state field, several typical models about interaction between atoms and optical field, and the generalized Tavis-Cummings model.Chapter II:The entanglement of two moving two-level atoms interacting with a single-mode Fock field is investigated in Tavis-Cummings model. The entanglement dynamics of the two atoms are studied by varying the parameters of the initial entanglement of two atoms and the atomic velocity. The results indicate that the influences of these parameters on the two-atom entanglement are remarkable, and the maximum entanglement can be maintained when the some specific parameters are chosen.Chapterâ…¢:The entanglement of two moving two-level atoms interacting with a dual-mode entangled coherent field is also investigated. The results show that the initial entanglement of two atoms, the average photon number of the field and the velocity of atoms affect the entanglement dynamics of the two atoms remarkably. In the weak field case, the oscillating amplitude of the two-atom entanglement dynamics increases with the increase of the fields entanglement. In the strong field case, the dynamics of the entanglement of the two atoms increases with the increasing initial field entanglement. However, the oscillating amplitude of the entanglement dynamics decrease with the increase of the average photon number of the field. When appropriate parameters of the atomic initial state, the fields entanglement, and the atomic velocity are chosen, two-atom entanglement can reach zero in finite time (entanglement sudden death) and then revive in some specific time(entanglement revival). In addition, the sudden death and revival of the two-atom entanglement can be controlled by appropriately selecting the atomic velocity.Chapterâ…£:We will summarize the results and give some outlooks about the further investigation.