The Entanglement In A System Of Multi-atoms Interacting With Field

Quantum information originates from quantum mechanics and information science. In quantum information, the information storage, said and extraction all depend on quantum state and its evolution. Quantum entanglement is no doubt one of the most important subjects, and it not only has an important meaning to know the basic concepts of quantum mechanics, but it is useful information "resources."It plays a critical role in the line of quantum teleportation, quantum dense coding, quantum key distribution, as well as the acceleration of quantum computing, quantum error correction and anti-mistake. In this paper, we extended the Tavis-Cummings (TC) model to consider Multi-atoms or atomic movement of the atoms and the situation of two-photon transition, then we have studied the entanglement properties between a number of two-level atom and a light field, the entanglement properties between two atoms with dipole interaction and a light field with two-photon transition and the entanglement properties between two identical two-level atoms on ground state and a single mode light field with atomic motion and the dipole-dipole interaction. In order to calculate multi- entanglement properties, we have created some formulas according to the three assumptions definite from Horodecki etc. At last, we have calculated the entanglement properties in three(four, multi)-body W-entangled state. This paper includes the following seven chapters:In the first chapter, we introduce the concept of quantum entanglement, the history of the development of quantum information at the application, and describe the paper's subject-selecting background, significance and main work.In the second chapter, we introduces some relevant basic knowledge, entanglement theory then expand standard Tavis-Cummings model to the condition of atomic motion and the dipole interaction.In the third chapter, we have studied the entanglement properties in the T-C model which taking into account the dipole interaction between atoms and two-photon transition. Then we have studied the entanglement properties in the W- entangled state received by the theory discovered by Coffman etc.In the fourth chapter, we have studied the interaction of a two-level atoms on arbitrary state and two different-mode photons on entangled state, then has make detailed analysis of the results.In the fifth chapter, we have studied entanglement properties between two two-level atoms and the Single-mode light field in different initial state when we consider atomic motion and atomic dipole - dipole interaction at the same time.In the sixth chapter, we have studied the multipartite quantum entanglement in interaction of Multiple two-level atoms with a Single Mode Light Field,then we have defined some calculation formula according to three premises to compute the entanglement measure in multipartite quantum states .In the end, we have analyzed the entanglement measure in the three(four, n)-body W-entangled state W-entangled state.In the seventh Chapter which is the final chapter, we have make a summary of preliminary work and make a vision for the future.