Mutual Information In The Interaction Of Electromagnetic Field With Atoms

In the rapid development and application of classical electromagnetic theory, quantum electromagnetic theory has been intensively and extensively developed and applied. In particular, the advent of quantum information science has motivated the development of quantum electromagnetic theory. In this thesis, we study the mutual information and the tripartite quantum entanglement in an important model of the quantum electromagnetic field interacted with atoms. Moreover, we discuss the relationship between bipartite and tripartite entanglement in the model.Quantum mutual information and entanglement concurrence are two important quantities in quantum information science. The investigation on those two quantities is, however, limited to bipartite systems. In order to cover such drawback, we firstly summarize the novel development in the study of electromagnetic theory and quantum information. We briefly review quantum electromagnetic theory and several quantities in both classical and quantum information theory, so as to build a theoretical base for the following discussion. Secondly, we analytically and numerically explore the dynamics of quantum mutual information and entanglement concurrence for various initial states and couplings in the model of quantum electromagnetic field interacted with atoms. We further introduce a parameter to describe the dynamical correlation between mutual information and concurrence. The calculated results show that those two quantities are positive- or anti-correlated in irregular manner. However, they exhibit positive correlations under the localized states with lower excitation and weak couplings. Moreover, three bipartite-entanglements are positively correlated, so do they and concurrence. Those are helpful in the construction of a proper measure of quantum entanglement, and in the motivation of the deep investigation of multipartite systems from the achievement in bipartite entanglement. Finally, we discuss next work in future. The main results have been published (Int. J. Mod. Phys. B 29,1550063 (2015)).