The Field’s Interaction and Atomic Model

Miguel Orszag

Yang Zhi-yong

From the viewpoint of the quantum information theory,the J-C Model of an atom interacting with a single-model light-field is expanded to a union physical system model which consists of M(where M is any positive integer) pairs of two-level atoms and the M cavity-field with interaction respectively.By solving the evolution matrix of the system state vector,the process of the atoms interacting with the light-field is studied and the principle of exchange and preservation of quantum entanglement information in this system is discussed.It is found that not only the atom entanglement but also the light-field entanglement can be transferred and preserved under different time conditions.At the same time,the different form entanglement states can be prepared by using the interaction of the atoms with the cavity-field.

Miguel Orszag

Wangjun Lu, Cuilu Zhai, Shi-Qing Tang

In this paper, we present a method for measuring arbitrary-order correlation functions of the light field using a two-level atomic system. Theoretically, light field information should be mapped onto the atomic system after the light interacts with the atom. Therefore, we can measure the atomic system and thus obtain information about the light field. We study two typical models, the p-photon Jaynes–Cummings model, and the p-photon Tavis–Cummings model. In both models, we find that the pth-order correlation function of an unknown light field can be obtained by measuring the instantaneous change of energy of the two-level atoms with the aid of a known reference light field. Moreover, we find that the interactions other than the dipole interactions between light and atoms have no effect on the measurement results.

Eugene K. Bashkirov, Русакова Маргарита Сергеевна

The exact wave function is found in the work for the two-atom models with nondegenerate two-photon interaction and nondegenerate raman interaction. The asymptotic solutions for system state vectors are obtained in the approximation of strong field for considered models for different initial atom states and coherent field input. The reduced entropy dynamics is described for various initial atomic states and coherent field input, some conclusions about atom-field entanglement are made. We also show the possibility for the system being initially in the pure nonentangled state to revive into this state during the evolution process for the two-atom model with nondegenerate two-photon interaction and we obtain the times of such revivals.