The Evolution Of The Entropy And The Quantum Statistical Properties Of A Coherent Superposition State Interacting With A Two-Level Atom

In the quantum optics field, the study of the quantum properties in the system of the atom interacting with the field has been devoted to considerable attention. It is one of the important contents for the quantum optics to study of the field entropy and non-classical properties of the atom interacting with the field. In this paper, it is mainly discussed that the field entropy,the population inversion in a new system of the coherent superposition state of the squeezed coherent state and vacuum state interacting with a two-level atom,the squeezing effect and quantum statistical properties of the new coherent superposition state. The major content of this thesis is displayed as follows:In chapter 1, the simple development and theory of quantum entropy, non-classical effects of optical field and Schr?dinger cat state are introduced.In chapter 2, we study the field entropy of the system of the coherent superposition state of the squeezed coherent state and vacuum state interacting with a two-level atom. The results show that the field entropy displays quasi-periodicity with increasing time.In chapter 3, we study the population inversion of the coherent superposition state of the squeezed coherent state and vacuum state interacting with a two-level atom. The results indicate that the population inversion of the coherent superposition state have some behaviors of collapse and revival.In chapter 4, we study the squeezing effects, and the quantum statistical properties of the coherent superposition state of the squeezed coherent state and vacuum state. It has been shown that the coherent superposition state exhibits squeezing effects, bunching effect and super-poisson distribution. The squeezing effects depend on the changes of squeezing coefficient r and coherent coefficient S , as well as of coherent state phaseφand squeezing phaseθ.In chapter 5, we study that the quantum entanglement between a squeezed coherent state and aΛ-type three level atom is studied via quantum entropy theory. It has been found that the system could appear steady and maximal entanglement state periodically through modulating the squeezing coefficient, the coherent amplitude factor and the ratio of detuning to coupling constant.