Interacting of two level atom with amplitude coherent states have been studied by use of the Jayness-Cummings model,transition probability between every two levels of the system for atom and photon-field is also studied. At the same time, evolution of the field entropy is discussed.
The properties of the field quantum entropy evolution in a system of a single-mode squeezed coherent state field interacting with a two-level atom is studied by utilizing the complete quantum theory, and we focus our attention on the discussion of the influences of field squeezing parameter γ, atomic distribution angle θ and coupling strength g between the field and the atom on the properties of the evolution of field quantum entropy. The results obtained from numerical calculation indicate that the amplitude of oscillation of field quantum entropy evolution decreases with the increasing of squeezing parameter γ, and that both atomic distribution angle θ and coupling strength g between the field and the atom can influence the periodicity of field quantum entropy evolution.
An exact solution of the problem of two two-level atoms with nondegenerate two-photon transitions and intensitydependent coupling interacting with two-mode radiation field is presented. Asymptotic solution for system state vector is obtained in the approximation of large initial coherent fields. The atom-field entanglement is investigated on the basis of the reduced atomic entropy dynamics. The possibility of the system being initially in a pure disentangled state to revive into this state during the evolution process is shown. Conditions and times of disentanglement are derived.
By using the multiphoton Jaynes-Cummings model,the dynamical properties of the field entropy in the system that consists of a two-level atom interacting with a single-mode field via multiphoton transition are studied.The frequency of the field varying with time in the form of u sin wt has been considered.The results show that the time-evolution behavior of the field entropy is modulated by the frequency variation of field using the numerical.The modulation intensity is enchanced as the amplitude u of frequency variation of field increases.When the amplitude u of the time varying fields is larger than a fixed value,the time-evolution behavior of the field entropy will display periodic oscillation behavior.Its oscillation period agrees with the period of frequency varying.It shows that the evolution of field entropy is influenced by the frequency parameters w and u of the field varying with time.
The properties of quantum field entropy evolution in the system of a single-mode squeezed coherent states field interacting with a pair of identical coupled two-level atoms is studied by utilizing of the complete quantum theory,and the influences of the field squeezing parameter,the coupling strength between the field and the atoms and the coupling strength between the two identical two-level atoms on properties of evolution of quantum field entropy are discussed.The results obtained from the numerical results indicate that the field squeezing parameter influences the amplitude of vibration of the field quantum entropy evolution,the coupling strength between the field and the atoms affects the periodicity of the evolution of the field quantum entropy,while the coupling strength between the two identical two-level atoms influences not only the amplitude of the oscillation of the field quantum entropy evolution but also its periodicity.
We investigate some of the fundamental features of the interaction of squeezed light with two-level atoms in the framework of the Jaynes-Cummings model. We start our analysis by calculating the collapses and revivals of the atomic inversion. We discuss the degree of purity of the field (given by the entropy) and its disentanglement from the atomic source. The connection with the evolution of the Q-function is also made. We notice that contrary to the coherent state case, the field turns into a nearly pure (squeezed) state at the revival time as if the field was prepared in a coherent state. The field also becomes a superposition of squeezed states at half of the revival time, and this is confirmed by investigating the photon number distribution. The phase properties of the field are discussed using the Pegg-Barnett formalism.