Entropy squeezing and atomic inversion in the K-photon Jaynes–Cummings model in the presence of the Stark shift and a Kerr medium:A full nonlinear approach

The interaction between a two-level atom and a single-mode field in the k-photon Jaynes-Cummings model （JCM） in the presence of the Stark shift and a Kerr medium is studied. All terms in the Hamiltonian, such as the single-mode field, its interaction with the atom, the contribution of the Stark shift and the Kerr medium effects are considered to be f-deformed. In particular, the effect of the initial state of the radiation field on the dynamical evolution of some physical properties such as atomic inversion and entropy squeezing are investigated by considering different initial field states （coherent, squeezed and thermal states）.

Influence on Atomic Inversion Evolution in Medium System from Compton Scattering

In Jaynes-Cummings model,by using the modulation of the coupling coefficient formed by the atom,medium and scattering optical,atomic inversion evolution of arbitrary forms has been worked out.Its feasibility has been proved,and the curvature of the atomic inversion evolution of the arbitrary forms is obtained.It announces that the atom and coupling medium system are to express the operators of the atom and optical field quantum in Jaynes-Cummings model.These operators can express arbitrary medium system.In these systems,the coupling coefficient can be changed and exactly controlled in the longer coherent times.

Time evolution of atomic inversion in a standing wave light field

The interaction between an atomic beam of two-level atoms and a standing wave light field has been studied by the exact solution of a time-dependent quantum system developed recently. When the initial atomic state is choosen to be ground, we find that with the limit of zero detuning the atoms will oscillate between the upper and the lower levels with a decaying amplitude. The most interesting result obtained in this paper is when the initial atomic state is a particular superposition of the two levels, now the system does not oscillate at any time.

Inversion of an Atomic Wave Packet in a Circularly Polarized Electromagnetic Wave

We study behavior of an atomic wave packet in a circularly polarized electromagnetic wave, and particularly calculate the atomic inversion of the wave packet. A general method of calculation is presented. The results are interesting. For example, if the wave packet is very narrow or/and the interaction is very strong, no matter the atom is initially in its ground state or excited state, the atomic inversion approaches zero as time approaches infinity. If the atom is initially in its ground state and excited state with the probability 1/2 respectively, and if the momentum density is an even function, then the atomic inversion equals zero at any time.

Entropy squeezing of an atom with a k-photon in the Jaynes-Cummings model

The entropy squeezing of an atom with a k-photon in the Jaynes Cummings model is investigated. For comparison, we also study the corresponding variance squeezing and atomic inversion. Analytical results show that entropy squeezing is preferable to variance squeezing for zero atomic inversion. Moreover, for initial conditions of the system the relation between squeezing and photon transition number is also discussed. This provides a theoretical approach to finding out the optimal entropy squeezing.

Quantum Collapse and Revival of Atom in Mode-Mode Competing System

The atomic inversion dynamics in the mode-mode competing system is studied bymeans of fully quantum theory. A general solution to the Schroedinger equation of this system isobtained. The influence of the relative competing strength between the atom and the two-mode Geld onthe atomic inversion is disccussed. We show that the presence of the mode-mode competition canresult in periodical collapses-revivals of the atomic inversion.

INFLUENCE OF VIRTUAL PHOTON FIELD ON COLLAPSE AND REVIVAL PHENOMENON IN TWO PHOTON J C MODEL WITHOUT RWA

The time evolution of system in two photon Jaynes Cummings (J C) model without rotating waves approximation (RWA) is obtained by using the theory of ordinary differential equations. Based on the evolution, the mean value of the atom inversion operator 〈 S 3(t)〉 is gi ven. The influence of the “counter rotating term” on the collapse and revival phenomenon is discussed from the comparison between the cases with RWA and without RWA. It shows that the influence of the virtual photon field makes the quantum fluctuations appear on the collapse and revival phenomenon.

Exact Solution of the Milburn Equation for the Coupled—Channel Cavity QED Model

We give the exact solution of Milburn equation for a coupled-channel cavity QED model which includes the Stark term and the frequency detuning, and study the influence of the intrinsic decoherence on the atomic inversion of the system.

The Pancharatnam Phase of a Three-Level Atom Coupled to Two Systems of N-Two Level Atoms

In this paper, we present the analytical solution for the model that describes the interaction between a three-level atom and two systems of N-two level atoms. The effects of the quantum numbers and the coupling parameters between spins on the Pancharatnam phase and the atomic inversion, for some special cases of the initial states, are investigated. The comparison between the two effects shows that the analytic results are well consistent.

Spontaneous Emission Originating from Atomic BEC Interacting with a Single-Mode Quantized Field

In this paper we present a general theoretical model for the interaction between a number of two-level atoms constituting Bose-Einstein condensate （BEG） and a single-mode quantized field. In addition to the usual interacting terms, we take into account interatom as well as higher-order atom-field interactions. To simplify the Hamiltonian of system, after using the Bogoliubov approximation we proceed to calculate the transformed operators of atoms and field. Then, to quantify the spontaneous emission, we get analytical expressions for the expectation value of Jz as the atomic population inversion （API）, in the cases of number and coherent states for the atomic subsystem. Our results show that the above-mentioned model interaction leads to the appearance of collapse-revival phenomenon in API. In more detail, the revival time may be tuned by adjusting the interatom interaction constant. Also, the damping process lowers the amplitude of API, but does not change the CR times for weak damping. Moreover, increasing the damping may decrease the number of CRs in a given interval of time such that no revival occurs. Briefly, it may be concluded that in the resonant case the revival times are insensitive to the change of the higher-order atom-field interaction constant and are affected only by the interatom interactions. Finally, we express that, how we can find a practical procedure to measure the quantum states of atoms in BEG.