Narrow Results

We study the interaction between a moving four-level rubidium atom and a single mode cavity field in the presence of a nonlinear Kerr-like medium. We derive the basic equations of motion for the atomic system and show that it is exactly solvable in the rotating wave approximation. The momentum increment, the momentum diffusion and the quasi-probability distribution Q-function of this system are studied. We investigate numerically the influence of the Kerr medium on the evolution of the previous statistical properties in the exact resonant and nonresonant cases where the atom is initially in the ground state and the field is in a coherent state. It is found that the Kerr medium has an important effect on their evolutions. Finally, conclusions and discussion are given.

Schemes for the teleporting of the cavity mode state and the unknown atomic state are proposed in cavity quantum electrodynamics (QED) without joint Bell-state measurement (BSM). The presented schemes are implemented with separate atomic measurements instead of any type of joint measurement. The discussion of the scheme indicates that it can be realized by current technologies.

We investigate the entanglement of two two-mode two-photon Jaynes–Cummings models in the presence of phase decoherence. We find an explicit analytical solution of the system and discuss the influence of the phase decoherenc on the entanglement dynamics. Our results shows that the entanglement of the two initially entangled atoms can remain zero for a finite time and revive later. However, if the phase decoherence is taken into accounted, the entanglement cannot revive completely.

In this article, the problem of a double Ξ-type four-level atom interacting with a single-mode cavity field is considered. The considered model describes several distinct configurations of a four-level atom. Also, this model includes the detuning parameters of the atom-field system. We obtain the constants of motion and the wavefunction is derived when the atom is initially prepared in the upper state. We used this model for computing a number of the field aspects for the considered system. As an illustration, the model is used for studying the time evolution of the Mandel Q-parameter, amplitude-squared squeezing phenomenon and Q-function when the input field is considered in a coherent state. The results show that these phenomena are affected by the presence of detuning parameters.

The atomic system on which we focus is a single four-level atom interacting with two-mode cavity fields. We obtain the wavefunction when the atom is initially in an excited state. The result presented in this context is employed to discuss the collapses–revivals phenomenon, the photon statistics and frequency sum squeezing phenomenon. The influence of the detuning on these phenomena are investigated for two four-level atomic systems. We found that the presence of the detuning leads to an increase of the collapse time while the amount of squeezing decreases. Also, the photon statistics is affected by the existence of the detuning parameters where the anti-bunching effect appears.

We propose a one-step cluster state generation scheme via atomic cavity QED. The current scheme is insensitive to the cavity mode thermal state as well as the atomic spontaneous emission since the gate operations are independent of the cavity mode states and laser power is sufficiently weak. In addition, the needed operation is of geometric nature, so it is robust against random operation errors.

We propose a simple scheme for realizing two-qubit logic gate in cavity QED. In our scheme, the quantum controlled-not gate, phase gate and swap gate can be implemented without the ancillary level. The quantum controlled-not gate and phase gate can be realized easily by only one interaction between atoms and a highly detuned cavity mode with the assistance of a strong classical field. Thus, the scheme is insensitive to both the cavity decay and the thermal field.

In this paper, a model describing the interaction of a five-level (⁸⁵Rb) atom with one-mode cavity field including Kerr nonlinearity is discussed. Analytical solution for this model is presented when the atom is initially prepared in its upper state. The obtained results are then employed to examine the dynamical behavior of atomic inversion, field statistics and field squeezing when the input field is initially considered in a coherent state. It is found that the atom-field properties are influenced by the changing of the coupling constants, the detuning parameters and the Kerr medium.

We propose a scheme for concentrating an arbitrary two-particle non-maximally entangled state into a maximally entangled state assisted with three cavities. The scheme involves two interaction–detection cycles and resonant interaction between atom and cavity mode. With the help of the atom trapped in the cavity, the concentration of a two-particle non-maximally entangled state trapped in separate cavities can be realized with a certain probability according to the results of photon detectors. The important feature of our scheme is that we can realize the concentration of an arbitrary two-atom non-maximally entangled state and we do not perform Bell-state measurements.