Intensity-dependent Jaynes-Cummings Model Research Articles

Generation of a class of SU(1,1) coherent states of the Gilmore–Perelomov type and a class of SU(2) coherent states and their superposition

In this paper, we first suggest a scheme for the generation of a particular class of Gilmore–Perelomov-type SU(1,1) coherent states, which may be established as nonlinear coherent states. The proposal employs a two-level atom that interacts with a single-mode quantized cavity field (by using an intensity-dependent Jaynes–Cummings model) and at the same time a strong external classical field. The time evolution of the system first leads to the generation of a superposition of SU(1,1) coherent states. Depending on the initial states of the atom and the field which may be appropriately prepared, and also under the conditions in which the atom is detected (in the excited or ground state) after the occurrence of the interaction, the field will be collapsed to arbitrary combinations or a single class of Gilmore–Perelomov-type SU(1,1) coherent states. Then, it is shown that, following a similar procedure, our proposed scheme can successfully generate various superpositions and, in particular, a single class of SU(2) coherent states, too.

COLLAPSE AND REVIVAL OF ATOMIC ENTANGLEMENT IN AN INTENSITY DEPENDENT JAYNES–CUMMINGS INTERACTION

The evolution of entanglement of a bipartite spin-1/2 system coupled to a micromaser cavity field in an intensity-dependent Jaynes–Cummings model is studied in this paper. The dynamical process of the entanglement is investigated for different cavity fields. We find that the interactions lead to a phenomenon of periodic entanglement and disentanglement between the qubits. Effects such as the growth of the magnitude of atomic entanglement with the increase of the cavity photon number, arising out of the intensity-dependent atom-cavity coupling lead to interesting dissimilarities from the case of entanglement generated by the standard Jaynes–Cummings interaction.

A NEW FEATURE ON THE SUDDEN DEATH OF ENTANGLEMENT

Based on the exactly analytic solution obtained of the intensity-dependent Jaynes–Cummings model for a certain class of initial entangled mixed states, we explore the time evolution of the entanglement between two atoms, initially non-locally correlated and separately interacting with two distinct cavities. The results show that entanglement sudden death is dependent on the different initial states of atoms, and the length of the time interval for the zero entanglement is invariant for a certain class of initial mixed states.

Revival-collapse phenomenon in the quadrature squeezing of the multiphoton intensity-dependent Jaynes–Cummings model

For the multiphoton intensity-dependent Jaynes–Cummings model (JCM) described by a two-level atom interacting with a radiation field, we prove that there is a relationship between the atomic inversion and the quadrature squeezing. We give the required condition to obtain best information from this relation. Also we show that this relation is only sensitive to large values of the detuning parameter. Furthermore, we discuss briefly such relation for the off-resonance standard JCM.

A theoretical scheme for generation of nonlinear coherent states in a micromaser under intensity-dependent Jaynes-Cummings model

In this paper we propose a theoretical scheme to show the possibility of generating various families of nonlinear (f-deformed) coherent states of the radiation field in a micromaser. We show that these states can be provided in a lossless micromaser cavity under the weak Jaynes-Cummings interaction with intensity–dependent coupling of large number of individually injected two-level atoms in a coherent superposition of the upper and lower states. In particular, we show that the so-called nonlinear squeezed vacuum and nonlinear squeezed first excited states, as well as the even and odd nonlinear coherent states can be generated in a two-photon micromaser.

INFLUENCE OF SUPERPOSITION OF COHERENT STATES OF LIGHT ON THE EVOLUTION OF THE FIELD ENTROPY AND ENTANGLEMENT IN THE INTENSITY-DEPENDENT JCM

We investigate the influence of superposition of coherent states of light on population inversion and the evolution of the field entropy for two-level atoms in the framework of the Jaynes–Cummings model. We compare the behavior of the system in the case of having a coherent superposition state and a statistical mixture of coherent states as an initial field. Our results show that the superposition of coherent states plays an important role in the evolution of the field entropy in the intensity-dependent Jaynes–Cummings model (JCM).

Real and imaginary negative binomial states

The real and imaginary negative binomial states formed by a superposition of the negative binomial states are introduced. The sub-Poissonian statistics, Wigner function and squeezing properties of the real and imaginary states are studied in detail. The oscillatory character of the photon distribution due to the quantum interference between the two components is shown. Moreover, we find that these states are real and imaginary nonlinear Schrodinger cat states and give the corresponding ladder operator formalisms. We also discuss how to generate these general real quantum superposition states based on the intensity-dependent Jaynes-Cummings model.

Exact eigenstates of the intensity-dependent Jaynes–Cummings model with the counter-rotating term

We have investigated the eigenenergy spectrum of the intensity-dependent Jaynes–Cummings (JC) model with and without the rotating-wave approximation (RWA). Our analysis has indicated that the counter-rotating term dramatically changes the nature of the RWA energy spectrum and that the non-RWA spectrum can be approximated by the RWA spectrum only in the range of a sufficiently small coupling constant. Furthermore, the intensity-dependent JC model without the RWA is well defined only if the coupling parameter is below a certain critical value. As a result, the dynamics of the intensity-dependent JC model without the RWA is significantly different from its RWA counterpart. For instance, the counter-rotating term can dramatically enhance the field squeezing effect. Furthermore, we believe that our results are of immediate relevance to the system of a trapped and laser-irradiated ion, which has been shown to exhibit an intensity-dependent JC dynamics recently.

Quantum dynamics of the intensity-dependent Tavis-Cummings model

An exactly solvable generalization of the intensity-dependent Jaynes-Cummings model to the case of N0 atoms is introduced together with its solution. The quantum dynamics of the model including the squeezing properties of the su(1,1) Perelomov and Glauber coherent states is investigated. The cases of one and two atoms present in the cavity are analysed in detail. These two cases are compared in the situation when the atomic subsystem is initially prepared in the ground state, the Dicke state and the state of thermal equilibrium.

The multiquantum intensity-dependent Jaynes–Cummings model with the counterrotating terms

Abstract In this paper we have investigated the eigen energy spectrum of the k-photon intensity-dependent Jaynes–Cummings (JC) model without the rotating-wave approximation (RWA). Our analysis shows that for k⩾2 the k-photon intensity-dependent JC model without the RWA does not have eigenstates in the Hilbert space spanned by the photon number states, i.e. the model becomes ill-defined. Hence, the k-photon intensity-dependent JC model without the RWA is qualitatively different from the RWA counterpart which is valid for all values of k and the coupling parameter. As a consequence, previous studies of the effects of the counterrotating terms in the k-photon intensity-dependent JC model for k⩾2 are all invalid.

Field purification in the intensity-dependent Jaynes-Cummings model

We have found that, in the intensity-dependent Jaynes-Cummings model, a field initially prepared in a statistical mixture of two coherent states, |α〉 and | − α〉, evolves toward a pure state. We have also shown that an even-coherent state turns periodically into a rotated odd-coherent state during the evolution.

PRODUCTION AND DETECTION OF SCHRDINGER CAT STATE AND ITS EFFECT ON THE EVOLUTION OF JAYNES-CUMMINGS MODEL

In this article, we have studied how to generate macroscopic quantum superposition states in electromagnetic field, the Schrodinger cat states, from the large-detuning degenerate Raman process and the large-detuning two-photon Jaynes-Cummings model. The homodyne detection of these states is also discussed. When the initial state of the field is the Schrodinger cat state, the effects of the cat state on the collapse and revival phenomena in the intensity-dependent Jaynes-Cummings model are investigated. The revival in varying degrees occurs in the collapse region resulted from the evolution of initial coherent state.

Generation of Even and Odd Coherent States in the Intensity Dependent Jaynes—Cummings Model

Abstract We study the evolution of the wavefunction in the intensity dependent Jaynes—Cummings model. It is shown that apart from the periodic revivals indicated by the dynamics of inversion, half-time revivals of the wavefunction take place in the limit of [nbar] ≫ 1. The decoupled atomic state is a superposition of the upper and lower levels and is independent of the initial atomic condition. The decoupled field state is an even or odd coherent state with a spiked distribution function, depending on the initial atomic state.