It is shown that the system of a three-level atom coupled to two modes of quantized cavity fields in the \ensuremath{\Xi} configuration with arbitrary detunings can be exactly reduced to a two-level system with an effective coupling which depends nonlinearly on the intensity of the two cavity fields.
It is shown that the system of a three-level atom coupled with two modes of quantized cavity fields in the V-configuration with arbitrary detunings can be exactly reduced to a two-level system with a nonsingular effective coupling which depends nonlinearly on the intensity of the two cavity fields. By performing a unitary transformation, we obtain an exact transformed Hamiltonian in which one of the three levels is decoupled for all values of the detunings including the zero-detuning. We also present the analytical expressions of energy eigenvdues and eigenvectors, evolution operator, time-varying atomic inversion operator and photon number operators of the two modes for the effective two-level model.
It is shown that a three-level atom in the \ensuremath{\Lambda} configuration with arbitrary detunings can be exactly reduced to a two-level system with an effective Raman coupling, which depends nonlinearly on the intensity of the two radiation fields. This is done by exactly evaluating the unitary transformation introduced by Alexanian and Bose [Phys. Rev. A 52, 2218 (1995)] for a three-level atom coupled to two modes of the radiation field. We obtain an exact transformed Hamiltonian in which one of the three levels is decoupled for all values of the detunings. In particular, our result is then valid for any ratios of the coupling constants to detunings, even for zero detuning, in contrast to earlier work which requires that these ratios be small. We find the the eigenvalues of the exact transformed Hamiltonian and study its population dynamics. \textcopyright{} 1996 The American Physical Society.
The system of a three-level atom in the Ξ configuration coupled to two quantized field modes with arbitrary detuning and density-dependent multiphoton interaction is studied by dynamical algebraic method. With the help of an su(3) algebraic structure, we diagonalize the Hamiltonian by making use of unitary transformations and obtain the eigenvalues, eigenstates and time evolution operator for the system. Based on this su(3) structure, we also show that the system of a three-level atom in the Ξ configuration can be exactly transformed to an effective two-level Hamiltonian by an unitary transformation. Finally, we show that there exist an su (N) algebraic structure in the system of a N-level atom interacting with N-1 field modes.
In this paper, the problem of a three-level atom interacting with a single mode of the quantized electromagnetic cavity field is considered. The considered theoretical model describes the distinct configurations of a three-level atom. Also, this model includes a detuning and arbitrary forms of both the field and the intensity-dependent atom-field coupling. We obtain the general forms for both the constants of motion and the wavefunction when the atom is initially prepared in one of its states. We use this model for computing a number of statistical aspects of the three-level system. As an illustration, we use the model for studying the time evolution of the second-order correlation function when the atom is initially in an upper state and the field is considered in a coherent state.
We study the interaction of a three-level atom with a single-mode field in a cavity. We take explicitly into account the existence of the forms of nonlinearities of both the field and the intensity-dependent atom-field coupling. The wavefunction for the atomic system of the Ξ configuration is obtained when the atom is initially prepared in the excited state. The electromagnetic field may assume a squeezed coherent or binomial state. The analytical forms of the fluorescence and absorption spectra are calculated using the dressed states of the system. We investigate the influences of the mean number of photons, detunings, and the nonlinearities forms on the spectrum of the resulting field states. It is shown that the features of the fluorescence and absorption spectra are influenced significantly by the kinds of nonlinearities.
A treatment of a multi-photon Ξ-type three-level atom interacting with a single-mode field in a cavity, taking explicitly the existence of forms of nonlinearities of both the field and the intensity-dependent atom–field coupling into account. Analytical expressions of the emission spectrum are presented using the dressed states of the system. The characteristics of the emission spectrum, considering the field to be initially in a binomial state, are exhibited. The effects of the photon multiplicities, mean number of photons, detuning, and the nonlinearities on the spectrum are investigated.