Interaction of a two-level atom with an external field

�. V. Lugin, Stanislav D. Tvorogov

Hammad Alotaibi, Eied Mahmoud Khalil, S. Abdel‐Khalek +1 more

In this study, we consider three interacting atoms, one of them represented by N-level atom based on SU(2) Lie algebra and the other represented by a two two-level atom in presence of the external field. The effect of the external field on the dynamics of the proposed system is discussed in detail for certain values for the external field. The dynamical expression of the observable operators is obtained by using the Heisenberg equation of motion. The general solution via solving Schrodinger equation is obtained. The fidelity and concurrence formula as a measure of entanglement between two two-level atom are calculated and discussed in detail. We explore the sudden death and sudden birth phenomena with and without the presence of external field. Finally, we compare the results of the fidelity, concurrence and second-order correlation function for some values of the initial state and the external field parameters.

Dipankar Bhattacharyya, Jyotirmoy Guha

Deng-Yu Zhang

The coherence of two-level atom in a thermal radiation field without rotating wave approximation through an external controllable driving field was investigated. The time evolution properties of non-opposite angle element of two-level atom's reducible density rectangular array was discussed. Coherence properties of two-level atom was studied in degenerate two-photon processes when the two-level atom interacts with an driving field in the thermal radiation field . We obtained the properties of an external driving field when two-level atom's coherence is maintained.

Aleksandr V Vinogradov

The Keldysh diagram technique is used in the problem of a two-level atom interacting with an external field and a thermostat. A system of kinetic equations is obtained for an arbitrary external field. The special cases of the kinetic equations in weak and strong fields are derived by going to the appropriate limits. In the case of some specific cases new formulas are found for the absorption, resonance fluorescence, and polarization of a two-level atom in an external electromagnetic field.

Peter R. Fontana