Single and collective regimes in three-level systems interacting with a one-mode electromagnetic field

8th International Symposium on Quantum Theory and Symmetries

Castaños, O.^1 ; Cordero, S.^1 ; López-Peña, R.^1 ; Nahmad-Achar, E.^1

Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Apdo. Postal 70-543, México 04510 D.F, Mexico^1

关键词: Catastrophe theory;    Equilibrium properties;    Expectation values;    Quantum phase transitions;    Semiclassical analysis;    Three level atoms;    Three level systems;    Totally symmetric;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/512/1/012006/pdf
DOI  :  10.1088/1742-6596/512/1/012006

来源: IOP

【 摘 要 】

A semiclassical analysis is presented to determine the quantum phase transition from single to collective regimes in three-level atoms in the presence of a radiation field. The energy surfaces of the Ξ, V, and Λ configurations are constructed by taking the expectation value with respect to U(3) coherent states that carry the totally symmetric representation, determined by the total number of atoms. The corresponding stability and equilibrium properties are calculated by means of the catastrophe theory, discovering the bifurcation and Maxwell sets. We establish that the atoms with Λ and Ξ configurations have the presence of double points, i.e., there are two independent quantum states with the same energy that can be obtained depending on the values of the dipolar strengths of the interaction between the atoms and the radiation field. Additionally, the Ξ configuration exhibits a fixed triple point.