A general system of n levels interacting with l electromagnetic modes

作者：Cordero S^*; Nahmad Achar E; Castanos O; Lopez Pena R

来源：Physica Scripta, 2017, 92(4): 044004.

DOI：10.1088/1402-4896/aa6363

• phase diagrams
• matter-field interaction
• symmetry adapted states
• variational methods

The phase diagram corresponding to the ground state of a completely general system of atoms interacting dipolarly with a radiation field, in a cavity, is established. The system is most general in that we consider any finite number N-a of atoms, any number n of atomic levels, any number l of field modes, and we do not restrict a radiation mode to interact with a sole pair of atomic levels. The study is carried out through a variational procedure. The test function is constructed from the tensorial product of coherent states associated to the matter and field components. In the parameter space of the dipolar field-matter couplings, we show that the ground state of the system suffers quantum phase transitions described by a phase diagram which divides itself into monochromatic regions. Linear combinations of coherent states are considered to restore the symmetries of the Hamiltonian and, in the thermodynamic limit, we show that the corresponding symmetry-adapted energy surface approaches that of the separable coherent states.

• 出版日期2017-4