Quasienergy of a two-level system in an intense monochromatic field

В. Г. Коломиец

Shaoul Ezekiel

Petr A. Braun, George P. Miroshnichenko

Wilhelm Becker

The continued-fraction equation which determines the quasienergy of a two-level system in an external monochromatic field is derived by a simple semiclassical argument. The perturbation expansion of the quasienergy is extended to tenth order in the coupling constant.

Tozaburo Otsu, Tadashi Watanabe

Dong‐Sheng Guo, J. T. Wang, Yong-Shi Wu

A computation with unprecedented precision is presented for quasienergies of a two-level atom in a monochromatic radiation on the basis of a recently obtained exact expression [D.-S. Guo et al., Phys. Rev. A 73, 023419 (2006)]. We start with the proof of an expression theorem. With this theorem the quasienergies for any two-level atom can be expressed in terms of the quasienergies for only those with the original energy spacing (per field photon energy) being an integer (preresonances). Then we carry out a numerical evaluation of the quasienergies at the two-photon preresonance, which involves computing an infinite determinant, up to the 18th power of the coupling strength. The theoretical prediction presents an experimental challenge for high-precision tests of quantum mechanics and could be exploited for precise calibration of high laser intensities.