Relaxation of Quantum Systems in Strong Electromagnetic Field - New Nonlinear Effects

V. M. Kenkre

É. G. Pestov, Anatoly N. Oraevsky

The new nonlinear dynamical effects due to the influence of strong laser field (LF) on relaxation processes in two-level quantum systems are investigated. The dramatic change of the dependence of the probe field absorption spectral line shape and four-wave mixing amplification coefficient of weak field on LF intensity is discussed.

Hermann Grabert

Andrew I. Trubilko, Ashat M. Basharov

The radiation of a quantum particle in a thermostatic electromagnetic field with a nonzero photon density in the presence of a strong Stark interaction between the particle and field is considered. New fundamental effects—the suppression of radiation by the Stark interaction in an intense broadband field and an additional “decay” shift in the energy of the decaying level, which is different from the Lamb and Stark level shifts—have been established. A new effect of the suppression of radiation is complementary to the effect of suppression of the polarization relaxation of the quantum particle in a squeezed field, which is discovered earlier by Gardiner. The new effect can occur independently of the effect established by Gardiner.

Marek Czachor

Vyacheslav I. Yukalov, Elizaveta P. Yukalova

Collective phenomena in strongly nonequilibrium systems interacting with electromagnetic field are considered. Such systems are described by complicated nonlinear differential or integro-differential equations. The aim of this review is to show that many nonlinear collective phenomena can be successfully treated by a recently developed method called the Scale Separation Approach whose name is due to the idea of separating different characteristic space-time scales existing in nonequilibrium statistical systems. This approach is rather general and can be applied to various nonequilibrium physical problems, several of which are discussed here. The problems considered not only serve as illustrations of the method but are quite important by themselves presenting interesting physical effects, such as Collective Liberation of Light, Turbulent Photon Filamentation, Superradiant Spin Relaxation, Negative Electric Current, and Magnetic Semiconfinement of Atoms.