(BQ) Part 2 book "Atoms in electromagnetic fields" has contents: Atoms in high frequency fields or in the vacuum field simple physical pictures for radiative corrections, sisyphus cooling and subrecoil cooling, levy statistics and laser cooling,. and other contents. | Section 5 Atoms in High Frequency Fields or in the Vacuum Field Simple Physical Pictures for Radiative Corrections 333 An atomic electron in the vacuum field can emit and reabsorb photons of any frequency. Such virtual processes give rise to well-known radiative corrections (Lamb shift, g — 2 spin anomaly). We have also seen in Sees. 1 and 2 that similar effects can be induced by the interaction of the electron with an applied electromagnetic field (light shifts, modification of the Lande factor by interaction with a high frequency rf field). The papers presented in this section try to get new physical insight into radiative processes by comparing these two types of "spontaneous" and "stimulated" effects. These are a few examples of questions which are addressed here: - Is it possible to understand radiative corrections as being only "induced" by vacuum fluctuations, . by a fluctuating field having a spectral power density equal to hu>/2 permode w? - On the contrary, can one attribute them only to the interaction of the electron with its self-field? - If these two effects (vacuum fluctuations and radiation reaction) are simultaneously acting, is it possible to separate their respective contributions? - Why is the electron spin moment enhanced by radiative corrections (g — 2 is positive), whereas the magnetic moment of a neutral moment is always reduced by interaction with a high frequency rf field? 335 Paper P. Avan, C. Cohen-Tannoudji, J. Dupont-Roc, and C. Fabre, "Effect of high frequency irradiation on the dynamical properties of weakly bound electrons," J. Phys. (Paris) 37, 993-1009 (1976). Reprinted with permission of Les Editions de Physique. The "stimulated" corrections studied in Sees. 1 and 2 correspond to two extreme situations for the incident field, leading to simple calculations. The first one corresponds to a resonant or quasiresonant excitation, so that only a single atomic transition needs to be considered. Nonperturbative treatments
