Chapter 3 - Vacuum-Induced Processes in Multilevel Atoms

Abstract

Publisher Summary Atoms commonly do not act as isolated objects, but rather are open quantum systems, as they interact with the environment. Typically, this environment is formed by the electromagnetic vacuum field. The interaction of atoms with the environment modifies the atomic dynamics, with spontaneous emission as the most obvious example. Spontaneous emission is generally recognized as incoherent process, which leads to decoherence and, therefore, forms a major limitation for many schemes of current theoretical and experimental interest. But vacuum-induced processes can also generate coherent time evolution. These coherences can be interpreted as arising from vacuum-induced transitions between different atomic states. The situation becomes even more interesting if different atoms can exchange energy via the vacuum. Such dipole–dipole interactions induce both coherent and incoherent atomic dynamics, leading to significant deviations from the single-atom properties. Finally, a complex interplay of vacuum-induced interatomic and intraatomic dynamics may arise if several multilevel atoms are considered. These vacuum-induced processes form the basis for a large number of applications, for which the vacuum-induced dynamics can be favorable, perturbing, or even both. Most applications can be improved, if the vacuum-induced processes can be modified or even controlled. Thus, a profound understanding of vacuum-induced processes is desirable. Motivated by this, this chapter discusses vacuum-induced processes in multilevel atoms.