Rydberg Atoms and Cavity Quantum Electrodynamics
Rydberg atoms (highly excited atoms) provide a new experimental tool for studying quantum electrodynamic phenomena. Spontaneous and stimulated emission rates can be dramatically altered by a cavity, either enhanced or suppressed, compared to the free space values. Radiation by an ensemble of atoms is inherently cooperative. A number of these effects have already been observed using Rydberg atom methods. Experiments are in progress in which a single atom is observed as it interacts with an undamped cavity. Instead of exponential damping, the atom-cavity system is expected to exhibit reversible oscillatory behavior. Other types of novel behavior have also been predicted, including the possibility of “super-cooling” a radiation field so that it is in its ground state even though the walls of the cavity are at a relatively high temperature.