Atomic self-trapping induced by single-atom lasing.

We study atomic center of mass motion and field dynamics of a single-atom laser consisting of a single incoherently pumped free atom moving in an optical high-Q resonator. For sufficient pumping, the system starts lasing whenever the atom is close to a field antinode. If the field mode eigenfrequency is larger than the atomic transition frequency, the generated laser light attracts the atom to the field antinode and cools its motion. Using quantum Monte Carlo wave function simulations, we investigate this coupled atom-field dynamics including photon recoil and cavity decay. In the regime of strong coupling, the generated field shows strong nonclassical features such as photon antibunching, and the atom is spatially confined and cooled to sub-Doppler temperatures.

Enhanced atom capturing in a high-Q cavity by help of several transverse modes.

We predict a strong enhancement of the capture rate and the friction force for atoms crossing a driven high-Q cavity field if several near degenerate cavity modes are simultaneously coupled to the atom. In contrast to the case of a single TEM00 mode, circular orbits are not stable and damping of the angular and radial motion occurs. Depending on the chosen atom-field detuning the atoms phase lock the cavity modes to create a localized field minimum or maximum at their current positions. This corresponds to a local potential minimum, which the atom drags along with its motion. The stimulated photon redistribution between the modes then creates a large friction force. The effect is further enhanced if the atom is directly driven by a coherent field from the side. Several atoms in the field interact via the cavity modes, which leads to a strongly correlated motion.