1. Collective Cavity Cooling of Classical Atoms Sponsors

Laser cooling of atoms has not only enabled Bose-Einstein condensation, but has also resulted in a number of important applications and devices, many of which are tied to precision measurements and atomic clocks. However, laser cooling has so far been limited to atoms with a relatively simple internal structure, and the cooling of molecules or even of atoms with a more complicated level scheme has not been possible. In Doppler cooling, the preferred absorption of photons from a beam counterpropagating relative to the atom’s motion leads to slowing and cooling of the atom. Since the momentum “kick” associated with each photon absorption event is much smaller than the momentum of a thermal atom, several thousand absorption-emission events are required to significantly change the atom’s velocity. Therefore laser cooling has only been demonstrated with atoms that can be optically cycled many times between two states. However, most atoms (and all molecules) have multiple ground states to which the excited state can decay. Once the atom reaches a different ground state, the laser no longer has the correct detuning relative to the atomic transition, and the cooling stops. In particular, molecules have many vibrational and rotational levels, and consequently no laser cooling of molecules has been demonstrated