Quantum rotor atoms in light beams with orbital angular momentum: Highly accurate rotation sensor

Atoms trapped in a red-detuned retroreflected Laguerre-Gaussian beam undergo orbital motion within rings whose centers are on the axis of the laser beam. We determine the wave functions, energies, and degeneracies of such quantum rotors (QRs), and the microwave transitions between the energy levels. We then show how such QR atoms can be used as highly accurate rotation sensors when the rings are singly occupied.