Inelastic collisions in an ultracold quasi-two-dimensional gas

We present a formalism for rigorous calculations of cross sections for inelastic and reactive collisions of ultracold atoms and molecules confined by laser fields in quasi-two-dimensional geometry. Our results show that the elastic-to-inelastic ratios of collision cross sections are enhanced in the presence of a laser confinement and that the threshold energy dependence of the collision cross sections can be tuned by varying the confinement strength and external magnetic fields. The enhancement of the elastic-to-inelastic ratios is inversely proportional to epsilon/h omega(0), where epsilon is the kinetic energy and omega(0) is the oscillation frequency of the trapped particles in the confinement potential.