Electric field suppression of ultracold confined chemical rates

Abstract

We consider ultracold collisions of polar molecules confined in a one dimensional optical lattice. Using a quantum scattering formalism and a frame transformation method, we calculate elastic and chemical quenching rate constants for fermionic molecules. Taking KRb molecules as a prototype, we find that the rate of quenching collisions is enhanced at zero electric field as the confinement is increased, but that this rate is suppressed when the electric field is turned on. For molecules with 500 nK of collision energy, for realistic molecular densities, and for achievable experimental electric fields and trap confinements, we predict lifetimes of KRb molecules of 1 s. We find a ratio of elastic to quenching collision rates of about 100, which may be sufficient to achieve efficient experimental evaporative cooling of polar KRb molecules.