Ultracold radiative charge transfer in hybrid ion-atom traps

We present ab initio quantum chemistry calculations for elastic scattering and the radiative charge transfer reaction process and collision rates for trapped ytterbium ions immersed in a quantum degenerate rubidium vapor. <br/>The collision of the ion (or ions) with the quasiatom is the key mechanism to transfer quantum coherences between the systems. We use first-principles <br/>quantum chemistry codes to obtain the potential surfaces and coupling terms for the two-body interaction of Yb^+ with Rb. We find that the low energy collision has an inelastic radiative charge transfer process in agreement with recent experiments. <br/>The charge transfer cross section agrees well with the semiclassical Langevin model at higher energies but is dominated by resonances at submillikelvin temperatures.