Conventional radio-frequency ion traps provide limited controls over the confining potential. In this manuscript, we theoretically and numerically investigate a hybrid trapping architecture by incorporating optical tweezers (laser beams tightly focused on individual ions) in a conventional trap. The local control over the potential would offer many capabilities - such as engineering a target set of phonon modes, fixing the motional de-coupling problem in a multi-species ion system, and allowing novel experiments in quantum thermodynamics. In the context of multi-species ion systems, optical tweezers would enable efficient sympathetic cooling and faster logic gates between species by taking control over the participation of ions in the collective phonon modes.

Abstract: We propose an experimental architecture where an array of optical tweezers affords site-dependent control over the confining potential of a conventional radio-frequency ion trap. The site-dependent control enables programmable manipulation of phonon modes of ions, with many potential applications in quantum information processing (QIP) and thermodynamics. We describe protocols for programming the array of optical tweezers to attain a set of target phonon modes with high accuracy. We propose applications of such controls in simulating quantum thermodynamics of a particle of programmable effective mass via Jarzynski’s equality and improving the efficiency of sympathetic cooling and quantum logic gates in a multi-species ion system of disparate masses. We discuss the required optical parameters in a realistic ion trap system and potential adverse effects of optical tweezers in QIP. Our scheme extends the utility of trapped-ions as a platform for quantum computation and simulation.