We demonstrate full quantum state control of two species of single atoms using optical tweezers and assemble the atoms into a molecule. Our demonstration includes 3D ground-state cooling of a single atom (Cs) in an optical tweezer, transport by several microns with minimal heating, and merging with a single Na atom. Subsequently, both atoms occupy the simultaneous motional ground state with 61(4)% probability. This realizes a sample of exactly two co-trapped atoms near the phase-space-density limit of one, and allows for efficient stimulated-Raman transfer of a pair of atoms into a molecular bound state of the triplet electronic ground potential a 3 Σ + . The results are key steps toward coherent creation of single ultracold molecules, for future exploration of quantum simulation and quantum information processing.

Microscopically controlled neutral atoms in optical tweezers and lattices have led to exciting advances in the study of quantum information and quantum many-body systems. The light shifts of atomic levels from the trapping potential in these systems can result in detrimental effects such as fluctuating dipole force heating, inhomogeneous detunings, and inhibition of laser cooling, which limits the atomic species that can be manipulated. In particular, these light shifts can be large enough to prevent loading into optical tweezers directly from a magneto-optical trap. We present a general solution to these limitations by loading, cooling, and imaging single atoms with temporally alternating beams. Because this technique does not depend on any specific spectral properties, we expect it to enable the optical tweezer method to control nearly any atomic or molecular species that can be laser cooled and optically trapped. Furthermore, we present an analysis of the role of heating and required cooling for single atom tweezer loading.

No abstract