Optical Traps for sympathetic Cooling of Ions with ultracold neutral Atoms

We report the trapping of ultracold neutral $\text{Rb}$ atoms and ${\text{Ba}}^{+}$ ions in a common optical potential in absence of any radiofrequency (RF) fields. We prepare ${\text{Ba}}^{+}$ at $370\mu K$ and demonstrate efficient sympathetic cooling by $100\mu K$ after one collision. Our approach is currently limited by the $\text{Rb}$ density and related three-body losses, but it overcomes the fundamental limitation in RF traps set by RF-driven, micromotion-induced heating. It is applicable to a wide range of ion-atom species, and may enable novel ultracold chemistry experiments and complex many-body dynamics.