Title: Motional Ground State Cooling Outside the Lamb-Dicke Regime,
Abstract: We report Raman sideband cooling of a single sodium atom to its
three-dimensional motional ground state in an optical tweezer. Despite a large
Lamb-Dicke parameter, high initial temperature, and large differential light
shifts between the excited state and the ground state, we achieve a ground
state population of $93.5(7)$% after $53$ ms of cooling. Our technique includes
addressing high-order sidebands, where several motional quanta are removed by a
single laser pulse, and fast modulation of the optical tweezer intensity. We
demonstrate that Raman sideband cooling to the 3D motional ground state is
possible, even without tight confinement and low initial temperature.