Three dimensional projection cooling

We have significantly improved the laser cooling of single atoms trapped in a 3D optical lattice with 5 \textit{$\mu $}m spacing. We use microwaves to drive lower sideband transitions between two spin states, whose spatial wavefunctions are temporarily displaced by a small lattice polarization rotation. Subsequent optical pumping completes a cooling cycle in one dimension, similar to Raman sideband cooling, but without the Raman beams [1]. We perform this cycle for each spatial direction, and repeat the process 30 times. The final vibrational excitation is below 0.2\textit{h$\nu $} in each direction, despite the Lamb-Dicke parameter being a relatively high \textit{$\eta $} = 0.37. We will also discuss our progress on performing arbitrary single qubit rotations on a target atom without affecting its neighbors. These are both important elements in the development of a site-addressable neutral atom quantum computer. \\[4pt] [1] Leonid Forster, \textit{et al} PRL 103, 233001 (2009)