title: Coherence and Raman sideband cooling of a single atom in an optical tweezer.
abstract: We investigate quantum control of a single atom in a tightly focused optical tweezer trap. We show that inevitable spatially varying polarization gives rise to significant internal-state decoherence but that this effect can be mitigated by an appropriately chosen magnetic bias field. This enables Raman sideband cooling of a single atom close to its three-dimensional ground state (vibrational quantum numbers n(x)=n(y)=0.01, n(z)=8) even for a trap beam waist as small as w=900  nm. The small atomic wave packet with δx=δy=24  nm and δz=270  nm represents a promising starting point for future hybrid quantum systems where atoms are placed in close proximity to surfaces.
authors.affiliation: Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: J D
authors.initials: JD
authors.lastname: Thompson
authors.forename: T G
authors.initials: TG
authors.lastname: Tiecke
authors.forename: A S
authors.initials: AS
authors.lastname: Zibrov
authors.forename: V
authors.initials: V
authors.lastname: Vuletić
authors.forename: M D
authors.initials: MD
authors.lastname: Lukin