title: Spin-dependent forces on trapped ions for phase-stable quantum gates and entangled states of spin and motion.
abstract: Favored schemes for trapped-ion quantum logic gates use bichromatic laser fields to couple internal qubit states with external motion through a "spin-dependent force." We introduce a new degree of freedom in this coupling that reduces its sensitivity to phase decoherence. We demonstrate bichromatic spin-dependent forces on a single trapped 111Cd+ ion, and show that phase coherence of the resulting entangled states of spin and motion depends critically upon the spectral arrangement of the optical fields. This applies directly to the operation of entangling gates on multiple ions.
authors.affiliation: FOCUS Center and Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: P C
authors.initials: PC
authors.lastname: Haljan
authors.forename: K-A
authors.initials: KA
authors.lastname: Brickman
authors.forename: L
authors.initials: L
authors.lastname: Deslauriers
authors.forename: P J
authors.initials: PJ
authors.lastname: Lee
authors.forename: C
authors.initials: C
authors.lastname: Monroe