  We have investigated ion dynamics associated with a dual linear ion trap
where ions can be stored in and moved between two distinct locations. Such a
trap is a building block for a system to engineer arbitrary quantum states of
ion ensembles. Specifically, this trap is the unit cell in a strategy for
scalable quantum computing using a series of interconnected ion traps. We have
transferred an ion between trap locations 1.2 mm apart in 50 $\mu$s with near
unit efficiency ($> 10^{6}$ consecutive transfers) and negligible motional
heating, while maintaining internal-state coherence. In addition, we have
separated two ions held in a common trap into two distinct traps.
