  Novel ion traps that provide either a static or a dynamic magnetic gradient
field allow for the use of radio frequency (rf) radiation for coupling internal
and motional states of ions, which is essential for conditional quantum logic.
We show that the coupling mechanism in the presence of a dynamic gradient is
the same, in a dressed state basis, as in the case of a static gradient. Then,
it is shown how demanding experimental requirements arising when using a
dynamic gradient could be overcome. Thus, using dressed states in a dynamic
gradient field could decisively reduce experimental complexity on the route
towards a scalable device for quantum information science based on rf-driven
trapped ions.
