  We propose a tractor atom interferometer (TAI) based on three-dimensonal
tight confinement and transport of split atomic wavefunction components in
programmable tractor traps. Using Crank-Nicolson simulations of scalar and
spinor wavefunction evolution, we confirm validity of the path-integral
formalism over the pre-determined tractor-trap trajectories in several
examples, quantify projected gravimeter sensitivity, and study robustness of
scalar and spinor TAI matter-wave splitters against non-adiabatic effects. We
discuss the advantages of TAI over other matter-wave interferometers and
address aspects for future experimental realizations of TAI for acceleration
and rotation sensing.
