Phase-selected momentum transport in ultra-cold atoms

We propose a phase selected transport scenario for ultra-cold matter waves subject to pulsed optical lattices in which equally-populated momentum eigenstates with a flipped phase are localized while all other states are transported ballistically. The phenomenon relies on the concepts of quantum resonance and anti-resonance in two optical lattice potentials - one with half the wavelength of the other. We demonstrate the effectiveness of the technique in the presence of likely experimental noise sources, including the non-ideal situation where the momentum components are not all of equal amplitude. We also discuss possible uses for atom interferometric experiments and detail how to observe the phenomenon experimentally by creating an ideal initial state using standard atom-optical procedures.