Quantum transport in bipartite lattices via Landau-Zener tunneling

A scheme for directed transport of quantum particles in a static bipartite lattice driven by an ac force, based on a sequence of Landau-Zener transitions, is proposed theoretically. As compared to directed transport in bipartite lattices exploiting the phenomenon of coherent destruction of tunneling recently suggested by Creffield [Phys. Rev. Lett. 99, 110501 (2007)], the present scheme realizes a robust quantum state transport owing to the adiabaticity of the particle transfer. The transport is realized by an external force with a sawtooth profile and does not require modulation of lattice parameters (intersite couplings and energy levels). The effects of lattice disorder and particle interaction on the directed quantum transport are discussed.