Coherent Directed Transport of Neutral Atoms in Unmodulated Optical Lattices

We introduce a fully coherent way for directed transport of neutral atoms in optical lattices by regularly performing phase shifts on the lattice potential during the free evolution of the system. This paves the way for realizing quantum gates and entanglement generation by bringing two individual atoms in the proximity of each other and let them interact. The speed of our protocol is truly determined by the tunneling amplitudes of the atoms and thus is much faster than the speed of the dynamics resulted from superexchange interaction in spin chains or renormalized tunnelings in AC-driven quantum rachets. We also introduce an entanglement witness which allows for experimentally detecting entanglement through local rotations and measurements. Our scheme is robust against possible imperfections and perhaps its main advantage is its simplicity which does not need sophisticated cooling mechanism and all its requirements have been already achieved in recent experiments.