Quantum computations with atoms in optical lattices: Marker qubits and molecular interactions

We develop a scheme for quantum computation with neutral atoms, based on the concept of ``marker'' atoms, i.e., auxiliary atoms that can be efficiently transported in state-independent periodic external traps to operate quantum gates between physically distant qubits. This allows for relaxing a number of experimental constraints for quantum computation with neutral atoms in microscopic potential, including single-atom laser addressability. We discuss the advantages of this approach in a concrete physical scenario involving molecular interactions.