Microwave Controlled Transport and Collisions of Cs Atoms in an Optical Lattice

Quantum information processing with atomic qubits in optical lattices requires two-qubit entangling operations that can be implemented by e.g. controlled pairwise collisions. As a step in this direction we are working on an experiment that uses microwave transitions to control the motion of Cs atoms between the sites of an anti-ferromagnetic lattice. In Cs the relevant ground state scattering length is large enough for a pair of atoms at neighboring spin-up/down sites to be bound together in a long range molecular state whose energy can be shifted by a large amount relative to isolated, non-interacting atoms. In principle this shift can be used as the basis for a quantum phase gate. We are currently attempting to observe distinct lines in the microwave spectrum corresponding to excitation of this molecular state.