Phase gate and readout with an atom-molecule hybrid platform

In order to optimize quantum information processing in individual traps such as optical lattices, we propose a combined atom-molecule system. In particular, gates, initialization, and readout are suggested, using two atoms of different species-one atom carrying the qubit and the other enabling interaction. We describe in some detail the implementation of a two-qubit phase gate in which a pair of atoms is transferred into the ground rovibrational state of a polar molecule with a large dipole moment, thus allowing molecules in adjacent sites to interact via their dipole-dipole interaction. We also discuss how the reverse process could be used as a nondestructive readout tool.