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.