Coherent Spin Oscillations Driven by Collisions in AN Optical Lattice

We observe coherent, purely collisionally driven spin dynamics of atom pairs confined at the sites of a deep optical lattice. Spin changing collisions induce coherent oscillations between two-particle Zeeman states with equal magnetization. This mechanism could be a way to create robust entangled atom pairs in an optical lattice with high efficiency. Moreover, measurement of the oscillation frequency allows for precise determination of the coupling parameters of the spin-changing collisional interaction, and thus constitute a stringent test of model potentials to describe the collision between two Rb atoms.