Collapses and revivals of the coherence of a mesoscopic superposition of motional states.

A scheme is proposed to observe the collapses and revivals of a mesoscopic superposition of coherent states in the motion of a trapped ion. In the scheme the ion motion in the x-axis is first prepared in a Schrodinger cat state, and then coupled to the motion in the z-axis. With the vibrational excitation exchange between the two modes, the mesoscopic quantum coherence collapses and revives periodically, providing an example for complementarity.