Spin-motion entanglement and state diagnosis with squeezed oscillator wavepackets.

Mesoscopic superpositions of distinguishable coherent states provide an analogue of the 'Schrödinger's cat' thought experiment. For mechanical oscillators these have primarily been realized using coherent wavepackets, for which the distinguishability arises as a result of the spatial separation of the superposed states. Here we demonstrate superpositions composed of squeezed wavepackets, which we generate by applying an internal-state-dependent force to a single trapped ion initialized in a squeezed vacuum state with nine decibel reduction in the quadrature variance.