Using a superconducting qubit to perform sideband-cooling and measurement of a low frequency mechanical oscillator*

Preparation and observation of arbitrary quantum states of motion in a macroscopic object is a challenge in the field of opto- and eletro-mechanics. We demonstrate the first step towards this goal by dispersively coupling a Cooper pair box qubit to a 25 MHz aluminum drumhead mechanical oscillator. Driving sideband transitions, we demonstrate cooling of mechanical motion using a qubit. The large motion-induced AC Stark shift changes the qubit line shape and allows us to detect thermal and coherent motion. Further improvement could allow us to enter the strong dispersive regime in which the single phonon Stark shift exceeds the qubit linewidth.