BEC magnetometry as a probe of hybrid quantum systems

We describe our progress towards realization of a hybrid quantum system consisting of a Bose Condensate magnetically coupled to a micromechanical oscillator. Due to the presence of a magnetic domain on the oscillator, the micromotion of the oscillator results in a periodically varying Zeeman shift that we measure using non-destructive imaging [1]. We estimate the sensitivity of the position readout to be comparable to the zero-point motion of the oscillator. We also outline prospects of achieving the strong-coupling limit of this BEC-membrane system to enable sympathetic cooling and the creation of non-classical states of this mechanical device [2]. In order to achieve this strong-coupling limit, we are investigating both cavity-enhanced schemes as well as coupling the BEC to a graphene membrane whose mass is comparable to that of the atomic gas. \\[4pt] [1] M. Vengalattore {\em et al}, Phys. Rev. Lett. \textbf{98}, 200801 (2007);\\[0pt] [2] S. Singh {\em et al}, ``Quantifying measurement back-action on a macroscopic object: BEC magnetometry on mechanical oscillators.'' Phys. Rev. A {\bf 84}, 023841 (2011).