Ramsey Interferometry Using the Zeeman Sublevels in a Spin-2 Bose Gas

We perform atom interferometry using the Zeeman sublevels of a spin-2 Bose–Einstein condensate of 87Rb. The observed fringes are strongly peaked, and fringe repetition rates higher than the fundamental Ramsey frequency are found in agreement with a simple theory based on spin rotations. With a suitable choice of initial states, the interferometer could function as a useful tool for magnetometry and studies of spinor dynamics in general.