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 ${}^{87}$Rb. 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.