Atomic spatial coherence monitoring and engineering with magnetic fields -art. no. 053603

We report on a simple and versatile method by which to measure and tailor m assive particle ensemble coherences using pulsed magnetic fields. A multipl e wave atom interferometer is demonstrated that uses a spin-echo procedure associated with the spatial separation of the Zeeman sublevel wave packets induced by magnetic forces. This scheme provides a means to determine:ultra low temperatures by measuring the sample coherence length. Furthermore, we show how a pulsed quasiparabolic magnetic potential can be used to enhance the atom ensemble coherence length by a factor of 2.