Atomic interferences in a comoving magnetic field

The use of comoving magnetic fields in Stern-Gerlach atom interferometry allows, in principle, one to reach a range of very low kinetic energies (a few tens of neV); it also allows the device to be used as an interference filter for atomic waves. The technique used to produce such fields moving at atomic velocities is described. Experimental interference patterns obtained with a beam of H*(2S) atoms are in good agreement with the calculations, which clearly demonstrates the feasibility of the method.