A Study of Oscillating Magnetic Fields with Neutron Spin Interferometry

In this study, we evaluate spin interferometry with high-frequency magnetic fields using a continuous neutron beam. We derive an analytical formula for neutron spin interference with oscillating magnetic fields parallel to the quantization axis. The formula indicates that the phase of the interference pattern was not shifted but its amplitude, or visibility, was reduced by the oscillating magnetic fields. The experiment at MINE2 effectively reproduced this phenomenon and the degree of the amplitude reduction also followed the formula. Monochromatic neutron beams with long wavelengths such as 8.8 Å at MINE2 make it easy to polarize the beams to conduct high-visibility spin interferometric experiments. As a result, MINE2 is useful for testing new aspects of phenomena based on neutron spin optics.