Neutron wave-interference experiments with adiabatic passage of neutron spin through resonant coils - art. no. 013614

Neutron resonance spin echo phenomena, produced by resonance coils with adi abatic passage of the neutron spin, are investigated experimentally and the oretically. The adiabatic passage of the neutron spin through a resonance c oil requires a specific configuration of the magnetic field. The solution o f the Schrodinger equation, obtained for the required configuration, shows the probability of a spin-flip process;it also shows the phase shift, which the neutron experienced, when it flies through it. The precession phase in side the coil consists of three contributions in the rotating frame approac h. The first, biggest contribution is the phase of the rotating frame omega (0)tau The second is the precession phase of the neutron spin in the rotat ing frame since it follows adiabatically the effective field as seen in thi s frame. The third, smallest contribution is Berry's phase since the magnet ic field rotates over an angle approaching pi in this rotating frame. This rotation is followed adiabatically by the neutron spin. Finally, the amplit ude of the interference pattern and the phase shift between the neutron-spi n states are derived for a system consisting of two such flippers. The theo retical consideration is experimentally confirmed.