Quantum beat experiments using cold neutron spin interferometer

We have carried out quantum beat experiments using cold neutron spin interferometers installed at C3-1-2 beam line of JRR-3M of JAERI (Japan Atomic Energy Research Institute) and at CN-1 port KUR (Kyoto University Reactor). Energy difference between two superposed states are generated by a couple of rf flippers. Here, we report beat experiments using rf-π/2 flippers without spin echo arrangement. Quantum beat with frequencies between 20 μHz and 34 kHz have been observed. These frequencies correspond to energy difference of 1.41 x 10-10 - 8.27 x 10-20 eV. Quantum beat by three energy levels are also observed using three rf-π/2 flippers. This phenomena may be applicable to some kind of inelastic scatterings or study of time dependent phenomenon such as tunneling time. (author)