REALIZATION OF A DELAYED CHOICE EXPERIMENT USING A MULTILAYER COLD NEUTRON PULSER

A delayed choice experiment was done using the cold neutron spin inter ferometer of Jamin-type arrangement which is installed at the JRR-3M o f JAERI. A pair of identical composite neutron mirrors composes the pa ir of the wave splitters of the interferometer. The composite neutron mirror consists of a Ni/Ti multilayer ((Ni: 85 Angstrom/Ti: 85 Angstro m) x 5 (layers)), a Ge gap layer (4000 Angstrom), and a Permalloy (Fe5 5Ni45)/Ge multilayer ((Permalloy: 85 Angstrom/Ge: 85 Angstrom) x 5 (la yers)) (PGM), evaporated in series on the single Si wafer in a magneti c field of 130 G. The second composite mirror was placed in the pulsed magnetic field for producing the conditions of whether the second wav e splitter is introduced or not when a polarized neutron reaches the s econd wave splitter. It was shown that whether the interference fringe is obtained or not depends only on whether the second wave splitter i s introduced or not, after the neutron passed through the first wave s plitter. Delaying choice has no effect on the interference. We could d educe that the neutron propagates both ways with equal probability aft er being split by the wave splitter and does not choose one of two way s, as explained by quantum mechanics. (C) 1998 Elsevier Science B.V. A ll rights reserved.