Spatial Non-Cyclic Geometric Phase in Neutron Interferometry.
We present a split-beam neutron interferometric experiment to test the non-cyclic geometric phase tied to the spatial evolution of the system: the subjacent two-dimensional Hilbert space is spanned by the two possible paths in the interferometer and the evolution of the state is controlled by phase shifters and absorbers. A related experiment was reported previously by some of the authors to verify the cyclic spatial geometric phase. The interpretation of this experiment, namely to ascribe a geometric phase to this particular state evolution, has met severe criticism. The extension to non-cyclic evolution manifests the correctness of the interpretation of the previous experiment by means of an explicit calculation of the non-cyclic geometric phase in terms of paths on the Bloch-sphere. The theoretical treatment comprises the cyclic geometric phase as a special case, which is confirmed by experiment.
Atominstitut der Österreichischen Universitäten, Stadionallee 2, A-1020 Vienna, Austria.
Stefan
S
Filipp
Atominstitut der Osterreichischen Universitaten, Stadionallee 2, A-1020 Vienna, Austria.
Yuji
Y
Hasegawa
Atominstitut der Osterreichischen Universitäten, Stadionallee 2, A-1020 Vienna, Austria.
Rudolf
R
Loidl
Atominstitut der Österreichischen Universitäten, Stadionallee 2, A-1020 Vienna, Austria.
Helmut
H
Rauch
geometric phase; neutron interferometry