Experimental separation of geometric and dynamical phases using neutron interferometry

We present results of the first experiment clearly demarcating geometric and dynamical phases. These two phases arise from two distinct physical operations, a rotation and a linear translation, respectively, performed on two identical spin flippers in a neutron interferometer. A reversal of the current in one flipper results in a pure geometric phase shift of pi radians. This observation constitutes the first direct verification of Pauli anticommutation, implemented in neutron interferometry.