Behavior of neutrons in electromagnetic fields

J.-Q. Liang, X. X. Ding

R. Simonovits

H. Rauch

Perfect crystal neutron interferometry has provided the basis for the realization of many basic experiments for testing quantum mechanics with massive particles. The following quantum effects have been verified: 4π-symmetry of spinors, spin-superposition, gravity-induced quantum interference effects, the Aharonov-Casher effect, the magnetic Josephson effects, the scalar Aharonov-Bohm effect etc. More recently, steps towards neutron quantum optics have been undertaken. Measurements have dealt with the coherence properties of the neutron beam, the photon exchange between the neutron and various electromagnetic fields, the particle number-phase uncertainty, squeezing phenomena, and the Wigner-functional behavior of a neutron system. These achievements opened the field of direct Fourier spectroscopy which brings a direct access to the space and time dependent correlation functions which describe condensed matter. Various perspectives for further experiments in the field of fundamental and condensed matter physics are discussed.

J. Anandan, C. R. Hägen

The question as to whether neutron acceleration can occur in uniform electromagnetic fields is examined. Although such an effect has been predicted using the canonical equations of motion, some doubt has been raised recently as to whether it is in principle observable for a spin-1/2 particle. To resolve this issue a gedanken experiment is proposed and analyzed using wave-packet construction for the neutron beam. By allowing an arbitrary orientation for the neutron spin as well as for the electric and magnetic fields, a nonvanishing acceleration of the center of the neutron wave packet is found that confirms the predictions of the canonical formalism.

Stanley A. Bruce, M. D. Campos, Joaquín F. Díaz-Valdés

Ding Xiu

The dynamics of neutral spinning particles in electromagnetic fields is investigated. The phase interference of unpolarized neutron beams is reasonably interpreted as the observed spin precession in external fields instead of potential effects in the quantum physics; namely, the Aharonov-Bohm and Aharonov-Casher effects. It is also pointed out that the recent experiment claimed to be the verification of Aharonov-Casher phase with neutron interferometry, however, can be considered as a test of new anyon model.