Neutron waves in an accelerating matter

A.I. Frank
Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna

At the end of last century, it was predicted, that the wave number and frequency of light change when wave passes through an accelerating sample of a refractive matter. Later the same result was predicted for the neutron waves. Subsequently it was recognized that one can speak about the very general Accelerating Matter Effect (AME).
The AME for light is so small that despite the fantastic sensitivity of modern optical methods, it has not been observed yet. However, the neutron-optics experiments of this kind appeared to be feasible and were performed with Ultra Cold Neutrons (UCN) in 2007-2011. It was experimentally demonstrated that the energy of UCN passing through an accelerating sample of a refractive matter changes. The experimental results were in a good agreement with theoretical prediction based on the assumption that dispersion law of neutron waves in accelerating matter does not differ from the same in the matter in rest.
Recently some reasons that this assumption is valid only when the acceleration is below a certain critical value have been presented. The status of the experiments for the test of this reasons will be also reported.