COHERENT MULTIPHOTON EXCHANGE BETWEEN A NEUTRON AND AN OSCILLATING MAGNETIC-FIELD

We calculate a neutron's transition amplitudes to various energy and spin states when it interacts with a magnetic field oscillating in time. Two field configurations are analyzed: the oscillating component normal to the static component when the rotating-wave approximation is inapplicable and the oscillating and static components parallel to each other. The two cases require different mechanisms of angular momentum conservation. Experimental tests are proposed including neutron interferometry and double crystal diffraction, the latter permitting observation of quantized energy transfer from fields oscillating at only a few hundred kilohertz.