Ultracold neutrons: Their role in studies of condensed matter

Ultracold neutrons, that is, neutrons whose energy is so low that they can be contained for long periods of time in material and magnetic bottles, provide the basis for the currently most sensitive experiments seeking to detect the neutron electric dipole moment and to measure the neutron lifetime. The goal of this article is to review the work that has been done to date in applying ultracold neutrons to the study of condensed matter and to discuss the future prospects for this type of research. [S0034-6861(96)00202-4]